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  • 1980-1984  (3,838)
  • 1970-1974  (4,290)
  • 1920-1924  (3,032)
  • 1850-1859
  • Inorganic Chemistry  (10,403)
  • Electron microscopy  (757)
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Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Epithelium of the human chorion laeve in diabetes mellitus (1984)
    Springer
    Virchows Archiv 402 (1984), S. 289-296 
    Details
    ISSN: 1432-2307
    Keywords: Epithelium ; Chorion laeve ; Diabetes mellitus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The epithelium of human chorion laeve from pregnancies complicated by diabetes mellitus was examined under the light and electron microscopy. In comparison with normal chorion laeve, the epithelium of chorion laeve in diabetes mellitus shows the following morphological changes: 1. The trophoblast cells display more microvilli and cell processes on their surface. 2. Trophoblast cells with different cytoplasmic characteristics can be seen. Some display few organelles and large glycogen depositions; other are rich in organelles. Furthermore, some cells with electron dense filaments and few cell organelles can be found. 3. Necrotic cells are frequently present in the outer epithelial layers. 4. The intercellular spaces in the epithelial layers near the basement membrane are narrower. Since vasculopathy of the decidual arteries with disturbance of blood circulation is often found in pathological pregnancies, we assume that the morphological changes found are due to deficiency in nutrient and oxygen supply.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00695082
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructure and membrane permeability of cultured pancreaticβ-cells exposed to alloxan or 6-hydroxydopamine (1984)
    Springer
    Virchows Archiv 404 (1984), S. 31-38 
    Details
    ISSN: 1432-2307
    Keywords: Alloxan ; Culture ; Electron microscopy ; 6-Hydroxydopamine ; Pancreaticβ-cells ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stereological techniques on electron microscopy micrographs were used to evaluate the morphological changes of cultured isletβ cells that had been exposed to alloxan or 6-hydroxydopamine. Trypan Blue exclusion by cells cultured for 3 days indicated that the cells were 100% viable. Electron microscopy revealed that nearly all of the surviving cultured cells wereβ cells. Exposure to 5 mmol/l alloxan or 1–5 mmol/l 6-hydroxydopamine for 10 or 30 min caused a general swelling of the cultured cells with a concomitant swelling of mitochondria and nuclei. The size of the secretory granules was not affected by the drugs. Only 3–10% of the cells excluded Trypan Blue after exposure to 5 mmol/l alloxan or 6-hydroxydopamine. The data conform with the hypothesis that a primary action of alloxan and 6-hydroxydopamine is at the plasma membrane level ofβ cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00704248
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  • 3
    Electronic Resource
    Electronic Resource
    Small cell neuroendocrine (oat cell) carcinoma of the male breast (1984)
    Springer
    Virchows Archiv 404 (1984), S. 213-221 
    Details
    ISSN: 1432-2307
    Keywords: Oat cell carcinoma ; Male breast ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of small cell neuroendocrine (oat cell) carcinoma of the breast in a 52-year old male is presented. Oat cell carcinomas have been reported in various extrapulmonary sites, but this is the second case of a primary oat cell carcinoma of the breast and the first one to have been documented in a male. The tumor was investigated histologically, immunocytochemically and ultrastructurally. The relationship to so-called “carcinoid” mammary tumors is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00704065
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  • 4
    Electronic Resource
    Electronic Resource
    Elephantiasis neuromatosa (1984)
    Springer
    Virchows Archiv 404 (1984), S. 427-434 
    Details
    ISSN: 1432-2307
    Keywords: Elephantiasis neuromatosa ; Neurofibromatosis ; Electron microscopy ; Immunohistochemistry ; S-100 protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An example of elephantiasis neuromatosa, an unusual variant of neurofibromatosis, coexistent with lipomatosis is presented. This dual cell population produced a diffuse swelling of the gluteal sulcus of a young female. The neurogenous origin of the spindle cell component was substantiated by immunoreactivity for S-100 protein as well as by the fine structural observation of a regular basement membrane coating and a profusion of Luse bodies. As far as can be ascertained, this is the first reported immunohistochemical and ultrastructural study of this particular variant of peripheral nerve sheath lesion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00695226
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  • 5
    Electronic Resource
    Electronic Resource
    Histoenzymological and ultrastructural study of a bifocal calcifying epithelial odontogenic tumor. characteristics of epithelial cells and histogenesis of amyloid-like material (1984)
    Springer
    Virchows Archiv 403 (1984), S. 67-76 
    Details
    ISSN: 1432-2307
    Keywords: Calcifying epithelial odontogenic tumor ; Electron microscopy ; Histoenzymology ; Ameloblast ; Amyloid-like substance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A calcifying epithelial odontogenic tumor, simultaneously located in the two jaws (maxilla and mandible) was examined by histochemical and electron microscopic methods. Squamous tumor cells without secretory polarity were different from those of common ameloblastoma. High activities of alkaline phosphatase and ATPases were demonstrated by light and electron microscopy on the cytoplasmic membrane, findings similar to those in the stratum intermedium cells of the normal dental germ from which these tumor cells seem to arise. The tumor cells, like preameloblasts of the dental germ, also produce a granulo-filamentous material in intracytoplasmic vesicles and discharge it into the stroma. This “pseudo-amyloid” substance represents an abnormal protein of the enamel matrix and calcification, mainly occurring in that substance, might be an attempt at mineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689339
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  • 6
    Electronic Resource
    Electronic Resource
    Granular cell tumour of the mammary gland simulating malignancy (1984)
    Springer
    Virchows Archiv 403 (1984), S. 391-400 
    Details
    ISSN: 1432-2307
    Keywords: Immunohistochemistry ; Electron microscopy ; Light microscopy ; Granular cell tumour ; Mammary gland neoplasm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Primary granular cell tumours of the breast in 35 2and 55 year old women were studied by light microscopy, transmission electron microscopy and immunohistochemistry. Light and electron microscopy revealed a neural origin of the tumours and this was further substantiated by immunohistochemical studies, with positive S-100 protein reaction and negative reactions for surface heavy and light chains, CEA, alfa-1-antitrypsin, muramidase and GFA-protein. Granular cell tumour of the mammary gland is a very rare tumour. Clinically it sometimes simulates carcinoma because of its fibrous consistency, fixation to pectoral fascia and skin retraction. The diagnosis of granular cell tumour should be included in the differential diagnosis of carcinoma of the breast. The granular cell tumour is derived from neuro-ectodermal tissue. Whether it represents a neurogenic cell-confined metabolic disturbance with lysosomal activation, or a true neoplasm remains to be elucidated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00737288
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  • 7
    Electronic Resource
    Electronic Resource
    Electron microscopy of urinary calculi — Some facts and artefacts (1984)
    Springer
    Urological research 12 (1984), S. 17-22 
    Details
    ISSN: 1434-0879
    Keywords: Urinary calculi ; Electron microscopy ; X-ray microanalysis ; Artefacts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Material in urinary calculi is prone to irradiation damage during electron microscopy and this suggests the need for care in the interpretation of data. It is shown, however, that minimum-dose transmission microscopy is feasible for single-crystal electron diffraction work, and that although internal damage in severe, morphological artefacts are unlikely in the SEM unless the incident electron flux is greater than 10-13 A nm-2. During EDX micro-analysis, the detection of light elements is impaired by irradiation effects unless a minimum-dose procedure is used. For the preparation of SEM samples, artefacts can be created by cleaving air-dried material-and it is therefore important to consider more lengthy preparation methods such as cryogenics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00256304
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  • 8
    Electronic Resource
    Electronic Resource
    Distribution of concanavalin A binding sites on normal human urinary bladder mucosa and bladder tumors by transmission and scanning electron microscopy and x-ray microanalysis (1984)
    Springer
    Urological research 12 (1984), S. 135-141 
    Details
    ISSN: 1434-0879
    Keywords: Concanavalin A ; Lectin receptors ; Bladder tumor ; Electron microscopy ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We used concanavalin A (con A)-peroxidase-iron dextran-diaminobenzidine (DAB) technique for the electron microscopic detection of con A binding sites on cell membranes. Normal bladder mucosa showed a sparse distribution of con A binding sites with both transmission (TEM) and scanning (SEM) electron microscopy, but bladder tumors showed a higher concentration in the distribution of con A binding sites in proportion to the histopathological grade of transitional cell carcinoma. Quantitative estimation of the con A binding sites was attempted using scanning X-ray pulse analysis of iron elements contained in the reaction complexes. Con A binding sites were quantitatively the smallest in normal mucosa, increasing proportionate to the grade of the bladder tumor. Some specimens were compared by the ferritin-labelled method and the pattern of ferritin conjugates distribution was similar to that seen with the con A-peroxidase-iron dextran method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257180
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  • 9
    Electronic Resource
    Electronic Resource
    A study of the ultrastructure of urinary calculi by scanning electron microscopy (1984)
    Springer
    Urological research 12 (1984), S. 227-230 
    Details
    ISSN: 1434-0879
    Keywords: Urinary calculi ; Stone ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A study of urinary stones obtained from patients after surgery in the Medical College Hospital, Trivandrum, under the scanning electron microscope showed the presence of calcium oxalate and calcium biphosphate crystals as the main constituents. However, the pattern of the different phases of crystal growth was not uniform. Within the crystal lattice, fibrous structures, possibly of protein matrix, were invariably observed. Electron microscopy may be usefully adapted as a particularly suitable method for ultramicroscopic investigation of the fine structure of urinary stones including single crystal surface structure, section of urinary calculi and for possible presence of hitherto unknown components within the calculus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00256809
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  • 10
    Electronic Resource
    Electronic Resource
    Peroxisomes in sebaceous glands (1984)
    Springer
    Anatomy and embryology 169 (1984), S. 9-20 
    Details
    ISSN: 1432-0568
    Keywords: Peroxisomes ; Marginal plates ; DAB-Cytochemistry ; Electron microscopy ; Freeze-etching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the canine circumanal gland, the morphological alterations of peroxisomes during differentiation and maturation of the glandular cells were studied by electron microscopy, cytochemistry and freeze-etch technique. Each of the following three cell types has its own characteristic peroxisomal population: 1) The basal cell contains only a few small peroxisomes, which appear as spherical and tubular profiles showing strong DAB reaction. In the differentiating basal cells, these are joined by a few dilated, hemispherical organelles with intensely stained small marginal plates. 2) In the intermediate cell, additional to spherical and tubular peroxisomes, numerous clongated organelles with distinct marginal plates are observed, displaying weak catalase activity. 3) In the mature cell, dumbbell-shaped peroxisomes with enlarged marginal plates predominate. Serial section analysis and freeze-etching studies reveal that these dilated particles are of erythrocyte-like shape. They exhibit very weak catalase activity or do not contain any visible DAB reaction product. In their flattened, thin central portions, the memoranes enclose the marginal plates and form straight cisternae, which are closely associated with adjacent fenestrated cisternae of ER on both sides, referred to as paramarginal cisternae. Dumbbell-shaped peroxisomes with their corresponding paramarginal cisternae form large peroxisome-ER-complexes. Furthermore, three to five dumbbell-shaped particles are often stacked in parallel. Only at their flat poles are the organelles in close contact with paramarginal cisternae. The observation of continuities, in particular between erythrocyte-like organelles and tubular peroxisomes in mature glandular cells, indicates the existence of a peroxisomal compartment composed of two segments in the mature stage. In freeze-etch replicas of mature glandular cells, only the dilated segments of the peroxisomal compartment can be easily recognized because of their unusual size and erythrocyte-like shape. Additionally, on the E-face of their central portion, a straight, square or rectangular area with a distinct crystalline pattern is seen, which corresponds to the marginal plate. These findings indicate that the circumanal gland of the dog offers unique possibility to analyze the biological properties of a well-defined peroxisomal compartment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300582
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  • 11
    Electronic Resource
    Electronic Resource
    Ultrastructure of the wall of the Dandy-Walker cyst (1984)
    Springer
    Acta neuropathologica 62 (1984), S. 225-229 
    Details
    ISSN: 1432-0533
    Keywords: Dandy-Walker syndrome ; Dandy-Walker cyst ; Ependymal cell ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the wall of the Dandy-Walker cyst has been described rarely. A boy aged 2 years was confirmed clinically, neuroradiologically, and operatively as having a Dandy-Walker cyst in the posterior fossa. The cyst wall obtained during surgery consisted of an outer arachnoid cell layer, intermediate interwoven neuroglial strands, and an inner layer of cells which lacked the characteristic appearance of ependyma. An unusual finding was a small, buried island of ependymal cells in the intermediate layer of the neuroglial tissue. Ultrastructural study of the cyst wall provides a better understanding of the pathogenesis of the Dandy-Walker syndrome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691856
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  • 12
    Electronic Resource
    Electronic Resource
    Peripheral nerve findings in hereditary coproporphyria (1984)
    Springer
    Acta neuropathologica 63 (1984), S. 96-107 
    Details
    ISSN: 1432-0533
    Keywords: Hereditary coproporphyria ; Hereditary hepatic porphyrias ; Sural nerve biopsy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In spite of several cases reported in the literature, the exact pathogenetic mechanism of neuropathic changes in porphyric neuropathy remains uncertain. Various authors have ascribed the neuropathologic findings to either a dying-back axonal degeneration or segmental demyelination. In recent years, the hypothesis of an axonal and myelinic disorder has received support by the demonstration of a combined and simultaneous involvement of both these structures. Such different opinions are also a consequence of the reduced number of detailed bioptic observations in the different forms of acute porphyria not only during acute phases but also between attacks. In this paper we report the results of light- and electronmicroscopic examination of two sural nerve biopsies from subjects with hereditary coproporphyria. The first was performed 6 months after an acute attack, the second specimen was obtained from a patient without acute attacks, who had clinical and electrophysiologic signs of a chronic progressive neuropathy. In both cases a dying-back axonal degeneration is considered the primary change. The pathogenetic mechanism of peripheral nerve lesions in porphyric neuropathy will be discussed finally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697191
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  • 13
    Electronic Resource
    Electronic Resource
    Hemiplegic atrophy (1984)
    Springer
    Acta neuropathologica 62 (1984), S. 324-331 
    Details
    ISSN: 1432-0533
    Keywords: Human skeletal muscle ; Hemiplegia ; Cerebral vascular disease ; Histopathology ; Electron microscopy ; Rehabilitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Anterior tibial muscle biopsies of the hemiplegic side of 16 patients with a cerebrovascular accident in the middle cerebral artery region were analyzed qualitatively and quantitatively by enzyme histochemistry and electron microscopy. Patients grouped according to the time lapsed as from the occurrence of the accident (1–17 months) demonstrated a progressive decrease in the fiber diameter and changes in fiber type distribution with predominant type II atrophy and type I predominance. Nuclear internalization, myopathic alterations, and perifascicular fatty infiltrations were observed constantly. In the affected fibers the ultrastructural findings were myofibrillar alterations with the formation of rods and cytoplasmic bodies. There was accumulation of lipofuscin, glycogen, and lipid droplets. Microvascular changes were observed frequently. Biopsies from the asymptomatic legs were either normal or showed age-related muscle alterations. Correlation was noted between the clinical and functional status of the patients and the morphological aspects seen in muscle biopsies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687615
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  • 14
    Electronic Resource
    Electronic Resource
    Ultrastructure of carbon disulphide neuropathy (1984)
    Springer
    Acta neuropathologica 63 (1984), S. 255-263 
    Details
    ISSN: 1432-0533
    Keywords: Carbon disulphide ; Electron microscopy ; Giant axonopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Adult Wistar rats were exposed to carbon disulphide (CS2) vapour at a concentration of 2.4 mg/l of air for 5 days a week (6h a day), and the ultrastructure of peripheral nerves, neuromuscular junctions and muscles was investigated after 6 months of exposure to CS2. Numerous giant axons, i.e. paranodal or internodal swellings, were seen in the peripheral nerves. At the swollen paranodes, the myelin sheath was thinned, in other regions large intramyelinic vacuoles indicative of more dramatic demyelination were observed at axonal enlargements. Axonal enlargements consisted essentially of whorls of tightly packed neurofilaments. A number of nerve fibres underwent complete degeneration, but at the same time there was evidence of nerve regeneration. Nerve terminals were affected in a similar way following CS2 exposure. At neuromuscular junctions, filamentous swellings of nerve terminals preceded their degeneration and eventual denudation of synaptic gutters. As a rule, the postsynaptic part of neuromuscular junctions remained unimpaired by CS2 treatment. Muscles were affected by both atrophy and degeneration. Clusters of dense and lamellar bodies and numerous autophagosomes indicative of direct myotoxic effect of CS2 were frequently encountered in the investigated muscles. Some muscle fibres apparently underwent necrosis judging from the occurrence of myotubes characteristic of muscle degeneration and regeneration. The pathomorphology of CS2 neuropathy resembles that of other toxic neuropathies which presumably have a common origin in impaired energy metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685252
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  • 15
    Electronic Resource
    Electronic Resource
    Peroxisomes in sebaceous glands (1984)
    Springer
    Anatomy and embryology 169 (1984), S. 261-270 
    Details
    ISSN: 1432-0568
    Keywords: Peroxisomes ; DAB-cytochemistry ; Electron microscopy ; Three-dimensional reconstruction ; Preputial gland ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of peroxisomes in partially differentiated cells of the mouse preputial gland was investigated using serial thin sections and three-dimensional reconstruction as well as the alkaline diaminobenzidine technique for visualization of the peroxidatic activity of catalase. An analysis of serial sections indicates that the different types of intensely stained peroxisomal profiles, classified according to their shape, represent random planes through highly complex peroxisomes. These organelles exceed 4 μm in length and exhibit a focal heterogeneity with respect to their size, shape and enzyme distribution. The graphical three-dimensional reconstruction demonstrates that the most intricate peroxisomes are characterized by tortuous, elongate, and branched tubular segments of varying diameter equipped with enlarged terminal hollow-spherical structures which engulf areas of cytoplasm. A close spatial relationship is established between adjacent peroxisomes and peroxisomes and mitochondria, the latter two of which synchronously develop into highly complex structures. A close association is also observed between peroxisomes and the endoplasmic reticulum, whereby membrane continuities between the two compartments cannot be demonstrated. These observations are inconsistent with traditional concepts concerning peroxisomal shape and size, the number per cell, as well as their biogenesis from the endoplasmic reticulum. The functional significance of individual highly complex peroxisomes and their assemblage forming an extensive netlike membraneous system throughout the cell is discussed with respect to intracellular energy transport and trans-membrane electron exchange.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315631
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  • 16
    Electronic Resource
    Electronic Resource
    Ultrastructural studies of the temporal relationship between loss of zona pellucida and appearance of blastocyst-induced stromal changes during normal pregnancy in rats (1984)
    Springer
    Anatomy and embryology 170 (1984), S. 45-49 
    Details
    ISSN: 1432-0568
    Keywords: Implantation ; Blastocyst ; Zona pellucida ; Decidual reaction ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural studies were undertaken to investigate the temporal relationship between loss of the zona pellucida around the blastocyst and the appearance of decidual changes in the endometrial stroma during normal implantation in rats. Blastocyst-free and blastocyst-containing sites of pregnant uterine horns were studied and compared with control sites from contralateral salpingectomized horns and horns of pseudopregnant animals from 24.00 h on Day 4 and onwards. There were no membrane contacts between the blastocyst and the uterine epithelium at 10.00 h on Day 5 and earlier because of an intervening zona pellucida. From 14.00 h onwards, however, such contacts were present and at 18.00 h, the zona pellucida had disappeared and the blastocyst had attached onto the uterine epithelium. The stromal cells of pregnant and control horns were indistinguishable from each other at 24.00 h on Day 4, but from 06.00 h on Day 5 onwards specific changes were noted in the stromal cell nucleoli of the pregnant horns. The results therefore suggest that the first morphological sign of decidualization occurs about 12 h before the Pontamine Blue reaction and is initiated by the blastocyst early on Day 5 while it is still encased by the zona pellucida.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319456
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  • 17
    Electronic Resource
    Electronic Resource
    An ultrastructural study on the “meconium corpuscles” in rat foetal intestinal epithelium with particular reference to apoptosis (1984)
    Springer
    Anatomy and embryology 169 (1984), S. 119-124 
    Details
    ISSN: 1432-0568
    Keywords: Meconium corpuscles ; Apoptosis ; Foetal intestine ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During the embryonic development of the intestine, programmed deletion of epithelial cells plays a vital role in the formation of secondary lumina and of villi. Electron microscopy shows that this deletion is effected by apoptosis, a distinctive mode of cellular death recently recognised as being implicated in normal tissue involution in the adult, as well as during intrauterine development. The process involves cellular condensation and budding to form membrane-bounded apoptotic bodies containing well-preserved organelles. These are then either engulfed by neighbouring principal cells or sloughed off into the intestinal lumen. Engulfed apoptotic bodies that show various degrees of lysosomal degradation have previously been reforred to as “meconium corpuscles”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303140
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  • 18
    Electronic Resource
    Electronic Resource
    The use of semiautomatic morphometry in the study of normal rat gastrocnemius muscle fibers (1984)
    Springer
    Acta neuropathologica 64 (1984), S. 108-113 
    Details
    ISSN: 1432-0533
    Keywords: Image analysis ; Electron microscopy ; Muscle fibers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Based on a fixed number of EM photomicrographs a semiautomatic image analysis is made of normal gastrocnemius muscle fibers to obtain reference values for comparison with pathologic data. Z disc, mitochondria, tubular system, and sarcoplasmic reticulum are measured. It is stated that no definite fiber type differentiation is possible based on these quantitative data. However, measurements of Z disc and mitochondria are suggestive of such a differentiation. On the other hand, all data reach a Gaussian distribution on a logarithmic scale after a 5% correction factor is introduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00695573
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  • 19
    Electronic Resource
    Electronic Resource
    A possible paracellular route for the resolution of hydrocephalic edema (1984)
    Springer
    Acta neuropathologica 64 (1984), S. 122-128 
    Details
    ISSN: 1432-0533
    Keywords: Hydrocephalus ; Blood-brain barrier ; Tight junctions ; Paracellular pathway ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Considering the possibility of a paracellular route for edema resolution we studied the microvasculature of the subependymal and subcortical white matter in hydrocephalic rats. Normal adult rats were used as controls. After injection of kaolin suspension into the cisterna magna, the animals were killed at intervals of 1, 2, 4, and 8 weeks. In hydrocephalic rats at 1 week after kaolin injection, widening of the interendothelical cleft between the tight junction (dehiscence) was seen in 27 of 76 (35%) vessels. At 2 weeks after kaolin injection, the number of the dehiscences had increased (39/7:56%) and some were enlarged, forming interendothelial blisters. At 4 weeks in hydrocephalic rats, both dehiscences and blisters were still prominent (45/73∶63%) and at 8 weeks the dehiscences were still prominent, but the number of the blisters had decreased (25/81∶31%). The blisters and dehiscences were most pronounced in the corpus callosum and occipital regions. Following i.v. injection of horseradish peroxidase, the interendothelial dehiscences and blisters were completely devoid of the marker substance. These findings indicate that in obstructive hydrocephalus the tight junctions may constitute part of a paracellular pathway for the resorption of interstitial edema fluid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00695575
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  • 20
    Electronic Resource
    Electronic Resource
    A semiquantitative light and electron microscopic analysis of histopathologic changes in photochemotherapy-induced freckles (1984)
    Springer
    Archives of dermatological research 276 (1984), S. 2-11 
    Details
    ISSN: 1432-069X
    Keywords: Photochemotherapy ; Freckles ; Electron microscopy ; Melanocytes ; Langerhans cells ; Retinoid therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Photochemotherapy (PUVA)-induced freckles were found in 25 patients (41%) who had received more than 1,000 J/cm2 of PUVA. The patients had been treated with PUVA for more than 2 years, with more than 150 exposures before PUVA lentigines appeared on the thighs, the upper arm, the mid-lower arm, the waist, and the buttocks. The histopathology of these freckles was analyzed by light and electron microscopy. Light microscopy showed an increased amount of pigment and melanophages and increased numbers and size of melanocytes. The keratinocytes often displayed atypical features such as enlarged nuclei, giant size, or fibrillar degeneration. Homogenization of the papillary dermis was observed in 11 patients. The activation of melanocytes was confirmed electron microscopically, and pathological features such as large amounts of lipid droplets and lysosome-melanosome complexes within the melanocytes were seen. The Langerhans cells were mostly normal, whereas the keratinocytes showed cytolytic changes, fibrillar degeneration, and vacuolization. A close follow-up of patients with prolonged PUVA treatment is recommended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00412555
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  • 21
    Electronic Resource
    Electronic Resource
    Electron microscopic study on Langerhans cells and related cells in lymph nodes of DNCB-sensitive mice (1984)
    Springer
    Archives of dermatological research 277 (1984), S. 44-54 
    Details
    ISSN: 1432-069X
    Keywords: Birbeck granule ; Birbeck granule-like structure ; Electron microscopy ; Langerhans cell ; Lymph node
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To understand contact hypersensitivity, it is important to know the kinetics of Langerhans cells (LC) and related cells in the lymph node (LN), as well as in the skin. For this purpose, we tried experimentally to induce increased numbers of LCs, Birbeck granule-like structure (BgS)-containing cells, and interdigitating reticulum cells (IDC) in DNCB-sensitive mice and studied them by means of electron microscopy with the following results: (1) cytologically, LC, BgS-containing cells and IDC were closely related; (2) BgS seemed to arise from rough-surfaced endoplasmic reticulum (r-ER), and BgS-containing cells were midway in nature between LC and IDC from the morphological view point. From these findings, it appears that IDC, BgS-containing cells, and LCs were simultaneously involved in the contact hypersensitivity reactions of LNs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406480
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  • 22
    Electronic Resource
    Electronic Resource
    Hereditary motor and sensory neuropathy of demyelinating and remyelinating type in children (1984)
    Springer
    Acta neuropathologica 65 (1984), S. 1-9 
    Details
    ISSN: 1432-0533
    Keywords: Polyneuropathy ; Hereditary disease ; Chiloren ; Sural nerve biopsy ; Electron microscopy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ten autosomal recessive/sporadic cases of hereditary motor and sensory neuropathy type I (HMSN I), nine of which originated from the northern part of Sweden, were included in the study. Parents were free from neurologic symptoms. Motor and sensory conduction velocity was normal when recorded, i.e., in 19 and 17 parents, respectively. Sural nerve biopsies from the ten cases revealed a varying degree of onion bulb formation. In eight of the cases the onion bulbs consisted of abundant basement membranes, whereas the Schwann cells were few and sometimes lacking. There were in some cases considerable differences between separate fascicles as to the loss of myelinated nerve fibers. In the six biopsies in which teasing was performed signs of present and previous demyelination were noticed. Numerous internodal segments were abnormally thin with reference to their length. In many such segments there were marked local thickenings of the nerve fiber. In cross sections the probable counterparts to these thickenings were nerve fibers with unduly thick myelin sheaths and complex folding of the myelin. Ultrastructural axonal changes were seen in the majority of the cases. The pathogenetic and diagnostic implications of the present findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689822
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  • 23
    Electronic Resource
    Electronic Resource
    Axonopathy and microangiopathy in chronic alloxan diabetes (1984)
    Springer
    Acta neuropathologica 65 (1984), S. 128-137 
    Details
    ISSN: 1432-0533
    Keywords: Quantitative ; Electron microscopy ; Microangiopathy ; Pi granules ; Schwann cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A significant reduction in the myelinated nerve fiber population was observed during quantitative electron-microscopic examination of peripheral nerves in chronic alloxan diabetic rats. Dystrophic axonal abnormalities and regenerating fibers were more numerous in diabetics than age-matched controls. Schwann cells showed reactive changes including prominent pi granules of Reich and intracytoplasmic filament accumulation. Enumeration of these alterations, however, revealed no singificant difference from controls. Endoneurial macrophages in diabetic rats were also filled with lamellar intracytoplasmic inclusions characteristic of a chronic neuropathy. Quantitation of pathologic lesions in teased nerve fibers confirmed the preponderance of axonal over demyelinative disease and showed demyelination to be segmental. Microangiopathy was noted throughout the vasa nervorum of diabetic rats, and quantitative electron microscopy showed endothelial proliferation with doubling of the number of endothelial cells and proportional capillary mural thickening. Swollen, reactive endothelial cells appeared to effece the vascular lumen and may impair capillary perfusion. These microcirculatory changes, in the presence of biochemical and rheologic disturbances may contribute to tissue hypoxia and underly the loss of axons in experimental diabetic neuropathy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690466
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  • 24
    Electronic Resource
    Electronic Resource
    Site of action of the natural algicide, cyanobacterin, in the blue-green alga, Synechococcus sp. (1984)
    Springer
    Archives of microbiology 138 (1984), S. 273-277 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Secondary metabolite ; Allelopathy ; Photosynthesis ; Electron transport ; Thylakoids ; Herbicides ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyanobacterin is a secondary metabolite produced by the cyanobacterium, Scytonema hofmanni. Highly purified cyanobacterin was found to inhibit the growth of many cyanobacteria at a minimum effective dose of 2 μg/ml (4.6 μM). The antibiotic had no effect on eubacteria including the photosynthetic Rhodospirillum rubrum. The site of action of cyanobacterin was further investigated in the unicellular cyanobacterium, Synechococcus sp. Electron micrographs of antibiotic-treated Synechococcus cells indicated that cyanobacterin affects thylakoid membrane structure. The antibiotic also inhibited light-dependent oxygen evolution in Synechococcus cells and in spheroplasts. These data support our conclusion that cyanobacterin specifically inhibits photosynthetic electron transport. This activity is similar to herbicides such as 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU). The anhydro analog of cyanobacterin had no biological activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402134
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  • 25
    Electronic Resource
    Electronic Resource
    Structural analysis of EcoRI-DNA complexes as revealed by electron microscopy (1984)
    Springer
    Archives of microbiology 140 (1984), S. 265-270 
    Details
    ISSN: 1432-072X
    Keywords: EcoRI ; EcoRI-DNA complexes ; EcoRI* activity ; Recognition sites ; Frequency of binding ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electron microscopy of negatively stained isolated restriction enzyme EcoRI revealed particle projections with triangular or square outlines, indicating that the enzyme, in its tetrameric state, is tetrahedron-like. The two dimers making up the tetramer appear to be arranged in two planes orthogonal to each other. Complexes formed by EcoRI with the plasmids pBR322 or pGW10 were investigated by electron microscopic spreading techniques. In the presence of Mg2+, EcoRI was bound to the DNA molecules to form pearl necklace-like aggregates. The number of bound EcoRI particles was much higher as the sum of EcoRI-and 5′..AATT..3′ sites (with exceptions, the 5′..AATT..3′ sites may function as one type of EcoRI* sites) along the DNAs, indicating unspecific binding. In the absence of Mg2+, EcoRI was bound to the DNA only at the recognition site for EcoRI and the sites where the tetranucleotide sequence 5′..AATT..3′ was present. A direct correlation of the local concentrations of the bases A and T within the flanking sequences of the binding sites with the frequency of EcoRI to the DNA was observed. Dimers and tetramers of the enzyme was found to bind to the DNA. Tetramers occasionally exhibited two binding sites for DNA as indicated by the observation of DNA loops originating at the sites of bound tetrameric EcoRI particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454940
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  • 26
    Electronic Resource
    Electronic Resource
    Phospholipase activity in human tumors: Localization by cytochemical staining (1984)
    Springer
    Journal of cancer research and clinical oncology 107 (1984), S. 242-244 
    Details
    ISSN: 1432-1335
    Keywords: Phospholipase ; Plasma membrane ; Cytochemistry ; Electron microscopy ; Human tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Phospholipase activity was localized for the first time by cytochemical staining at the plasma membrane of malginant cells in gastric adenocarcinomas by electron microscopy. This activity was not found in benign cells of the same tumor, e.g., in components of the connective tissue underlying the glandular epithelium, or in cells beyond the margin of the same tumor. Neither benign nor maligant cells of colorectal tumors, nor those in malignant melanoma, had any phospholipase activity that could be demonstrated by the method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01032616
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  • 27
    Electronic Resource
    Electronic Resource
    Cytoplasmic inclusions and X-ray microprobe analysis in a case of prolymphocytic leukemia (1984)
    Springer
    Journal of cancer research and clinical oncology 107 (1984), S. 229-232 
    Details
    ISSN: 1432-1335
    Keywords: Prolymphocytic leukemia ; Cytoplasmic inclusions ; X-ray microanalysis ; Chronic lymphocytic leukemia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A patient with prolymphocytic leukemia is described. The peripheral blood and bone-marrow cells contained nuclear pockets, bridges, and appendices, as well as cytoplasmic inclusions that were not membrane bound or connected with the endoplasmic reticulum. X-ray microanalysis of the cells showed them to contain large amounts of phosphorus, sulfur, chlorine, and calcium, as well as a smaller amount of sodium and magnesium in comparison with control lymphocytes. When compared with lymphocytes of a patient with chronic lymphocytic leukemia (CLL), the patient's cells showed higher amounts of magnesium, sulfur, and chlorine, while the sodium content was decreased. The usefulness of electron microscopy and X-ray microanalysis in the diagnosis of this type of leukemia is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01032613
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  • 28
    Electronic Resource
    Electronic Resource
    Ellipsoids in the human spleen (1984)
    Springer
    Virchows Archiv 403 (1984), S. 27-40 
    Details
    ISSN: 1432-2307
    Keywords: Spleen ; Ellipsoids ; Morphometry ; Electron microscopy ; Lymphocyte traffic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A study of ellipsoids (EL) in the human spleen was done on 25 surgically resected specimens in order to assess the number of EL, their structure, the nature of the cuff cells and the problem of lymphocyte traffic through their wall. The results show that an average spleen of 200 g contains 1.6 × 107 EL. They are localized in a constant segment of the vascular tree, just at the transition of the penicillary arterioles into capillaries and they consist of a capillary (not an arteriole) surrounded by a cuff of cells. These cells are neither endothelial nor smooth muscle cells, display lysosomal activity and are considered as fixed specialized pericapillary cells capable of cytoplasmic expansion. Since their number is inconstant in different individuals and in different species they are considered to be dynamic histological structures. Because of the constant presence of lymphocytes in their walls we consider the EL to be a transit system for lymphocytes and the splenic equivalent of the high endothelial venules in the lymph nodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689336
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  • 29
    Electronic Resource
    Electronic Resource
    Distribution of collagen types I and III and basal lamina in human gastric carcinoma: An immunohistochemical and electron microscopic study (1984)
    Springer
    Virchows Archiv 403 (1984), S. 313-322 
    Details
    ISSN: 1432-2307
    Keywords: Gastric carcinoma ; Scirrhous carcinoma ; Collagen ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Collagen types I and III were examined immunohistochemically in 32 cases of gastric carcinoma classified as poorly differentiated adenocarcinoma with scirrhous stroma, well differentiated adenocarcinoma with intermediate stroma, or poorly differentiated adenocarcinoma with medullary stroma. In the stroma of scirrhous carcinoma, types I and III collagens were distributed abundantly in fibrillar or granular patterns with little difference in the intensity of staining. In well differentiated adenocarcinoma, type I collagen was diffusely distributed in the stroma with type III collagen distributed sparsely. In poorly differentiated adenocarcinoma with medullary stroma, the two types of collagen were only found around capillaries, constituting the tumor interstitium. Electron microscopic examination of scirrhous carcinoma showed tumor cells partially covered with fibroblasts, and discontinuous basal lamina, collagen fibers and microfibrils present between tumor cells and fibroblasts. In well differentiated carcinoma, tumor cells were surrounded by fibroblasts, and well developed basal lamina was observed beneath the tumor cells. In poorly differentiated carcinoma with medullary stroma, the stroma consisted of capillaries and very few fibroblasts with discontinuous basal lamina occasionally being present between tumor cells and fibroblasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00737282
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  • 30
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in the spermatogonia and spermatocytes of Poecilia reticulata during spermatogenesis (1984)
    Springer
    Cell & tissue research 237 (1984), S. 219-226 
    Details
    ISSN: 1432-0878
    Keywords: Spermatogonia ; Spermatocytes ; Carbohydrates ; Guppy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of guppy (Poecilia reticulata) spermatogonia and spermatocytes has been studied using electron microscopy. The spermatogonia, situated at the apex of the seminiferous tubule, are almost all surrounded by a network of Sertoli cells; they have very diffuse chromatin and one or two large nucleoli. The cytoplasm contains relatively few organelles, although annulate lamellae are found. The mitochondria have few cristae and are concentrated at one pole of the cell; they are sometimes found with intermitochondrial cement. These spermatogonia are separated from each other, having no intercellular bridges or inclusion in Sertoli cells, and are relatively undifferentiated; they correspond to stem cells. The spermatogonia beneath the apex are organized into cysts. First-generation spermatogonia are more dense and heterogeneous, their nuclei becoming smaller and their chromatin becoming denser during successive generations. In spermatocytes, the synaptinemal complex exists as a modified form until metaphase. The concentration of organelles in the cytoplasm increases and the organelles become more diversified as spermatogenesis progresses. Many cytoplasmic bridges are observed (several per cell), indicating that the cells remain in contact after several divisions. These changes in germ cell structure have been related to some of the characteristic features of spermatogenesis in guppy, e.g. the large number of spermatogonial generations and the complexity of spermiogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217139
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  • 31
    Electronic Resource
    Electronic Resource
    Marginal plates in hepatic peroxisomes of Ichthyophis glutinosus (Amphibia: Gymnophiona) (1984)
    Springer
    Cell & tissue research 238 (1984), S. 413-416 
    Details
    ISSN: 1432-0878
    Keywords: Peroxisomes ; DAB-cytochemistry ; Electron microscopy ; Liver, amphibian ; Gymnophiona ; Ichthyophis glutinosus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of hepatic peroxisomes was investigated in Ichthyophis glutinosus (Amphibia: Gymnophiona), employing perfusion fixation and the diaminobenzidine (DAB) technique for the visualization of catalase. The majority of peroxisomes is circular or rod-shaped, although elongated particles occasionally occur. They contain a finely granular matrix, lightly stained after the DAB procedure. Their mean diameter is approximately 0.25 μm. Serial sections reveal that the circular and rod-shaped peroxisomal profiles are cross and oblique sections of highly tortuous, tubular organelles exceeding 2 μm in length. In addition to tubular profiles, elongated, rectangular particles, as well as straight dumbbell-shaped organelles with distinct marginal plates are observed. They range from 900 to 1650 nm in length (mean = 1200 nm). In the flattened, thin central portion of the dumbbell-shaped particle, the peroxisomal membranes form a cisterna enclosing one or two uniformly thick marginal plates, which display a definite substructure with a periodicity of 10 nm. These findings indicate that peroxisomes in the liver of Ichthyophis exhibit a complex organization. It is suggested that the organelles undergo a specific differentiation process, morphologically characterized by the formation of enlarged segments of unusual shape.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217316
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  • 32
    Electronic Resource
    Electronic Resource
    Studies on the morphology of the isolated perfused rabbit ovary (1984)
    Springer
    Cell & tissue research 235 (1984), S. 59-63 
    Details
    ISSN: 1432-0878
    Keywords: Ovulation (rabbit) ; Graafian follicle ; Perfusion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Isolated ovaries from untreated, sexually mature rabbits were introduced into an in vitro perfusion system and perfused with a chemically defined medium containing albumin. The ovaries were perfused for up to 15 h (mean 11.5 h) and then processed for morphological investigation. Both at the light- and electron-microscopical levels, most of the ovaries exhibited a normal structure comparable with ovaries in situ. In two cases, however, marked accumulations of bacteria were found, although not inside the follicles. Since ovulation in the rabbit normally occurs between 9.5–13 h after mating or human chorionic gonadotrophin treatment, this model seems adequate for studies of ovulation in vitro. It is, however, important to study the ovaries microscopically after the perfusion to detect artifacts, e.g., bacterial infection, that may have influence on the process of ovulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213723
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  • 33
    Electronic Resource
    Electronic Resource
    Regions of putative acetylcholine receptors at synaptic contacts between neurons maintained in culture and subsequently fixed in solutions containing tannic acid (1984)
    Springer
    Cell & tissue research 235 (1984), S. 85-89 
    Details
    ISSN: 1432-0878
    Keywords: Tannic acid ; Acetylcholine receptors ; Tissue culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spinal cord neurons from 9-day chick embryos were maintained in culture for up to 35 days and then fixed in 4% cacodylate-buffered glutaraldehyde containing 2% tannic acid. After about 15 days in culture a small percentage of the synaptic specializations present were characterized by striking electron-dense striations averaging 15 nm in width, oriented perpendicular to the postsynaptic membrane. These structures increased in frequency with time in culture (to a maximum of about 10% of all synapses in the oldest cultures); they were asymmetrical, protruding approximately 8 nm into the synaptic cleft, and more deeply (approximately 15–18 nm), into the postsynaptic cytoplasm. On the basis of earlier work by Sealock (1980) they are interpreted as concentrations of acetylcholine receptors. Similar membrane differentiations were also seen associated with active-zone areas of a few presynaptic membranes, and the possibility that these represent presynaptic acetylcholine receptors is discussed. Additional observations reported are (1) the presence of striations resembling those seen at the postsynaptic membrane in the membranes of some postsynaptic vesicles, and (2) filamentous links between the striations and cytoskeletal elements of the postsynaptic cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213727
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  • 34
    Electronic Resource
    Electronic Resource
    Fine structure of monoamine-containing basal cells in the taste buds on the barbels of three species of teleosts (1984)
    Springer
    Cell & tissue research 235 (1984), S. 479-484 
    Details
    ISSN: 1432-0878
    Keywords: Monoamine-containing cells ; Taste bud ; Paracrine cells ; Mechanoreceptors ; Electron microscopy ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The taste buds on the barbels in three species of teleosts (Cyprinus carpio, Misgurnus anguillicaudatus, Parasilurus asotus) were studied by means of fluorescence and electron microscopy. Intensely yellow-fluorescent cells, which are disk-shaped and located exclusively in a basal position, are observed in the barbel-buds of all fishes examined. The basal cells contain a large number of small clear vesicles approximately 40–60 nm in diameter, which show a tendency to aggregate in the cytoplasm facing the junction of the nerve terminals; chemically transmitting synapses are seen in the latter region. It is suggested from the present observations that the basal cells in the barbel-bud may originate from Schwann cells and have a dual function both as mechanoreceptors and paracrine elements. Since the administration of 5,6-DHT results in an appearance of small dense vesicles among the small clear vesicles, the possibility exists that the basal cell may be capable of taking up monoamines and storing them in the small clear vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226942
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  • 35
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    Electronic Resource
    Electron-microscopic demonstration of the distribution of calcium deposits in the exocrine pancreas of the rat after application of carbachol, atropine, cholecystokinin, and procaine (1984)
    Springer
    Cell & tissue research 235 (1984), S. 683-690 
    Details
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Calcium pool ; Calcium release ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to identify a cellular Ca2+-pool, from which calcium is released when secretagogues are applied, tissue fragments of the rat exocrine pancreas were incubated and fixed with glutaraldehyde in the presence of calcium. By means of this procedure electron-dense deposits were found on plasma membranes. X-ray microanalysis showed that these deposits contain calcium. Stimulation of tissue fragments with the use of the secretagogues carbachol or cholecystokinin reduced the number of deposits by about 80%. When the antagonist atropine was applied after carbachol stimulation, deposits reappeared on cell membranes, which then disappeared again after a second stimulation with cholecystokinin. In the presence of procaine, carbachol was inhibited and only slightly reduced the Ca2+-deposits on the plasma membranes. These results suggest that a calcium pool, from which calcium is released to induce enzyme secretion on stimulation, is located in the cell membrane
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    URL: http://dx.doi.org/10.1007/BF00226969
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  • 36
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    Electronic Resource
    Morphological and morphometrical changes in chloride cells of the gills of Pimephales promelas after chronic exposure to acid water (1984)
    Springer
    Cell & tissue research 236 (1984), S. 121-128 
    Details
    ISSN: 1432-0878
    Keywords: Chloride cells ; Acid stress ; Gill ; Electron microscopy ; Fathead minnow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fathead minnows, Pimephales promelas, were exposed for 129 days to Lake Superior water acidified with sulfuric acid by means of a flow-through toxicant injection system. The effects of chronic acid stress (pH 6.5, 6.0, 5.5, 5.0) on gill histology were examined. Most of the histological effects were seen at pH 5.5 and 5.0 and were confined primarily to changes in numbers, distribution, and morphology of chloride cells. At low pH levels there tend to be more chloride cells in the gill epithelium and an increased percentage of these cells in the secondary lamellae. In contrast to normal chloride cells, chloride cells from fish exposed to low pH frequently had apical pits while some had bulbous apical evaginations. The occurrence of structural changes in chloride cells during exposure to acid water suggests that chloride cells may be involved in acclimation to acid stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216521
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  • 37
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    Electronic Resource
    Morphometric evaluation of lipid droplet associations with secretory vesicles, mitochondria and other components in the lactating cell (1984)
    Springer
    Cell & tissue research 236 (1984), S. 471-475 
    Details
    ISSN: 1432-0878
    Keywords: Lactating cell ; Lipid droplets ; Secretory vesicles ; Mitochondria ; Intracellular associations ; Electron microscopy ; Milk secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The size, cellular location, and identity of surface-associated components were determined for lipid droplets in lactating cells. Transmission electron-microscopic measurements were made involving 3801 droplets in approximately 211 cells from three rats and 1197 droplets in 66 cells from a mouse. For the purposes of droplet evaluation, cells were divided into seven locations ranging from basal to secreting positions. Droplets were also categorized with respect to contact with other droplets, basolateral plasma membrane, mitochondria, Golgi apparatus, secretory vesicles, and endoplasmic reticulum-cytoplasm (ERC). Data on droplet size showed that droplet growth occurs mainly in the secretory position, confirming previously published findings. Lipid droplets from mouse tissue, although somewhat smaller in size showed similar growth trends to those of the rat. Data on numbers of droplet contacts and percentages of droplet circumferences involved in associations with other cell components showed that the dominant interaction of lipid droplets was with the ERC. However, intimate association of droplets with mitochondria was noted in all cellular locations. In addition, nursed animals exhibited a greater proportion of droplet surface association with secretory vesicles and less in contact with mitochondria in comparison to those not nursed. The significance of these relationships to milk synthesis and secretion is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214252
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  • 38
    Electronic Resource
    Electronic Resource
    Electron-microscopic study of silver staining of nucleoli in growing oocytes of rat ovaries (1984)
    Springer
    Cell & tissue research 236 (1984), S. 249-255 
    Details
    ISSN: 1432-0878
    Keywords: Oocyte ; Nucleolus ; Silver staining ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The nucleoli of dictyate-stage growing oocytes in rat ovaries were examined both with routine electron microscopy and electron microscopy after silver nitrate and ammoniacal silver nitrate (Ag-AS) staining. The nucleoli of the unilaminar follicular oocytes consist of twisted strands of dense fibrillar components, aggregates of granular components, and small fibrillar centers. After Ag-AS staining, silver grains are numerous on the dense fibrillar strands, fewer on the fibrillar centers, and very sporadic on the granular aggregates. The same stainability of three nucleolar components with the Ag-AS method was also confirmed in the nucleoli segregated by actinomycin D. During the transition of growing oocytes from bilaminar to plurilaminar follicle stage, the nucleolar dense fibrillar strands gradually conglomerate and are transformed into large and compact spherules. The stainability of dense fibrillar components with the Ag-AS method was lost along with this nucleolar transformation. These results may provide some new clues on the functional significance of AgAS-positive proteins in the nucleoli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214225
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  • 39
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    Electronic Resource
    Structure of the parathyroid glands, as revealed by different methods of fixation (1984)
    Springer
    Cell & tissue research 235 (1984), S. 51-58 
    Details
    ISSN: 1432-0878
    Keywords: Parathyroid glands ; Electron microscopy ; Light microscopy ; Quantitative histology ; Mongolian gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stereology and semi-automatic image analysis were used with the aim of comparing the structure of parathyroid glands from untreated adult Mongolian gerbils fixed by immersion with those fixed by perfusion. Subclassification of the chief cells based upon the staining affinity or electron density of the cytoplasm was readily performed only in glands fixed by immersion, and so-called atrophic cells were observed only in these glands. The atrophic cells were often surrounded by “light” chief cells. In glands fixed by perfusion, “light” chief cells were only rarely encountered. A significant difference between glands fixed by immersion and those fixed by perfusion was found only with regard to the form of cells and nuclei, those fixed by perfusion being more spherical. When comparing individual cells within glands fixed by immersion, “light” chief cells were more spherical and had a significantly larger nuclear and cellular size, and a lower mitochondrial volume density than the “intermediate”/“dark” chief cells. Otherwise there were no significant differences in any of the parameters investigated. These data indicate that occurrence of socalled “light” chief cells and atrophic cells is a result of improper fixation. The results of this study do not favour the concept of a functional cycle with a simultaneous occurrence of active and inactive cells within parathyroid glands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213722
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  • 40
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    Electronic Resource
    Interdigitating cells in the lymphoid tissues of bovine fetuses and calves (1984)
    Springer
    Cell & tissue research 235 (1984), S. 153-158 
    Details
    ISSN: 1432-0878
    Keywords: Bovine ; Interdigitating cell ; Lymphoid tissues ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron-microscopic studies of lymphoid tissues from bovine fetuses and from calves disclosed a non-lymphoid cell type in the thymus-dependent zones of secondary lymphoid tissues and in the thymus that is distinguishable from reticulum cells, epithelial and endothelial cells, and macrophages. Based on morphological and topographical criteria, the cell is identified as the interdigitating cell. In addition, studies of the tissues of normal and virus-challenged fetuses, and of conventionally reared calves, indicated that the interdigitating cells originate from monocytoid cells, which undergo differentiation in the thymus-dependent zones during an immune response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213735
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  • 41
    Electronic Resource
    Electronic Resource
    The fine structure of identified electrotonic synapses following increased coupling resistance (1984)
    Springer
    Cell & tissue research 235 (1984), S. 243-249 
    Details
    ISSN: 1432-0878
    Keywords: Gap junction ; Electron microscopy ; Freeze fracture ; Cell-to-cell communication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gap junctions exist in the septa between the segments of the lateral giant axons in the ventral nerve cord of the crayfish Procambarus. A large increase in the resistance (uncoupling) of these gap junctions was brought about by mechanical injury to the axonal segments. Both thin sections and freeze-fracture preparations were used to monitor the morphological changes which occurred up to 45 min after injury. There was no apparent change in the organization (a loose polygonal array) of the intramembrane particles which make up the junctional complex up to 45 min after injury. In some instances, however, the intramembrane particles appeared to have moved away from the junctional area. Other junctional regions were internalized and appeared similar to what have been called annular gap junctions. Also at this time (20–25 min after injury), a dense cytoplasmic plug formed in uninjured axon near the junctional region. It is concluded that the gap junctions that exhibit a loose polygonal organization of the intramembrane particles may be either in a state of low resistance (coupled) or a state of high resistance (uncoupled).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217847
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  • 42
    Electronic Resource
    Electronic Resource
    Studies on the morphology of the isolated perfused rabbit ovary (1984)
    Springer
    Cell & tissue research 235 (1984), S. 565-573 
    Details
    ISSN: 1432-0878
    Keywords: Ovulation ; Perfusion ; Graafian follicle (rabbit) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ovulation was induced in rabbits by intravenous administration of human chorionic gonadotrophin (HCG), and 4–5 h later the ovaries were isolated and introduced into an in-vitro perfusion system containing synthetic medium with albumin. Rupture of follicles occurred in vitro within the physiological time range (mean 11.3 h after injection of HCG), although with a reduced frequency. Preovulatory and ruptured follicles were studied in detail by light and electron microscopy. In the granulosa layer of ruptured or preovulatory follicles cytoplasmic blebbing activity, disappearance of CallExner bodies and differentiation toward luteinized cells were found. Perhaps the most important sign of normal preovulatory development in vitro was that the basement membrane surrounding the granulosa layer was penetrated by projections of granulosa cells. In the absence of this penetration phenomenon the granulosa layer prolapsed out of the follicle. Immediately before rupture, follicles showed marked degeneration, restricted to the outer layers of the apical wall, which is compatible with the hypothesis that degradative enzymes are released close to the surface of preovulatory follicles. Although the majority of follicles that ovulated under in-vitro conditions showed the same kind of morphological alterations as can be seen in vivo, occasional atypical ruptures occurred without any overt signs during perfusion. Also technical manipulations of the perfusion system, e.g., nonphysiological increase of perfusion pressure, could force follicles to rupture. This illustrates the importance of careful morphological study of all ovaries perfused in vitro before conclusions are drawn.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226954
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  • 43
    Electronic Resource
    Electronic Resource
    Electron-microscopic investigation of the innervation of the pars distalis of the hypophysis in adult Rana temporaria L. (1984)
    Springer
    Cell & tissue research 237 (1984), S. 149-154 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars distalis ; Innervation ; Synaptoid contacts ; Electron microscopy ; Rana temporaria L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pars distalis of the hypophysis of adult Rana temporaria, three types of nerve-fiber profiles were found at two distinct sites, in both lateral parts of the bordering regions of the anterior lobe with the intermediate lobe of the hypophysis. The first type of nerve-fiber profile consists of bundles of very fine axonal elements (diameter: 〈0.7 μm). The second type is formed by larger nerve fibers (diameter up to 4 μm) containing a few neurosecretory granules of approximately 100 nm. The third type of nervefiber profile resembles the second type but these nerve fibers make synaptoid contacts on at least two different types of glandular cells. The possible functional significance of these nerve fibers in the pars distalis is discussed. No nerve fibers were found (1) in the central part of the bordering region of the pars distalis with the intermediate lobe, (2) at the bordering region with the median eminence and (3) with the neurohypophysial stalk, and (4) in all other parts of the pars distalis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229210
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  • 44
    Electronic Resource
    Electronic Resource
    Vascularization and glomerular ultrastructure in the pig mesonephros (1984)
    Springer
    Cell & tissue research 238 (1984), S. 165-175 
    Details
    ISSN: 1432-0878
    Keywords: Mesonephros ; Pig embryo ; Glomerulus ; Microvasculature ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vascularization of the pig mesonephros was investigated in embryos 5–8 cm in length. Vascular injections with microfil were cleared and dissected; corrosion casts were studied under the scanning electron microscope (SEM). Perfusion-fixed tissue was used for SEM and transmission electron microscope (TEM) studies, including freeze-fracture specimens. The branches of one mesonephric artery carry up to 15 glomeruli. Several glomeruli occupy the same arterial branch, with very short afferent arterioles proper. The efferent vessels, frequently 2–5, leave the extensive vascular pole opposite the entering arteriole and split into peritubular capillaries radiating towards the superficial veins. These capillaries form vascular regions in the shape of flattened pyramids. Along its course, one nephron is supplied by vessels derived from 4–7 glomeruli. The nephrons have less vascular contact than in the definitive kidney. The ultrastructure of the single mesonephric vessels matches the metanephric counterparts. Epithelioid cells with renin granules are common in afferent arterioles, larger arteries, and efferent vessels. The lobulated glomeruli are up to 750 μm long and flattened, showing the usual features of podocytes, mesangial cells, and an attenuated endothelium with fenestrations between 50 and 250 μm. It partially retains its own basement membrane. There is no proximal mesangium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215158
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  • 45
    Electronic Resource
    Electronic Resource
    The effect of long-term denervation on the ultrastructure of Pacinian corpuscles in the cat (1984)
    Springer
    Cell & tissue research 238 (1984), S. 387-394 
    Details
    ISSN: 1432-0878
    Keywords: Pacinian corpuscles, cat ; Denervation ; Atrophy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Pacinian corpuscles of the cat located in the crural region and innervated by the interosseous nerve was studied 1 to 14 months after denervation. Both the Pacinian inner core and capsule remained well preserved one month after denervation. However, the denervated inner cores underwent progressive atrophy and wasting, which resulted in a gradual reduction of the amount of inner-core cells and lamellae, widening of interlamellar clefts, formation of empty spaces in the axial region and a considerable increase in the number of collagen fibrils. In spite of the wasting, the inner core still survived 14 months after denervation, but at least half of its volume became occupied by collagen fibrils which surrounded the remaining inner-core cells and lamellae. Collagen fibrils assembled in the denervated core were markedly thinner than those found in the capsule, as is also the case in normal Pacinian corpuscles. In the capsule, discrete focal degeneration, occasional pyknosis of the innermost capsular cells and macrophage infiltration were observed from the first month after nerve section onward, but the number of capsular layers remained within the normal range (30–40) up to 14 months after denervation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217312
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  • 46
    Electronic Resource
    Electronic Resource
    Enhanced cellular membrane contrast in a marine alga by Osmium-azole complexes (1984)
    Springer
    Protoplasma 119 (1984), S. 48-54 
    Details
    ISSN: 1615-6102
    Keywords: Electron microscopy ; Marine alga ; Membrane contrast ; Osmium-azole complexes ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Addition of certain heterocyclic nitrogen-carbon compounds to standard osmium tetroxide solutions used as secondary fixative resulted in an enhanced general membrane contrast in cells of the marine algaEmiliania huxleyi (Lohmann) Kamptner. Ultrastructural cell morphology and the contrast distribution were compared between cells treated according to a standard secondary fixation procedure and cells post-fixed when above mentioned heterocyclic compounds were introduced; in both cases some of the ultrathin sections were post-stained. Different compounds were tested: 1,2,4-triazole (TRA), 3-amino-1,2,4-triazole (A-TRA), 5-amino-tetrazole (A-TEA) and 2,4,6-tri-amino-1,3,5-triazine (melamine). The results were interpreted to indicate the possible bonding types arising from interaction of the heterocyclic compounds with osmium tetroxide and with membrane constituents. Interpretations were partly inspired by considerations from coordination chemistry. All above tests which did not include post-staining of thin sections could be performed at alkaline pH, and consequently calcified structures were preserved. The enhanced osmium accumulation at membranes was verified with X-ray microanalysis, which also showed that in the cases where membranes were visibly contrasted, localization of probable sites of intracellular non-crystalline calcium was facilitated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01287816
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  • 47
    Electronic Resource
    Electronic Resource
    Biological and biochemical analysis of soils (1984)
    Springer
    Plant and soil 76 (1984), S. 127-137 
    Details
    ISSN: 1573-5036
    Keywords: Adenylate pool ; Biomass volume ; CO2 evolution ; Chitin ; DNA ; Electron microscopy ; Enzymes ; Fluorescent antibody ; Fumigation-respiration ; Fungi Histochemistry ; Imunofluorecence ; Jones-Mollison technique ; Microcosms ; Monoclonal antibodies ; Nitrogen ; Nutrients ; Oxygen consumption ; Phosphorus ; Phytotoxins ; Plate counts ; Rhizobium ; Rhizosphere ; Sulphur ; Xenobiotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary There is an immense literature on biological and biochemical analyses of soils. Such analyses have revealed the enormous richness of species in soil and their vast range of metabolic potentials and ecological diversity. Accordingly, the approaches used to investigate the soil biota and its biochemistry usually have to be modified or adapted depending upon the purpose of the investigation. Studies of micro-organisms in the soil environment, are complicated because microbial cells are commonly attached to surfaces where they live side-by-side with other populations in consortia usually containing different morphological and physiological types. Such assemblages of organisms cannot be described quantitatively using cultural techniques, such as plate counts, which underestimate both cell numbers and viable biomass. The development of more powerful observational and staining techniques has improved our knowledge of the diverse morphological and biochemical composition of soil micro-communities. Such findings have been amplified at a grosser level by laboratory studies with multi-component systems (microcosms) to mimic field situations and to assess the range of biochemical potentials of microbial consortia. But despite notable advances in analytical methods we are still, with a few exceptions, unable to detect or identify those microorganisms which carry out specific biochemical transformations or determine whether particular cells are alive, dormant or dead at the time of observation. Considerable work has been done to define some of the fundamental ecological attributes of microbial assemblages in soil. Productive work on the metabolic activities of the soil microbiota, specially geochemical transformations of C, N, S and P, has been under way for more than a century. But only in more recent years have more sensitive and reproducible analytical methods become available to measure viable biomass in soil. This will enable some insight to be gained into the role that microbial biomass plays as a labile source and sink for plant nutrients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02205573
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  • 48
    Electronic Resource
    Electronic Resource
    Soil organic matter and structural stability: mechanisms and implications for management (1984)
    Springer
    Plant and soil 76 (1984), S. 319-337 
    Details
    ISSN: 1573-5036
    Keywords: Aggregates ; Aluminium ; Bacterial mucilage ; Binding agents ; Calcium ; Cation bridges ; Complexing agents ; Dispersion ; Electron microscopy ; Electrophoretic mobility ; Fungal hyphae ; Glues Iron ; Management Periodate ; Polysaccharides ; Rhizosphere ; Roots ; Slaking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The stability of pores and particles is essential for optimum growth of plants. Two categories of aggregates macro- (〉 250 μm) and micro- (〈250 μm) depend on organic matter for stability against disruptive forces caused by rapid wetting. Dispersion of clay particles from microaggregates is promoted by adsorption of complexing organic acids which increase the negative charge on clays. The acids are produced by plants, bacteria and fungi. However, the dispersibility of clay in microaggregates is offset by the binding action of polysaccharides, mainly mucilages produced by bacteria, but also by plant roots and fungal hyphae. The stability of microaggregates is also enhanced by multivalent cations which act as bridges between organic colloids and clays. Macroaggregates are enmeshed by plant roots, both living and decomposing, and are thus sensitive to management, and increase in number when grasses are grown and the soil is not disturbed. Lack of root growth,i.e. fallow, has the opposite effect. Various implications for management of soil structure are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02205590
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  • 49
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    Electronic Resource
    Cytochemical localization of adenylcyclase in the lateral wall of the inner ear (1984)
    Springer
    European archives of oto-rhino-laryngology and head & neck 240 (1984), S. 55-61 
    Details
    ISSN: 1434-4726
    Keywords: Inner ear ; Adenylcyclase ; Ouabain-insensitive endothelial ATPase ; Cytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cytochemical localization of adenylcyclase in the lateral cochlear wall was studied using a modification of the Reik-Howell method. All the cell membranes of the stria vascularis and spiral prominence cells, except the vascular endothelium, showed a low enzyme activity. In the marginal cell and spiral prominence epithelium facing the endolymph, this activity was limited to the perilymphatic membrane sections. The results are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464345
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  • 50
    Electronic Resource
    Electronic Resource
    Charge-Transfer-Komplexe von Tetrathiafulvalen (TTF) mit 1,2,5-Thiadiazolchinonen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1940-1953 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Charge-Transfer Complexes of Tetrathiafulvalene (TTF) with 1,2,5-Thiadiazolequinones1)The syntheses and the X-ray structure analyses of the charge-transfer complexes of tetrathiafulvalene (TTF) with naphtho[2,3-c][1,2,5]thiadiazole-4,9-dione (1 : 2) (2) and benzol[1,2-c: 4,5-c′]-bis[1,2,5]thiadiazole-4,8-dione (1 : 1) (4) are reported. In their crystal structures both compounds are built up by mixed columnar stacks of donors and acceptors, forming a characteristic packing motive for organic D-A complexes with properties of an electrical insulator.
    Notes: Es wird über die Synthese und die Einkristallröntgenstrukturanalysen der Charge-Transfer-Komplexe von Tetrathiafulvalen mit Naphtho[2,3-c][1,2,5]thiadiazol-4,9-dion (1 : 2) (2) und Benzo-[1,2-c: 4,5-c′]bis[1,2,5]thiadiazol-4,8-dion (1 : 1) (4) berichtet. Beide Verbindungen weisen in ihrer Kristallstruktur aus Donoren und Acceptoren gemischte kolumnare Stapel auf, ein charakteristisches Packungsmotiv organischer D-A-Komplexe mit elektrischen Isolatoreigenschaften.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170523
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  • 51
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    Notizen. Die Erzeugung von Nitrosylsalzen in wasserfreien organischen Medien (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1973-1976 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Generation of Nitrosyl Salts in Dry Organic MediaTrimethylsilyl halides (CH3)3SiX (2a - c, X = Cl, Br, I) are sufficiently electrophilic to cleave, in an equilibrium reaction, alkyl nitrites O = NOR (1a, b, R = i-C5H11, C2H5) with formation of O = NX (3a - c) and (CH3)3SiOR (4a, b). This reaction serves as a convenient in-situ-method to generate nitrosyl compounds NOX in chlorinated hydrocarbons as inert organic media.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170526
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  • 52
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    Electronic Resource
    Iminoborane beim thermischen Zerfall der Dialkylazidoborane (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1954-1964 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Iminoboranes from the Thermal Decomposition of DialkylazidoboranesIminoboranes RB = NR (1a - f) are formed by the thermal decomposition of azidoboranes R2BN3 (5a - f) in the gas phase or in solution. At low temperature, the iminoboranes 1b, d, e (R = iPr, iBu, sBu) can be trapped from the gas phase. They are characterized and brought to reaction as isolated species. Without other reactands, the iminoboranes dimerize or trimerize to form the cyclic products 2 or 3, respectively, or polymerize to the wax-like solids 4. Produced in solution below 100 °C, the iminoboranes are azidoborated by the educts 5 to give the (azidoboryl)amines 6 which are transformed into the borazines 3 at 160 - 180 °C. Iminoboranes undergo an ethyloboration with BEt3, a cycloaddition with PhN3, and in the absence of the strongly reactive R2BN3 a concurring cycloaddition and azidosilation with Me3SiN3 with formation of 7 - 10, respectively.
    Notes: Iminoborane RB = NR (1a - f) entstehen beim thermischen Zerfall von Azidoboranen R2BN3 (5a - f) in der Gasphase oder in Lösung. Die aus der Gasphase abgeschiedenen Produkte 1b, d, e (R = iPr, iBu, sBu) lassen sich bei tiefer Temperatur isolieren, charakterisieren und isoliert umsetzen. Mit sich selbst reagieren die in der Gasphase ergzeugten Iminoborane 1a - f unter Cyclodi-oder -trimerisierung oder unter Polymerisierung zu Produkten von Typ 2, 3 bzw. 4. In Lösung unterhalb 100 °C erzeugt, werden die Iminoborane von den Edukten 5 zu Produkten 6 azidoboriert; diese lassen sich bei 160 - 180 °C in Borazine 3 überführen. Iminoborane erfahren durch BEt3 eine Ethyloborierung zu 7, mit PhN3 eine Cycloaddition zu 8 und mit Me3SiN3 nebeneinander eine Cycloaddition zu 9 und eine Azidosilierung zu 10, sofern nicht das Edukt R2BN3 zugegen ist, das dem Azid Me3SiN3 in der Reaktivität gegenüber 1 überlegen ist.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170524
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    Azodesilylierung  -  eine neue aprotische Diazotierungstechnik (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1965-1972 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azodesilylation - a Novel Aprotic Diazotization TechniqueNitrosyl compounds NOA (4a - e, A = Cl, Br, BF4, CF3SO3, I) - generated partially in situ from O = N - OR/(CH3)3SiA (7a, b, R = i-C5H11, C2H5/8a, b, e, A = Cl, Br, I) - react in aprotic organic media with N,N-bissilylated organylamines RN[Si(CH3)3]2 (3b, R = C6H5; 15, R = CH3) under generation of diazonium systems R - N2+ A- and formation of non-nucleophilic hexamethyldisiloxane (6b). This method represents the first nucleophile excluding diazotization technique on the basis of three-coordinated nitrogen and is termed „azodesilylation“.
    Notes: Nitrosylverbindungen NOA (4a - e, A = Cl, Br, BF4, CF3SO3, I) - teilweise in situ hergestellt aus O = N - OR/(CH3)3SiA (7a, b, R = i-C5H11, C2H5/8a, b, e, A = Cl, Br, I) - reagieren mit N,N-bissilylierten Organylaminen RN[Si(CH3)3]2 (3b, R = C6H5; 15, R = CH3) in aprotischen organischen Medien unter Bildung von Diazonium-Systemen R - N2+ A- und nicht-nucleophilem Hexamethyldisiloxan (6b). Diese Methode repräsentiert die erste, Nucleophile ausschließende Diazotierungstechnik auf der Basis von 3fach koordiniertem Stickstoff und wird als „Azodesilylierung“ bezeichnet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170525
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    Acid-catalyzed Cyclization of the Ene-Product Derived from α-Pinene and PTAD (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1977-1979 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Säurekatalysierte Cyclisierung des En-Produkts aus α-Pinen und PTADAluminiumchlorid-katalysierte Reaktion des En-Produkts 2 aus 4-Phenyl-4H-1,2,4-triazol-3,5-dion (PTAD) und α-Pinen (1), des 1-(6,6-Dimelthyl-2-methylenbicyclo[3.1.1]hept-3-yl)-4-phenyl-1,2,4-triazolidin-3,5-dions, ergab 3,8,8-Trimelthyl-N-phenyl-4,5-diazatricyclo[4.2.1.03,7]nonan-4,5-dicarboxamid (6) in 78% Ausbeute. Auch Bortrifluorid-etherat, trockener Chlorwasserstoff und p-Toluolsulfonsäure katalysieren die Cyclisierung von 2 zu 6, aber nicht in diesem Maße. Der Mechanismus der Cyclisierung wird über eine Gerüstumlagerung der Carbenium-Ionen-Zwischenstufen gedeutet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170527
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  • 55
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    Kettenverlängerung bei Tetrafluor-1,2-ethandisulfenyldichlorid durch Reaktion mit Wasserstoffperoxid (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1980-1981 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chain Lengthening of Tetrafluoro-1,2-ethanedisulfenyl Dichloride by the Reaction with Hydrogen PeroxideThe reaction of the little compound ClSCF2CF2SCl (1) with aqueous H2O2 results in the formation of ClS2CF2CF2SSCF2CF2SO2Cl(2), which is characterized on the basis of 19F NMR, mass, IR, and Raman spectroscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170528
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  • 56
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    Fluorierungen von Adamantanderivaten mit Sauerstoffdifluorid (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1982-1986 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fluorination of Adamantane Derivatives with Oxygen DifluorideFluorination of adamantane and adamantane derivatives 1 with OF2 in the absence of an HF-trap gives fluoroadamantanes 2 and adamantanols 3 in varying amounts. Increasing yields of 2 are obtained in the presence of Na2CO3 as an HF-trap. In addition, the fluorooxahomoadamantanes 4b and e are formed in this reaction. The fluorination of adamantanone (5) with OF2 leads to analogous products.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170529
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  • 57
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    Photoelectron Spectra of Some Reduction Products of [2.2]Paracyclophane (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1987-1990 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoelektronenspektren einiger Reduktionsprodukte von [2.2]ParacyclophanAnhand des He(I)-Photoelektronen(PE)-Spektrums von 2,3′,5,6′-Tetrahydro[2.2]paracyclophan (2) wird gezeigt, daß die Through-Bond-Wechselwirkung zwischen den Sechsringen klein, innerhalb der Cyclohexadienringe aber groß ist. Über die PE-Spektren der weiteren Hydrierungsprodukte 3 und 4 wird berichtet.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19841170530
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    Synthesen mit Cyclobutadienen, 5. 5,5,6,6-Tetracyan-5,6-dihydrodewarbenzol/3,3,4,4-Tetracyan-3,4-dihydrobenzavalen - ein neues äquilibrierendes System (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1991-1993 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with Cyclobutadienes, 51). 5,5,6,6-Tetracyano-5,6-dihydro-Dewar benzene/3,3,4,4-Tetracyano-3,4-dihydrobenzvalene - a Novel Equilibrating SystemThe cyclobutadiene 3 reacts with tetracyanoethylene to give a 1 : 1-mixture of the dihydro-Dewar benzene 5 and the dihydrobenzvalene 6, which can be separated by crystallisation. In deuteriochloroform solution 5 and 6 are in a 1 : 1 equilibrium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170531
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    Masthead (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170601
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    Elektronenreiche Heterocyclen als Donorgruppen in Fluoreszenzfarbstoffen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2275-2286 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electron Rich Heterocycles as Donor Groups in Fluorescent DyesThe synthesis of N-methylphthalimides substituted with the donor groups pyrazole, triazole, benzotriazole, and naphthotriazole in position 4 is described (17, 18, 14, 12). The substituent constants of these groups are obtained by alkaline hydrolysis of the corresponding phthalimide dyes. Their solvatochromism in absorption and fluorescence gives information about charge distribution in ground- and excited state.
    Notes: Die Darstellung von N-Methylphtalimiden wird beschrieben, die in 4-Stellung die Donorgruppen Pyrazol, Triazol, Benzotriazol und Naphthotriazol tragen (17, 18, 14, 12). über die alkalische Hydrolyse des Imids werden die Substituentenkonstanten der Reste bestimmt. Die Solvatochromie in Absorption und Fluoreszenz gibt Information über die Ladungsverteilung in Grund- und angeregtem Zustand.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170619
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    Aromaten(phosphan)metall-Komplexe, IV. Darstellung von (6-Phosphonio-η5-cyclohexadienyl)-ruthenium(II)-Verbindungen und ihre Umwandlung in dikationische (Benzol)ruthenium(II)-Komplexe [C6H6Ru(PR3′)PR3″]2+ (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 142-151 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, IV1). Synthesis of (6-Phosphonio-η5-cyclohexadienyl)ruthenium(II) Compounds and their Conversion into Dicationic (Benzene)ruthenium(II) Complexes[C6H6Ru(PR3)(PR3′)PR3″]2+The complexes [C6H6RuCl(PR3)PR3′]PF6 (1 - 4) and [C6H6RuCl2(PR3)] (9, 10) react with phosphanes PR3″ in the presence of NH4PF6 to give the (6-phosphonio-η5-cyclohexadienyl)ruthenium(II) compounds [(6-R3″P-η5-C6H6)Ru(PR3)(PR3′)PR3″](PF6)2 (5 - 8 11). Similarly, from [C6H6Ru(CH3CN)3](PF6)2 (12) and PMe3 the complex [(6-Me3P-η5-C6H6)Ru(PMe3)2CH3CN](PF6)2 (13) is formed. The IR and NMR spectra of 5 - 8, 11, and 13 indicate that the phosphonio group is in the exo-position at the sp3 carbon atom of the cyclohexadienyl ligand. Below - 30°C, rotation around the metal-ring bond is so hindered that rigid conformers are detected. Compounds 5 - 8 react with trifluoroacetic acid with elimination of the phosphonio group to yield the PF6 salts of the half-sandwich type complexes [C6H6Ru(PR3)(PR3′)PR3″]2+ (14 - 17).
    Notes: Die Komplexe [C6H6RuCl(PR3)PR3)]PF6 (1 - 4) und [C6H6RuCl2(PR3)] (9, 10) reagieren mit Phosphanen PR3″ in Gegenwart von NH4PF4 zu den (6-Phosphonio-η5-cyclohexadienyl)-ruthenium(II)-Verbindungen [(6-R3″P-η5-C6H6)Ru(PR3)(PR3″](PF6)2 (5 - 8, 11). Aus [C6H6Ru(CH3CN)3](PF6)2 (12) und PMe3 erhält man analog den Komplex (6-Me3P-η5-C6H6)Ru(PMe3)2CH3CN](PF6)2 (13). Die IR- und NMR-Spektren von 5 - 8, 11 und 13 weisen darauf hin, daß sich die Phosphoniogruppierung in der exo-Position am sp3-C-Atom des Cyclohexadienylliganden befindet. Unterhalb - 30°C ist die Rotation um die Metall-Ring-Bindung so stark behindert, daß starre Konformere nachweisbar sind. Die Verbindungen 5 - 8 reagieren mit Trifluoressigsäure unter Abspaltung der Phosphoniogruppe zu den PF6-Salzen der Halbsandwich-Komplexe [C6H6Ru(PR3)(PR3′)PR3″]2+ (14 - 17).
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170111
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    Aromaten(phosphan)metall-Komplexe, VI. Synthese von [(RC6H5)OsI(PMe3)2PF6 aus (exo-6-RC6H6)OsI(PMe3)2: Ein Beitrag zum Mechanismus der Aromatisierung substituierter Cyclohexadienylliganden durch „endo-H-Abstraktion“ (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 161-171 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, VI1). Synthesis of [(RC6H5)OsI(PMe3)2]PF6 from (exo-6-RC6H6)OsI(PMe3)2: A contribution to the Mechanism of Aromatization of Substituted Cyclohexadienyl Ligands by „endo-H Abstraction“The compounds (exo-6-RC6H6)OsI(PMe3)2 (2 - 5, 7) react smoothly with [CPh3]PF6 in acetone to give the (arene)osmium(II) complexes [(RC6H5)OsI(PMe3)2]PF6 (8 - 12) in quantitative yield. The hydride elimination proceeds via two (cyclohexadienyl)hydridoosmium(IV) intermediates (13 and 14, 15, respectively) which can be prepared from 2, 5, 6 (R = CH3, n-C4H9, t-C4H9) and CF3CO2H/NH4PF6. The (cyclohexadienyl)hydrido complexes [(RC6H6)Os(H)I(PMe3)2]+ undergo an intramolecular isomerization which leads to a cation possessing a CH2 group in the six-membered ring. This cationic complex or (more probably) the neutral compound (2- or 3-RC6H6)OsI(PMe3)2 formed on deprotonation reacts with [CPh3]+ by abstraction of an exo-hydrogen atom.
    Notes: Die Verbindungen (exo-6-RC6H6)OsI(PMe3)2 (2 - 5, 7) reagieren mit [CPh3]PF6 in Aceton rasch und quantitativ zu den (Aromaten)osmium(II)-Komplexen [(RC6H5)OsI(PMe3)2]PF6 (8 - 12). Die Hydrid-Eliminierung verläuft über zwei (Cyclohexadienyl)hydridoosmium(IV)-Zwischenstufen (13 bzw. 14, 15), die aus 2, 5, 6 (R = CH3, n-C4H9, t-C4H9) und CF3CO2H/NH4PF6 synthetisiert werden können. Die (Cyclohexadienyl)hydrido-Komplexe [(RC6H6)Os(H)I(PMe3)2]+ gehen eine intramolekulare Isomerisierung ein, wobei ein Kation mit einer CH2-Gruppe im Sechsring entsteht. Dieses Komplexkation oder (wahrscheinlicher) die nach Deprotonierung erhaltene Neutralverbindung (2- bzw. 3-RC6H6)OsI(PMe3)2 reagiert mit [CPh3]+ unter Abstraktion eines exo-H-Atoms.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170113
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    Aromaten(phosphan)metall-Komplexe, V. Zur Addition von Carbanionen an (Benzol)ruthenium(II)- und -osmium(II)-Komplexe. Kristall- und Molekülstruktur von (exo-6-n-C4H9-η5-C6H6)OsI(PMe3)2 (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 152-160 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, V1). On the Addition of Carbanions to (Benzene)ruthenium(II) and -osmium(II) Complexes. The Crystal and Molecular Structure of (exo-6-n-C4H9-η5-C6H6)OsI(PMe3)2The complex [C6H6RuCl(PMe3)2]PF6 (1) reacts with methyllithium to give a mixture of products that contains (η5-C6H6CH3)RuCH3(PMe3)2 (2) as the main component. From 1 and LiC6H5/LiBr the bromide 3 is primarily formed but the final product is (η5-C6H6C6)H5RuC6H5(PMe3)2 (4). Reaction of [C6H6OsI(PMe3)2]PF6 (5) with organyllithium compounds LiR (R = CH3, C2H5, n-C3H7, n-C4H9, t-C4H9, C6H5) yields the complexes (η5-C6H6R)OsI(PMe3)2 (6 - 11). 31P NMR spectra of 6 - 11 indicate restricted rotation at low temperatures around the metal-ring axis. According to X-ray structure analysis of 9 (R = n-C4H9) the cyclohexadienyl ring possesses an envelope conformation. The n-butyl group occupies the exo-position at the sp3-C atom.
    Notes: Der Komplex [C6H6RuCl(PMe3)2]PF6 (1) reagiert mit Methyllithium zu einem Produktgemisch, welches (η5-C6H6CH3)RuCH3(PMe3)2 (2) als Hauptkomponente enthält. Aus 1 und LiC6H5/LiBr entsteht über 3 bei längeren Reaktionszeiten (η5-C6H6C6H5)RuC6H5(PMe3)2 (4). Die Umsetzung von [C6H6OsI(PMe3)2]PF6 (5) mit Organyllithium-Verbindungen LiR (R = CH3, C2H5, n-C3H7, n-C4H9, t-C4H9, C6H5 ergibt die Komplexe (η5-C6H6R)OsI(PMe3)2 (6 - 11), in denen nach den 31P-NMR-Spektren die Rotation um die Metall-Ring-Bindung bei tiefen Temperaturen stark eingeschränkt ist. Die Röntgenstrukturanalyse von 9 (R = n-C4H9) beweist die „Envelope“-Konformation des Cyclohexadienylrings. Die n-Butylgruppe befindet sich in der exo-Position am sp3-C-Atom.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19841170112
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    Radikalionen, 55. Die Einelektronen-Oxidation von Tetrahedran zum Cyclobutadien-Radikalkation (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 172-186 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radical Ions, 55. The One-Electron Oxidation of Tetrahedrane to Cyclobutadiene Radical CationTetra-tert-butyltetrahedrane, on one-electron oxidation using AlCl3 in CH2Cl2, opens to form tetra-tert-butylcyclobutadiene radical cation, which can also be generated under identical reaction conditions from tetra-tert-butylcyclobutadiene itself. The assignments of the ESR and ENDOR spectra are supported by deutero substitution of one tert-butyl group and by MNDO hypersurfaces for the thermal and for the oxidative structural changes of both C4 skeletons. The feasible formation of a valence isomeric tert-butyl(tri-tert-butylcyclopropenyl)carbene radical cation is discussed.
    Notes: Tetra-tert-butyltetrahedran öffnet sich bei Einelektronen-Oxidation mit AlCl3 in CH2Cl2 zum Tetra-tert-butylcyclobutadien-Radikalkation, das unter gleichen Reaktionsbedingungen auch aus Tetra-tert-butylcyclobutadien erzeugt werden kann. Die Zuordnungen der ESR- und ENDOR-Spektren werden durch Deutero-Substitution einer tert-Butyl-Gruppe sowie durch MNDO-Hyperflächen für die thermischen und oxidativen Strukturänderungen der beiden C4-Gerüste gestützt. Die mögliche Bildung eines valenzisomeren tert-Butyl(tri-tert-butylcyclopropenyl)carben-Radikalkations wird diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170114
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    Saure Komplexone mit Donor-verstärkter Pyridin-Ankergruppe (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 948-954 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acidic Complexones Bearing Donor-enhancing Pyridine Anchour GroupsThe synthesis, complex stability and -selectivity for alkaline earth metal ions of 2,6-pyridinebis-(methylamine)-N, N, N′, N′-tetraacetic acid (3a) and of their donor-enforced analogues 3b, c are described. The acid dissociation constants and the stability constants of the metal complexes have been measured potentiometrically at 25°C in water of constants ionic strength (μ = 0.1). The stability order is Ca 〉 Mg 〉 Sr 〉 Ba which is analogues to the selectivity of EDTA and comparable aliphatic complexones. The magnitudes of the stability constants of 3a are comparable to those of EDTA, while the donor-enforced analogues 3b, c form less stable complexes with alkaline earth metal ions.
    Notes: Synthese, Komplexstabilität und -selektivität gegenüber Erdalkalimetall-Ionen von 2,6-Pyridinbis(methylamin)-N, N, N′, N′-tetraessigsäure (3a) und ihren Donor-verstäkten Analoga 3b, c werden beschrieben. Die Bestimmung der Dissoziations- und Komplexbildungskonstanten erfolgt potentionmetrisch bei 25°C in Wasser konstanter ionaler Stärke (μ = 0.1). Die Bildungskonstanten der Metallkomplexe nehmen in der Reihenfolge Ca 〉 Mg 〉 Sr 〉 Ba ab und folgen damit der bei EDTA und vergleichbaren aliphatischen Komplexonen vorgefundenen Selektivität. 3a weist mit EDTA vergleichbare hohe Komplexbildungskonstanten auf, während die Donor-verstärkten Analoga 3b, c schwächere Erdalkalimetallkomplexe bilden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170308
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    Darstellung und Röntgenstrukturanalyse des Diels-Alder-Addukts von 4-Phenyl-4H-1,2,4-triazol-3,5-dion an Octavalen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 959-965 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and X-Ray Structure Analysis of the Diels-Alder Adduct of 4-Phenyl-4H-1,2,4-triazole-3,5-dione with OctavaleneIn the reaction of 4-phenyl-4H-1,2,4-triazole-3,5-dione with octavalene (1) the Diels-Alder adduct 2 is formed. From its X-ray structure analysis the dihedral angle for the bicyclo[1.1.0]butane group, the 2- and 4-positions of which are spanned by four atoms, has been determined to be 122.7°. The bridging bond C1 - C3 has a length of 1.487 Å.
    Notes: Aus Octavalen (1) und 4-Phenyl-4H-1,2,4-triazol-3,5-dion bildet sich das Diels-Alder-Addukt 2. Seine Röntgenstrukturanalyse ergab für das Bicyclo[1.1.0]butan-Gerüst, dessen 2- und 4-Stellung durch vier Atome überbrückt sind, einen Interplanarwinkel von 122.7°. Die Brückenbindung C1 - C3 hat eine Länge von 1.487 Å.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19841170310
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    Kondensierte Ringsysteme, XV. Über die Reaktion von α-Chlorsulfoxiden mit Kalium-tert-butylat am Beispiel der Synthese von Oxapropellenen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 966-981 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Condensed Ring Systems, XV. About the Reaction of α-Chloro Sulfoxides with Potassium tert-Butoxide by the Example of the Synthesis of OxapropellenesThe synthesis of dithia- 1a - 3a and oxathiapropellenes 1b - 3b is described. From 1b - 3b the α-chloro sulfoxides 4 - 6 and α-chloro sulfones 4a - 6a are prepared, or which in most cases several stereoisomeric racemates are obtained. The constitution, configuration, and conformation of the α-chloro sulfoxide 4, the main product obtained from 1b, was elucidated by X-ray structure analysis. Only in that way it was possible to deduce the constitutions and configurations of the other stereoisomeric α-chloro sulfoxides 4 - 6 and α-chloro sulfones 4a - 6a, respectively, using 13C NMR spectroscopy. By the reaction of the α-chloro sulfones 4a - 6a with potassium tert-butoxide (Ramberg-Bäcklund reaction) the corresponding oxapropellenes 7 - 9 are obtained only in low yields (〈 10%). Contrary, the α-chloro sulfoxides 4 - 6, und analogous conditions give yields of 80 - 90% (from 4, 6) and 25% (from 5).
    Notes: Es wird die Synthese der Dithia- 1a - 3a und Oxathiapropellene 1b - 3b beschrieben. Aus 1b - 3b werden die α-Chlorsulfoxide 4 - 6 und α-Chlorsulfone 4a - 6a hergestellt, von denen meist mehrere stereoisomere Racemate erhalten werden. Konstitution, Konfiguration und Konformation des Hauptprodukts der aus 1b erhaltenen α-Chlorsulfoxide 4 wurden durch Röntgenstrukturanalyse ermittelt. Erst dadurch wurde es möglich, mit Hilfe der 13C-NMR-Spektroskopie die Konstitutionen und Konfigurationen der anderen stereoisomeren α-Chlorsulfoxide 4 - 6 und α-Chlorsulfone 4a - 6a aufzuklären. Bei der Reaktion der α-Chlorsulfone 4a - 6a mit Kalium-tert-butylat (Ramberg-Bäcklund-Reaktion) erhält man die entsprechenden Oxapropellene 7 - 9 nur in geringer Ausbeute (〈 10%), während die α-Chlorsulfoxide 4 - 6 unter analogen Bedingungen Ausbeuten von 80 - 90% (aus 4, 6) und 25% (aus 5) ergeben.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19841170311
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    Über die Selektivität bei der Umsetzung von Carbokationen mit Nucleophilen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 982-989 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Selectivity of the Reaction of Carbocations with NucleophilesThe problem of the selectivity of the nucleophilic attack on carbocations according to the HSAB-principle is discussed in relation to the solvolysis in ether of 7,7-bis(trifluoromethylsulfonyloxy)-norbornane (2) and 7,7-bis(trifluoromethylsulfonyloxy)-2-norbornene (4) in presence of dimethyl-magnesium, magnesium iodide and methylmagnesium iodide. The nucleophiles and carbocations are arranged according to the hard-soft-scale, so our results can be explained.
    Notes: Das Problem der Selektivität beim nucleophilen Angriff an Carbokationen wird im Rahmen des HSAB-Prinzips am Beispiel der Solvolysen in Ether von 7,7-Bis(trifluormethylsulfonyloxy)norbornan (2) und 7,7-Bis(trifluormethylsulfonyloxy)-2-norbornen (4) in Anwesenheit von Dimethylmagnesium, Magnesiumiodid und Methylmagnesiumiodid erörtert. Die Nucleophile und die als Zwischenstufen auftretenden Carbokationen werden auf der Hart-weich-Skala eingeordnet, wobei die Ergebnisse erklärt werden können.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170312
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    Dichloropalladium(II)-Komplexe mit α-Aminosäuren, α-Aminosäureestern, Dipeptiden und Dipeptidestern (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1003-1012 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dichloropalladium(II) Complexes with α-Amino Acids, α-Amino Acid Esters, Dipeptides, and Dipeptide EstersA series of trans-dichloropalladium(II) complexes Cl2PdL2 (L = α-amino acid, α-amino acid ester, dipeptide, dipeptide esters) and cis-Cl2Pd(histidine) has been prepared and spectroscopically characterized. The X-ray structure of trans-Cl2Pd(GlyOEt)2 (3b) has been determined.
    Notes: Eine Reihe von trans-Dichloropalladium(II)-Komplexen Cl2PdL2 mit (L = α-Aminosäure, α-Aminosäureester, Dipeptid, Dipeptidester) sowie cis-Cl2Pd(Histidin) wurde dargestellt und spektroskopisch charakterisiert. Die Röntgenstruktur von trans-Cl2Pd(GlyOEt)2 (3b) wurde bestimmt.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19841170314
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    Der Nachweis eines Radikalketten-Mechanismus für die Knabe-Reaktion von 1,2-Dihydro-2-methylpapaverin (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1436-1454 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Evidence for a Radical Chain Mechanism for the Knabe Reaction of 1,2-Dihydro-2-methylpapaverineA free radical chain mechanism is proposed for the Knabe reaction and the accompanying elimination reaction on account of their nonintegral reaction order and of successful inhibition experiments. 3,4-Dimethoxybenzyl radicals are the chain carrying species. Battersby's synthesis of N-methylpavine (19) from 1,2-dihydro-2-methylpapaverine (9) is dependent on the presence of formic acid as radical chain inhibitor. In the presence of inhibitors 1-benzyl-1,4-dihydro-2-methyl-isoquinolinium ions like 10 are persistent species whose chemistry can now be investigated.
    Notes: Die Knabe-Reaktion von 1,2-Dihydro-2-methylpapaverin (9) und die begleitende Eliminierungsreaktion wurden durch ihre gebrochene Reaktionsordnung und durch die Möglichkeit der Inhibition als Radikalkettenreaktionen erkannt, deren kettentragendes Radikal das 3,4-Dimethoxybenzylradikal ist. Die Synthese von N-Methylpavin (19) aus 1,2-Dihydro-2-methylpapaverin (9) ist an die Anwesenheit von Ameisensäure als Inhibitor der Radikalketten gebunden. Durch Zusatz von Inhibitoren können nun Immoniumionen 10 und analoge Verbindungen stabilisiert und ihre Chemie untersucht werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170414
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    Azobrücken aus Azinen, III. Unerwartete Bildung einer Verbindung mit parallelen C=C- und N=N-Bindungen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1455-1464 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azo Bridges from Azines, III. Unexpected Formation of a Compounds with Parallel C=C and N=N Bonds2)Dialdehyde 5 reacts with hydrazine at pH 〉 7 to form the trimeric azine 6Tr, at pH 〈 4, however, to yield unexpectedly 8, which contains parallel C=C and N=N bonds in close proximity. The complex reaction is clarified. 8 is characterized by structure proving reactions and its spectroscopic data.
    Notes: Der Dialdehyd 5 reagiert mit Hydrazin bei pH 〉 7 zu dem trimeren Azin 6Tr, bei pH 〈 4 unerwartet zu 8, das parallel benachbarte C=C- und N=N-Bindungen besitzt. Der komplexe Reaktionsverlauf wird aufgeklärt. 8 wird durch struktursichernde Reaktionen und spektroskopische Daten charakterisiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170415
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    Azobrücken aus Azinen, IV. Intramolekulare [2 + 2]-Photocycloaddition zwischen parallelen C=C- und N=N-Bindungen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1465-1475 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azo Bridges from Azines, IV1). Intramolecular [2 + 2] Photocycloaddition of Parallel C=C and N=N BondsThe parallel C=C and N=N bonds in the rigid molecules 1 - 10 photocyclize nearly quantitatively, forming 1,2-diazetidines 11 - 20. Their structure is confirmed by spectroscopic methods and for 13 by X-ray analysis. Radiation induced denitrogenation, the normal reaction for similar compounds without neighbouring C=C bonds, is suppressed even with the sensitive derivatives of 2,3-diazabicyclo[2.2.1]heptene. Photocyclization of 6, carrying two neighbouring C=C bonds, includes only the norbornene bond.
    Notes: In den starren Molekülen 1 - 10 reagieren die benachbarten parallelen C=C- und N=N-Bindungen nahezu quantitativ unter Photocyclisierung zu den 1,2-Diazetidinen 11 - 20, deren Struktur spektroskopisch und für 13 durch Kristallstrukturanalyse bewiesen wird. Die in Abwesenheit der C=C-Bindung beobachtete Photo-Denitrogenierung unterbleibt selbst bei den empfindlichen Derivaten des 2,3-Diazabicyclo[2.2.1]heptens. Photocyclisierung von 6 mit zwei zur N=N-Bindung benachbarten C=C-Bindungen tritt nur mit der Norbornendoppelbindung ein.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170416
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    Aminosäuren, 2. N-Acetyl-α,β-didehydro-α-aminosäureester durch Stickstoffabspaltung aus α-Azidocarbonsäureestern mit Rhenium-Katalysatoren (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1497-1512 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids, 21,2). N-Acetyl α,β-Didehydro α-Amino Acid Esters from α-Azidocarboxylic Acid Esters and Acetic Anhydride by Nitrogen Elimination with Rhenium Catalystsα-Azidocarboxylic acid esters 2 react with acetic anhydride in presence of catalytic amounts of rhenium heptasulfide and - if necessary - by addition of hydrochloric acid to give N-acetyl 3 or/and N,N-diacetyl-α,β-didehydro-α-amino acids esters 4 in very good yields. Exclusively monoacetylated products 3 are formed if water ist added before work up.
    Notes: Beim Erwärmen von α-Azidocarbonsäureestern 2 in Acetanhydrid/Essigsäure in Gegenwart katalytischer Mengen Rheniumheptasulfid und gegebenenfalls unter Zugabe von Chlorwasserstoff entstehen in sehr guten Ausbeuten N-Acetyl- 3 und/oder N,N-Diacetyl-α-β-didehydro-α-amino-säureester 4. Durch Zugabe von Wasser vor der Aufarbeitung erfolgt partielle Deacetylierung unter ausschließlicher Bildung der N-Monoacetylverbindungen 3.
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170419
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    Aminosäuren, 3. N-Acetylierte α-β-Didehydro-α-aminosäure-Derivate durch Stickstoffabspaltung aus α-Azidocarbonsäureamiden und α-Azido-ω-aminocarbonsäurelactamen mit Rhenium-Katalysatoren (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1513-1522 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids, 31). N-Acetylated α-β-Didehydro α-Amino Acid Derivatives by Nitrogen Elimination from α-Azido-carboxylic Acid Amides and α-Azido-ω-aminocarboxylic Acid Lactams with Rhenium Catalystsα-Azidocarboxylic acid amides 2 and α-azido-ω-aminocarboxylic acid lactams 6, respectively, react with acetic anhydride in the presence of rhenium catalysts by nitrogen eliminations to give N-acetyl- 7 and N,N-diacetyl-α,β-didehydro-α-amino acid amides 8, α-acetylamino- 11 and α-diacetylamino-α,β-didehydro-ω-aminocarboxylic acid lactams 12, respectively. Reactions of the educts 6c, d - with a ring size 7 or 8 - additionally lead to the oxazoloazepine 14c and the oxazoloazocine 14d, respectively.
    Notes: Bei der Umsetzung von α-Azidocarbonsäureamiden 2 mit Acetanhydrid in Gegenwart von Rheniumkatalysatoren entstehen unter Stickstoffabspaltung N-Acetyl- 7 und N,N-Diacetyl-α,β-didehydro-α-aminosäureamide 8, bei der von α-Azido-ω-aminocarbonsäurelactamen 6 α-Acetyl-amino- 11 und α-Diacetylamino-α,β-didehydro-ω-aminocarbonsäurelactamen 12, wobei sich aus den Verbindungen 6c, d, mit der Ringgliederzahl 7 bzw. 8 außerdem noch das Oxazoloazepin 14c bzw. das Oxazoloazocin 14d bilden.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170420
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    Beiträge zur Chemie des Phosphors, 1311,2). Synthese und Eigenschaften der Methylendiphosphirane (t-BuP)2C = CR2 (R = H, Me, 4-ClC6H4) (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1542-1550 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus, 131. Synthesis and Properties of the Methylenediphosphiranes (t-BuP)2)C = CR2 (R = H, Me, 4-ClC6H4)The first methylenediphosphiranes (diphosphamethylenecyclopropanes) (t-BuP)2C = CH2 (1), (t-BuP)2C = CMe2 (2), and (t-BuP)2C = C(4-ClC6H4)2 (3) were synthesized by [2 + 1] cyclocondensation of K(t-Bu)P - P(t-Bu)K with the corresponding 1,1-dichloroolefins. The homocyclophosphanes (t-BuP)n (n = 4,3) and in the case of 1 mainly H(t-Bu)P - P(t-Bu)H are formed as by-products. The three-membered heterocycles 2 and 3 could be purely isolated as surprisingly stable compounds. According to an X-ray single-crystal analysis 3 possesses approximately C2 symmetry and exhibits one of the smallest bonding angles ψ (P - P - C) = 52.4° on a phosphorus atom experimentally proved so far. Along [100] there are canals filled with disordered n-pentane molecules.
    Notes: Die ersten Methylendiphosphirane (Diphosphamethylencyclopropane) (t-BuP)2C = CH2 (1), (t-BuP)2C = CMe2 (2) und (t-BuP)2C = C(4-ClC6H4)2 (3) wurden durch [2 + 1]-Cyclokondensation von K(t-Bu)P - P(t-Bu)K mit den entsprechenden 1,1-Dichlorolefinen synthetisiert. Als Nebenprodukte entstehen die Homocyclophosphane (t-BuP)n (n = 4,3) und im Fall von 1 vor allem H(t-Bu)P - P(t-Bu)H. Die Dreiringheterocyclen 2 und 3 konnten als thermisch überraschend beständige Verbindungen in reiner Form isoliert werden. 3 besitzt nach der Röntgenstrukturanalyse annähernd die Symmetrie C2 und enthält mit ψ (P - P - C) = 52.4° einen der kleinsten experimentell gesicherten Bindungswinkel am Phosphor. Längs [100] liegen fehlgeordnet mit n-Pentan gefüllte Kanäle vor.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19841170422
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    Amination, III. Trimethylsilanol as Leaving Group, V. Silylation - Amination of Hydroxy N-Heterocycles (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1523-1541 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminierung, III. Trimethylsilanol als austretende Gruppe, V. Silylierung-Aminierung von Hydroxy-N-heterocyclenDurch Silylierung-Aminierung lassen sich Hydroxy-N-heterocyclen (z. B. 18, 21, 26 u. a.) bequem in einer Einstufen-Eintopfreaktion aminieren (→ 20, 23 - 25 etc.). Aromatische Hydroxy-N-heterocyclen werden durch Silylierung in aktivierte und lipophile Zwischenprodukte vom Typ 3, 8 umgewandelt, die sich in situ mit Ammoniak, primären oder sekundären Aminen zu den entsprechenden mono-, bis- und tris-aminierten Produkten (5, 10) umsetzen. Die Additions-Eliminierungsreaktion von Aminen an O-silylierte Heterocyclen ist Lewissäure-katalysiert und verläuft gewöhnlich in hohen Ausbeuten, falls die austretende Gruppe Trimethylsilanol in situ durch überschüssiges Silylierungsmittel in Hexamethyldisiloxan umgewandelt wird. Anwendungsbreite und Grenzen dieser einfachen Methode werden diskutiert.
    Notes: Hydroxy N-heterocycles such as 18, 21, 26, and others are efficiently aminated in a one-step/one-pot procedure by silylation-amination to give 20, 23 - 25 etc. Silylation converts aromatic hydroxy N-heterocycles into activated and lipophilic intermediates of type 3, 8 which react in situ with ammonia, primary or secondary amines to form the corresponding mono-, bis- or tris-aminated products (5, 10). This addition-elimination of amines to O-silylated heterocycles in Lewis acid-catalyzed and proceeds usually in high yields if the leaving group trimethylsilanol is converted in situ by excess silylated agent into hexamethyldisiloxane. Scope and limitations of this simple procedure are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170421
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    Benzonitril als 6-Elektronen-Donor-Ligand: Die Cluster Fe3(CO)9(μ3(η2)-NCC6H5) und Fe4(CO)12(μ4(η2)-NCC6H5) (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1572-1582 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Benzonitrile as a 6-Electron Donor Ligand: The Clusters Fe3(CO)9(μ3(η2)-NCC6H5) and Fe4(CO)12(μ4(η2)-NCC6H5)The reaction of Fe3(CO)12 with benzonitrile in the presence of hydrogen leads to the benzonitrile complexes Fe3(CO)9(μ3(η2)-NCC6H5) (1a) and Fe4(CO)12(μ4(η2)-NCC6H5) (2). Their structures were determined crystallographically. The benzonitrile ligand is coordinated to the iron atoms formally via on „s̰-bond“ and two „π-bonds“ in 1a, and via three s̰-bonds and one π-bond in 2.
    Notes: Die Reaktion von Fe3(CO)12 mit Benzonitril in Anwesenheit von Wasserstoff führt zu den beiden Benzonitril-Komplexen Fe3(CO)9(μ3(μ2)-NCC6H5) (1a) und Fe4(CO)12(μ4(η2)-NCC6H5) (2). Ihre Strukturen wurden kristallographisch aufgeklärt. Der Benzonitril-Ligand ist in 1a formal über eine „s̰-Bindung“ und zwei „π-Bindungen“, in 2 über drei s̰-Bindungen und eine π-Bindung an die Eisenatome koordiniert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170425
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    Kernspin-Kopplungskonstanten mit Platin-195 als Kriterien für die Konfigurations-Bestimmung platin-organischer Verbindungen des zweiwertigen Platins (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1606-1619 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Spin-Spin Coupling Constants by Platinium-195 as Criteria for a Configuration Determination in Platinum Organic CompoundsThe platinum organic compounds [Pt(η4-1,5-cyclooctadiene)(XC6H4)2] and cis-[Pt(P(n-Bu)3)2-(XC6H4)2] (X = H, 4-CH3, 4-(CH3)3C, 4-(CH3)2N, 3-F, 4-F, 4-CH3O, 4-CF3; 3a - 4, cis-4a - h) as well as trans-[Pt(P(n-Bu)3)2(4-CH3OC6H4)2] (trans-4g) and trans-[Pt(P(n-Bu)3)2(4-CF3C6H4)2] (trans-4h) have been studied by 31P-, 13C-, and 1H NMR spectroscopy. The coupling constants 1J[195Pt, 31P], nJ[195Pt, 13C], nJ[195Pt, H], and 2J[31P, 13C] show a clear correlation to the ligand configuration at the dsp2-hybridized platinum and can therefore be used as basis for configuration determination.
    Notes: Die platin-organischen Verbindungen [Pt(η4-1,5-cyclooctadien)(XC6H4)2] und cis-[Pt(P(n-Bu)3)2-(XC6H4)] (X = H, 4-CH3, 4-(CH3)3C, 4-(CH3)2N, 3-F, 4-F, 4-CH3O, 4-CF3; 3a - h, cis-4a - h) sowie trans-[Pt(P(n-Bu)3)2(4-CH3OC6H4)2] (trans-4g) und trans-[Pt(P(n-Bu)3)2(4-CF3C6H4)2] (trans-4h) wurden 31P-, 13C- und 1-NMR-spektroskopisch untersucht. Die Kopplungskonstanten 1J[195Pt, 31P], nJ[195Pt, 13C], nJ[195Pt, H] und 2J[31P, 13C] zeigen eine eindeutige Abhängigkeit von der Konfiguration der Liganden am dsp2-hybridisierten Platin; sie können daher zur sicheren Konfigurations-Bestimmung verwendet werden.
    Additional Material: 8 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170429
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    Zur Struktur von N-Methylencarbonsäureamiden: Röntgenstrukturergebnisse, spektroskopische Untersuchung und quantenmechanische Berechnungen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1597-1605 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of N-Methylenecarboxamides: X-Ray Data, Spectroscopy, and Quantum Mechanical CalculationsN-(Diphenylmethylene)acetamide (1) has been studied by X-ray crystallography as an example for the polyfunctional, highly reactive N-methyleneamides. The dihedral angle (C = N - C = O = 73°) and the bond lengths indicate that there is only little interaction between the C = O and the C = N groups. Extensive ab initio 3-21G calculations for the parent molecule H2C = N - CH = O (2) predict a C - N rotational barrier of ca. 4 kcal/mol with a cisoid form (C = N - C = O = 23°) as the most stable structure. MNDO data as well as spectroscopic properties (IR, 13C NMR) suggest high molecular flexibility due to the many electronic interactions possible for the nitrogen atom.
    Notes: Als Beispiel für die polyfunktionellen N-Methylencarbonsäureamide wurde N-(Diphenylmethylen)acetamid (1) röntgenographisch untersucht. C = N - C = O-Torsionswinkel (73°) und Bindungslängen deuten auf nur geringe Wechselwirkungen zwischen C = O- und C = N-Molekülteil. Ausführliche ab initio-3-21G-Berechnungen am Grundsystem H2C = N - CH = O (2) sagen eine C - N-Rotationsbarriere von ca. 4 kcal/mol voraus, wobei als stabilste Struktur eine cisoide Form (C = N - C = O-Winkel = 23°) gefunden wurde. MNDO-Daten und spektroskopische Untersuchungen (IR, 13C-NMR) deuten ebenfalls auf hohe molekulare Beweglichkeit, die vor allem durch die vielfältigen elektronischen Wechselwirkungsmöglichkeiten des Stickstoffatoms verursacht wird.
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    URL: http://dx.doi.org/10.1002/cber.19841170428
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    Reduktion von β-Lactamen, I. Reduktion von 3,3,3′,3′-Tetramethyl[1,1′-biazetidin]-2,2′-dion mit komplexen Hydriden (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1659-1670 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reduction of β-Lactams, I. Reduction of 3,3,3′,3′-Tetramethyl[1,1′-biazetidine]-2,2′-dione with Complex HydridesReduction of the title compound 7 with lithium aluminium hydride leads to four products 8 to 11 in yields depending on the reaction conditions. Compounds 8 to 10 are also obtained from the bicyclic hydrazide 12, isomeric with 7. Therefore, the reduction of 7 and 12 is likely to proceed in part via common intermediates. A reaction scheme is proposed to account for the generation of the products. With other hydride reagents complex reaction mixtures are obtained from 7. The reduction of 7 to 3,3,3′,3′-tetramethyl-1,1′-biazetidine (13) failed.
    Notes: Die Reduktion der Titelverbindung 7 mit Lithiumaluminiumhydrid liefert die vier Produkte 8 - 11 in von den Reaktionsbedingungen abhängigen Mengenverhältnissen. Da die Verbindungen 8 - 10 auch aus dem mit 7 isomeren bicyclischen Hydrazid 12 erhalten werden, muß die Reduktion von 7 und 12 z. T. einheitlich ablaufen. Hierfür wird ein Reaktionsschema vorgeschlagen. Mit anderen Hydridübertragungsreagenizen entstehen aus 7 komplexe Produktgemische. Die Reduktion von 7 zu 3,3,3′,3′-Tetramethyl-1,1′-biazetidin (13) gelang nicht.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170503
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    Synthese von (Trimethylstannyl)adamantan-Derivaten (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 565-574 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (Trimethylstannyl)adamantane DerivativesReaction of brominated adamantane compounds with (trimethylstannyl)lithium afforded a series of (trimethylstannyl)adamantane derivatives. Additionally, we found products from fragmentation and reduction reactions which allowed conclusions concerning the mechanisms. Surprisingly high stereoselectivities were observed in most instances. By Wurtz synthesis we obtained 2-adamantyltriphenylstannane.
    Notes: Die Umsetzung bromierter Adamantanverbindungen mit (Trimethylstannyl)lithium lieferte eine Reihe von (Trimethylstannyl)adamantan-Derivaten. Wir fanden zusätzlich Fragmentierungs- und Reduktionsprodukte, die Rückschlüsse auf den Mechanismus zuließen. Überraschend ist die hohe Stereoselektivität der meisten Reaktionen. Durch Wurtz-Synthese wurde auch 2-Adamantyltriphenylstannan erhalten.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19841170212
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    Substituenteneinflüsse auf das Valenzgleichgewicht 4,8-substituierter Homotropilidene (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 575-584 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Influence of Substituents on the Valence-tautomeric Equilibrium of 4,8-Substituted HomotropilidenesThe valence-tautomeric equilibrium of 4,8-substituted homotropilidenes 2 - 4 is governed by electronic (preference of a substituent for attachment to a cyclopropyl or an aliphatic carbon atom) and steric factors. The conformational change chair → boat, which precedes the Cope rearrangement of a homotropilidene, cannot take place when both endo-8- and cis-4-substituents are present.
    Notes: Das Valenzgleichgewicht 4,8-substituierter Homotropilidene 2 - 4 wird durch elektronische (Präferenz eines Substituenten für Cyclopropyl- oder aliphatische Verknüpfung) und sterische Faktoren bestimmt. Die der Cope-Umlagerung vorgeschaltete Konformationsänderung Sessel → Boot wird verhindert, wenn das Homotropiliden sowohl in endo-8- wie in cis-4-Stellung substituiert ist.
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    URL: http://dx.doi.org/10.1002/cber.19841170213
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    Heterocyclische β-Enaminoester, 311). Neue 6:7-, 6:8- und 5:6:7-Kombinationen heterokondensierter Pyrimidine aus den Iminophosphoranen heterocyclischer β-Enaminoester. - Stabile heterocyclische Ylide (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 585-621 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic β-Enamino Esters, 311). Novel 6:7-, 6:8, and 5:6:7-Combinations of Heterocondensed Pyrimidines from Iminophosphoranes of Heterocyclic β-Enamino Esters. - Stable Heterocyclic YlidesWith acetylenic esters the (5-azolylimino)triphenylphosphoranes 10a - d do not show any cyclo-addition tendency, while the (2-thienylimino)triphenylphosphoranes 8a, b yield the stable ylids 13a, b. By treatment with phenyl isocyanate the iminophosphoranes 16a - m, 17, and 18a, b afford the carbodiimides 19a - m, 20, and 21a, b; however, 10b - d give the O-ethylisoureas 24b - d. 19a, b, e, f, h are transformed in aqueous ethanol into 6:7-bicycles, namely into oxepino[2,3-d]pyrimidines 25a, b, e, f, h. With isopropylamine the 2-isopropylamino-6:7-bicycles 31a - c, e - h are formed analogously, while in the case of thiocin 21a the 6:8-bicycle 34 is obtained. The salts 33f, g are formed by treating 19f, g or 25f with aqueous diethylamine. Accordingly, 2-aminoethanol, 3-aminopropanol, and ethylenediamine react with 19a, b, f, l to afford the 2-hydroxy- and 2-aminoalkyl-6:7-bicycles 36a - f; by treatment with hydrazine the 2-hydrazinooxepino- and -thiepino[2,3-d]pyrimidines 38a - h and 39 are obtained, which are converted with functional C1-units into 5:6:7-tricycles 43a - d, 45'a, b.
    Notes: Die (5-Azolylimino)triphenylphosphorane 10a - d zeigen mit Acetylendicarbonsäureestern keine Tendenz zur Cycloaddition, während die (2-Thienylimino)triphenylphosphorane 8a, b, zu den stabilen Yliden 13a, b reagieren. Mit Phenylisocyanat ergeben die Iminophosphorane 16a - m, 17 und 18a, b die Carbodiimide 19a - m, 20 und 21a, b; 10b - d liefern statt dessen die O-Ethylisoharnstoffe 24b - d. In wäßrigem Ethanol werden 19a, b, e, f, h in 6:7-Bicyclen, nämlich in die Oxepino[2,3-d]pyrimidine 25a, b, e, f, h umgewandelt. Mit Isopropylamin bilden sich die 2-Isopropylamino-6:7-Bicyclen 31a - c, e - h und im Fall des Thiocins 21a der 6:8-Bicyclus 34. Die Salze 33f, g entstehen durch Einwirkung von wäßrigem Diethylamin auf 19f, g bzw. auf 25f. 2-Aminoethanol, 3-Aminopropanol und Ethylendiamin ergeben mit 19a, b, f. l analog die 2-Hydroxy- und 2-Aminoalkyl-6:7-Bicyclen 36a - f; mit Hydrazin werden die 2-Hydrazinooxepino- und -thiepino[2,3-d]pyrimidine 38a - h und 39 erhalten, die mit funktionellen C1-Bausteinen zu den 5:6:7-Tricyclen 43a - d, 45'a, b führen.
    Additional Material: 24 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170214
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    Addition von Aldehyden an aktivierte Doppelbindungen, XXXIV1). Addition von Aldehyden an cyclische α-Methylenketone (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 682-693 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XXXIV1). Addition of Aldehydes to Cyclic α-Methylene KetonesThe thiazolium salt-catalyzed addition of aldehydes to the cyclic α-methylene ketones 3, 4, 7, 8, 48, and 49 leads to γ-diketones 9 - 22, 50 - 53; some of them were converted into unsaturated ketones 23 - 28, pyrroles 29 - 34, 37 - 43, and furans 35, 36, 44 - 46. The α-methylene ketones were synthesized by retro Diels-Alder reaction of the corresponding norbornene compounds 1, 2, 5, 6, 47.
    Notes: Die Thiazoliumsalz-katalysierte Addition von Aldehyden an die cyclischen α-Methylenketone 3, 4, 7, 8, 48 und 49 führt zu γ-Diketonen 9 - 22, 50 - 53, aus denen einige ungesättigte Ketone 23 - 28, Pyrrol- 29 - 34, 37 - 43 und Furanderivate 35, 36, 44 - 46 synthetisiert wurden. Die Darstellung der α-Methylenketone erfolgte durch Retrospaltung entsprechender Norbornenderivate 1, 2, 5, 6 und 47.
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170221
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    Diazadienes as Controlling Ligands in Catalysis, 51). Synthesis of Chiral Diazadienes R* - N = CR' - CR' = N - R* (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 694-701 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diazadiene als Steuerliganden in der Katalyse, 51). Synthese chiraler Diazadiene R* - N = CR' - CR' = N - R*Die im Prinzip einfache Kondensationsreaktion von Glyoxal (als Hydrat) und 2,3-Butandion mit primären Aminen führt leider bei aliphatischen Aminen mit tertiärem bzw. sekundärem α-Kohlenstoff oftmals zu unerwünschten Additionsprodukten. Unter speziellen Synthesebedingungen können mit (R)-1-Phenylethylamin (1) und (1S,2S,3S,5R)-3-(Aminomethyl)pinan die gewünschten Diimine (Diazadiene (dad): R* - N = CR' - CR' = N - R*, R' = H, CH3) 4, 6 - 8 erhalten werden. Aus (S)-2-Amino-1-butanol (3) werden je nach Dion-Komponente ein Morpholinomorpholin 9 bzw. ein Bioxazolidin 10 gebildet, die von elektronenreichen Metallen in ihrer isomeren Form als Diazadiene gebunden werden ((dad)Mo(CO)4 11 und 12). Die offenkettige dad-Form ist durch O-Silylierung (14, 15) stabilisierbar. Die (dad)Eisen(0)-katalysierte Dimerisierung von Butadien zu 4-Vinyl-1-cyclohexen mit diesen dad-Liganden ergibt Enantiomerenüberschüsse e.e. bis zu 16%.
    Notes: The condensation of glyoxal (as hydrate) or 2,3-butanedione with primary amines is, in principle, a simple reaction. Unfortunately, aliphatic amines with secondary or tertiary α-carbons often give unwanted addition products. Under special reaction conditions the desired diimines (diazadienes (dad): R* - N = CR' - CR' = N - R*, R' = H, CH3) 4, and 6 - 8 are obtained from (R-1-phenyl-ethylamine (1) and (1S,2S,3S,5R)-3-(aminomethyl)pinane (2). Depending on the dione, a morpholinomorpholine 9 and a bioxazolidine 10 are formed from (S)-2-amino-1-butanol (3), which are bound by electron-rich metals in their isomeric dad form ((dad)Mo(CO)4 11 and 12). The acyclic dad structure is stabilized by O-silylation (14, 15). The (dad)iron(0) catalyzed dimerization of butadiene with these controlling ligands to 4-vinyl-1-cyclohexene occurs with an enantiomeric excess up to 16%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170222
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  • 86
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    Anwendung der hochaufgelösten Festkörper-NMR-Spektroskopie zur Bestimmung der Ring-Ketten-Tautomerie (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 702-709 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Application of High-Resolution Solid State NMR Spectroscopy for the Determination of the Ring-Chain TautomerismThe structure of the benzaldehyde derivatives 1 and 2 showing ring-chain tautomerism was investigated by NMR spectroscopy in the solid state and in solution. Difficulties in preparing single crystals, low solubility, and the presence of solvent in the crystal prevent an X-ray analysis and other spectroscopic methods. The structural problem was solved by C-13 CP-MAS NMR spectroscopy. 2-[2-(Methylamino)ethyl]-3-nitrobenzaldoxime (1) exists in the chain form in the crystal but is in equilibrium with the cyclic isomer in solution. Two different types of crystals were obtained from the aminoethenylbenzaldehyde derivative 2, one of them containing the chain the other the cyclic form of 2. Signal assignments in the solid state result from comparison with the spectra in solution, which have been partially assigned by 2D 1H 13C NMR shift correlation.
    Notes: Die Struktur der Benzaldehyd-Derivate 1 und 2, die Ring-Ketten-Tautomerie zeigen, wird durch NMR-Spektroskopie im festen und gelösten Zustand untersucht. Schwierigkeiten beim Züchten von Einkristallen sowie die Schwerlöslichkeit bzw. die Anwesenheit von Kristallösungsmittel verhinderten die Anwendung der Röntgenstrukturanalyse und anderer spektroskopischer Methoden. Mit Hilfe von C-13-CP-MAS-NMR-Spektren wird das Strukturproblem lösbar. In 2-[2-(Methyl-amino)ethyl]-3-nitrobenzaldoxim (1) liegt im Kristall die offene Form vor, die in Lösung mit dem cyclischen Tautomeren 1b im Gleichgewicht steht. Vom Aminoethenylbenzaldehyd-Derivat 2 lassen sich zwei verschiedene Kristalle gewinnen, in denen alternativ die offene und die cyclische Struktur vorliegt. Zur Signalzuordnung werden die Festkörper-NMR-Spektren mit den z. T. durch 2D-1H-13C-NMR-Verschiebungskorrelation zugeordneten C-13-Spektren verglichen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170223
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    Asymmetrische Katalysen, 121). Neue optisch aktive P, N-Liganden und ihr Einsatz in der Rh-katalysierten asymmetrischen Hydrierung und Hydrosilylierung (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 710-724 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Catalyses, 121). New Optically Active P,N Ligands and Their Use in Rh-Catalyzed Asymmetric Hydrogenation and HydrosilylationNew P,N-ligands 2, 4 and 5 were prepared by Schiff base condensation of (2-formylphenyl)diphenyl- and tris(2-formylphenyl)phosphane with (R)-(+)-1-phenylethylamine and ethylenediamine. (R)-(+)-aminphos (6) was obtained by hydrogenation of the C = N bond in (R)-(+)-iminphos (2). The new imine ligands form stable chelate complexes. The pseudotetrahedral CpFe(CO)[R)-(+)-iminphos]PF6 was separated into the diastereoisomes with respect to the Fe configuration. The square planar Rh[(R)-(+)-iminphos]2X is obtained as a cis/trans mixture. The isolated Rh complexes and the combinations [Rh(COD)Cl]2/2, 4, and 6, respectively, were used as catalysts for the homogeneous hydrogenation of (Z)-α-(acetylamino)cinnamic acid and for the hydrosilylation of acetophenone with diphenysilane. The optical yield of 1-phenyl-ethanol, the product of hydrolysis of the hydrosilylation, increases with increasing ligand excess, decreasing catalyst concentration, and decreasing temperature.
    Notes: Neue P,N-Liganden 2, 4 und 5 wurden durch Schiffbasenkondensation von (2-Formylphenyl)diphenyl- und Tris(2-formylphenyl)phosphan mit (R)-(+)-1-Phenylethylamin und Ethylendiamin dargestellt. (R)-(+)-aminphos (6) wurde durch Hydrierung der C = N-Bindung in (R)-(+)-iminphos (2) erhalten. Die neuen Imin-Liganden bilden stabile Chelatkomplexe. Das pseudotetraedrische CpFe(CO)[(R)-(+)-iminphos]PF6 wurde in die Diastereomeren bezüglich der Fe-Konfiguration getrennt. Das quadratisch-planare Rh[(R)-(+)-iminphos]2X fällt als cis/trans-Gemisch an. Die isolierten Rh-Komplexe und die Kombinationen [Rh(COD)Cl]2/ 2, 4 bzw. 6 wurden als Katalysatoren für die homogene Hydrierung von (Z)-α-(Acetylamino)zimtsäure und für die Hydrosilylierung von Acetophenon mit Diphenylsilan eingesetzt. Die optische Ausbeute an 1-Phenylethanol, dem Hydrolyseprodukt der Hydrosilylierung, steigt mit zunehmendem Ligandenüberschuß, mit abnehmender Katalysatorkonzentration und mit abnehmender Temperatur.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170224
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    Synthese und Solvolyse von (Z)/(E)-1-Methyl-2-[2-(1-propin-1-yl)phenyl]vinyl-triflat und 1-Methylen-2-[2-(1-propin-1-yl)-phenyl]ethyl-triflat (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3021-3033 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Solvolysis of (Z)/(E)-1-Methyl-2-[2-(1-propyn-1-yl)phenyl]vinyl Triflate and 1-Methylene-2-[2-(1-propyn-1-yl)phenyl]ethyl TriflateThe synthesis and solvolysis of the triflates (Z)/(E)-8 and 20 in various solvents are described. The (E)-triflate 8 reacts in trifluoroethanol by rearrangement via the intermediate naphthyl cation 9 to give the naphthyl ether 22 and the naphthyl triflate 24. The identification of 1-bromo-2,3-dimethylnaphthalene (26) after addition of bromide ions to the solvolysis confirms 9 as a reactive intermediate. The (Z)-triflate 8 solvolyses preferably to the elimination product 28, the formation of [(3-methyl-2-naphthyl)methyl] (trifluoroethyl) ether (23), however, can not be explained via the cation 9 as an intermediate. The solvolysis of the triflate 20 leads also to the rearranged products 22 and 23.
    Notes: Die Synthese und Solvolyse der Triflate (Z)/(E)-8 und 20 in verschiedenen Lösungsmitteln wird beschrieben. Das (E)-Triflat 8 reagiert in Trifluorethanol bevorzugt unter Umlagerung über das intermediäre Naphthylkation 9 zum Naphthylether 22 und zum Naphthyltriflat 24. Der Nachweis von 1-Brom-2,3-dimethylnaphthalin (26) nach Bromidionenzusatz zur Solvolyse bestätigt 9 als reaktive Zwischenstufe. Das (Z)-Triflat 8 solvolysiert bevorzugt zum Eliminierungsprodukt 28, die Bildung des [(3-Methyl-2-naphthyl)methyl]-(trifluorethyl)-ethers (23) kann jedoch nicht über das Kation 9 als Zwischenstufe erklärt werden. Die Solvolyse des Triflates 20 führt ebenfalls zu den Umlagerungsprodukten 22 und 23.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841171004
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    Notizen.Bestimmung absoluter Geschwindigkeitskonstanten bei der radikalischen Addition an Alkene nach der “Quecksilbermethode” (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3160-3164 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurement of Absolute Rates of Radical Additions to Alkenes by the “Mercury Method”Using the 5-hexenyl radical (2) as “radical clock” the rates of radical additions to methyl acrylate (5a) and acrylonitrile (5b) are measured by the “mercury method” (Table 1). Alkyl radicals are trapped by the alkylmercury hydride 1 with rate constants of at least 107 1 · mol-1 · s-1.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841171015
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  • 90
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    Masthead (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841171101
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    Radikalkettenreaktionen mit Maleinsäureanhydriden  -  Zur kontrathermodynamischen Stereoselektivität (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3175-3182 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radical Chain Reactions with Maleic Anhydrides  -  Contrathermodynamic StereoselectivityThe reactions of cyclohexylmercuric chloride with NaBH4 and alkenes 1a-g yield 60-84% of products 3, 4 and 6 in a radical chain process (table 1). Caused by steric effects of substituents Z at least 97% of the radical attack occurs at the unsubstituted carbon atom of maleic anhydrides 1c-g. Only fluoromaleic anhydride 1b is attacked by cyclohexyl radicals predominantly at the substituted carbon atom, because fluorine is a tiny, electron releasing substituent. Radicals 2 are trapped predominantly from the anti-direction by the H-donor (figure 1), yielding cis-compounds 3 as main products. This „contrathermodynamic“ stereoselectivity ranges between 2.3 and 19 (table 1).
    Notes: Die Reaktion von Cyclohexylquecksilberchlorid mit NaBH4 und den Alkenen 1a-g liefert in einer Radikalkettenreaktion die Produkte 3, 4 und 6 in 60- bis 84proz. Ausbeuten (s. Tab. 1). Wegen der sterischen Effekte der Substituenten Z erfolgt der Angriff der Radikale zu mindestens 97% am unsubstituierten C-Atom der Maleinsäureanhydride 1c-g. Allein das Fluormaleinsäureanhydrid 1b wird bevorzugt am substituierten C-Atom durch Cyclohexyl-Radikale angegriffen. Die Ursache für diese umgekehrte Regioselektivität liegt in der geringen Raumerfüllung und dem elektronenspendenden Effekt des Fluoratoms. Die H-Übertragung auf die Radikale 2 erfolgt überwiegend von der anti-Seite (s. Abb. 1), so daß die thermodynamisch instabileren cis-Verbindungen 3 als Hauptprodukte entstehen. Diese „kontrathermodynamische“ Stereoselektivität liegt zwischen 2.3 und 19 (s. Tab. 1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841171103
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    Reaktive Platin-Komplexe mit α-Aminosäurederivaten und ihre P- und N-Kernresonanzspektren (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1241-1245 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive Platinum Complexes with α-Amino Acid Derivatives and their 31P- and 15N Nuclear Magnetic Resonance SpectraThe α-amino acidate chelate complexes (n-Bu3P)(Cl)⊓PtNH2CH(R)COO (1a - c) (R = H, CH3, CHMe2) react with thionyl chloride, phosphorus pentachloride, or acetyl chloride by cleavage of the chelate ring to give complexes with α-amino acyl chloride or acetic glycine anhydride as ligands: (n-Bu3P)Cl2Pt(NH2CH2COCl) (2), (n-Bu3P)Cl4Pt(NH2CH(CHMe2)COCl) (6), (n-Bu3P)-Cl2Pt(NH2CH2CO(O)OCCH3) (4). Using 15N enriched amino acids, the IR, 15N and 31P NMR spectra indicate cis orientation of phosphane and amino groups in all these complexes.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170336
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    Synthesen mit Alkendiazoniumsalzen, III. ω,ω′-Di-1H-1,2,3-triazolylalkane aus Ethendiazonium- hexachloroantimonaten und ω,ω′-Diaminoalkanen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1246-1249 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with Alkenediazonium Salts, III. ω,ω′-Di-1H-1,2,3-triazolylalkanes from Ethenediazonium Hexachloroantimonates and ω,ω′-DiaminoalkanesReaction of the ethenediazonium hexachloroantimonates 2 with ω,ω′-diaminoalkanes 3 leads to ω,ω′-di-1H-1,2,3-triazolylalkanes 5.
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    URL: http://dx.doi.org/10.1002/cber.19841170337
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    Beiträge zur Chemie des Bors, 135. Additionsverbindungen von 1,3,2-Diazaborolidinen mit Aluminium- und Galliumhalogeniden (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1222-1234 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 1351). Addition Compounds of 1,3,2-Diazaborolidines with Aluminium and Gallium Halides1,3-Dimethyl-1,3,2-diazaborolidines 3 - 6 add aluminium and gallium halides, respectively, in a 1 : 1 molar ratio. The ligand is monodentate in these coordination compounds (3a - e, 4a, 5a, b, 6a). Addition occurs at one of the ring nitrogen atoms irrespective of the B-substituent. A consequence of this coordination is a long BN bond to the chiral tetracoordinated nitrogen atom as well as a considerable shortening of the BN bond involving the tricoordinate ring nitrogen. In addition, the almost planar five-membered ring adopts the envelope conformation as shown by an X-ray structure analysis of 5a. In contrast, the 2-(dimethylamino)diazaborolidine 7 yields unstable 1 : 1 besides stable 1 : 2 adducts 8. In these the Lewis acid is also coordinated to the ring nitrogen atoms only.
    Notes: Die 1,3-Dimethyl-1,3,2-diazaborolidine 3 - 6 addieren Aluminium- oder Galliumhalogenide im Molverhältnis 1 : 1 zu Koordinationsverbindungen 3a - e, 4a, 5a, b, 6a, in denen der Ligand einzähnig ist. Die Anlagerung erfolgt unabhängig vom B-Substituenten an einem Ringstickstoff-Atom. Folge dieser Koordination ist die Ausbildung einer langen BN-Bindung zum chiralen tetra-koordinierten Ring-Stickstoff, eine erhebliche Verkürzung der BN-Bindung zum dreifach koordinierten endocyclischen Stickstoffatom und der Übergang des nahezu planaren Fünfrings in die „envelope“-Konformation, wie die Röntgenstrukturanalyse von 5a belegt. Im Gegensatz dazu liefert das 2-(Dimethylamino)diazaborolidin 7 mit AlX3 und GaX3 instabile 1 : 1- und stabile 1 : 2-Addukte 8. In diesen ist die Lewis-Säure nur an den Ringstickstoff-Atomen koordiniert.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19841170334
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    Eine einfache Synthese primärer Amine über ihre N,N-Bis(trimethylsilyl)-Derivate (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1250-1254 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Simple Synthesis of Primary Amines via their N,N-Bis(trimethylsilyl) DerivativesPrimary halogen compounds 1 or the corresponding tosylates react with sodium bis(trimethylsilyl)amide (2) in hexamethyldisilazine to form N,N-bis(trimethylsilyl)amines 3, which are converted into the amine hydrochlorides 5 by treatment with aqueous HCl.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19841170338
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    Dibenz[a,j]anthracene via Photo-cyclodehydrogenation of 9,10-Dihydro-2-styrylphenanthrene (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1255-1258 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dibenz[a,j]anthracen durch Photocyclodehydrierung von 9,10-Dihydro-2-styrylphenanthrenWährend aus 2-Styrylphenanthren (1) durch Photocyclodehydrierung Benzo[c]chrysen (2) entsteht, läßt sich unter Ausnutzung der „ΣF*-Regel“5) aus 9,10-Dihydro-2-styrylphenanthren (4) durch Photocyclodehydrierung zu 6 und anschließende Dehydrierung Dibenz[a,j]anthracen (3) erhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170339
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  • 97
    Electronic Resource
    Electronic Resource
    Eine einfache Synthese der 5-Cyan-2-pyridincarbonsäure und ihres Amids (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1259-1261 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Simple Synthesis of 5-Cyano-2-pyridinecarboxylic Acid and its AmideThe title compounds 3 and 2 (X = CN) are prepared in good yields by regioselective carbamoylation of 3-cyanopyridine in a Minisci reaction and by consecutive amide hydrolysis with amyl nitrite in HCl-saturated acetic acid. The observed regioselectivity apparently remains confined to carbamoyl and possibly acyl radicals and to - M-effect substituents in 3-position.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170340
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  • 98
    Electronic Resource
    Electronic Resource
    Masthead (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170401
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  • 99
    Electronic Resource
    Electronic Resource
    Masthead (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170101
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  • 100
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    Zur Umsetzung von 2-Pyrrolcarbaldehyd mit heterosubstituierten Ethenen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1424-1435 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reaction of 2-Pyrrolecarbaldehyde with Hetero-substituted Ethenes3H-Pyrrolizines 1 have been obtained from reactions of 2-pyrrolecarbaldehyde with ethenylphosphonates 2 and the phosphane oxide 5, respectively, the ratio of products depending on the structure of the educts. On varying the reaction conditions a controlled synthesis of both isomers 1e/f was achieved. Pyrrolizines, formed in a reaction of 2 pyrrolecarbaldehyde with ethenyl phenyl sulfone (3), could not be isolated since the reaction proceeded to give more complex pyrrolizine derivatives and the cyclazine 11. A mechanism is proposed for this multistep reaction. N-Alkylation of 2-pyrrolecarbaldehyde with dihaloalkanes has been carried out using phase transfer catalysis.
    Notes: Umsetzungen des 2-Pyrrolcarbaldehyds mit Ethenylphosphonaten 2 und dem Phosphanoxid 5 führten zu 3H-Pyrrolizinen 1, wobei das Mengenverhältnis der gebildeten Isomeren von der Struktur der Edukte abhängt. In einem Falle (1e/1f) gelang die gezielte Synthese beider Isomeren durch Variation der Reaktionsbedingungen. Die aus 2-Pyrrolcarbaldehyd und Ethenylphenylsulfon (3) entstandenen Pyrrolizine 1e/f reagieren weiter unter Bildung komplexer Pyrrolizinderivate und des Cyclazins 11. Für diese Mehrstufenreaktion wird ein Mechanismus vorgeschlagen. Unter Phasentransfer-Bedingungen gelingen Alkylierungen des 2-Pyrrolcarbaldehyds mit Dihalogenalkanen.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170413
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