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  • Artikel: DFG Deutsche Nationallizenzen  (5.804)
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  • ZIB Katalog
  • Artikel: DFG Deutsche Nationallizenzen  (5.804)
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  • 1
    Digitale Medien
    Digitale Medien
    Stereoselective excretion of (3-methoxy-4-sulphooxyphenyl)ethylene glycol (MHPG sulphate) in the dog (1980)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 314 (1980), S. 89-96 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Methoxyhydroxyphenylglycol ; Sulphates ; Conjugation ; Stereoisomers ; Kidney
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 3-Methoxy-4-hydroxyphenylethylene glycol (MHPG) labelled with six deuterium atoms ([2H6]MHPG) was infused into two female greyhound dogs. Plasma and urine were analyzed for endogenous MHPG and [2H6]MHPG and their conjugates by the technique of selected ion monitoring gas chromatography-mass spectrometry. This analysis showed that the major forms of MHPG and [2H6]MHPG in the plasma and urine of the greyhounds were the sulphate conjugates. However, the plasma concentration of [2H6]MHPG sulphate increased continuously during the infusion period and the renal clearance of this compound was found to be much less than that of the endogenous sulphate. The explanation that this was due either to saturation of a renal transport mechanism or to a deuterium isotope effect was eliminated. Stereochemical analysis showed that, while the [2H6]MHPG used for infusion was a racemic mixture of two stereoisomers, much more of the natural(−)stereoisomer of [2H6]MHPG sulphate was excreted in the dog urine. It was also shown that both the (+) and (−)stereoisomers of [2H6]MHPG sulphate were sulphoconjugated at the 4-position of the aromatic ring.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00498435
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  • 2
    Digitale Medien
    Digitale Medien
    Urinary prostaglandins in human neonates: Relationship to kidney function and blood pressure (1980)
    Springer
    Journal of molecular medicine 58 (1980), S. 449-455 
    Details
    ISSN: 1432-1440
    Schlagwort(e): Blutdruck ; Neugeborene ; Prostaglandine ; Niere ; Osmolalität ; Blood pressure ; Neonates ; Prostaglandins ; Kidney ; Osmolality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary We studied the excretion of prostaglandin (PG) E2 and of PGF2α in 172 healthy newborns during the first week of life to detect possible biochemical markers for the individual susceptibility to hypertension. PG excretion was compared to urinary electrolytes, urinary osmolality, and blood pressure. In addition, blood pressure of the newborns was related to the blood pressure of the mothers and to the history of hypertension in parents and/or grandparents. PGE2-excretion increased from 0.7 ng/mg creatinine on the third day to 1.5 ng on the fifth day of life (p〈0.001) while PGF2α excretion remained unchanged at 2 ng/mg creatinine. PGE2 (but not PGF2α) was inversely correlated to urinary osmolality (p〈0.001) while urinary potassium was positively correlated to PGF2α (p〈0.001). On the fifth day of life systolic blood pressure of the newborns was correlated to PGF2α-excretion and to systolic blood pressure of the mother (p〈0.05). Blood pressure was significantly higher in newborns with a history of hypertension in parents or grandparents than in those without hypertension in relatives (p〈0.02). The data suggest that renal PG:s are involved in the regulation of urinary osmolality and potassium excretion in the neonate. The positive correlation between PGF2α excretion and blood pressure may indicate a genetically determined PG-related renal influence on the level of systemic blood pressure.
    Notizen: Zusammenfassung Auf der Suche nach einem biochemischen Parameter als Marker für die Hypertonie-Gefährdung wurde bei 172 gesunden Neugeborenen am 3. und 5. Lebenstag die Ausscheidung von PGE2 und von PGF2α gemessen und mit dem Blutdruck, der Elektrolytausscheidung sowie der Urinosmolalität verglichen. Daneben wurde der Blutdruck der Neugeborenen in Beziehung gesetzt zum Blutdruck der Mutter und zur Hypertonie-Anamnese in den Familien der Eltern. Die PGE2-Ausscheidung stieg von 0,7 ng/mg Kreatinin am 3. Tag auf 1,5 am 5. Tag (p〈0,001), während die PGF2α-Exkretion bei 2 ng/mg Kreatinin konstant blieb. Es bestand eine inverse Korrelation zwischen PGE2 und der Urinosmolalität (p〈0,001), während die Kalium-Ausscheidung positiv zur PGF2α-Exkretion korreliert war (p〈0,001). Am 5. Lebenstag war der systolische Blutdruck der Neugeborenen signifikant korreliert zu der PGF2α-Ausscheidung (p〈0,05). Es bestand weiterhin eine positive Korrelation des systolischen Blutdrucks der Neugeborenen zum systolischen Blutdruck der Mütter (p〈0,05). Der Blutdruck bei Neugeborenen mit Hypertonie in der Familienanamnese war bereits in der ersten Lebenswoche signifikant höher als der Blutdruck bei Kindern ohne Hypertonie bei Eltern und/oder Großeltern. Die Untersuchungen deuten darauf hin, daß beim Neugeborenen renale Prostaglandine bei der Regulation der Urinosmolalität und der Kalium-Ausscheidung beteiligt sind. Die positive Korrelation zwischen PGF2α-Ausscheidung und Blutdruck wird als möglicher Marker eines genetisch determinierten Einflusses des renalen PG-Systems auf die Blutdruckregulation gedeutet.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01476799
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  • 3
    Digitale Medien
    Digitale Medien
    Fibrous histiocytoma (fibroxanthoma) of a cervical vertebra (1980)
    Springer
    Skeletal radiology 5 (1980), S. 241-246 
    Details
    ISSN: 1432-2161
    Schlagwort(e): Fibrous histiocytoma ; Metaphyseal fibrous defect ; Non-ossifying fibroma ; Fibroma ; Bone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A patient with a benign appearing intraosseous fibrous lesion of the cervical vertebra is presented. The lesion had the histologic features of non-ossifying fibroma (metaphyseal fibrous defect). Because of its atypical location and unusual radiologic appearance, the lesion was diagnosed as a fibrous histiocytoma, a tumor whose histology is similar to non-ossifying fibroma. The literature was reviewed for similar cases located outside the metaphysis of the long bones. Support is given for designating such lesions as fibrous histiocytomas rather than non-ossifying fibromas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00580597
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  • 4
    Digitale Medien
    Digitale Medien
    Rosoxacin distribution in kidney and prostate: experimental studies in dogs (1980)
    Springer
    Urological research 8 (1980), S. 113-116 
    Details
    ISSN: 1434-0879
    Schlagwort(e): Rosoxacin ; Renal lymph ; Interstitial fluid ; Kidney ; Prostate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Concentrations of rosoxacin, a new quinolone derivative, in the renal hilar lymph, renal interstitial fluid, prostatic interstitial fluid, and prostatic secretion were investigated in dogs during constant intravenous infusion. The lymph was obtained by direct cannulation of the lymphatics and the interstitial fluid from small plastic tissue chambers implanted six weeks before the experiments. Renal clearance of rosoxacin was compared to the glomerular filtration rate, as measured by 125I-iothalamate clearance, and showed a net reabsorption of rosoxacin. The renal lymph and interstitial fluid concentrations in both kidney and prostate were found to be lower than the simultaneous plasma concentrations, corresponding well with earlier findings for several other antimicrobial agents. However the concentrations in lymph and interstitial fluids were higher than the minimum inhibitory concentrations for most enterobacteriaceae normally encountered in urinary tract infections.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00271438
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  • 5
    Digitale Medien
    Digitale Medien
    The anatomy and blood system of the kidney in the river lamprey, Lampetra fluviatilis (1980)
    Springer
    Anatomy and embryology 158 (1980), S. 245-252 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Kidney ; Lamprey ; Vasculature ; Nephron ; Microanatomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The anatomy and blood system of the kidney in the river lamprey, Lampetra fluviatilis, was studied after injecting microfil into nephrons or the arterial system. Renal arteries arose at irregular intervals from the dorsal aorta and gave rise to a regular arrangement of afferent arterioles supplying the network of glomerular capillaries. Nephron units were arranged in two longitudinal series on each side of the glomerular capillaries, with the capsule of each nephron closely related to the capillary network. A short neck segment lead into the convoluted proximal segment, which accounted for over half the length of each nephron and was surrounded by a network of capillaries and sinusoids supplied by efferent glomerular arterioles. The end of each proximal segment formed the descending limb of a nephron loop, which lay parallel to the ascending distal limb and the end of each collecting duct. Peritubular blood flow in this region was generally opposite the flow of tubular fluid and blood eventually drained into large thin-walled sinuses connected to the post-cardinal vein.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315909
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  • 6
    Digitale Medien
    Digitale Medien
    The mammalian renal pelvis: Physiological implications from morphometric analyses (1980)
    Springer
    Anatomy and embryology 160 (1980), S. 131-144 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Kidney ; Renal pelvis ; Urine concentration ; Renal medulla ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Morphometric analyses have been used to study the renal pelvises of four common rodents: laboratory rat (R), hamster (H), gerbil (M), sand rat (P). Measurements on photographs of serial sections were used to determine the 1) area of the outer kidney surface, 2) surface area of each kidney zone and hilum facing the pelvic space, 3) volume of the pelvic space, 4) volume of each kidney zone. As a standard measure the total pelvic surface area (kidney zones plus hilum) of each species was expressed as a percent of its respective outer kidney surface area: R=25.0%, H=32.6%, M=48.7%, P=97.2%. The medullary tissue formed about 80% of the total pelvic surface area in each species while cortex and hilum formed the remaining 20%. The outer medulla had about twice as much surface area facing the pelvic urine as did the inner medulla. The amount of inner stripe of the outer medulla was greater than the outer stripe of the outer medulla as the following progression of ratios (mm2/mm2) shows: R=1.8, H=2.5, M=2.2, P=4.9. When the volume of the pelvic space and each kidney zone of each species was compared to the total volume of the respective kidney as a standard measure, it was determined that 1) the pelvic space was small being less than 5% of the total kidney volume, 2) the cortex was the largest kidney zone in all species: R=69.6%, H=68.1%, M=69.9%, P=51.6%, 3) the outer medulla was intermediate: R=25.8%, H=27.4%, M=23.1%, P=33.8%, 4) the inner medulla formed the smallest tissue zone in all species but was noticeably larger in P (10.7%) in comparison to the values for R=2.1%, H=2.5% and M=5.2%. The simultaneous increases (from R to H to M to P) in: a) relative inner medullary volume, b) relative pelvic surface area, c) maximum urine concentrating capacity (Schmidt-Nielsen and O'Dell 1961; Munkasci and Miklos 1977) may support earlier hypotheses which suggest that a back diffusion of pelvic urine solutes augments medullary interstitial tonicity and thus is an intergral part of the urine concentrating mechanism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00301856
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  • 7
    Digitale Medien
    Digitale Medien
    Bone cell kinetics during longitudinal bone growth in the rat (1980)
    Springer
    Calcified tissue international 32 (1980), S. 123-133 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Cell kinetics ; Osteoprogenitor cell ; Migration ; Differentiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The purpose of this work was to provide further knowledge about bone cell kinetics in the metaphysis of the growing long bone. Seventy rats were sacrificed from 1 to 120 h after injection of tritiated thymidine. Autoradiographs of 3 µm thick sections of the proximal tibial metaphysis were studied in a manner which allowed evaluation of labeled cell nuclei as a function of increasing age of metaphyseal tissue. A cell cycle duration study for osteoprogenitor cells was done. Labeled osteoprogenitor cells and osteoblasts first appeared at 1 h post-injection. The great majority of all labeled osteoprogenitor cells and osteoblasts was found within 1 mm of the growth cartilage-metaphyseal junction (GCMJ) at all times, apparently migrating with the moving GCMJ. In contrast, labeled osteoclast nuclei first appeared at 24 h post-injection within 0.3 mm of the GCMJ and remained always with the area of bone surface with which they were first associated, even as the GCMJ migrated away. By 5 days post-injection, the source of new labeled osteoclast nuclei in the metaphysis near the GCMJ was depleted, whereas that for the osteoblasts remained. The existence of two kinetically different, as well as ultrastructurally different, members of the metaphyseal osteoprogenitor cells population is postulated. A cell cycle time of 39±18 h was found for the osteoprogenitor cell population, but has limited meaning. A schema for metaphyseal bone cell movements during longitudinal bone growth is presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408531
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  • 8
    Digitale Medien
    Digitale Medien
    Kinetic studies of bone and mineral metabolism during treatment with (3-amino-1-hydroxypropylidene)-1,1-bisphosphonate (APD) in rats (1980)
    Springer
    Calcified tissue international 32 (1980), S. 145-157 
    Details
    ISSN: 1432-0827
    Schlagwort(e): APD ; Bisphosphonate ; Bone ; Resorption ; Formation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Dose-related effects of APD on bone metabolism and Ca homeostasis were studied in rats. The experimental approach consisted of longitudinal and cross-sectional observations, aiming at a kinetic interpretation. Bone and cartilage resorption was inhibited within 2–8 days at doses between 0.16 and 16 µmol/kg body weight/day. This was followed by changes in bone apposition that needed at least 23 days for a maximal effect. The time lag created a transient dissociation between resorption and apposition resulting in excess Ca and P retention, adding to increased metaphyseal bone mass. At high doses of APD (≥40 µmol/kg/day) the mineral content of new matrix decreased, associated with impairment of longitudinal growth of long bones. It is concluded that the lower doses of APD inhibited resorption of bone and cartilage, possibly by physicochemical stabilization of bone mineral, whereas the effect on bone apposition was due to a cellular homeostatic mechanism. Inhibition of growth and of matrix calcification, requiring much higher doses, may be due to a direct, toxic effect on bone cells. The modes of action of APD are discussed in relation to EHDP and Cl2MDP.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408534
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  • 9
    Digitale Medien
    Digitale Medien
    Decreased breaking strength of diabetic rat bone and its improvement by insulin treatment (1980)
    Springer
    Calcified tissue international 32 (1980), S. 195-199 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Diabetes ; Insulin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary A simple instrument is described which measures the breaking strength of rat bones. The apparatus yields reproducible results and is suitable for use in measuring the strength of bones from both large and small animals. Diabetic rat femurs were more fragile and required less force to break in contrast to those from diabetic rats treated with insulin or normal rats. Daily insulin treatment significantly improved the bone cortical thickness and enhanced their capacity to withstand pressure, although these did not reach the level of the normal controls. The amount of force required to break the bone appears to be related to its cortical thickness and mass.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408541
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  • 10
    Digitale Medien
    Digitale Medien
    Human vertebral bone: Relation of strength, porosity, and mineralization to fluoride content (1980)
    Springer
    Calcified tissue international 32 (1980), S. 189-194 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Fluoride ; Strength ; Porosity ; Mineralization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Radiographically normal vertebral bone cylinders from 80 male subjects were tested mechanically by static compression and analyzed for porosity, fluoride and ash content. As a group, they had low fluoride content, suggesting little prior intake, consonent with this geographic area. Nevertheless, increasing levels of fluoride were associated with bulkier bone, less porosity, and less mineral per unit of bone, which in direction though not degree suggested changes similar to those of osteomalacia and opposite from those of osteoporosis without apparent threshold. The higher fluoride hard tissue was weaker in static tests than that with less fluoride, but the increased bulk apparently offset this, resulting in bones of unchanged static strength. Hence, water fluoridation should not alter static bone strength. There has, however, been a recent report suggesting that increased mineralization of bone renders it more brittle and thus more likely to fracture on impact. Therefore, the possibility that fluoridation may increase impact resistance by lessening mineralization can be entertained.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408540
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  • 11
    Digitale Medien
    Digitale Medien
    Blood/bone disequilibrium: IV. Reciprocal effects of calcium and phosphate concentrations on ion fluxes (1980)
    Springer
    Calcified tissue international 32 (1980), S. 229-236 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Ion influxes ; Calcium ; Phosphate ; Exchange
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Quantitative measurements were made of the ion fluxes of calcium and phosphate into and from calvaria (mouse or rat) when clamped in specially designed micro-Ussing chambers. The effects of varying concentrations of calcium were examined on the influx and efflux of calcium and of its counterion, phosphate. A comparable series of experiments was performed with varying phosphate concentrations. Both ions, as their concentrations increased, depressed their own influx, increased their own efflux, and significantly increased the equilibrium concentration, E/K, supported by the calvaria. Similarly, both ions, as their concentrations increased, affected the influx or efflux of their counterion only slightly but did depress the counterion's equilibrium level, E/K, significantly. In spite of these changes it was shown that calvaria effectively buffered the medium at physiological concentrations of calcium and phosphate. The buffering capacity, however, was small, and the balance, E/K, was modified by small uptake or loss of either ion. The small size of the interacting mineral pool was confirmed by direct measurement of the rapidly exchanging fractions of both calcium or phosphate. They were only ∼1% of the total ions present. The significance of these findings is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408546
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  • 12
    Digitale Medien
    Digitale Medien
    Uptake and loss of plutonium from osteoclasts and macrophages in the mandibular condyle of the rat (1980)
    Springer
    Calcified tissue international 30 (1980), S. 15-20 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Osteoclasts ; Macrophage ; Resorption ; Plutonium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Female rats were used to study the kinetics of plutonium transfer from the bone surfaces of the mandibular condyle to osteoclasts and macrophages. This study was made using autoradiographs prepared from plastic sections of the mineralized bones of animals which had been injected with241 Pu citrate. Measurements of the concentration of plutonium in the osteoclasts and macrophages at different times after the injection of plutonium showed that plutonium was concentrated by osteoclasts from bone surfaces and was retained with a half-time of ∼ 70 h. Subsequently, plutonium appeared to be transferred to macrophages. The results showed that plutonium was unlikely to be accumulated by macrophages as a result of their participation in bone resorption.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408601
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  • 13
    Digitale Medien
    Digitale Medien
    Alkaline phosphatase and ATPase activities of rat bone: Separation and characterization (1980)
    Springer
    Calcified tissue international 30 (1980), S. 67-71 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Alkaline phosphatase ; ATPase ; Bone ; Triton
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Extraction with Triton X-100 has proved effective in solubilizing alkaline phosphatase from rat bone particles, whereas ATPase with optimum activity at pH 8 remains attached to the bone particles. The kinetic characteristics of the ATPase activity of the Triton extracts are different from those of the same enzyme attached to bone particles, but the kinetic characteristics of the particle-bound and solubilized alkaline phosphatases are similar. The results suggest that the Triton extracts do not have true ATPase activity and provide a means of separating the ATPase and alkaline phosphatase activities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408608
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  • 14
    Digitale Medien
    Digitale Medien
    On the measurement of water compartments, pH, and gradients in calvaria (1980)
    Springer
    Calcified tissue international 31 (1980), S. 135-145 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; water compartments ; marker ; methods ; pH ; potassium ; lactate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The concept of fluid compartmentalization in bone has emphasized the need for and lack of suitable methodology for the quantitation of water “spaces” in bone, in particular intracellular water, ICF, and extracellular water, BECF. Over a dozen commonly used marker substances were studied intensively. Small columns of hydroxyapatite crystals were employed to reveal physiochemical interactions with the mineral phase, and isotope distributions in live and dead calvaria (rat pup, and adult mice) were employed to evaluate interactions with the combined organic-inorganic matrix of bone itself. The results were most discouraging. For example, for total water space, only water itself (either by direct weight or by3H2O exchange) is a reliable measure in all instances. All markers studied were passively concentrated or excluded to varying degrees. In the end, it was necessary to measure intracellular space “by difference.” An extracellular marker, polyethylene glycol (14C-, mol. wt. 4000), was incubated with viable calvariae and also with comparable calvariae having lysed cells (0.1% Triton X-100). The intracellular space thus determined by difference agreed well with correlative data obtained on mixed cell-isolates from similar specimens. In neonatal calvariae, the intracellular space was 30% of the total water present; that of adult mouse tibia, 18%; and that of adult mouse calvariae, 14.5%. Measurements of dimethyl-2,4-oxazolidinedione (DMO) distribution in live and lysed calvaria revealed an overall pH differential (inside bone vs. medium) of 0.1 unit or less. Using the best available data for ICF, BECF, and the passive concentrating effects of matrix-K+ interactions, there still remained an unexplained excess of K+ in the BECF.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02407174
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  • 15
    Digitale Medien
    Digitale Medien
    Histological observations on the failure of rachitic rat bones to respond to 1,25/OH)2D3 (1980)
    Springer
    Calcified tissue international 31 (1980), S. 215-223 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; 1,25(OH)2D3 ; 25OHD3 ; Histology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Rachitic rats, maintained on diets with low or normal P contents, were given daily intraperitoneal doses of 1,25(OH)2D3 or 25OHD3 at levels of 100 or 200 ng. Plasma chemistry was measured and the ash content and histological appearance of the bones investigated. Using labeled material it was shown that the dosing levels of 1,25(OH)2D3 employed ensured a higher than normal plasma concentration of that metabolite over the period between doses. 1,25(OH)2D3 was not as effective as 25OHD3 in raising bone ash or reducing the amount of osteoid. The difference between the effects of the metabolites was evident at both dietary P levels, but more marked at the higher P level. In contrast, the metabolites reduced the width of the epiphyseal plate to an approximately similar degree, and this is possibly the reason why there are discrepancies between previous reports of the effectiveness of 1,25(OH)2D3 compared with 25OHD3 or vitamin D3. Dosing with 1,25(OH)2D3 failed to maintain a constant plasma Pi value over the period between doses in animals fed the low P diet.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02407184
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  • 16
    Digitale Medien
    Digitale Medien
    Calcium homeostasis and bone pathology in magnesium deficient rats (1980)
    Springer
    Calcified tissue international 31 (1980), S. 231-238 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Magnesium ; Bone ; Calcium ; Parathyroid gland
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Calcium homeostasis and bone pathology were studied in weanling rats fed a low (70 ppm) magnesium diet for 2–21 days. The rats developed significant, progressive hypercalcemia after 6 days on the diet. The increase in blood calcium was accompanied by progressive hypoactivity of the parathyroid gland (PTG), as determined by histologic and morphometric analyses. Thus hyperactivity of the PTG could not have been responsible for the hypercalcemia observed. Histologic examination of femora and humeri from magnesium-deficient rats showed progressive subperiosteal hyperplasia, consisting of undifferentiated osteoprogenitor cells and fibrous tissue, after 7 days of deficiency. The presence of unmineralized osteoid tissue in the metaphyses indicated that mineralization was not proceeding normally. The alterations in differentiation of osteoprogenitor cells, together with the failure of mineralization, resulted in significantly lower rates of bone formation (as measured by fluorochrome labeling) in the magnesium-deficient rats. Basophilic cementing lines and inactive osteocytes in the cortices of bones from magnesium-deficient rats indicated that bone resorption was also severely reduced in magnesium deficiency. We postulate that bone magnesium depletion (66% by day 21) has a direct negative effect on osteoblastic and osteocytic activity, and may explain, in part, the decreased responsiveness of bone to parathyroid hormone (PTH) that has been observed in magnesium-deficient animals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02407186
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  • 17
    Digitale Medien
    Digitale Medien
    Limitations of radioactive microspheres as tracers for bone blood flow and extraction ratio studies (1980)
    Springer
    Calcified tissue international 31 (1980), S. 261-265 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; blood flow ; microspheres ; fluorine ; strontium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Radioactive microspheres have been used for measuring bone blood flow and the extraction ratios of bone-seeking radionuclides, but we have shown that the technique is not completely valid. Bone uptake of18F and85Sr was compared with that of microspheres simultaneously injected into the heart or aorta of rats and rabbits under a variety of conditions. In single-passage experiments with quick killing to avoid recirculation, attention was focused on the tibiae and femora which could be dissected quickly to avoid post-mortem migration. For the rest of the skeleton, the effect of the latter was minimized by allowing recirculation for 5 min and comparing blood flow determinations in conjunction with a cardiac output measurement. The apparent extraction ratio of18F was variable and always exceeded unity in the single-passage experiments. With recirculation, there were significant differences between the extraction ratios for some bones, and the ratios sometimes exceeded unity. Extraction ratios for85Sr were similarly variable, but lower. When85Sr was compared directly with18F, the relative extraction ratio was 0.8, with little variation between bones or animals. It is concluded that the flux of microspheres entering the vasculature of bone is not representative of blood flow, owing to the removal of some microspheres in pre-osseous capillary beds. Microspheres are therefore not a satisfactory standard for the determination of extraction ratios.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02407191
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  • 18
    Digitale Medien
    Digitale Medien
    Tumoral calcinosis: Evidence for concurrent defects in renal tubular phosphorus transport and in 1α,25-dihydroxycholecalciferol synthesis (1980)
    Springer
    Calcified tissue international 32 (1980), S. 1-6 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Ectopic calcification ; 1,25-dihydroxyvitamin D ; hyperphosphatemia ; Bone ; Renal tubule
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary A 50-year-old Latin American man with tumoral calcinosis presented with hyperphosphatemia (6.62±1.04 SD mg/dl), elevated renal threshold phosphorus concentration (TmP) (7.3 mg/GFR), and 1,25-dihydroxyvitamin D [1,25-(OH)2D] (69 pg/ml) hypercalciuria (239 mg/day), and a high fractional intestinal calcium (Ca) absorption (0.74). Sodium cellulose phosphate therapy (20 g/day) lowered urinary Ca, and partially reduced serum phosphorus (P) and TmP to 5.91±0.63 mg/dl and 6.2 mg/GFR, respectively. Serum 1,25-(OH)120D remained elevated at 58–64 pg/ml. Amphojel therapy (4 oz/day) decreased urinary P to 23±21 mg/day and lowered serum P to 5.75±0.36 mg/dl (P〈0.05). TmP increased to a value of 8.0 mg/GFR while serum 1,25-(OH)2D continued to remain elevated at 53 pg/ml. This case illustrates the probable operation of dual abnormalities in tumoral calcinosis represented by augmented renal conservation of P and an elevation in the circulating concentration of 1,25-(OH)2D.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408515
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  • 19
    Digitale Medien
    Digitale Medien
    Use of tracer microspheres to measure bone blood flow in conscious dogs (1980)
    Springer
    Calcified tissue international 32 (1980), S. 69-76 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Marrow ; Blood flow ; Microspheres
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Blood flow was measured in mature and immature dogs by means of tracer microspheres. Microspheres of 15 µm were found to be the most suitable size in the dog. Total body nonentrapment in the awake, standing dog is likely to be less than 10%. Cortical bone flood flow, devoid of periosteum and marrow, is 2.5 ml/100 g/min in mature dogs and 7.0 ml/100 g/min in immature dogs,P〈0.005. Blood flow in cancellous bone is greater than that in cortical bone in mature (P〈0.001) and immature (P〈0.02) dogs. Flow is different in different regions of a long bone because of different proportions of cortical and cancellous bone, probably because of interrelationships of function (surfaces undergoing remodeling) and, therefore, of energy metabolism and blood flow.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408523
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  • 20
    Digitale Medien
    Digitale Medien
    Paradoxical effect of 1.25 dihydroxycholecalciferol on osteoblastic and osteoclastic activity in the skeleton of the eelAnguilla anguilla L (1980)
    Springer
    Calcified tissue international 32 (1980), S. 83-87 
    Details
    ISSN: 1432-0827
    Schlagwort(e): 1.25 (OH)2D3 ; Fish ; Bone ; Osteoblasts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Female mature eels (300 to 500 g) received one intraperitoneal injection of 1.25 (OH)2D3 (10 µg). Their vertebral bone was compared, 8 h and 24 h after the injection, with vertebral bone of control mature female eels receiving solvent alone (ethanol). Sexual maturation in female eels induces a bone decalcification with hypercalcaemia and hyperphosphataemia. The control eels showed marked osteoclastic resorption and osteocytic osteolysis and the degree of mineralization of the intercellular substance decreased. Injection of 1.25 (OH)2D3 into these female mature eels provoked as early as 8 h : 1) an increase in hypercalcaemia and hyperphosphataemia ; 2) a major conversion of lining cells to osteoblasts and a stimulation of osteoblastic activity with new bone formation ; 3) diminished osteoclastic resorption without changing osteocytic osteolysis or bone matrix mineralization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408525
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  • 21
    Digitale Medien
    Digitale Medien
    A quantitative histologic analysis of the growing long bone metaphysis (1980)
    Springer
    Calcified tissue international 32 (1980), S. 113-122 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Rat ; Bone ; Metaphysis ; Quantitative ; Aging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The purpose of this work was to analyze the proximal tibial metaphysis of the 170 g rat in a quantitative histologic fashion which would allow some relation to tissue age to be established. Stained 3 µm thick tissue sections were analyzed with the aid of a Merz grid on an eyepiece reticule and a light microscope. Tissue mass and cell distribution were studied in all areas. The rate of change in tissue mass during aging of the metaphysis was calculated. Two regions of the metaphysis were identified. One, corresponding to the primary spongiosa, less than 4.45 days of age, is a region of high turnover of hard tissue and high numbers of osteoblasts and osteoprogenitor cells. The other, corresponding to the secondary spongiosa, is a region of relatively low net tissue turnover and low numbers of osteoblasts and osteoprogenitor cells. Osteoclasts were found relatively more uniformly distributed through the metaphysis than were osteoblasts and osteoprogenitor cells. The rate of bone formation in the primary spongiosa is 50 times that found in the Haversian bone of the rib of 5-year-old humans and about 500 times that found at the cortical-endosteal surface of ribs of 5-year-old humans. It is argued that both cell distribution and tissue distribution in the metaphysis support the concept that osteoblasts and osteoclasts, rather than osteocytes, are responsible for the maturation of the metaphysis. The inhomogeneous distribution of both cells and tissue in the metaphysis has definite meaning for the interpretation of findings concerning the incorporation of radionuclides into the skeleton.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02408530
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  • 22
    Digitale Medien
    Digitale Medien
    Renal response to cadmium in a population living in a nonferrous smelter area in Belgium (1980)
    Springer
    International archives of occupational and environmental health 45 (1980), S. 271-274 
    Details
    ISSN: 1432-1246
    Schlagwort(e): Cadmium ; Kidney ; Environmental pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The exposure to cadmium and the kidney function of 60 women (more than 60 years old) who have lived in a cadmium-polluted area in Belgium have been compared with those of 70 women of the same age who have lived in another industrial area not polluted by cadmium. None of the subjects had been occupationally exposed to heavy metals. The group of women from the cadmium-polluted area (Liège) had a higher cadmium body burden as reflected by an increased excretion of cadmium in urine and a higher prevalence of signs of renal dysfunction than the women from the control area.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00380790
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  • 23
    Digitale Medien
    Digitale Medien
    On the correlation between alkaline phosphatase and phosphate transport in rat renal brush border membrane vesicles (1980)
    Springer
    Pflügers Archiv 384 (1980), S. 149-153 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Inorganic phosphate ; Alkaline phosphatase ; Kidney ; Brush borders
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Alkaline phosphatase activity in renal cortex homogenates and in isolated brush border membrane vesicles was compared with the rates of sodium-dependent transport of inorganic phosphate (Pi) by isolated brush border membranes. Brush border membrane vesicles were isolated from renal cortical homogenates of rats adapted during a period of 5–7 weeks to diets with different dietary contents of Pi (low Pi diet=0.15 g%, high Pi diet=2.0 g%). Alkaline phosphatase activity was not increased in the low Pi diet group as compared to the standard Pi diet group but was reduced in the high Pi diet group. Sodium-dependent transport of Pi was increased 2–3-fold in the low Pi diet group as compared to the standard Pi diet group, whereas transport activity was only unsignificantly decreased in the high Pi diet group. Studying kinetik parameters in the two extreme dietary groups it has been found that these differences are due to alteredV max of the transport activity as well as of alkaline phosphatase activity. TheK m for both activities remained unaltered. Alkaline phosphatase activity and transport of Pi in brush border membrane vesicles were also compared in the presence of EDTA or Zn2+ at concentrations which inhibit alkaline phosphatase activity. Transport of Pi was not affected by the inhibitors even when alkaline phosphatase was inhibited by more than 70% (0.5 mmol/l Zn2+) or completely (0.5 mmol/l EDTA). The experiments suggest that no correlation between alkaline phosphatase activity and transport of Pi exists in isolated brush border membrane vesicles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00584431
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  • 24
    Digitale Medien
    Digitale Medien
    The radiographic manifestations of bone changes in copper deficiency (1980)
    Springer
    Pediatric radiology 9 (1980), S. 101-104 
    Details
    ISSN: 1432-1998
    Schlagwort(e): Copper ; Bone ; Metaphyseal spurs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The bone changes in infants with copper deficiency are typified by osteopenia and the symmetrical appearance of sickle-shaped metaphyseal spurs. Four examples are demonstrated and the differential diagnosis is extensively discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00977672
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  • 25
    Digitale Medien
    Digitale Medien
    Renal factors in juvenile hypertension (1980)
    Springer
    Journal of molecular medicine 58 (1980), S. 1099-1104 
    Details
    ISSN: 1432-1440
    Schlagwort(e): Juvenile Hypertonie ; Niere ; Prostaglandine ; Kallikrein ; Renin ; Juvenile hypertension ; Kidney ; Prostaglandins ; Kallikrein ; Renin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Essential hypertension in infancy, once believed to occur rarely if ever, is now increasingly recognized as a potential precursor of essential hypertension in adulthood. The mechanisms responsible for hypertension in childhood and adolescence are only beginning to be delineated. Renal factors assumed to be operative in juvenile hypertension are involving either volume control (by renal regulation of sodium-chloride and water balance) or vasoactive substances like the kallikrein-kinin, the renin-angiotensin and the prostaglandin system and other less well defined hormones. There is a close interrelationship of all these hormones with each other as well as a close linking of these vasoactive compounds to the renal regulation of sodium-chloride and water balance, thus interfering with a major environmental factor necessary for the development of essential hypertension. At present, data are insufficient to delineate a single hormone or a single hemodynamic abnormality as the only primary factor in juvenile hypertension. Further research into the pathomechanisms responsible for the elevation of blood pressure at its very beginning will improve our understanding of hypertension and possibly benefit its management by early intervention.
    Notizen: Zusammenfassung Abweichend von früheren Auffassungen wird heute zunehmend die essentielle Hypertonie als eine Erkrankung auch des Kindes- und Jugendalters angesehen, aus der sich später die essentielle Hypertonie des Erwachsenen entwickelt. Die zur Entstehung der juvenilen Hypertonie führenden Pathomechanismen wurden in klinischen, epidemiologischen und tierexperimentellen Studien untersucht. Zu den renalen Mechanismen, die wahrscheinlich bei der Entstehung der juvenilen Hypertonie eine Rolle spielen, gehören Faktoren, die die renale Kontrolle der Salz-Wasser-Bilanz beeinflussen und vasoaktive Substanzen wie das renale Kallikrein-Kinin-System, das Renin-Angiotensin-System, das Prostaglandin-System und andere bislang weniger gut definierte Hormone. Diese renalen Hormone haben zahlreiche Wechselwirkungen untereinander. Neben ihren direkten Wirkungen auf die Gefäßwand können sie die Salz-Wasser-Bilanz beeinflussen bzw. werden von ihr beeinflußt, wodurch eine enge Verbindung mit Kochsalz, dem wohl entscheidendsten Umweltfaktor für die Entstehung der essentiellen Hypertonie, hergestellt ist. Fortgesetzte Bemühungen um die Aufklärung insbesondere der renalen Pathomechanismen, die am Beginn der Blutdruckerhöhung im Kindes- und Jugendalter wirksam sind, werden das Verständnis der essentiellen Hypertonie verbessern und unter Umständen durch frühzeitige Intervention sogar die Prävention dieser Erkrankung ermöglichen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01476880
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  • 26
    Digitale Medien
    Digitale Medien
    Progressive dialysis encephalopathy (“dialysis dementia”) (1980)
    Springer
    Journal of neurology 222 (1980), S. 145-157 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Dialysis ; Dementia ; Encephalopathy ; Kidney ; Transplant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei Patienten, die über lange Zeiträume hämodialysiert wurden, wurde bisher in insgesamt 60 Fällen eine progrediente und letal endende Enzephalopathie beschrieben. Eine Analyse dieser Falldarstellungen zeigt, daß die mittlere Dauer der Dialyse vor Beginn der Symptome 2,5 Jahre betrug und die mittlere Dauer des Verlaufes bis zum Tode 6,3 Monate. Die häufigsten klinischen Symptome sind Kommunikationsstörungen (87%), Störungen der Wahrnehmungen (66%) und der Bewegungen (93%). In allen Fällen sind nichtspezifische elektroenzephalographische Anomalies vorhanden. Möglicherweise steht die Störung in Zusammenhang mit noch nicht geklärten Stoffwechselanomalien. Es ist keine wirksame Therapie bekannt.
    Notizen: Summary Sixty cases of distinctive progressive and fatal encephalopathy have been reported in patients undergoing long-term hemodialysis. An analysis of their records reveals that mean duration of hemodialysis prior to onset is 2.5 years, while mean duration of clinical course until death is 6.3 months. The most frequent clinical manifestations include disturbances in communication (87%), cognition (66%) and movement (93%). Nonspecific electroencephalographic abnormalities are present in all cases. The condition is possibly related to some yet unidentified metabolic disorder. There is no effective therapy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00313113
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  • 27
    Digitale Medien
    Digitale Medien
    Acquired cystic transformation of the kidneys of haemodialysed patients (1980)
    Springer
    Virchows Archiv 386 (1980), S. 189-200 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Haemodialysis ; Kidney ; Cystic transformation ; Neoplastic transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the present study, the kidneys of patients who had been on maintenance haemodialysis for variable periods of time were examined at autopsy. In 21 of the 22 patients, multiple pinhead-size to pea-size, nonloculated cysts were observed both in the cortex and the medulla. In some of the cysts (4/20 patients), papillary adenomata were observed which were visible by light microscopy in 3 cases and macroscopically in 1 case. Clinical complications resulting from haemorrhage or neoplastic transformation were not observed in any of the patients of this series. Similar cysts, smaller in size and fewer in number, were also observed in kidneys of uraemic patients who had not been dialysed. Thus, the lesion does not appear to be a specific consequence of maintenance haemodialysis. It appears more likely that extensive cystic transformation of the kidneys of patients in terminal renal failure is made possible by prolonged survival on maintenance haemodialysis. The possibility of malignant transformation of the papillomata cannot be refuted, but epidemiological surveys fail to document more frequent occurrence of renal carcinoma in dialysed patients.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00427230
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  • 28
    Digitale Medien
    Digitale Medien
    Alterations in nuclear structure in dark cells of the collecting tubules in the kidney of castrated rats (1980)
    Springer
    Cell & tissue research 210 (1980), S. 485-492 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Collecting tubules ; Dark cells ; Kidney ; Castration ; Nuclear changes ; Nuclear bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Following castration, the nucleus of the dark cells of the subcortical portions of the collecting tubules in the rat kidney showed two types of morphological alterations: 1) Decomposition of the nuclear membrane in a circumscribed area. This phenomenon is independent of the sex of the animal and becomes more frequent up to the 30th day after castration. Occasionally, decomposed nuclei can also be observed in controls. 2) Giant nuclear bodies. These inclusions occurred only in castrated males. Early stages were already observed at the 10th day after orchiectomy, whereas fully developed giant nuclear bodies could not be demonstrated until about the 20th day after castration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220204
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  • 29
    Digitale Medien
    Digitale Medien
    Neue Wege zu 1H- und 2H-Pyrrolen (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 658-663 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New Routes to 1H- and 2H-PyrrolesA synthesis of 1H-pyrroles is described starting with pyridine analogues of chalcones and involving the reaction of acetic anhydride with 1-pyrroline-1-oxides. Another route leads from 1-pyrrolines to 2 H-pyrroles via bromination with N-bromosuccinimide and subsequent dehydrobromination in dimethylformamide.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630313
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  • 30
    Digitale Medien
    Digitale Medien
    Erratum (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 681-681 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630317
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  • 31
    Digitale Medien
    Digitale Medien
    Nucleophilic addition to C,C double bonds. IIIFor Part I, see [1]; for Part II, see [2].. Chemical reactivity of 1endo, 4endo: 5exo, 8exo-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalen-10syn-ol and X-ray structure analysis of its p-nitrobenzoate (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 674-681 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The title compound 1 is a further example of an olefinic alcohol that undergoes ether formation under basic conditions (→ 3) although the double bond is not activated by an electron-attracting group. This unusual reactivity is due to steric compression, which is increased in the 10-methyl analogue 2. This forms the corresponding ether 7 at a much higher rate. - In a deuteriated medium, base-catalysed cyclization of 1 gives the exo-deuteriated ether 6, corresponding to trans-addition. - An X-ray structure analysis of 4, the p-nitrobenzoate of 1, is presented.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630316
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  • 32
    Digitale Medien
    Digitale Medien
    The Synthesis of β,γ- and α,β-Unsaturated Aldehydes via Polyene EpoxidesDedicated to Dr. O. Isler on the occasion of his 70th birthday (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1665-1674 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A substitute for the Darzens glycidic ester synthesis for converting unsaturated ketones or aldehydes into the homologated β,γ- or α,β-unsaturated aldehydes employing sulfur ylides is described. The carbonyl group is converted into the unsaturated oxirane which is then rearranged to the new aldehyde. High yields of isomerically pure aldehydes are available by this method and the process is of practical importance in the conversion of β-ionone into the β-C14-aldehyde, a key intermediate in the Isler synthesis of vitamin A. The efficient preparation of α- and β-cyclocitral by the novel process is also described.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630636
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  • 33
    Digitale Medien
    Digitale Medien
    Globularifolin, A New Acyl Iridoid Glucoside from Globularia cordifoliaPart 3 in the series ‘Glycosides of Globulariaceae’. For parts 1 and 2 see [1] [2]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 117-120 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Six iridoid glucosides have been isolated from Globularia cordifolia by the combination of open column - and high performance liquid chromatography. The structure of the new compound, named globularifolin, and the identity of the others have been established by chemical transformations and spectral evidence of the compounds and their derivatives.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630112
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  • 34
    Digitale Medien
    Digitale Medien
    Photofragmentation of Dibenzyl Ketone in the Presence of Tetramethylpiperidine Derivatives. Studies on light stabilizer mechanisms [1] (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 132-147 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The interaction of selected tetramethylpiperidine derivatives with radicals arising from the Norrish-type I cleavage of dibenzyl ketone under oxygen was studied. Product analyses and kinetic studies showed that the investigated sterically hindered piperidine derivatives have a pronounced effect on both the nature and distribution of the products of photolysis of dibenzyl ketone in the presence of oxygen. Observations indicated that the phenylperacetoxyl radical is formed as an intermediate during irradiation and that it interacts with the additives used. Possible mechanisms of the reactions studied are discussed.The observation that oxidation of an isolated double bond by the radicals formed in dibenzyl ketone photolysis under oxygen is strongly inhibited in the presence of the studied sterically hindered amines is discussed in the light of the results presented. The findings are considered in relation to the problem of polymer stabilization.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630114
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  • 35
    Digitale Medien
    Digitale Medien
    Approaches to the Synthesis of Cytochalasans. Part 2. Pyrrolinone derivatives as basic unitsPart 1: [1].Part of the Ph.D. Thesis of T. Schmidlin, Basel 1979. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 121-131 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Several attempts to prepare 3-acetyl-5-benzyl-3-pyrrolin-2-one (7) from phenylalanine are described. This goal was only reached formally, because compound 7 exists in the tautomeric form of (Z)-5-benzyl-3-(1′-hydroxyethylidene)-4-pyrrolin-2-one (17) according to the spectral data. The problem of tautomerism in pyrrolinone systems is discussed.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630113
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  • 36
    Digitale Medien
    Digitale Medien
    Nucleophile Aminoalkylierung mit ThiopivalamidenVorläufige Mitt. [1]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 102-116 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Nucleophilic Aminoalkylation with ThiopivalamidesVorläufige Mitt. [1].Of the twelve thioamides 7a-e and 8a-g, only N,N-dimethylthiopivalamide (7a) could be metallated at the CH-group in a-position to the N-Atom. The reagent 9 thus obtained (Table 1) reacts in high yields with primary haloalkanes, with aldehydes, and with non-enolizable ketones (Table 2). As shown in Scheme 1, the products can be hydrolyzed to pivalamides, cleaved to secondary amines, or reduced to neopentylamines (see 18/19, 15/equation (4) and (5), and 16/20, respectively).
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630111
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  • 37
    Digitale Medien
    Digitale Medien
    Laser Induced Excitation Spectra of the Cations of Some Fluoro-substituted Phenols (B̃2 A″ ↔ X̃2 A″) in the Gaseous Phase (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1920-1925 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Excitation spectra of the cations of pentafluorophenol, 2,3,4-trifluorophenol, 2,4,5-trifluorophenol, 2,5-difluorophenol and 3,5-difluorophenol have been obtained by pumping the B̃2 A″ ← X̃2A″ transition with a dye laser. The cations were first produced in their ground states by Penning ionisation using argon metastables. Vibrational frequencies of some of the fundamentals have been inferred for these cations in the B̃2 A″ state from the excitation spectra, and in the X̃2 A″ state from the emission spectra. Possible applications of the reported results are suggested.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630719
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  • 38
    Digitale Medien
    Digitale Medien
    Synthesen von polyhalogenierten Butyrylchloriden, Vorläufern der pyrethroiden Haloketene1. Mitteilung über Cu+-katalysierte Radikaladditionen von Polyhalogenverbindungen an Olefine.Auszugsweise präsentiert am ‘International Symposium on Chemistry of the Pyrethroids’ vom 16.-19. Juli 1979 in Oxford, am ‘1st European Symposium on Organic Chemistry’ vom 20.-23. August 1979 in Köln, am ‘178th ACS National Meeting’ vom 9.-14. September 1979 in Washington, D.C., sowie an der Herbstversammlung der Schweizerischen Chemischen Gesellschaft vom 19.-20. Oktober 1979 in Bern. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1947-1957 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis of Polyhalogenated Butyryl Chlorides, Precursors of Pyrethroid HaloketenesThe copper (I)-catalyzed free radical addition of halomethanes to acrylates and the addition of halogenated acetic acid derivatives to fluoro- or chloro-substituted ethylenes affords polyhalogenated butyric acid derivatives. Chlorides of these acids serve as precursors for haloketenes used in efficient syntheses of pyrethroids.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630722
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  • 39
    Digitale Medien
    Digitale Medien
    High Acceleration and Improved Diastereoselectivity of Intramolecular Ene-Type Reactions by Diethylaluminum Chloride. Preliminary Communication (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2010-2014 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The pyrrolidines 2 and 10 were obtained by thermal ene-reactions at +70° and +180° from the (Z)-4-aza-1, 6-diene 1 and from the (E)-4-aza-1, 6-diene 9 in the ratios of 75:25 and 50:50, respectively. On the other hand, these cyclizations proceeded readily in the presence of diethylaluminum chloride at - 78° and - 35° giving in high yield the trans-pyrrolidine 2 from 1 with 100% and from 9 with 89% diastereoselectivity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630728
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  • 40
    Digitale Medien
    Digitale Medien
    Tieftemperatur 13C-NMR.-Spektren von 13C-und 6Li-markierten Chlor-, Brom- und Jod-Lithium-Carbenoiden. Vorläufige Mitteilung (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2046-2053 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Low Temperature 13C-NMR. Spectra of 13C- and 6Li-Labelled Chloro-, Bromo-, and Iodo-lithiumcarbenoidsThe 13C-NMR. spectra of tetrahydrofuran solutions of 16 chloro-, bromo-, and iodo-6lithio- and -7lithio-carbenoids with 13C-labelled methane, ethane, ethylene, and cyclopropane C-skeletons have been measured at temperatures around - 100° (for examples see Fig. 1 and 2). Invariably, the exchange of hydrogen or halogen by lithium causes deshielding (Δδ, see Table 1) of the 13C-signal by up to 289 and 434 ppm, respectively, and decrease of 1J (1H, 13C) and 1J(13C,13C) couplings (see Table 2) with the C-atom of up to 104 and 30 Hz, respectively. The 1J(6Li, 13C) and 1J(7Li, 13C) coupling of ca. 17 and 45 Hz, respectively, obtained in ten cases (Table 1) is independant of the substitution pattern of the C-skeleton and of the particular halogen atom.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630732
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  • 41
    Digitale Medien
    Digitale Medien
    The trans-Influence in Platinum (II) Complexes. 1H- and 13C-NMR. and X-ray structural studies of tridentate Schiff's base complexes of platinum (II) (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2071-2086 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1H- and 13C-NMR. data are reported for the complexes [Pt(1)L] and [Pt(2)L]; 1 = OC6H4CH = NCH2CH2O, 2 = OC6H4CH = NC6H4O; L = PR3, AsR3, C ≡ N (cyclohexyl), DMSO, pyridine, secondary amine. The molecular structures of [Pt (2) (NHEt2)] (I) and [Pt (2) (PPh3)] (II) have been determined by X-ray analysis. Relevant bond distances for I: Pt-N (amine) = 2.076 Å, Pt-N (imine) = 2.017 Å, Pt-O = 1.992 Å and 2.002 Å; for II: Pt-P = 2.248 Å, Pt-N = 2.064 Å, Pt-O = 1.964 and 2.005 Å. Both the solid and solution state data are interpreted in terms of differences in the trans influence of the ligand L. The question of metal-ligand d-p π back bonding to the imine is discussed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630734
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  • 42
    Digitale Medien
    Digitale Medien
    A Model for Nicotinamide-Trytophane Charge-Transfer Interactions: The complexation of nicotinamide-ammonium salts by a macrocyclic receptor molecule bearing tryptophane side chains (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2112-2118 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The complexation of primary ammonium salt substrates by macrocyclic polyether receptor molecules provides a general method for studying the nature and stereochemistry of intermolecular interactions. The substrates and receptors are fitted each with one of the interacting units and the resulting effects in the complex are analyzed. The method is used to study the biologically important indole-pyridinium donor-acceptor interaction. The complexes between macrocycles, bearing an indole group in side chains, and pyridinium-ammonium salts display a characteristic charge-transfer band. The absorption coefficients and stability constants have been determined. Competition experiments also provide a new method for measuring the stability constants of macrocycle-ammonium complexes in organic solvents.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630737
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  • 43
    Digitale Medien
    Digitale Medien
    Aristoserratin, ein neues Indolalkaloid aus Aristotelia serrata W.R.B. OLIVER und A. peduncularis (LABILL.) HOOK. F. 178. Mitteilung über organische Naturstoffe177. Mitt. s. [1].Teil der geplanten Dissertation von R.K., Universität Zürich. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2130-2134 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Aristoserratine, a New Indole Alkaloid from Aristotelia serrata W.R.B. OLIVER and from A. peduncularis (LABILL.) HOOK. F.The new indole alkaloid aristoserratine (2) has been isolated from Aristotelia. Its structure and absolute configuration were elucidated on the basis of spectroscopic data.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630739
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  • 44
    Digitale Medien
    Digitale Medien
    Polar Substituent Effects in the Solvolysis of Primary and Tertiary Alkyl Halides. Polar Effect IX (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2152-2158 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: When the Hammett-Taft equation log (k/ko)=ρq · σ1q is applied to the solvolysis of the 3-substituted propyl bromides 6a-6i in ethanol/water 4:1 (v/v) log k correlates linearly with σ1q except in cases where R exerts an anchimeric effect. The reaction constant ρq for 6 is - 0.12 and is typical for a nucleophilic solvent-assisted ks process at a primary C-atom. The tertiary halides 1 and 3, however, which react with little or no nucleophilic solvent assistance, i.e. by kc processes, lead to larger ρq values of -0.71 and -1.14, respectively. The reaction constant pq is therefore a sensitive gauge for charge development in the transition state for solvolysis of saturated compounds.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630804
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  • 45
    Digitale Medien
    Digitale Medien
    Action du cyanure mercurique sur quelques halogénures de désoxy-3-trifluoroacétamido-3-D-ribofurannosyle. Note de laboratoire (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2258-2263 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reactions of Some 3-Deoxy-3-trifluoroacetamido-D-ribofuranosyl Halides with Mercuric CyanideThe expected 2,5-anhydro-D-allononitrile 11 was obtained when the 2-O-benzoyl-3-deoxy-3-trifluoroacetamido-D-ribofuranosyl bromide reacted with mercuric cyanide, whereas the isomeric 1,2-O (1-cyanoethylidene) derivative was formed from the 2-O-acetylated halide; no reaction occurred when the halide was 2-O-p-nitrobenzoylated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630814
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  • 46
    Digitale Medien
    Digitale Medien
    Lipophilic Amides of EDTA, NTA and Iminodiacetic Acid as Ionophores for Alkaline Earth Metal Cations (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2264-2270 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A series of electrically neutral lipophilic di-, tri-, and tetra-amides containing tertiary-amine N-atoms were prepared in order to investigate their selectivity for alkali and alkaline earth metal cations in solvent polymeric membranes. Considerable selectivity changes were observed for membranes incorporating certain of these ligands as compared with ligand-free membranes. A 1:1 cation/ligand complex was isolated from N, N′, N″-triheptyl-N, N′, N″-trimethyl-nitrilotriacetamid and Mg (SCN)2 whereas with Ca (SCN)2 the corresponding 2:3 cation/ligand complex was formed. N, N′, N″, N‴, N‴-tetramethyl-ethylenediaminetetraacetamide yields a 1:1 cation/ligand complex with Mg (SCN)2.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630815
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  • 47
    Digitale Medien
    Digitale Medien
    Beitrag zur massenspektrometrischen retro-Diels-Alder-Reaktion: 1,2,3,4-Tetrahydrophenanthren. 35. Mitteilung über massenspektrometrische Untersuchungen34. Mitt.: s. [1]. Auszugsweise vorgetragen an der 13. Diskussionstagung der Arbeitsgemeinschaft Massenspektrometrie, 28.-30. Mai 1980 in Köln. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2295-2301 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Contribution to the Mass Spectral retro-Diels-Alder Reaction: 1,2,3,4-Tetrahydrophenanthrene[1,4-13C]-1,2,3,4-Tetrahydrophenanthrene (1) was synthesized starting from [1,4-13C]-succinic acid. The mass spectral behavior (EI./MS., 70eV) of 1 is very similar to that of tetraline [2] concerning its loss of ethylene from the molecular ion. Similarly the fragmentation reaction of the synthetic precursors, ketones 7 and 8, seems to partly undergo a carbon rearrangement reaction prior to the elimination of ethylene which is unlike to the behavior of α-tetralone.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630819
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  • 48
    Digitale Medien
    Digitale Medien
    Beiträge zur Kenntnis des chromophoren Systems der Corrine. XIX. Mitt.: [1].. Über die Reaktion von Derivaten des Cobyrinsäure-heptamethylesters mit unterchloriger SäureMeinem verehrten Kollegen Oskar Glemser gewidmet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2320-2327 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Contributions to the Knowledge of the Corrin Chromophore, X. Reaction of Derivatives of Cobyrinic Acid Heptamethyl Ester with Hypochlorous Acid(Cobalt)-dicyano-, chloro-cyano-, and dichloro-cobyrinic acid heptamethylesters (1, 2 and 3), respectively, as well as their 10-chloro derivatives 4, 5 and 6 react with hypochlorous acid. A report on the structure and some properties of the reaction products 8, 9 and 10 is given.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630822
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  • 49
    Digitale Medien
    Digitale Medien
    Steroids and sex hormons. Part 264Part 263, s. [1].. Lewis acid catalyzed reversible [1,5]-hydride shift in 3,19-epoxy-steroids (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2342-2357 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 3β, 19-Epoxy-3 α-methoxy-steroids (e.g. 1, Scheme 1) are converted into the corresponding 3 α-methoxy-19-oxo compounds (e.g. 3) in the presence of boron trifluoride etherate, via an intramolecular hydride ion transfer from C (19) to (3) which is shown to be an equilibrium process. By subjecting the specifically deuteriated (19 S)- and (19 R)-compounds 1b and 1c to this reaction it was shown to be highly stereoselective.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630825
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  • 50
    Digitale Medien
    Digitale Medien
    Synthesis of Pure Al35Cl3 and Al37Cl3 (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2375-2379 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chemically and isotopically pure Al35Cl3 and Al37Cl3 are synthesized from Al (s) and HCl (g). The yield is quantitative and no measurable decrease in isotopic content from HCl to AlCl3 takes place.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630829
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  • 51
    Digitale Medien
    Digitale Medien
    A Norrish Type I cleavage in the photolysis of a steroidal α,β-unsaturated δ-lactonePart of the doctoral thesis of A. Cánovas, I.Q.S., Barcelona, 1980.. Photochemical Reactions. XIV [1] (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2390-2392 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The UV. irradiation of 17 β-acetoxy-4-oxa-5 α-androst-1-en-3-one (1) yields A,B-diseco-steroids originating from a Norrish I process of the lactone function.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630831
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  • 52
    Digitale Medien
    Digitale Medien
    Die Strukturdynamik von Pentadienylmetall-Verbindungen mit endständiger Alkyl-Gruppe: zugleich «stereoselektive» und «stereodefensive» Synthese eines natürlichen RiechstoffesTeil VIII der Reihe «Selektive Synthesen mit Organometallen»; VII. Mitteilung s. [1]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2393-2403 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Structural Dynamics of Pentadienyl Metal-Compounds Bearing a Terminal Alkyl Substituent: Both ‘Stereoselective’ and ‘Stereodefensive’ Synthesis of a Natural Perfume.The (2Z, 4E)-, (2E, 4Z)- and (2E, 4E)-isomers of 2,4-decadien-1-ol (5) have been obtained with high and predictable stereochemical homogeneity starting from both (Z)- and (E)-1, 4-decadiene. These hydrocarbons were hydroxylated in a reaction sequence consisting of metallation (by means of s-butyllithium or butyllithium/potassium-t-butoxide, giving rise to organometallic intermediates of specific conformation), dimethoxyborylation and oxidation. The different decadienols as well as (2E, 4Z)-2, 4-undecadien-1-ol were converted into the isovalerates, the ester derived from (2E, 4Z)-2, 4-decadien-1-ol being a natural flavor component.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630832
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  • 53
    Digitale Medien
    Digitale Medien
    Regio- and Stereoselective Functionalizations of Tricyclo [3.3.0.02,8]octan-3-one, a Potential Synthon for Polycyclopentanoid Terpenes and Prostacyclin Analogs. Preliminary CommunicationPresented in parts at the ESOC I Conference, Köln 1979 [1], and in full at the VIII IUPAC Symposium on Photochemistry, Seefeld 1980 [2]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2440-2445 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chemical transformation of tricyclo [3.3.0.02,8]octan-3-one (1) have been carried out in order to explore its potential utility as a versatile synthon for polycyclopentanoid terpenes and prostacyclin analogs. Various functionalizations of rings A and B and annulation of a third ring C were achieved in generally high yields. The system provides for a large measure of regio- and stereoselective reaction control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630837
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  • 54
    Digitale Medien
    Digitale Medien
    Methyl-triisopropoxy-titanium, a highly selective nucleophilic methylating reagentPresented by D.S. at the meeting of the Organic Division of the German Chemical Society, Bad Nauheim, October 16, 1980.. Preliminary Communication (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2451-2454 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Replacement of lithium or magnesium by titanium can furnish nucleophilic organometallic reagents of high selectivity as exemplified by the title compound 1 (see Tables 1-3).
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630839
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  • 55
    Digitale Medien
    Digitale Medien
    Nucleoside und Nucleotide. Teil 15. Synthese von Desoxyribonucleosid-monophosphaten und -triphosphaten mit 2(1H)-Pyrimidinon, 2(1H)-Pyridinon und 4-Amino-2(1H)-pyridinon als BasenTeil 14 s. [1].Für Einzelheiten vgl. [2][3]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2488-2494 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Nucleosides and Nucleotide. Part 15. Synthesis of Deoxyribonucleoside Monophosphates and Triphosphates with 2(1H)-Pyrimidinone, 2(1H)-Pyridinone and 4-Amino-2(1H)-pyridinone as the BasesThe phosphorylation of the modified nucleosides 1-(2′-deoxy-β-D-ribofuranosyl)-2(1 H)-pyrimidinone (Md, 4), 4-amino-1-(2′-deoxy-β-D-ribofuranosyl)-2(1 H)-pyridinone (Zd, 6) and the synthesis of 1-2′-deoxy-β-D-ribofuranosyl-2(1 H)-pyrimidinone-5′-O-triphosphate (pppMd, 1), 1-(2′-deoxy-β-Dribofuranosyl)-2(1 H)-pyridinone-5′-O-triphosphate (pppIId, 2), and 4-amino-1-(2′-deoxy-βD-ribofuranosyl)-2(1 H)-pyridinone-5′-O-triphosphate (pppZd, 3) are described. The nucleoside-5′-monophosphates pMd (5) and pZd (7) were obtained by selective phosphorylation of Md (4) and Zd (6), respectively, using phosphorylchloride in triethyl phosphate or in acetonitril. The reaction of pMd (5) pII d (8) or pZd (7) with morpholine in the presence of DCC led to the phosphoric amides 9, 10 and 11, respectively, which were converted with tributylammonium pyrophosphate in dried dimethylsulfoxide to the nucleoside-5′triphosphates 1, 2 and 3, respectively.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630842
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  • 56
    Digitale Medien
    Digitale Medien
    Synthesis of cannabinoid model compounds. Part 2Part 1: see [1].: (3R, 4R)-Δ1(6)-Tetrahydrocannabinol-5″-oic acid and 4″(R, S)-Methyl-(3R, 4R)-Δ1(6)-tetrahydrocannabinol-5″-oic Acid (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2508-2514 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two novel cannabinoid model compounds, (3R, 4R)-Δ1(6)-tetrahydrocannabinol-5″-oic acid (22) and 4″(R, S)-methyl-(3R, 4R)-Δ1(6)-tetrahydrocannabinol-5″-oic acid (23) were synthesized by acid-catalyzed condensation of (+)-trans-p-mentha-2, 8-dien-l-ol (1) with the substituted resorcinols 18 and 19 obtained by a Wittig reaction between 3, 5-bis(benzyloxy)benzaldehyde (7) and methyl 4-bromobutanoate (10) or methyl 4-bromo-2(R, S)-methylbutanoate (11) resp. with subsequent hydrogenation. The resulting methyl esters 20 and 21 were hydrolyzed to give acids 22 and 23.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630845
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  • 57
    Digitale Medien
    Digitale Medien
    Unambiguous Proof for Alcoxycarbonyl-group Migration in Wagner-Meerwein Rearrangements (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2538-2553 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In HSO3F/SO2ClF the β-hydroxy esters Ph-CHOH-CMe2-COOR (1, R=Me, Et) are doubly protonated, then transformed into the fluorosulfates 7 and (partly) into the fluorides 8. At -15°, both 7 and 8 undergo a rearrangement, forming derivatives of Me2C=C(Ph)COOR (2). By labelling 1 with 13C, singly (13C(3)) and doubly (13C(1,3)), it could be shown that exclusively the ROOC groups undergo a 1,2-shift. Compound 2 is also formed in HSO3F/SO2ClF from the isomeric Me2COH-CHPh-COOR (3) by elimination, and less easily from the α-hydroxy ester Ph-CMe2-CHOH-COOR (5) via a phenyl 1,2-shift. Another isomer, Ph-C(OH)Me-CHMe-COOR (4) gives products different from 2.Using more acidic systems containing SbF5, the free carbenium ions 13 (Ph-CH+-CMe2-COOR) can be stabilized; they do not form 2, possibly because of complexation of the ester group with SbF5. The energy profile and the mechanism of the rearrangement 1 → 2 are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630849
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  • 58
    Digitale Medien
    Digitale Medien
    Transition metal complexes with bidentate ligand 2, 11-Bis (diphenylphosphinomethyl)benzo[c]phenanthrene (1). XPart IX: see [1].. Preparation and spectroscopic properties of cis-[PtCl2 (1)] trans- and cis-[PtH (PPh3) (1)] [BF4] and crystal and molecular structure of cis-[PtCl2 (1)] · CHCl3 (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2519-2530 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: It is shown that ligand 1, designed to span trans-positions, under appropriate conditions also gives cis-mononuclear complexes of platinum (II). The structure of cis-[PtCl2 (1)] (2) has been determined by single-crystal X-ray diffraction. The major distortion from square planar coordination is the P-Pt-P angle of 104.8°. Values of valence angles within the bidentate ligand indicate that this part of the molecule is very strained. Two phenyl groups, one on each phosphorus, lie almost parallel to each other separated by ca. 3.2-3.3 Å. The 1H-NMR. data for this compound show that the π-phenyl interactions observed in the solid state occur also in solution. The preparation and NMR.-spectroscopic properties of trans- and cis-[PtH(PPh3) (1)] [BF4] are reported.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630847
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  • 59
    Digitale Medien
    Digitale Medien
    Über Pterinchemie 76. Mitteilung [1] Eine einfache Synthese von LeucovorinTeil der Dissertation von E. Khalifa, Universität Zürich 1980. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2554-2558 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A Convenient Synthesis of LeucovorinThe synthesis of leucovorin, a 5-formyl-(6R or S)-5,6,7,8-tetrahydropteroyl-L-glutamic acid (II) is described. The L-folic acid was first reduced to (6R, S)-tetrahy-dro-L-folic acid (I); formylation with methyl-formate in DMSO gave directly leucovorin (as a diastereomeric mixture) in good yields. To demonstrate, that the formylation occurred regiospecifically at N (5) and not at N (10), N (10)-nitroso-(6 R, S)-tetrahydro-L-folic acid was formylated under the same conditions. Reductive elimination of the N (10)-nitrosogroup gave the identical leucovorin as in the previous case. The synthetic leucovorin was biologically as active as the natural product with Streptococcus faecalis ATCC 8043 and Pediococcus cerevisiae ATCC 8081.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630850
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  • 60
    Digitale Medien
    Digitale Medien
    Synthèse partielle et propriétés oncostatiques des pseudo-tubulosines, analogues de l'émétine et de la tubulosine (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1335-1346 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Partial Synthesis and Oncostatic Properties of Pseudotubulosines, Analogues of Emetine and TubulosinePseudotubulosines, structural analogues of emetine and tubulosine, have been synthesized by either Pictet-Spengler or Bischler-Napieralski condensation from dihydrocorynantheal or corynantheidal. Spectral data, cytotoxic and oncostatic properties of these new alkaloids are described.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630525
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  • 61
    Digitale Medien
    Digitale Medien
    Stoffwechselprodukte von Mikroorganismen. 193. Mitteilung192. Mitt. s. [1].. Ferrithiocin (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1400-1406 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Metabolites of Microorganisms. FerrithiocinThe strain Tü 1998 from Streptomyces antibioticus produces besides the indicator antibiotics β- and γ-rubromycins a new sulfur containing metabolite. This metabolite, called ferrithiocin, has been isolated in the form of a iron complex. The structure 1 of the iron-free compound was elucidated by spectroscopic studies and chemical degradation.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630608
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  • 62
    Digitale Medien
    Digitale Medien
    Die Hydrolyse von 6exo-substituierten 2exo- und 2endo-Norbornylestern der p-Toluolsulfonsäure. Norbornanreihe. 3. Mitteilung (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 928-937 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Hydrolysis of 6exo-Substituted 2exo- and 2endo-Norbornyl p-Toluenesulfonates. Norbornane Series. Part 3Hydrolysis of the 6exo-substituted 2exo- and 2endo-norbornyl p-toluenesulfonates 1b-1 and 2b-1, respectively, in 70% dioxane led to different amounts of the following products: Unrearranged 2exo-norbornanols 3 and norbornenes 5, accompanied in somes cases by small amounts of the rearranged Rendo-epimers 4 and 6 and by norticyclenes 7. When the 6exo-substituent was a nucleophilic group as in 1e-1 and 2e-1, various amounts of tricyclic products were also formed by endo-cyclization. These results show that the 2exo- and 2endo-esters 1 and 2, respectively, react by way of different intermediates. In cases where the 6exo-substituent was an n-electron donor, as in 1m-r and 2m-r, quantitative fragmentation to (3-cyclopentenyl)acetaldehyde (13) occurred.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630422
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  • 63
    Digitale Medien
    Digitale Medien
    The Radical Ions of Naphtho [1,8-cd]-[1,2,6]thiadiazine and Some of Its Derivatives (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2144-2151 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The radical cations and anions of naphtho [1,8-cd]-[1,2,6]thiadiazine (1) and 6,7-dihydroacenaphtho [5, 6-cd]-[1,2,6]thiadiazine (2), as well as the radical anion of acenaphtho [5, 6-cd]-[1,2,6]thiadiazine (3) have been characterized by ESR. spectroscopy. The π-spin distributions in the radical cations \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\oplus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\oplus \atop \dot{}}$\end{document} strongly resemble those in the iso-π-electronic phenalenyl radical. A prominent feature of the radical anions \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\ominus \atop \dot{}}$\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\ominus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{\ominus \atop \dot{}}$\end{document} is the substantial localization of the π-spin population on the thiadiazine fragment. These findings are satisfactorily accounted for by HMO models using conventional heteroatom parameters.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630803
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  • 64
    Digitale Medien
    Digitale Medien
    Two Furanosesquiterpene Marine Metabolites with Antifeedant PropertiesA preliminary account of this work was presented at the International Colloquium CNRSORSTOM on Natural Products of Biological Interest of the Pacific, in Noumea, New Caledonia, September 1979. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2159-2167 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two new sesquiterpenoids, nakafuran-8 (1) and -9 (8), have been isolated from the marine sponge Dysidea fragilis and from its prey, the nudibranchs Hypselodoris godeffroyana and Chromodoris maridadilus. The structures were established by spectral analysis and chemical transformations. Both compounds possess antifeedant properties when assayed in the laboratory against common reef fishes, Chaetodon spp.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630805
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  • 65
    Digitale Medien
    Digitale Medien
    Synthesis of 5-Methyluridine and Its 5′-Mercapto-, 2-Amino-, and 4′,5′-Unsaturated Analogues (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2179-2186 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The stereospecific cis-hydroxylation of 1-(2,3-dideoxy-β-D-glyceropent-2-enofuranosyl)thymine (1) into 1-β-D-ribofuranosylthymine (2) by osmium tetroxide is described. Treatment of 2′,3′-O, O-isopropylidene-5-methyl-2,5′-anhydrouridine (8) with hydrogen sulfide or methanolic ammonia afforded 5′-deoxy-2′,3′-O, O-isopropylidene-5′-mercapto-5-methyluridine (9) and 2′,3′-O, O-isopropylidene-5-methyl-isocytidine (10), respectively. The action of ethanolic potassium hydroxide on 5′-deoxy-5′-iodo-2′,3′-O, O-isopropylidene-5-methyluridine (7) gave rise to the corresponding 1-(5-deoxy-β-D-erythropent-4-enofuranosyl)5-methyluracil (13) and 2-O-ethyl-5-methyluridine (14).The hydrogenation of 2 and its 2′,3′-O, O-isopropylidene derivative 4 over 5% Rh/Al2O3 as catalyst generated diastereoisomers of the corresponding 5-methyl-5,6-dihydrouridine (17 and 18).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630808
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  • 66
    Digitale Medien
    Digitale Medien
    Photochemische Reaktionen 114. Mitteilung [1]. Zur Photochemie cyclischer Acetale vom 1,3-Dioxa-4,6-cycloheptadien-Typus (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2221-2229 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Photochemistry of Cyclic Acetals of the 1,3-Dioxa-4,6-cycloheptadiene TypeUV.-irradiation (λ=254 nm) of 3 gives the isomers (E)-5 (4%), (Z)-5 (60%) and 6 (3%). On triplet sensitization (acetone; λ ≥ 280 nm) 3 is converted to (E)-5 (3%), (Z)-5 (7%) and 7 (9%). - The 1π,π*-excitation (λ=254 nm) of 4 yields the isomers 2 (9%), 8 (10%), 9 (34%), 10 (20%) and 11 (3%). On thermolysis (200°) 4 gives 10 (87%) by a Claisen-rearrangement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630812
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  • 67
    Digitale Medien
    Digitale Medien
    Photochemische Reaktionen 115. Mitteilung [1]. Zur Photochemie konjugierter γ,δ-Epoxyenone: Der Einfluss eines Hydroxylsubstituenten in ∊-StellungMit den besten Wünschen Herrn Dr. Willy G. Stoll zum 70. Geburtstag zugeeignet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2230-2257 
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    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Photochemistry of Conjugated γ,δ-Epoxyenones: The Influence of a Hydroxy Substituent in ∊-PositionOn 1n, π*- or 1π,π*-excitation (λ ≥ 347 or λ=254 nm), the ε-hydroxy-γ;,δ-epoxyenone 8 undergoes fission of the C(γ)—O bond followed by the cleavage of the C(δ)-C(ε) bond. This hitherto unknown sequence of reactions is evidenced by the structure determination of the new type products 10-17 and 25, including a synthetic proof for 12 and the X-ray analysis of 11 (X-ray data: triclinic P1; a=7,386(2), b=8,904(4), c=9,684(5)Å; α=82,29(4)°, β=74,46(3)°, γ=82,29(3)°; Z=2).The selective 1π,π*-excitation also induces competitive C(γ)-C(δ) bond cleavage to yield the bicyclic acetal 18 and a ketonium-ylide intermediate a, which photochemically forms a carbene b giving the allene 19 and the cyclopropene 20.On 1n,π*-excitation of the acetate 9 the initial C(γ)-O bond fission is, in contrast to the behaviour of the corresponding alcohol 8, followed by a 1,2-methyl shift affording (E/Z)-28 or by a cyclization-autoxidation process yielding the lactone 29.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630813
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  • 68
    Digitale Medien
    Digitale Medien
    Zur Synthese sulfonierter Derivate von 4- und 5-Aminoindan (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2280-2286 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: On the Synthesis of Sulfonated Derivatives of 4- and 5-AminoindanBaking the hydrogensulfate salt of 4-aminoindan (1) and 5-aminoindan (2) led, respectively, to 4-aminoindan-7-sulfonic acid (3) and 5-aminoindan-6-sulfonic acid (4). Acid 4 was also obtained by direct sulfonation of 2. 4-Aminoindan-6-sulfonic acid (5) and 6-aminoindan-4-sulfonic acid (6) were prepared by sulfonation of 4-nitroindan (7) and 5-nitroindan (9), respectively, to 4-nitroindan-6-sulfonic acid (8) and 6-nitroindan-4-sulfonic acid (10), followed by a Béchamp-reduction. Treatment of 1 with amidosulfuric acid gave 3, whereas the same reaction with 2 led to a mixture of 4 and 5-aminoindan-4-sulfonic acid (11). Independent synthesis of 11 was achieved by the following sequence of reactions: sulfur dioxide treatment of the diazonium chloride derived from 4-amino-5-nitrodan (13) gave 5-nitroindan-4-sulfonyl chloride (14); hydrolysis to 5-nitroindan-4-sulfonic acid (15), and final reduction. The 4-aminoindan-5-sulfonic acid (16) was synthesized by treatment of 4-amino-7-bromoindan (18) with amidosulfuric acid to give 4-amino-7-bromoindan-5-sulfonic acid (19) followed by hydrogenolysis. Sulfonation of 4-acetyl-amino-7-bromoindan (17) with oleum followed by hydrolysis led to 7-amino-4-bromoindan-5-sulfonic acid (20), the structure of which was confirmed by reductive dehalogenation to 5.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630817
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  • 69
    Digitale Medien
    Digitale Medien
    Micellar Solubilization of Biopolymers in Hydrocarbon Solvents III. Empirical Definition of an Acidity Scale in Reverse Micelles (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2302-2311 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: This paper deals with the problem of defining, and measuring, the pH inside the water pool (which we define as pHwp) of reverse micelles, i.e. micelles formed by surfactants dissolved in apolar solvents in the presence of minimal amounts of water. The conceptual and experimental difficulties are discussed, and it is argued that no absolute determination of pHwp is possible, mostly because water in the water pools of reverse micelles is a new solvent, for which no standardization of acidity is available. The problem can be approached only on the basis of an empirical acidity scale.An empirical acidity scale for water pools in reverse micelles of bis (2-ethyl-hexyl) sodium sulfosuccinate (AOT) in isooctane has been defined by measuring the 31P-chemical shifts of phosphate buffers. The chemical shifts in bulk water were compared to those found in reverse micelles under the assumption that the pK of phosphate ion is the same in the two systems. It was found that in most cases there was little difference (less than 0.4 pH units) between pHwp and the pH of the starting buffer in bulk water (which we define as pHst). However, this difference between pHwp and pHst may become much larger in certain cases.The difference (pHwp-pHst) is measured under a variety of conditions, and this permits the determination of an operational acidity in the micelle water pools as a function of the pHst with which the aqueous micelles are prepared. The significance of such data for interpreting the behaviour of enzymes confined in the micelles water pool is discussed. Based on the pHwp scale, the apparent pKa of phenol-red and 4-nitrophenol were determined in reverse micelles containing different buffers and different water content. The pKa values obtained were rather sensitive to changes of both these factors, which was taken to signify that organic dies have only a very limited applicability to measure the acidity of the water pools of reverse micelles.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630820
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  • 70
    Digitale Medien
    Digitale Medien
    Über Pterinchemie. 73. Mitteilung [1]. Zum Verlauf der katalytischen Reduktion von 7-Methylpterin (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 395-401 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: On the Pathway of the Catalytic Reduction of 7-MethylpterinThe catalytic hydrogenation of 7-methylpterin (VII) in a neutral solution occurs first by the reduction of the 7,8-double bond (thermodynamically-controlled reaction) followed by the reduction of the 5,6-double bond. On the contrary, in an acidic medium like CF3COOH, the 5,6-double bond is reduced first (kinetically-controlled reaction). The dihydro-intermediate then undergoes a [1,2]-H-rearrangement leading to the formation of the thermodynamically more stable 7-methyl-7,8-dihydropterin (XV) which on further reduction gives 7-methyl-5,6,7,8-tetrahydropterin (VIII). The catalytic reduction of 7-methyl-7,8-dihydropterin (XV) with deuterium gives stereoselectively a sole product with D at C(6) in the equatorial position.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630209
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  • 71
    Digitale Medien
    Digitale Medien
    Photochemische Reaktionen. 107. Mitteilung. Zur Photochemie offenkettiger 2,6-bzw. 2,7-Dien-Carbonylverbindungen (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 571-587 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Photochemistry of Open-Chained 2,6- or 2,7-Dien-Carbonyl CompoundsOn 1n, π*-excitation (λ 〉 347 nm) citral (5) and the methyl ketone 10 isomerize to compounds A (7, 19) and B (6, 20), whereas the phenyl ketone 11 changes into the isomer 24 of type E. Evidence is given that the conversions to A and B may arise from the 3n, π*-state of the 2,6-diene-carbonyl compounds.On 1n, π*-excitation (λ = 254 nm) 5 and 10 yield the isomers A (7, 19) and D (18, 22), but no products of type B. Furthermore, conversion of 10 to the isomer 21 of type C is observed.Selective 1n, π*-excitation (λ = 254 nm) as well as selective 1n, π*-excitation (λ 〉 347 nm) of the 2,7-diene-carbonyl compounds 12 and 13 give rise to isomerization to the compounds F (25, 28), exclusively. The intramolecular [2 + 2]-photocycloadditions are shown to be triplet processes.UV.-irradiation (λ 〉 280 nm) of compounds F (25, 28) furnishes the isomeric products G (26, 29) which photoisomerize to oxetanes of type H (27, 30).
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630305
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  • 72
    Digitale Medien
    Digitale Medien
    Saponins with Molluscicidal Activity from Hedera helixL (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 606-609 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Four triterpenoid saponins (1-4) have been isolated from the berries of Hedera helix L. (Araliaceae) by droplet counter-current and preparative liquid chromatography. The structures have been established by FD./MS. and 13C-NMR. spectroscopy. The isolated compounds were found to possess strong molluscicidal activity against the bilharziasis-transmitting snail Biomphalaria glabrata. Saponin 4, identified as hederagenin 3-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranoside, is a new natural product.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630307
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  • 73
    Digitale Medien
    Digitale Medien
    Photoreaktionen des 3-(2-Thienyl)-2,2-dimethyl-2H-azirins (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 645-652 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis and Photochemistry of 3-(2-Thienyl)-2,2-dimethyl-2H-azirineThe synthesis of 3-(2-thienyl)-2,2-dimethyl-2 H-azirine (1) is described. UV. irradiation of 1 in benzene solution generates the nitrile isopropylide 2 which reacts in a regiospecific manner with activated C, C and C, O double bonds to give 1-pyrrolines and 3-oxazolines, respectively. With chelidonic acid diethyl ester the cycloaddition of 2 to the C, C double bond is preferred.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630311
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  • 74
    Digitale Medien
    Digitale Medien
    Synthese von optisch aktiven, natürlichen Carotinoiden und strukturell verwandten Naturprodukten. IV. Synthese von (3R, 3′R, 6′R)-Lutein. Vorläufige MitteilungHerrn Dr. Otto Isler zum 70. Geburtstag gewidmet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1451-1455 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis of optically active natural carotenoids and structurally related compounds. IV. Synthesis of (3R, 3′R, 6′R)-luteinThe synthesis of (3R, 3′R, 6′R)-lutein (19) according to the building principle C25+C15=C40 is reported utilizing (R)-4-hydroxy-2,6,6-trimethyl-2-cyclohexen-1-one (4) as a readily available key intermediate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630614
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  • 75
    Digitale Medien
    Digitale Medien
    Synthese von optisch aktiven, natürlichen Carotinoiden und strukturell verwandten Naturprodukten. VIII. Synthese von (3S,3′S)-7,8,7′,8′-Tetradehydroastaxanthin und (3S,3′S)-7,8-Didehydroastaxanthin (Asterinsäure)Teilweise vorgetragen am 5th International Symposium on Carotenoids 1978, Madison, Wisconsin, U.S.A.Herrn Dr. Otto Isler zum 70. Geburtstag gewidmet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1473-1490 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis of Optically Active Natural Carotenoids and Structurally Related Compounds. VIII. Synthesis of (3S,3′S)-7,8,7′,8′-Tetradehydroastaxanthin and (3S,3′S)-7,8-Didehydroastaxanthin (Asterinic Acid)The synthesis of all-trans-(3S,3′S)-3,3′-dihydroxy-7,8, 7′,8′-tetradehydro-β, β-carotene-4,4′-dione (1), of all-trans-(3S,3′S)-3,3′-dihydroxy-7, 8-didehydro-β,β-carotene-4,4′-dione (2) (asterinic acid = mixture of 1 and 2), and of their 9,9′-di-cis- and 9-cis-isomers is reported starting from (4′S)(2E)-5-(4′-hydroxy-2′, 6′,6′-trimethyl-3′-oxo-l′-cyclohexenyl)-3-methyl-2-penten-4-ynal (8). The absolute configuration (3S,3′S) for both components 1 and 2 of asterinic acid ex Asterias rubens is confirmed on the basis of spectroscopic and direct comparison.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630618
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  • 76
    Digitale Medien
    Digitale Medien
    Etude de la fragmentation par impact électronique de dérivés du benzothiazoleDédié au Prof. E. Giovannini a I'occasion de son 70e anniversaire. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 682-692 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Study of Electron-Impact Fragmentation of Benzothiazole DerivativesThe mass spectra of eighteen substituted benzothiazoles are reported and discussed. All these compounds are thermodynamically stable and give an intense molecular ion, which undergoes different types of fragmentation depending on the nature of the substituent which is rarely eliminated directly. β-Cleavage with respect to the heterocyclic double bond is often observed. Specific 2H-, 13C-, 15N- and 34S-labelling have been used in order to confirm the fragmentation patterns.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630318
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  • 77
    Digitale Medien
    Digitale Medien
    Complete Racemization in the Base Hydrolysis of Optically Active mer-[Chloro(diethylene triamine) (1,3-diaminopropan-2-ol-N,N′) cobalt (III)]tetrachlorozincate (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 693-696 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The base hydrolysis of the optically active title compound proceeds with full racemization whilst the meridional arrangement of the diethylenetriamine ligand is fully retained. The optically active hydroxo complex prepared independently with retention of configuration racemizes ≳ 104 times slower. This unique result is discussed in terms of the classical π-stabilization hypothesis for the base hydrolysis mechanism.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630319
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  • 78
    Digitale Medien
    Digitale Medien
    Synthesis, Properties, and Crystal Structure of Silyl Nitronates (Silyl Esters of aci-Nitroalkanes): Towards the SN2 Reaction Path with Retention of Configuration at Silicon (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 697-710 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An efficient and flexible method for the preparation of silyl nitronates is described (see 1-10). NMR. spectral investigations indicate a rapid 1,3-silyl migration process, with an activation energy of about 10 kcal mol-1. X-ray crystallographic studies on the silyl nitronates 3 and 8 show structures that lean towards an SN2 retention pathway at silicon.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630320
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  • 79
    Digitale Medien
    Digitale Medien
    Natural Occurrence of Enantiomeric and meso-Astaxanthin 1. Ex Lobster Eggs (Homarus gammarus) (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 711-715 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Astaxanthin (1; 3,3′-dihydroxy-β,β-carotene-4,4′-dione) isolated from lobster eggs (Homarus gammarus) was unexpectedly found to be a mixture of all three optical isomers as determined by HPLC. analysis of the corresponding diesters of (-)-camphanic acid. This is the first finding of meso-astaxanthin and a meso-carotenoid in general in nature.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630321
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  • 80
    Digitale Medien
    Digitale Medien
    Erhöhung der Nachweisempfindlichkeit von Cyclosporin A durch Derivatisierung mit 2-Naphthylselenylchlorid (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 728-732 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Enhancement of Detection Sensitivity of Cyclosporin A by Derivatization with 2-NapthylselenylchlorideThe UV./HPLC. detection sensitivity of cyclosporine A 1, an immunosuppressive cyclic undecapeptide containing one D-aminoacid and seven N-methylated aminoacids, is enhanced by a factor of 3-4 (limit of detection 5 ng) by conversion of the characteristic side chain of amino-acid-1 to the β-naphthylseleno-substituted tetrahydrofuran derivative 4.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630323
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  • 81
    Digitale Medien
    Digitale Medien
    Synthesis, Enzymic Degradation, Lipophilic Properties, and Biological Activity of [D-Alanine2, t-butylglycine5]enkephalin AmideAbbreviations are according to the IUPAC-IUB Commission on Biochemical Nomenclature (see [3]). (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 824-831 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: L-Cα-t-Butylglycine (Bug), its amide, methyl ester, and Nα-t-butoxycarbonyl derivative were prepared by an asymmetric synthesis, and the Hansch side-chain hydrophobic (lipophilicity) parameter determined. A new enkephalin analogue, H · Tyr-D-Ala-Gly-Phe-Bug · NH2 was synthesized which is pharmacologically active in two in vitro assays and strongly resistant against a number of enzymes in vitro.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630410
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  • 82
    Digitale Medien
    Digitale Medien
    The Synthesis of 3,5-Diamino-1,2,4-oxadiazoles. 1st CommunicationDedicated to Professor Edgardo Giovannini on his 70th birthday (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 832-840 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of the 1-substituted-3-cyano-isothioureas 6 with hydroxylamine gave mixtures of the 5-amino-3-substituted-amino-1,2,4-oxadiazoles 1 and the isomeric 3-amino-5-substituted-amino-1,2,4-oxadiazoles 8 in which 1 usually predominated. The structural assignment of these products is discussed. In a second method, the 2-hydroxy-1-methyl-1-phenyl-guanidine 15 was converted to the corresponding 3-disubstituted-amino-5-trichloromethyl-1,2,4-oxadiazole 16, a precursor to the 5-amino derivatives 17 by nucleophilic displacement of the trichloromethyl group.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630411
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  • 83
    Digitale Medien
    Digitale Medien
    The Synthesis of 3,5-Diamino-1,2,4-oxadiazoles. 2nd CommunicationDedicated to Professor Edgardo Giovannini on his 70th birthday (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 841-859 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 5-amino-3-arylamino-1,2,4-oxadiazoles 2 are conveniently prepared by oxidative cyclization of the arylamidinoureas 10. The process is also capable of producing a variety of the 5-substituted-amino analogs 32 when the appropriately substituted guanidine 31 is employed as the substrate. Two different types of rearrangement leading to triazol-3-ones accompany cyclization depending on the choice of starting material. The structures of the rearranged products were established by X-ray crystallographic analysis and the reaction mechanisms leading to these unexpected products are discussed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630412
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  • 84
    Digitale Medien
    Digitale Medien
    9, 10-Secocholesta-(5Z)-5,8(14), 10(19)-trien-3β-ol und 18-Nor-14β-methyl-9,10-secocholesta-(5E)-5, 10(19), 13(17)-trien-3β-ol, zwei neue Doppelbindungsisomere des Vitamins D3. Strukturelle Abwandlungen am Vitamin D3: 5. Mitteilung [1] (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 860-865 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 9,10-Secocholesta-(5Z)-5,8(14),10(19)-triene-3β-ol and 18-Nor-14β-methyl-9,10-secocholesta-(5E)-5,10(19), 13(17)-trien-3β-ol, two new double bond isomers of vitamin D3. Structural modifications of vitamin D3: 5. Communication [1]The present paper reports the synthesis and structure elucidation of the two title compounds. Treatment of the 4-phenyl-1,2,4-triazolin-3,5-dione adducts of vitamin D3 with BF3O (C2H5)2 and KOH/butanol yields these two new vitamin D3 double bond isomers.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630413
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  • 85
    Digitale Medien
    Digitale Medien
    1,2endo-Trimethylenenorbornane. A novel isomer of adamantane (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 866-871 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An easy approach to the novel adamantane isomer 1,2endo-trimethylenenorbornane (2) is described. Starting from a mixture of pent-4-ynylcyclopentadienes 3 the tricyclic monosaturated key intermediate 5 was prepared by intramolecular cycloaddition (→4) and subsequent regioselective reduction of the C(5), C(6) double bond. The title hydrocarbon 2 was obtained from 5 upon stereoselective hydrogenation by diimide. In addition specifically deuteriated analogues of 2 were prepared applying dideuteriodiimide. Compound 2 rearranged to 2endo, 6endo-trimethylenenorbornane (4-homobrendane, 10) in sulfuric acid as well as with aluminium bromide in carbon disulfide.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630414
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  • 86
    Digitale Medien
    Digitale Medien
    Synthesen von Tricyclo [5.2.1.04,8]decan (2-Homobrendan) (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 872-886 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Syntheses of Tricyclo [5.2.1.04,8]decane (2-Homobrendane)Three different approaches to tricyclo [5.2.1.04,8] decane (5) (and derivatives thereof), one of the 19 isomeric hydrocarbons of the ‘adamantaneland’, are described: (1) Cyclization of properly functionalized bicyclo [3.2.1]octanes as 32(cyclialkylation), 40+42 (thermocyclization) and 44+45 (photocyclization); (2) Silver-(I)-ion catalyzed rearrangement of 5,7- and 5,10-Dehydroprotoadamantane (63 and 64, respectively) yielding tricyclo[5.2.1.04,8]dec-2- (39) and -5-ene (59), respectively; (3) Thermal eliminative rearrangement of the 10endo-p-toluenesulfonate and -methanesulfonate of protoadamantane (71 and 72) and protoadamant-4-ene (76 and 77), respectively, yielding tricyclo [5.2.1.04,8]dec-2-ene (39) and -2, 5-diene (15), respectively.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630415
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  • 87
    Digitale Medien
    Digitale Medien
    The Rates of Diazomethane Formation from Methylnitrosoamides. The stability of diazomethane solutions towards aqueous alkalis (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 887-891 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The rate of hydrolysis of N-methyl-N-nitrosoamides by aqueous alkalis varies greatly. Methylnitrosourea (1) is hydrolyzed rapidly by aqueous KOH-solutions at low temperatures to give a high yield of diazomethane. Under similar conditions, N,N′-dimethyl-N,N′-dinitroso-oxamide (3) is hydrolyzed more slowly, but also gives a good yield of diazomethane. N,N′-Dimethyl-N,N′-dinitrosoterephthal-amide (4), and (N-methyl-N-nitroso)-4-amino-4-methyl-2-pentanone (5) are less easily hydrolyzed by aqueous KOH-solutions. N-Methyl-N-nitroso-p-toluenesulfonamide (2) was the least reactive out of those tested. The hydrolysis of diazomethane in toluene with aqueous bases follows first order kinetics. The hydrolysis rate is greatly influenced by the concentration and strength of the base and temperature.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630416
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  • 88
    Digitale Medien
    Digitale Medien
    Über die Temperaturabhängigkeit der 13C-NMR.-Spektren von Tetracarbonyl (η-(Z)-cycloocten)eisen und (Z)-cycloocten (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 892-898 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: On the Temperature Dependence of the 13C-NMR.-Spectra of Tetracarbonyl (η-(Z)-cyclooctene)iron and of (Z)-CycloocteneReaction of (Z)-cyclooctene (1) with Fe2(CO)9 in pentane at 0° yielded tetracarbonyl(η-(Z)-cyclooctene)iron (2) as a yellow oil which can be stored over a longer period only at -78°.It is shown that the title compounds (1 and 2, respectively) are fluxional.The activation parameters for the conformational C-atom site exchange of (Z)-cyclooctene (1) and tetracarbonyl (η-(Z)-cyclooctene)iron (2) (in CCl2F2) have been determined between 113 K and 151 K for 1 and between 151 K and 205 K for 2, respectively, by a complete line shape analysis of the temperature dependent proton noise-decoupled 13C-NMR. signals of the olefinic C-atom. The kinetic data and activation parameters are given in Tables 1 and 2.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630417
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  • 89
    Digitale Medien
    Digitale Medien
    Notizen zur Synthese von 2-Aminophenylsulfonen (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1412-1419 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Syntheses of some Alkyl, Cycloalkyl and Aryl 2-Aminophenyl SulfonesSyntheses of the alkyl, cycloalkyl and aryl 2-aminophenyl sulfones 10 were achieved by oxidation of the corresponding 2-nitrophenyl sulfides 7 to the 2-nitrophenyl sulfones 9 followed by ethanolic Béchamp-reduction. The sulfides 7 in turn were obtained either by reactions of 2-nitro-thiophenol (8) with the appropriate alkyl and cycloalkyl halides or of 2-chloro-nitrobenzene (5) with the relevant thiols. Condensation of 2-nitrobenzenesulfinic acid (3) with bromoacetic acid in aqueous alkaline solution led - presumably via 2-nitrophenylsulfonylacetic acid (4) - to methyl 2 nitrophenyl sulfone (1), reduction of which gave 2-aminophenyl methyl sulfone (2). Treatment of 2-aminothiophenol (11) with t-butyl alcohol in aqueous sulfuric acid gave 2-aminophenyl t-butyl sulfide (12), which was acetylated to o-t-butylthio-acetanilide (13). Oxidation of the latter to o-t-butylsulfonyl-acetanilide (14) followed by hydrolysis led to 2-aminophenyl t-butyl sulfone (15).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630610
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  • 90
    Digitale Medien
    Digitale Medien
    Synthese von optisch aktiven, natürlichen Carotinoiden und strukturell verwandten Naturprodukten. V. Synthese von (3R, 3′R)-, (3S, 3′S)- und (3R,3′S; meso)-Zeaxanthin durch asymmetrische Hydroborierung. Ein neuer Zugang zu Optisch aktiven Carotinoidbausteinen. Vorläufige MitteilungHerrn Dr. Otto Isler zum 70. Geburtstag gewidmet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1456-1462 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis of Optically Active Natural Carotenoids and Structurally Related Compounds. V. Synthesis of (3R, 3′R)-, (3S, 3′S)- and (3R,3′S; meso)-zeaxanthin by Asymmetric Hydroboration. A New Approach to Optically Active Carotenoid Building UnitsThe synthesis of (3R, 3′R)-, (3S, 3′S)- and (3R,3′S; meso)-zeaxanthin (1), (19) and (21) is reported utilizing asymmetric hydroboration as the key reaction. Thus, safranol isopropenylmethylether (4) is hydroborated with (+)- and (-)-(IPC)2BH to give the optically pure key intermediates 5 and 7 resp., which are transformed into the above-mentioned C40-compounds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630615
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  • 91
    Digitale Medien
    Digitale Medien
    Reactions of oxygenated cobalt (II) complexes. XIIIPart XII of this series: s. [1].. Diastereoisomeric forms of μ-peroxo-μ-hydroxo-bis[bis(ethylenediamine) cobalt(III)]. Preparation, X-ray structure determination and reactivity (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1491-1498 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Oxygenation of solutions containing bis(ethylenediamine) cobalt(II) ions leads to a mixture of diastereomeric forms of μ-peroxo-μ-hydroxo-bis[bis(ethylenediamine) cobalt(III)] cations. The existence of a meso-isomer has now been proved by its isolation as perchlorate and by an X-ray structure determination. The crystals are monoclinic with space group P21/n and lattice constants: a = 19.280, b = 11.984, c = 11.654 Å, β = 99.190°.The UV./VIS. spectra of the isomers are practically identical but show different kinetic behaviour. In acidic solution the meso-isomer decomposes 4 times faster than the racemic form. In alkaline solution the meso-isomer isomerizes to the racemic form. A mechanism which explains all the kinetic observations has been devised.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630619
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  • 92
    Digitale Medien
    Digitale Medien
    Benzylidène-5-hydroxy-4-dihydro-2,5-thiophènecarboxanilides-3-(Z): Synthèse et isomérisation en benzyl-5-hydroxy-4-thiophènecarboxanilides-3En hommage au Dr. Otto Isler à l'occasion de son 70e anniversaire (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1542-1553 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: (Z)-5-Benzylidene-2,5-dihydro-4-hydroxy-3-thiophenecarboxanilides: Synthesis and Isomerization into 5-Benzyl-4-hydroxy-3-thiophenecarboxanilidesUpon treatment with an arylamine in boiling xylene, the esters I yield predominantly the corresponding anilides II, along with a small but variable amount of the isomeric thiophene derivatives III (Table 1). On the other hand, the derivatives III can be readily prepared by base- or acid-catalyzed isomerization of II. Esters I can also be isomerized to the corresponding thiophene derivatives IV (Scheme 6), but only in the presence of a strong acid (Table 4). The two series of isomers reported in Tables 2 and 3 present spectral differences which allow unambiguous structural assignments. The (Z)-configuration for compounds of Table 2 is confirmed by a NOE study carried out on the O-methyl derivatives 6a and 7a.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630623
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  • 93
    Digitale Medien
    Digitale Medien
    Steroide und Sexualhormone. 260. Mitteilung259. Mitt. vgl. [1].. Limonoide Bitterstoffe VIV. Mitt. vgl. [2].. Untersuchungen zur Stereochemie der C(8)-Alkylierung von 7-Oxo-13,17-secosteroiden (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1554-1561 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: On the Stereochemistry of the C(8)-Alkylation of 7-Oxo-13,17-secosteroidsIt is shown that the title compounds, e.g. 10, can be alkylated with methyl iodide under strongly basic conditions to afford 8α-methylated products, e.g. 11 (Scheme 1). The configuration was assigned by 13C-NMR.-spectroscopy, CD. measurements, and finally proved by a X-ray crystallographic structure analysis.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630624
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  • 94
    Digitale Medien
    Digitale Medien
    Two New Sesquiterpenoid Ketones from Cassia Oil (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1615-1618 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis of 2-methyl-6-(4′-methylphenyl)-l-hepten-3-one (1) and 2-methyl-6-(4′-methylphenyl)-3-heptanone (2), constituents of the oil of Cinnamomum cassia, is described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630631
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  • 95
    Digitale Medien
    Digitale Medien
    Cob(I)alamin as Catalyst. 8th Communication. Cob(I)alamin and Heptamethyl Cob(I)yrinate During the Reduction of α,β-Unsaturated Carbonyl DerivativesFor the 7th communication see [1].Dedicated to Dr. Otto Isler on the occasion of his 70th birthday (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1628-1643 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Hydrogen bonds as presented in Figure 2 cannot account for the enantioselective attack of cob(I)alamin (4(I)) or heptamethyl cob(I)yrinate (5(I)) on one of the two enantiotopic faces of the substrates. The attack of the strongly nucleophilic 3dz2 orbital is preferentially directed to the re-side of the starting materials with (Z)-configuration and leads, after the highly stereoselective reductive cleavage of the Co, C bond, to saturated products with (S)-configuration in varying enantiomeric excesses (see Schemes 1, 3 and Table 1).
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630633
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  • 96
    Digitale Medien
    Digitale Medien
    1,2-Epoxy-Carotinoide. 1. Mitteilung. Synthese von 1,2-Epoxy-lycopin und 1,2,1′,2′-Diepoxy-lycopinHerrn Dr. Otto Isler zum 70. Geburtstag gewidmetTeilweise vorgetragen am 5. International Symposium on Carotenoids 1978, Madison, Wisconsin, USA. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1367-1376 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1,2-Epoxy-Carotenoids. Synthesis of 1,2-Epoxy-lycopene and 1,2,1′,2′-Diepoxy-lycopeneThe synthesis of the naturally occuring 1,2-epoxy-lycopene and of 1,2,1′,2′-diepoxy-lycopene is described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630603
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  • 97
    Digitale Medien
    Digitale Medien
    Über die Stereoselektivität der α-Alkylierung von (1R, 2S) (+)-cis-2-hydroxy-cyclohexancarbonsäureäthylesterHerrn Dr. Otto Isler zum 70. Geburtstag gewidmet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1383-1390 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Stereoselectivity of the α-Alkylation of (+)-(1R, 2S)-cis-Ethyl-2-hydroxy-cyclohexanecarboxylateIn continuation of our work on the stereoselectivity of the α-alkylation of β-hydroxyesters [1] [2], we studied this reaction with the title compound (+)-2. The latter was prepared through reduction of 1 with baker's yeast. Alkylation of the dianion of (+)-2 furnished (-)-4 in 72% chemical yield (Scheme 1) and with a stereoselectivity of 95%. Analogously, (-)-7 was prepared with similar yields. Oxidation of (-)-4 and (-)-7 respectively furnished the ketones (-)-6 (Scheme 3) and (-)-8 (Scheme 4) respectively, each with about 76% enantiomeric excess (NMR.). It is noteworthy that yeast reduction of rac-6 (Scheme 3) is completely enantioselective with respect to substrate and product and gives optically pure (-)-4 in 10% yield, which was converted into optically pure (-)-6 (Scheme 3).The alkylation of the dianionic intermediate shows a higher stereoselectivity (95%) from the pseudoequatorial side than that of 1-acetyl- or 1-cyano-4-t-butyl-cyclohexane (71% and 85%) [9] or that of ethyl 2-methyl-cyclohexanecarboxylate (82%). The stereochemical outcome of the above alkylation is comparable with that found in open chain examples [1] [2].Finally (+)-(1R, 2S)-2 was also alkylated with Wichterle's reagent to give (-)-(1S, 2S)-9 in 64% yield. The latter was transformed into (-)-(S)-10 and further into (-)-(S)-11 (Scheme 5). (-)-(S)-10 and (-)-(S)-11 showed an e.e. of 76-78% (see also [11]). Comparison of these results with those in [11] confirmed our former stereochemical assignment concerning the alkylation step.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630605
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  • 98
    Digitale Medien
    Digitale Medien
    Synthesis of Enantiomeric 3-Oxa-analogues of cis-Rose Oxide and of Some Sesquiterpenoid Homologues (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1598-1603 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis, spectral properties and sensory evaluation of chiral oxa-analogues of cis-rose oxide, and of eight corresponding sesquiterpenoid homologues, are described.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630628
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  • 99
    Digitale Medien
    Digitale Medien
    Synthesis of (R)- and (R)-4-methyl-6-2′-methylprop-1′-enyl-5,6-dihydro-2H-pyran (Nerol oxide) and Natural Occurrence of its Racemate (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1582-1588 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Following a known procedure, a mixture of (-)-(2S,3R)- and (+)-(2R,3R)-2,3-epoxy-citronellols (5) was prepared from (-)-(R)-linalool (3) via epoxy alcohol 4 and then reduced to (-)-(R)-3-hydroxy-citronellol (6). Sensitized photooxygenation of (-)-(R)-diol 6 led in part to (-)-(R)-triol 8 which was cyclodehydrated by dilute acid to a mixture of diastereoisomeric tetrahydropyran-4-ols 9 and 10. Dehydration of hydroxy ethers 9 and 10 afforded (-)-(S)-nerol oxide (11) and (+)-(R)-nerol oxide (12), respectively, with an optical purity of 91%. Nerol oxide isolated from Bulgarian rose oil (0.038%) proved to be racemic. These results shed some light on the formation of nerol oxide in plants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630626
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  • 100
    Digitale Medien
    Digitale Medien
    Natural Abundance 13C-NMR. of Vitamin D3 Metabolites (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1609-1614 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chemical shifts of 13C- and 1H-NMR. spectra of vitamin D3 metabolites (2-7) are assigned. Substituent effect parameters due to hydroxyl groups are deduced by comparison with vitamin D3.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19800630630
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