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  • Electronic Resource  (257)
  • 2000-2004
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  • MRI
  • 1
    Electronic Resource
    Electronic Resource
    Anatomy of the acromial arch: correlation of anatomy and magnetic resonance imaging (1993)
    Springer
    Surgical and radiologic anatomy 15 (1993), S. 63-70 
    Details
    ISSN: 1279-8517
    Keywords: Shoulder ; Acromion ; Coracoacromial ligament ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé A partir de la lecture rétrospective de 179 dossiers d'IRM représentant quatre populations (patients présentant un conflit sans traumatisme reconnu (n=90), une douleur d'épaule post-traumatique (n=28), une instabilité ou une luxation (n=36) et sujets témoins (n=25)), les auteurs proposent des critères morphologiques pour définir des voûtes présumées normales et des voûtes susceptibles de rendre compte d'un conflit sous acromial. La voûte sous acromiale est présumée “normale” ou non conflictuelle si, sur les vues sagittales et frontales, elle apparait parallèle à la tête humérale et/ou il existe un liseré graisseux qui s'interpose entre la voûte et le m. supra-épineux. La voûte sous acromiale est présumée agressive ou susceptible de rendre compte d'un conflit si, sur l'une des vues sagittale ou frontale, il est observé une zone de rétrécissement du défilé sous acromial avec une empreinte de la voûte sur le tendon du m. supra-épineux ou un amincissement tendineux au niveau ou juste en dehors de cette zone de rétrécissement. A partir de ces critères, la lecture des 179 dossiers d'IRM permet de mettre en évidence une différence significative de répartition des voûtes dans les quatre populations. Les voûtes agressives s'observent chez 45.5 % des patients présentant un conflit, 25 % des patients pr%esentant une douleur au décours d'un traumatisme, 8.9 % des sujets examinés au décours d'une luxation aigue ou récidivante et 12 % des sujets témoins. A l'inverse, la voûte présumée normale est retrouvée chez 56 % des sujets témoins, 55 % des patients examinés pour une luxation, 25 % des douleurs d'épaule post traumatique et seulement 5.5 % des patients présentant un conflit clinique. Le conflit sous acromial peut être le fait d'une dysplasie acromiale de type 3 décrit par Bigliani ou d'un épaississement du ligament au niveau de son insertion acromiale. Ce travail est complété par 15 dissections anatomiques qui confirment la constance de l'insertion du ligament coraco-acromial sur la face inférieure de l'acromion le long de son bord latéral.
    Notes: Summary Based on a retrospective study of 179 MRI records covering four populations (patients presenting with impingement without known injury (n=90), post-traumatic shoulder pain (n=28), instability or dislocation (n=36) and controls (n=25)), morphologic criteria are suggested to define presumedly normal arches and arches compatible with subacromial impingement. The subacromial arch is presumed normal or without impingement if the sagittal and frontal views show it to be parallel to the humeral head, and/or if there is a fatty layer interposed between the arch and the supraspinatus m. The arch is presumed “aggressive” or actually capable of giving rise to impingement if, in either the sagittal or frontal view, there is a zone of narrowing of the subacromial passage with an impression of the arch on the supraspinatus tendon or tendinous thinning at this level or just lateral to this narrowed zone. Based on these criteria, study of the 179 MRI records demonstrated a significant difference of distribution of the arches in the four populations. “Aggressive” arches were found in 45.5% of patients with impingement, 25% of patients with posttraumatic pain, 8.9% of patients with an acute or recurrent dislocation and 12% of controls. Conversely, a presumedly normal arch was found in 56% of the controls, 55% of patients with dislocation, 25% of posttraumatic painful shoulders and only 5.5% of patients with clinical impingement. Subacromial impingement may be due to the type 3 acromial dysplasia described by Bigliani or to a thickening of the coracoacromial ligament at its acromial attachment. This study was supplemented by 15 anatomic dissections which confirmed the regularity of attachment of the coracoacromial ligament at the inferior aspect of the acromion along its lateral border.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01629865
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  • 2
    Electronic Resource
    Electronic Resource
    Iatrogenic epidural spinal abscess (1993)
    Springer
    Journal of molecular medicine 71 (1993), S. 780-786 
    Details
    ISSN: 1432-1440
    Keywords: Epidural spinal abscess ; MRI ; Cerobrospinal fluid ; Antibiotic treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We present four cases of iatrogenic epidural spinal abscess directly caused by externally introduced catheters or probes. In two patients the infection spread per continuum, in the other two patients due to haematogenous dissemination. Clinical presentation in each case included generalized malaise with fever, signs of meningeal inflammation and focal neurological signs at the spinal level. The diagnosis was made on the basis of inflammatory changes in the cerebral spinal fluid and localization of the abscess by means of computer and magnetic resonance tomography. A broad-spectrum antibiotic regimen included a penicillinase-resistant preparation because of the frequent involvement of Staphylococcus aureus. It is our experience that a good outcome is dependent on early and specific treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190318
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  • 3
    Electronic Resource
    Electronic Resource
    Moyamoya disease in childhood: a familial case report (1993)
    Springer
    Child's nervous system 9 (1993), S. 215-219 
    Details
    ISSN: 1433-0350
    Keywords: Moyamoya disease ; Children ; Cerebral angiography ; MRI ; Seizures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Moyamoya is an obstructive cerebrovascular disease characterized by a cerebral angiographic picture of stenosis or occlusion of main cerebral arteries with an abnormal vascular network at the base of the brain. No definitive cause has been found for this disease and opinion is still divided between a congenital and an acquired etiology. Hemiplegia of sudden onset and epileptic seizures are the prevailing presentation in childhood, while subarachnoid bleeding occurs more frequently in adults. We report a new case of childhood moyamoya with clinical onset of the neurological symptoms within the 3rd year of life; during the child's illness the maternal grandmother presented with moyamoya disease too. Antiaggregating and calcium-antagonist drugs seem effective in preventing further vascular accidents, while a surgical approach is not possible. Computed tomography, single positron emission computed tomography, and magnetic resonance imaging are very useful in the diagnosis of this rare disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303572
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  • 4
    Electronic Resource
    Electronic Resource
    Repeat angiography and magnetic resonance imaging (MRI) of dissecting aneurysms of the intracranial vertebral artery (1993)
    Springer
    Acta neurochirurgica 121 (1993), S. 123-129 
    Details
    ISSN: 0942-0940
    Keywords: Dissecting aneurysm ; repeat angiography ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We here present 4 cases with dissecting aneurysm (DA) of the intracranial vertebral artery, who were followed up by repeat cerebral angiography and MRI. The patients consisted of 2 males and 2 females, and the mean age was 43 years. Two cases were associated with polyarteritis nodosa (PN) and hypertension, respectively. Three of the cases developed subarachnoid haemorrhage (SAH), while the other one suffered from lateral medullary syndrome. In cerebral angiography, “pearl and string” signs were revealed in all cases, while a “double lumen” indicating a true diagnostic sign of DA was demonstrated in only one case. Repeat angiography showed that a bleb formation with a bulging of the aneurysmal sac was seen in 2 cases, and an irregularity of the wall in one case. On the other hand in one case, the ectatic part shrank, while the stenotic part was restored. In magnetic resonance imaging (MRI), a hyperintensity mass on T 1-weighted image (T 1-WI) adjacent to flow void suggesting either an intramural haematoma or a linear shape hyperintensity on T1-WI were demonstrated in 3 cases. In the follow up MRI done in 2 cases, a serial change in the intensity from iso-intensity to hyperintensity on T 1-WI was observed in one case suggesting intramural haemorrhage, while an enlargement of the ectatic flow void was seen in the other case. Three of 4 cases were operated on by trapping of the aneurysms. One, who had systemic vascular diseases due to PN, and repeat angiography showed a regression of the aneurysm, was conservatively treated. The outcome was excellent in the 3 surgical cases, whilst the one medically treated case was also excellent without any rebleeding. In conclusion, repeat neuro-imaging procedures are strongly recommended to clarify the possibility of a spontaneous repair of the dissection, and to consider the surgical strategy for the lesion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01809262
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  • 5
    Electronic Resource
    Electronic Resource
    Carcinoid of the intrahepatic ducts (1993)
    Springer
    Abdominal imaging 18 (1993), S. 242-244 
    Details
    ISSN: 1432-0509
    Keywords: Carcinoid tumor ; Bile ducts ; Bile duct tumor ; Carcinoid ; MRI ; Carcinoid angiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Carcinoid tumors of the biliary tree are rare. To the best of our knowledge, this is the first reported case of an intrahepatic ductal carcinoid and the thirteenth reported case of biliary carcinoid. The radiographic appearance is variable. A brief review of the previously described cases is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198113
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  • 6
    Electronic Resource
    Electronic Resource
    Contrast enhancement of the gastrointestinal tract on MR images using intravenous gadolinium-DTPA (1993)
    Springer
    Abdominal imaging 18 (1993), S. 215-219 
    Details
    ISSN: 1432-0509
    Keywords: Abdomen ; MRI ; Intestine contrast enhancement ; Gastrointestinal tract, MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Gadopentetate dimeglumine was administered intravenously to 16 patients undergoing abdominal magnetic resonance (MR) imaging. T1-weighted and fat-suppressed T1-weighted images were acquired before and after intravenous administration of 0.1 mmol/kg gadopentetate dimeglumine. The stomach, small bowel, and colon were analyzed regarding the presence and relative intensity of contrast enhancement. Diffuse enhancement of the gastrointestinal tract wall was observed in all patients following contrast material administration. Such enhancement was most conspicuous on fat-suppressed T1-weighted images. Quantitative measurements indicated that the wall of the gastrointestinal tract enhanced approximately 100% with gadopentetate dimeglumine. This study demonstrates that enhancement of the normal gastrointestinal tract occurs routinely when intravenous gadopentetate dimeglumine is administered, and such enhancement should not be considered indicative of gastrointestinal pathology. Furthermore, it suggests the potential utility for using intravenous rather than orally administered contrast agents to provide enhancement of the gastrointestinal tract on MR images.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198104
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  • 7
    Electronic Resource
    Electronic Resource
    Diffuse leptomeningeal melanomatosis of the spinal cord: a case report (1993)
    Springer
    Acta neurochirurgica 121 (1993), S. 206-211 
    Details
    ISSN: 0942-0940
    Keywords: Leptomeningeal melanosis ; MRI ; peritoneal shunt ; arachnoid cyst
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A rare case of diffuse leptomeningeal melanosis presenting with symptoms of spinal cord compression due to the presence of anterolateral arachnoid cyst and treated with Spetzler's drainage system is reported. The diagnosis of diffuse melanosis of the leptomeninges is rarely possible during life. In the present case MRI was of great help in the definition of the limits of the pathological process and the presence of the anterior compressing cyst. After laminectomy and a biopsy of the pathological tissue which achieved the histological diagnosis, an external drainage was inserted to reduce the cyst extension and to exclude the presence of melanocytes in the cystic fluid before a peritoneal shunt was placed. At 8 th month of follow-up the patient is doing well with a dramatic reduction of symptoms and a significant reduction of spinal cord compression. The diagnostic role of MRI and the relationship between leptomeningeal melanosis and arachnoid cyst are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01809277
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  • 8
    Electronic Resource
    Electronic Resource
    Evaluation of MRI score in the differentiation between glioblastoma multiforme and metastatic adenocarcinoma of the brain (1993)
    Springer
    Acta neurochirurgica 122 (1993), S. 54-59 
    Details
    ISSN: 0942-0940
    Keywords: Glioblastoma multiforme ; metastatic adenocarcinoma ; MRI ; MRI score
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The authors statistically analyzed the MR configurations of 14 glioblastoma multiformes (GBMs) and 15 metastatic adenocarcinomas (MACs) of the brain in order to distinguish these two histological types on MR images. MR configurations were classified and scored upon the 9 criteria of heterogeneity, cyst or necrosis, haemorrhage, crossing of the midline by the tumour, oedema or mass effect, border definition, flow void sign, degree and heterogeneity after contrast enhancement. The mean value of GBMs was 1.47±0.22, and that of MACs was 0.91±0.37 (P〈0.001). GBMs had significantly higher values in five out of the nine criteria: border definition, heterogeneity, crossing of the midline of the tumour, flow void sign, and degree of the contrast enhancement (P〈0.001–0.05). Border definition was the best criterion for distinguishing two histological types. Six cases of MACs displayed hypo-intense lesions on T2 weighted images in contrast to GBMs which showed hyperintense lesions in all cases. In 4 out of the 6 MACs which were shown as hyperintensities on T2 weighted images, a hypo-intense peritumoural rim was noticed between the tumour parenchyma and the surrounding oedema. These data strongly suggest that GBMs and MACs can be distinguished on MR image by using MRI score.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01446987
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  • 9
    Electronic Resource
    Electronic Resource
    Diagnosis and results of different treatment regimes in patients with spinal abscesses (1993)
    Springer
    Acta neurochirurgica 125 (1993), S. 105-114 
    Details
    ISSN: 0942-0940
    Keywords: Spinal abscess ; epidural ; subdural ; surgical treatment ; antibiotics ; risk factors ; diagnostic procedures ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bacterial abscesses involving the spinal canal are associated with a high morbidity and mortality. Most frequently, these lesions are found in the epidural, rarely in the subdural space. In this report, our clinical material consists of a series of 16 patients treated during the last seven years. The clinical presentation included local neurological signs (back pain, para-/tetraparesis, bladder dysfunction), disturbances of consciousness (ranging from drowsiness to deep coma) and general inflammatory signs (meningism, fever). All patients presented with risk factors (septic foci, chronic diseases, and iatrogenic causes). Laboratory investigations revealed typically pathological blood sedimentation rate, leucocytosis and CSF-pleocytosis. Radiologically, the diagnosis was confirmed by myelography, CT and preferably MRI. The abscesses were located epidurally in 14 and subdurally in 2 cases. The surgical treatment included laminectomy, or multiple flavectomies in extensive lesions. Drainage systems (either simple silicon outflow drains or suction-/irrigation systems) were installed in all cases, as well as antibiotic treatment. Results of treatment: Following an observation period of 0,5–6 years, we found complete recovery in six (38%) cases, six (38%) others were mildly disabled and four (25%) patients died. Focussing on the results of the two different drainage systems, we found a statistically significant superiority of the inflow-/outflow system. Complications included mandatory re-exploration, post-inflammatory hydrocephalus, syringomyelia, spinal instability, surgical treatment of peripheral septic foci and therapy resistant septicaemia. In conclusion, we propose that spinal epi-or subdural abscesses require surgical evacuation, using a suction-/irrigation drainage system, as well as antibiotic and intensive care treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01401836
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  • 10
    Electronic Resource
    Electronic Resource
    A study on peritumoural brain oedema around meningiomas by CT and MRI scanning (1993)
    Springer
    Acta neurochirurgica 125 (1993), S. 41-46 
    Details
    ISSN: 0942-0940
    Keywords: Brain oedema ; meningioma ; CT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary There is a great variability in the amount of peritumoural brain oedema accompanying meningiomas. In a previous study it was found that the degree of brain oedema in the white matter around meningiomas correlated with disruption of the layers (especially the cerebral cortex), which separate the tumour from the white matter, as well as with the size and histological subtype of the tumour. In the present study comprising 9 meningiomas, the volume of oedema was calculated by integration of the cross-sectional oedematous areas on serial MRI slices. The volume of oedema was zero in 3 cases and ranged from 11 to 176.4 ml in the other 6 cases. The MRI-scans also showed disruption of the cortex in all cases, ranging from slight to severe. T1 and T2 measurements were made at the level of maximum extension, using a mixed sequence at a field strength of 1.5 T. From the T2 values tissue water content in % was calculated using the equations: WC=39.36/(R2 + 37.2) for cortex, and WC=29.63/(R2 + 27.8) for white matter. These had been obtained by correlating water content with relaxation rates, measured in vitro on human brain autopsy specimens which were subjected to hydration with distilled water or dehydration by hyperosmolar solutions. Mean water content amounted to 82.53% for normal cortex, 74.72% for normal white matter, and 84.59% for oedematous white matter around the tumour. On the assumption that the spread of contrast agent marks the advancement of the front of oedema produced by the tumour, CT-studies were made before, and at 1 1/2, 3 and 6h after contrast infusion. The increase in diameter of the contrast-stained area on the CT-scan allows calculation of the excess of oedema production per unit tumour volume. Of 6 tumours with oedema (mean peritumoural water content of 91% and mean volume of oedema of 69.2 ml) the production excess at the steady-state was 0.18–1.08 ml/h/cm3 tumour volume, whereas 3 tumours without associated oedema had a production excess of 0.03–0.12 ml/h/cm3. Moreover, penetration of the cortex seems to constitute a separate factor determinig the spread of oedema.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01401826
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  • 11
    Electronic Resource
    Electronic Resource
    Conjoined lumbosacral nerve roots (1993)
    Springer
    Acta neurochirurgica 120 (1993), S. 155-158 
    Details
    ISSN: 0942-0940
    Keywords: Myelography ; MRI ; conjoined nerve roots ; lumbosacral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Conjoined lumbosacral nerve roots is a congenital anomaly that may produce lumbosciatic pain. When symptomatic and undiagnosed, it may be one of the causes of failed back syndrome. Diagnosis with water-soluble contrast myelography has a frequency of 4%. Anatomical studies have shown to have an incidence of 14%. High quality Magnetic Resonance Imaging (MRI) with coronal views may reveal this condition without recurring to computed tomography (CT)-myelography. In this paper we describe our recent experience with five consecutive cases observed during a one year period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02112035
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  • 12
    Electronic Resource
    Electronic Resource
    Pyknodysostosis: Imaging and laboratory observations (1993)
    Springer
    Calcified tissue international 53 (1993), S. 170-173 
    Details
    ISSN: 1432-0827
    Keywords: Pyknodysostosis ; MRI ; Monocyte function tests ; Interleukin-1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Pyknodysostosis is a rare form of sclerosing bone dysplasia with autosomal recessive inheritance. Affected members of two families were assessed as follows: three patients underwent densitometry measurements and bone scans; four patients underwent magnetic resonance imaging (MRI) and an immunological investigation, as well as a detailed endocrinological and biochemical laboratory review. Densitometry measurements revealed values of up to 291% of age-matched normal controls; this increased bone density was mainly in the trabecular bone and not in the cortical bone. The MRI showed the cortex to be of normal thickness, whereas the increase in trabecular bone limited the space within the medullary canal. Bone scans and single photon emission computerized tomography in three patients showed an increased uptake of [99mTc]methylene diphosphonate of up to 538% of age-matched controls, which reflected the increased bone density. Monocyte function tests demonstrated a normal phagocytic capacity, but their killing activity was impaired. Interleukin-1 secretion was also impaired, which may point to the pathogenesis of the disease, in view of its function as an osteoclast activator and its role in bone resorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01321833
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  • 13
    Electronic Resource
    Electronic Resource
    Therapy evaluation of neuroendocrine liver metastases with contrast-enhanced MRI (1993)
    Springer
    European radiology 3 (1993), S. 19-25 
    Details
    ISSN: 1432-1084
    Keywords: Liver ; MRI ; Neuroendocrine tumours ; Therapy monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Seventeen patients with neuroendocrine liver metastases, 14 of whom were treated with interferon, were examined with MRI before and after contrast administration to evaluate whether there were signal characteristics, differences in homogeneity and/or contrast enhancement patterns that indicated response to or failure of treatment. Of the treated patients 6 objectively responded to treatment (OR), 3 had progressive disease (PD) and 5 had stable disease (SD). A significant difference was found between the SD, untreated (UT) and OR groups of patients in terms of T1 (P = 0.01) and contrast enhancement (P = 0.02). The signal intensity ratio (SIR) in T2-weighted images between tumour and liver was significantly different (P = 0.05) between the OR and PD groups. This indicates that MRI may be used in therapy monitoring of patients with neuroendocrine metastases. Neuroendocrine metastases in the OR group had the same T1 and SIR values as those reported for haemangiomas, while patients in the PD, SD and UT groups had SIR values similar to those for colorectal metastases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00173517
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  • 14
    Electronic Resource
    Electronic Resource
    Radiographic, CT and MRI spectrum of hydatid disease of the chest: a pictorial essay (1993)
    Springer
    European radiology 3 (1993), S. 62-70 
    Details
    ISSN: 1432-1084
    Keywords: Chest ; CT ; Echinococcosis ; Hydatid disease ; MRI ; Radiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Thirty patients with thoracic hydatidosis (Echinococcus granulosus) were studied. The hydatid cysts were located in the lung parenchyma (70%), mediastinum (6.7%), inside the heart (10%), the pleurae (10%) and the chest wall (3.3%). complications of thoracic hydatid cysts, such as rupture, infection, pleural involvement, spread and calcifications are presented. Computed tomography (CT) without and/or with contrast enhancement was performed in all patients (30). Findings from conventional chest radiographs were compared with CT and confirmed by pathology (30). In 10 cases (33.3%), magnetic resonance imaging was also performed. The diagnostic spectrum of hydatid cysts, including variations and developmental stages, is presented in this pictorial essay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00173526
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  • 15
    Electronic Resource
    Electronic Resource
    MRI, CT, sonography and thallium-technetium subtraction scintigraphy for the detection of parathyroid disease: a four-year experience (1993)
    Springer
    European radiology 3 (1993), S. 71-76 
    Details
    ISSN: 1432-1084
    Keywords: Hyperparathyroidism ; MRI ; CT ; Sonography ; Scintigraphy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Sonography, subtraction scintigraphy, computed tomography and MRI were compared in 100 patients who had surgery 105 times for hyperparathyroidism (HPT). Surgical and pathological data were available for all operations. A total of 105 MR, 77 CT, 84 sonograms and 70 subtraction scintigrams were performed. The ability of the imaging modalities, individually and in combination, to detect HPT, histology, size, concomitant thyroid disease and location of the diseased glands has been evaluated. For primary HPT, sensitivity ranged from 68% for MRI to 40% for scintigraphy but was much lower for tertiary HPT with all modalities. The ability to identify diseased glands was strongly size dependent for all methods. If patients had had previous neck surgery, the most sensitive methods were MRI and scintigraphy and this also held true for patients with concomitant thyroid disease and ectopically located glands. The findings presented suggest that while sonography may be the only imaging examiantion warranted in newly diagnosed parathyroid disease, recurrent disease should be examined pre-operatively with MRI and possibly subtraction scintigraphy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00173527
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  • 16
    Electronic Resource
    Electronic Resource
    MRI of spinal hematoma as a result of lumbar puncture (1993)
    Springer
    European radiology 3 (1993), S. 386-388 
    Details
    ISSN: 1432-1084
    Keywords: Subarachanoid haemorrhage ; Intradural haematoma ; Spinal ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 59-year-old woman was suspected of having meningitis. A lumbar puncture was performed for CSF analysis; however, a traumatic tap induced hemorrhage in the subarachnoid space and formed a hematoma from the L3 to the S1 level. This resulted in a paraparesis. Myelography showed a band-like filling defect and a subsequent computed tomography (CT) myelogram showed a soft tissue mass in the intradural space. T1 weighted magnetic resonance imaging revealed a lesion with moderate hyperintensity within the dural sac, hinting that the lesion was a hematoma. Laminectomy was performed, and the hematoma was entirely removed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167477
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  • 17
    Electronic Resource
    Electronic Resource
    T1, T2 and proton density measurements in the grading of cerebral gliomas (1993)
    Springer
    European radiology 3 (1993), S. 49-52 
    Details
    ISSN: 1432-1084
    Keywords: Brain tumor ; MRI ; T1 ; T2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The possibility that cerebral tumours may be graded by measuring T1 or T2 with magnetic resonance (MR) imaging was studied. A consecutive series of patients with subsequently verified gliomas was enrolled, and studied with MR. Patients who had prior surgical, chemotherapeutic or steroid treatment were excluded. Single slice multiple saturation recovery and multiple spin echo techniques were used to measure T1, T2 and proton density in the tumour. In 33 patients with cerebral gliomas there were 5 grade I, 12 grade II, 7 grade III and 9 grade IV. T1 and T2 values tended to be smaller in grade I gliomas than in grades II, III and IV gliomas. Relaxation parameters overlapped considerably in tumours with different grades. Proton density values did not show much change between different grades of gliomas. Relaxation parameters cannot be used to determine tumour grade reliably.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00173524
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  • 18
    Electronic Resource
    Electronic Resource
    Gd-DTPA enhanced MRI of breast: the most sensitive method for detecting multicentric carcinomas in female breast? (1993)
    Springer
    European radiology 3 (1993), S. 223-226 
    Details
    ISSN: 1432-1084
    Keywords: MRI ; Female breast imaging ; Mammography ; Breast cancer ; Multicentricity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The first publications on the use of magnetic resonance for breast imaging (MRBI) appeared more than 10 years ago. According to the literature between 14% and 47% of all breast carcinomas are multicentric carcinoma (MCC), a substantial number of which are not detected by conventional mammography. In a prospective study our purpose was to establish a clinically relevant procedure with MRBI for women with a single suspect lesion on mammography. Eight (32%) of 25 patients with histologically confirmed carcinoma had an MCC. Seven MCC were detected with MRBI and only one was diagnosed by mammography; one was discovered with neither MRBI nor mammography. MRBI proved to be the superior technique, with a sensitivity of 0.88 compared with 0.13 for mammography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425898
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  • 19
    Electronic Resource
    Electronic Resource
    The value of gadoterate meglumine as a gastrointestinal contrast agent in MRI (1993)
    Springer
    European radiology 3 (1993), S. 248-252 
    Details
    ISSN: 1432-1084
    Keywords: Gadolinium ; Gastrointestinal tract ; MRI ; MRI contrast enhancement ; Paramagnetic contrast agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate the safety and efficacy of a gadoterate meglumine formulation as an oral contrast agent, MRI (0.5 T) was performed on 29 patients with abdominal disease before and after administration of contrast material. The patients ingested 16 ml/kg of a gadoterate meglumine solution (10 g/l glucose, 2 mmol/l gadoterate meglumine) over 1 h. Fourteen per cent of patients had mild side effects related to the contrast agent. Significant hyperintense contrast enhancement was achieved for the stomach and duodenum allowing better delineation of gastric and duodenal walls, entire pancreas and spleen on T1- and T2-weighted spin echo sequences. In 5 patients more diagnostic information was available from post-contrast images compared with precontrast images. This study shows that gadoterate meglumine is a safe and well-tolerated contrast agent that improves MRI of the proximal gastrointestinal tract and upper abdomen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425903
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  • 20
    Electronic Resource
    Electronic Resource
    Magnetic resonance imaging in patients with claustrophobia: results of treatment with intramuscular clorazepate (1993)
    Springer
    European radiology 3 (1993), S. 355-356 
    Details
    ISSN: 1432-1084
    Keywords: Claustrophobia ; Clorazepate ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Between July 1991 and April 1992 1125 patients were examined with MRI, 34 (3%) of whom were treated with 50 mg clorazepate intramuscularly because of severe claustrophobia. The examination was successfully completed in 31 patients (91%). Only minor side effects were observed. Clorazepate suppresses the symptoms of claustrophobia, allowing the MRI examination to proceed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167468
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  • 21
    Electronic Resource
    Electronic Resource
    Accuracy of diagnostic imaging in nephroblastoma before preoperative chemotherapy (1993)
    Springer
    European radiology 3 (1993), S. 115-122 
    Details
    ISSN: 1432-1084
    Keywords: Computed tomography ; Diagnosis ; MRI ; Radiography ; Ultrasonography ; Wilms' tumour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The main strategy in the treatment of nephroblastoma, as described in protocol SIOP 9/GPO, is preoperative chemotherapy for patients between 6 months and 16 years of age. Before treatment the diagnosis is made only by diagnostic imaging without biopsy. From July 1988 to February 1991, 130 children with the tentative diagnosis of nephroblastoma were treated preoperatively. The initial diagnostic images (excretory urography, ultrasound, CT, MRI) have been analysed both prospectively and retrosperatively and the findings correlated with the intraoperative and histological results. Of the preoperatively treated patients 93.8% had a Wilms' tumour or one of its variants. Five patients had a different malignant tumour and 3 patients, i.e. 2.3% of those preoperatively treated or 1.6% of all registered patients, had benign tumours of the kidney. Wilms' tumour generally presented as a well-defined mass with an inhomogeneous morphology on CT. On ultrasound only 24% of the tumours were homogeneous. Intratumoral haemorrhage and cystic areas occurred frequently; calcifications were rare (8%). With regard to caval involvement only ultrasound and MRI enabled the correct diagnosis, while CT could not differentiate compressions from invasion. The pretherapeutic diagnostic imaging was of sufficient accuracy to start preoperative chemotherapy without diagnostic biopsy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169783
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  • 22
    Electronic Resource
    Electronic Resource
    Neurosarcoidosis with unusual MRI findings (1993)
    Springer
    Neuroradiology 35 (1993), S. 146-148 
    Details
    ISSN: 1432-1920
    Keywords: Sarcoidosis ; Intra-cranial ; MRI ; Gadolinium ; CT scan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This 53-year-old white male presented with a 4-month-history of weakness and pain. Despite an initial partial response to steroid therapy, his neurologic deterioration progressed culminating in paraparesis, paresthesias, urinary incontinence, altered mentation and a 20 lb weight loss. A gadolinium-enhanced MRI study showed a pattern suggestive of perivascular involvement. A subsequent cerebral biopsy was diagnostic for neurosarcoidosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00593973
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  • 23
    Electronic Resource
    Electronic Resource
    MRI in acute transverse myelopathy (1993)
    Springer
    Neuroradiology 35 (1993), S. 221-226 
    Details
    ISSN: 1432-1920
    Keywords: MRI ; Acute transverse myelopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The MRI examinations of seven patients with acute transverse myelopathy (ATM) were analysed. The patients were examined 2–5 times during the course of their disease with short and long TR/TE spin-echo sequences in the sagittal projection. A previous history of autoimmune disorder and/or signs of infection at the onset of ATM were present in all cases. Cerebrospinal fluid analysis showed local synthesis of immunoglobulin in the nervous system in three cases and signs of infectious myelitis in one. During the acute phase four patients had local enlargement of the cord and all had increased signal on long TR/TE sequences. The outcome was grave in the majority of patients and there seemed to be a correlation between the degree of cord enlargement, persistence of increased signal intensity and limited recovery. Atrophy and remaining high signal intensity were noted on late MRI in patients with poor outcome. In one patient with probable anterior spinal artery occlusion, cavitation of the cord was seen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00588501
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  • 24
    Electronic Resource
    Electronic Resource
    Pathological findings correlated with MRI in HIV infection (1993)
    Springer
    Neuroradiology 35 (1993), S. 264-268 
    Details
    ISSN: 1432-1920
    Keywords: HIV ; MRI ; Basal ganglia ; postmortem examinations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract MRI forms an important part of the assessment of patients with HIV-related disease presenting with cerebral smyptoms. Eleven formalin-fixed brains were studied at 0.5 T using T2- and T1-weighted sequences. In two cases of progressive multifocal leucoencephalopathy and one case each of toxoplasmosis and lymphoma, the extent of white matter abnormality seen on MRI corresponded broadly with that on pathological examination. In general, however, histological changes were more frequent than lesions on MRI. Cases in which abnormalities were not seen with standard MRI included those with multiple tuberculous granulomata, multinucleate giant cells, microglial nodules, perivascular cuffing and cytomegalovirus inclusions. A common finding on MRI was punctate or patchy high signal in the basal ganglia on T2-weighted scans, seen in six cases. Corresponding histological changes included calcification of vessels with widened perivascular spaces, and mineralised neurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00602609
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  • 25
    Electronic Resource
    Electronic Resource
    In vivo MRI of the fetal brain (1993)
    Springer
    Neuroradiology 35 (1993), S. 431-436 
    Details
    ISSN: 1432-1920
    Keywords: MRI ; Fetal brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report MRI of the brain in 45 fetuses; the findings were confirmed by pathological examination or postnatal neuroradiological studies. MRI necessitates medication to eliminate fetal motion; curare was injected into the umbilical cord, and MRI is therefore limited to cases in which umbilical cord puncture is indicated. T1-weighted images were obtained in axial, sagittal and coronal planes; the last of these was generally as the most useful as regards morphology. We demonstrated cerebral malformations (n=13), brain haemorrhage (n=1), a facial angioma (n=1), a facial mass (n=1), hydrocephalus (n=5), unilateral ventricular enlargement (n=1), atrophy (n=4), a porencephalic cyst (n=1) and normal appearances of the brain in 18 cases. Twenty-two of the fetuses were born alive, and the clinical and/or neuroradiological examination confirmed the antenatal findings. The diagnosis was also confirmed in 8 cases in which a neuropathological examination was possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00602823
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  • 26
    Electronic Resource
    Electronic Resource
    Epidural spinal abscess containing gas: MRI demonstration (1993)
    Springer
    Neuroradiology 35 (1993), S. 497-498 
    Details
    ISSN: 1432-1920
    Keywords: Spinal epidural abscess ; Spinal air ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of spinal epidural abscess in which MRI demonstrated intraspinal gas is reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00588704
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  • 27
    Electronic Resource
    Electronic Resource
    MRI of cranial chordomas: the value of gadolinium (1993)
    Springer
    Neuroradiology 35 (1993), S. 543-545 
    Details
    ISSN: 1432-1920
    Keywords: Chordoma ; Chondroid chordoma ; Gadolinium ; MRI ; Skull base, neoplasms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two intracranial chordomas are presented: a typical chordoma and a chondroid tumour. MRI with gadolinium showed different enhancement patterns, which may be related to pathological findings. The value of differentiating the two types of chordoma lies in their very different prognosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00588719
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  • 28
    Electronic Resource
    Electronic Resource
    Pseudotumoral hepatic actinomycosis: contribution of diagnostic and interventional radiology (1993)
    Springer
    European radiology 3 (1993), S. 180-182 
    Details
    ISSN: 1432-1084
    Keywords: Liver ; actinomycosis ; CT ; MRI ; Percutaneous biopsy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of pseudo-tumoral actinomycosis of the liver was examined by ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). MRI with injection of Gadolinium-DOTA (Gd-DOTA) revealed irregular structures in the center with peripheral enhancement. Diagnosis was obtained on percutaneous biopsy in view of characteristic sulfur on the samples. Percutaneous drainage was not necessary and medical treatment with antibiotheraphy alone was successful.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169795
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  • 29
    Electronic Resource
    Electronic Resource
    MRI of soft tissue tumors (1993)
    Springer
    Skeletal radiology 22 (1993), S. 77-84 
    Details
    ISSN: 1432-2161
    Keywords: MRI ; Soft tissue tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Magnetic resonance imaging (MRI) is the only noninvasive method of defining a soft tissue tumor. The extent of the tumor and the question of involvement or noninvolvement of various adjacent tissues and structures can be determined. This information, determination of lymphatic and distant metastatic spread, is invaluable for staging and management of the disease. Whether or not the tumor type can be reliably determined, or even whether the malignant or benign nature of the tumor can be ascertained on MRI examination, is open to question. Review of the literature indicates proponents on both sides of the issue. This review illustrates the imaging features that are relevant to suggesting a histologic diagnosis, and the pitfalls that are encountered in trying to determine the malignancy or benignity of a lesion. The clinical significance of these determinations is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197982
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  • 30
    Electronic Resource
    Electronic Resource
    Chronological changes of MRI findings on striatal damage after acute cyanide intoxication: Pathogenesis of the damage and its selectivity, and prevention for neurological sequelae: A case report (1993)
    Springer
    European archives of psychiatry and clinical neuroscience 243 (1993), S. 71-74 
    Details
    ISSN: 1433-8491
    Keywords: Cyanide ; basal ganglia ; anti-epileptic drugs ; calcium antagonist ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 31-year-old male technician in an electroplating factory, who had been suffering from the temporal lobe epilepsy for 24 years and from hypertension for 3 years, took an unknown amount of potassium cyanide apparently over the lethal dose, in an attempt to commit suicide. He was treated successfully and survived without any neurological sequelae. The electroencephalograms and the nature of the seizures were not different before and after the poisoning. The T2-weighted magnetic resonance images at 9 and 51 days after the poisoning showed bilateral elevation of signals in the caudate nuclei and the putamina. At the 143th and 286th days, T2-weighted high-resonance areas were restricted to the lateral portion of the putamina. The T1-weighted images at the 51st day showed abnormal signal elevations in both putamina, while those of 9th, 143th and 286th days were mainly normal. Selective vulnerability of the putamen and the caudate nucleus may be due to their specific structural properties of high oxygen and glucose utilization, and enzyme distribution. Both chronological changes of striatal damage and the absence of neurological sequelae in this patient suggest the possibility that anti-epileptics and a calcium antagonist played a neuroprotective role in the acute cyanide intoxication.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02191567
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  • 31
    Electronic Resource
    Electronic Resource
    Application of magnetic resonance imaging in reptile medicine (1993)
    Springer
    Magnetic resonance materials in physics, biology and medicine 1 (1993), S. 61-63 
    Details
    ISSN: 1352-8661
    Keywords: magnetic resonance imaging ; MRI ; reptile medicine ; tortoise ; Chelonian
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics
    Notes: Abstract Clinical examinations of reptiles are physically limited and therefore usually have to be complemented by other methods. This is especially true for Chelonians. A modern imaging technique like magnetic resonance imaging is well suited for this purpose. Its application and practical experiences with tortoises are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01760401
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  • 32
    Electronic Resource
    Electronic Resource
    In vivo 3-D reconstruction and geometric characterization of the right ventricular free wall (1993)
    Springer
    Annals of biomedical engineering 21 (1993), S. 263-275 
    Details
    ISSN: 1573-9686
    Keywords: Right ventricle ; Ventricular geometry ; Curvature ; Wall thickness ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract A prerequisite to biomedical analyses of the right ventricular free wall (RVFW) is the characterization of itsin vivo geometry and instantaneous wall thickness (WT). We present a method to reconstruct and mathematically model thein vivo RVFW surface geometry using ECG-gated magnetic resonance imaging (MRI). From digitized contours we reconstructed the endo- and epicardial surfaces of the entire heart, and approximated the RVFW surface geometry by local biquadric surface patches. An insurface coordinate system was developed, with respect to which the metric tensor, curvature tensor, major (k 2), and minor (k 1) principal curvatures were computed. The method was evaluated using MRI data from one dog, which showed thatk 2 was about 10 timesk 1, withk 2 andk 1 approximately perpendicular and parallel to the RV long axis, respectively. During systole,k 1 and both principal curvature directions remained essentially unchanged, whilek 2 revealed only a 7% decrease (p〈0.05) in the sinus region. These results suggest that while the RVFW undergoes small changes in surface geometry during systole, its overall curvature remained constant. The WT/mean radius of curvature ratio was less than 0.1 during systole throughout the RVFW, indicating it can be idealized as a thin shell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02368182
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  • 33
    Electronic Resource
    Electronic Resource
    Advantages of magnetic resonance imaging in breast surgery treatment planning (1993)
    Springer
    Breast cancer research and treatment 25 (1993), S. 257-264 
    Details
    ISSN: 1573-7217
    Keywords: MRI ; breast cancer ; imaging ; surgery ; staging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Preoperative magnetic resonance imaging (MRI) was performed in 40 patients with malignant and benign breast tumors. Images were qualitatively evaluated to determine features of MRI that would benefit breast surgery treatment planning. MRI was found to be exceptional in demonstrating the relationship of tumors with respect to structures such as the chest wall, nipple, and skin. Tumor size was estimated by MRI, mammography, and gross pathological measurement in the 32 patients confirmed to have a malignant tumor of the breast. MRI estimated the tumor size to be larger than mammography in 71% of the cases and larger than pathological measurement in 84% of the cases. Compared with the standard method for determining tumor size (pathological measurement), MRI would have upstaged 22% of the evaluated cases from T1 to T2 and 10% of the cases from T2 to T3. MRI may prove useful in selecting patients for breast conserving therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689840
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  • 34
    Electronic Resource
    Electronic Resource
    Massive gastric bleeding from pancreatic pseudocyst, caused by rupture of pseudoaneurysm (1993)
    Springer
    Journal of hepato-biliary-pancreatic surgery 1 (1993), S. 17-21 
    Details
    ISSN: 1436-0691
    Keywords: hematemesis ; pseudocyst ; intracystic hemorrhage ; pseudoaneurysm ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Massive bleeding into a pancreatic pseudocyst is an unusual but life-threatening clinical condition. In this report, we present a case of massive gastric hemorrhage from a pancreatic pseudocyst, caused by rupture of a pseudoaneurysm of the splenic artery. The patient was successfully managed by total gastrectomy with splenectomy and distal pancreatectomy. Of a total of 66 cases in our Japanese literature review, only 5 cases of gastric hemorrhage associated with pancreatic pseudocyst have been reported, including the case herein presented. Diagnosis and therapeutic strategy are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01235929
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  • 35
    Electronic Resource
    Electronic Resource
    High resolution EEG (1993)
    Springer
    Brain topography 5 (1993), S. 321-325 
    Details
    ISSN: 1573-6792
    Keywords: EEG ; Evoked potential ; MRI ; Functional brain imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01128684
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  • 36
    Electronic Resource
    Electronic Resource
    The estimation of a realistic localization of dipole layers within the brain based on functional (EEG, MEG) and structural (MRI) data: A preliminary note (1993)
    Springer
    Brain topography 5 (1993), S. 327-330 
    Details
    ISSN: 1573-6792
    Keywords: EEG ; MEG ; MRI ; Dipole Layers ; Functional localization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01128685
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  • 37
    Electronic Resource
    Electronic Resource
    Gliomatosis cerebri in a young patient showing various cranial nerve manifestations: a case report (1993)
    Springer
    Brain tumor pathology 20 (1993), S. 93-96 
    Details
    ISSN: 1861-387X
    Keywords: Gliomatosis cerebri ; MRI ; Low-grade astrocytoma ; IFN-β ; PET
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of gliomatosis cerebri in a 27-year-old man showing various cranial nerve manifestations is described. He was diagnosed as having cranial mononeuritis multiplex (bilateral oculomotor nerve paralysis, left facial nerve paralysis, bulbar palsy manifestations, and hypoglossal nerve paralysis) and was hospitalized in the neurology department on August 1, 2000. Although he continued to visit the neurology department after discharge, his manifestations showed no improvement. He was sent to our department for brain biopsy in August 2001. A biopsy performed at the Sylvian fissure from the frontal lobe/temporal lobe cortex showed high intensity on T2-weighted and Flair magnetic resonance imaging (MRI). The pathological findings were diffuse low-grade astrocytoma infiltrating between the pia mater and the cerebral cortex. We believed that the astrocytoma spreading on the subpia mater was responsible for the various cranial nerve manifestations, and we started whole-brain irradiation (46 Gy)+interferon (IFN)-β D.I.V. from September 2001. The pathological findings of the brain biopsy showed diffuse astrocytoma. The clinical presentation was dramatically improved after radiotherapy. It seemed that this tumor had spread along the subpia mater and subependyma. When he was discharged in early December, he walked by himself. The characteristic features of this case are that no lesion in the cerebellum or brain stem was found on MRI, even though the main manifestations were cerebello-brain stem manifestations, and biopsy of the cerebral cortex revealed astrocytoma. It should be noted that the clinical manifestations of astrocytoma in some cases are dissociated from the imaging observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02483454
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  • 38
    Electronic Resource
    Electronic Resource
    Crossed aphasia. Report of a rare case in a glioblastoma patient (1993)
    Springer
    Neurological sciences 14 (1993), S. 329-332 
    Details
    ISSN: 1590-3478
    Keywords: Crossed aphasia ; hemispheric specialization ; MRI ; GBM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommario Viene descritto il caso di una donna destrimane che manifestò disturbi afasici all'esordio clinico di un glioblastoma emisferico destro. La paziente presentava afasia di Wernicke ed eminattenzione spaziale sinistra. L'integrità dell'emisfero sinistro fu documentata con la Risonanza Magnetica. Alcuni aspetti della specializzazione emisferica per le funzioni linguistiche, prassiche e spaziali vengono brevemente discussi.
    Notes: Abstract A rare case of a right-handed (on the Edinburgh Inventory) woman who developed aphasia at the clinical onset of a right hemisphere glioblastoma (GBM) is reported. She showed Wernicke aphasia and left spatial neglect. The integrity of the left hemisphere was assessed by Magnetic Resonance Imaging (MRI). A few aspects of hemispheric specialization for language, praxias and spatial abilities are briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02339301
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  • 39
    Electronic Resource
    Electronic Resource
    Processing MRI data for electromagnetic source imaging (1993)
    Springer
    Medical & biological engineering & computing 31 (1993), S. 600-606 
    Details
    ISSN: 1741-0444
    Keywords: EEG ; Image processing ; MEG ; MRI ; Segmentation ; Three-dimensional rendering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Estimation of the source of activity in the brain from electro- and magneto-encephalographic measurements is becoming increasingly common. Structural information could assist in improving the calculation of the sources as well as providing the context of the source location. Magnetic resonance images are very useful for this purpose, but they still need to undergo various processing steps. The paper describes in details a practical method for full automatic processing of MRI images of a head, including segmentation of the images and triangulation of the surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441808
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  • 40
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061101
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  • 41
    Electronic Resource
    Electronic Resource
    A reinvestigation of the reactions between diazomethane and 1-phenylurazole (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 601-608 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Exhaustive methylation of 1-phenylurazole (1), using ethereal diazomethane as the methylating agent, results in the formation of three products: 1-phenyl-3,5-dimethoxy-1,2,4-triazole (2), 1-phenyl-3-methoxy-4-methyl-Δ2-1,2,4-triazolinev5-one (3) and 1-phenyl-2,4-dimethylurazole (4). Based on the amounts of 2-4 isolated, the overall yields in these reactions are typically 〉90%. When 1 and diazomethane were allowed to react in a fashion that resulted in the formation of monomethylated analogues of 1, 1-phenyl-3-methoxy-Δ2-1,2,4-triazoline-5-one (5) and 1-phenylv2-methylurazole (6) were formed. In separate experiments, the monomethylated species 5 and 6 were allowed to react with diazomethane in efforts to develop a sequence of reactions that reasonably accounts for the formation of 2-4. Whereas N- and O-methylated products were obtained when 5 was treated with ethereal diazomethane, the reaction of 6 and diazomethane produced only the N-alkylated product 1-phenyl-2,4-dimethylurazole (in quantitative yield). The outcomes of these experiments are consistent with a sequence of reactions in which the treatment of 1 with diazomethane results, initially, in the formation of the monomethylated species 5 and 6. In the presence of sufficient diazomethane, 5 and 6 then undergo further mothylation, forming the dimethylated species 2-4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061102
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  • 42
    Electronic Resource
    Electronic Resource
    Conformational properties of disulphide bridges. 1. C—S Rotational potential in ethyl hydrodisulphide (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 615-620 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The potential for C—S rotation in ethyl hydrodisulphide, CH3CH2SSH, has been studied with ab initio methods. All stationary point structures were fully optimized at the HF/6-31G* and MP2/6-31G* levels. MP2/6-31G* molecular geometries were used in subsequent single-point energy calculations with several basis sets and including various amounts of electron correlation up to the MP4SDQ/6-311+G(2d,p) level of theory. Zero-point vibrational energies and thermal corrections were calculated and used to obtain relative values for ΔH0 and ΔH298. The stability order for the three energy minima is gauche - ≥ gauche + 〈 trans (positive disulphide chirality, C—S—S—H torsion ≈ 89°). The results have implications for force field calculations on disulphide bridge conformations in peptides and proteins.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610061104
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    Molecular rearrangements in homogeneous gas-phase elimination reactions. Pyrolysis kinetics of alkyl methanesulphonates (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 85-94 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rates of elimination of several alkyl methanesulphonates were determined in a seasoned, static reaction vessel over the temperature range 300-420°C and the pressure range 28-163 Torr. The reactions are homogeneous, unimolecular and follow a first-order rate law. The overall rate coefficients are given by the following equations: for isobutyl methanesulphonate, log k1 (s-1) = (12·51 ± 0·38) - (177·0 ± 2·1) kJ mol-1 (2·303RT)-1; for 2-phenyl-1-propyl methanesulphonate, log k1(s-1) = (12·62 ± 0·04) - (176·2 ± 0·5) kJ mol-1 (2·303RT)-1; for neopentyl methane-sulphonate, log k1(s-1) = (13·35 ± 0·42) - (198·2 ± 5·2) kJ mol-1 (2·303RT)-1; and for 3-chloro-2,2-dimethyl-1-propyl methanesulphonate, log k1(s-1) = (13·87 ± 0·42) - (218·2 ± 5·4) kJ mol-1 (2·303RT)-1. Rearrangements in these methanesulphonate pyrolyses may proceed via an intimate ion-pair type of mechanism. Consequently, the results appear to confirm that intramolecular migration through autosolvation is possible in gas-phase elimination reactions of certain types of organic molecules.
    Additional Material: 11 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610060204
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    Carbon and hydride migrations of cyclobutylhalocarbenes (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 126-131 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The photolysis of cyclobutylchlorodiazirine affords chlorocyclopentene and chloromethylenecyclobutane by direct rearrangements from the diazirine's excited state (65%) and by competitive formation and subsequent rearrangement of cyclobutylchlorocarbene. The involvement of excited diazirine in the analogous cyclobutylfluorodiazirine photolysis is much reduced (12%).
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060210
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    Masthead (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060301
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    Acid-base equilibria and kinetics between triarylmethane dye carbinols and organic acids in apolar aprotic solvents: Relative basicities of dye carbinols in toluene (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 145-152 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Equilibria and kinetics of acid-base reactions in toluene between a carboxylic acid (m-toluic, salicylic acid) and a set of carbinol bases (derived from basic triarylmethane dyes) were studied spectrophotometrically. The results for the equilibrium and kinetic parameters were critically analysed. The rate constant of the forward step of the acid-carbinol base equilbrium was found to provide a suitable scale of basicities in toluene. The basicities of the dye carbinols chosen decrease in the order Ethyl Violet- 〉Crystal Violet- 〉Methyl Violet- ≈ Victoria Pure Blue BO- ≫ Brilliant Green- 〉Malachite Green-carbinol. This is fairly consistent with the order observed in water. A fairly good correlation between base strengths of the carbinols and σR+ parameters of their para-alkylamino substituents was obtained.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610060304
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    Intramolecular photoinduced electron transfer (PET) bond cleavage in some sulfonium salt derivatives. Effect of distance and thermodynamics on PET rate (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 333-340 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rate of intramolecular photoinduced electron transfer (PET) between a naphthacene electron donor (D) and a sulfonium electron acceptor (A) was found to be dependent on the thermodynamics for PET and distance between D and A. The slopes of In kET vs through-bond and through-space distance plots was found to be -0·60 and -0·91 Å-1, respectively. The product distribution obtained from the photolysis of regioisomeric naphthacenyl sulfonium salt derivatives was found to be independent of distance. Photolysis of three regioisomeric naphthacenyl phenylmethyl-p-cyanobenzylsulfonium salts produced unsubstituted thiomethylphenylnaphthacene and mono-, di- and tri-p-cyanobenzyl-substituted thiomethylphenylnaphthacene. The appearance of the out-of-cage di- and trisubstituted photoproducts suggests that secondary photochemistry and intermolecular electron transfer bond-cleavage reactions are occurring when the concentration of the sulfonium salt in acetonitrile is 10-2 and 10-3 M and the degree of conversion is high. The primary photoproduct is the mono-substituted naphthacene derivative.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060604
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    Zn2+ complexes with N-(2-pyridyl)cinnamides: Characterization and UV studies (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 15-22 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Zinc(II) complexes of N-pyridylcinnamides (H, m-OCH3, p-OCH3 and p-OH derivatives) were studied by spectrophotometric methods in aprotic media, and represent a chemical model inhibition by cinnamides of coniferyl alcohol dehydrogenase (CAD), a zinc enzyme involved in the lignification process. The complexation of N-pyridylcinnamide and m-methoxy-N-pyridylcinnamide with zinc ion is effected according to a 1 : 1 stoichiometry (ML), whereas a two-step equilibrium (M + L ⇌ ML \documentclass{article}\pagestyle{empty}\begin{document}$ V_{\rm m} = 4 \cdot 45C_0 + 6 \cdot 44C_1 - 3 \cdot 33C_2 + 0 \cdot 46C_4 + 52 \cdot 9{\rm (}n = 300,r = 0 \cdot 999,s = 0 \cdot 81) $\end{document} ML2) is preferred with p-methoxy and p-hydroxy compounds. These ligands are mainly bonded through the carbonyl oxygen atom and the nitrogen of the pyridyl ring. Molar absorptivities for these complexes, not directly available, were calculated from analysis of the experiemental data. The UV complexation results are also supported by the stoichiometry of the complexes, which were synthesized and characterized.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060104
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    Generation of vinyl cations by nitrosation of N-silylated imines and enaminesPresented as a poster at the 10th IUPAC Conference on Physical Organic Chemistry at Technion, Haifa, Israel, August 5-10, 1990. (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 44-46 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reaction of monosilylated imines and a disilylated enamine with nitrosyl salts in dichloromethane at -78°C is shown to proceed via intermediate vinyl diazonium salts and vinyl cations.
    Additional Material: 1 Tab.
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    Masthead (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060201
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    Ambident reactivity of aryloxide ions towards 1,3,5-trinitrobenzene, low-temperature characterization of the elusive Oxygen-bonded σ-complexes by 1H and 13C NMR spectroscopy (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 71-82 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ambident reactivity of phenoxide ion towards 1,3,5-trinitrobenzene (TNB) was re-examined by means of a novel reaction system(CD3CN-glyme-d10) which allows the investigation of species formed at low temperatures (-40°C), contrasting with previous studies in dimethyl sulfoxide (DMSO) at ambient temperature. The new method coupled with 400 MHz NMR spectroscopy has allowed the definitive observation of both O- and C-bonded phenoxide σ-complex adducts for the first time, confirming the formation of the former through kinetic control and of the latter through thermodynamic control. The corresponding O-bonded σ-adduct in the TNB-mesitoxide system (whereC-bonded σ-adduct formation is not possible but where there is competing nitro group displacement) has also been characterized by 1H and 13C NBR. Another O-bonded aryloxide adduct characterized is that from the reaction of TNB with3,5-di-tert-butylphenoxide; in this system there is also competing NO2 displacement. Stereoelectronic factors in the O-bonded σ-adducts and aryl ethers are discussed.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060202
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    Stereochemical features of the (2+2) cycloaddition reactions of chiral allenes. V. Cycloaddition of 1-tert-butyl-3-methylallene with 1,1-dichloro-2,2-difluoroethene (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 95-100 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The (2 + 2) cycloaddtion reactions of 1-tert-butyl-3-methylallene (tBMA) with radicophiles were investigated. The attempted cycloaddition reactions with N-phenylmaleimide, acrylonitrile and methyl acrylate produce only (4 + 2) cycloadducts of 1-tert-butyl-1,3-butadiene which is formed by the more rapid [1.3] hydrogen sigmatropic rearrangement of the tBMA. The (2 × 2) cycloaddition of tBMA with 1,1-dichloro-2,2-difluoroethene (1122) occurs more rapidly than does the sigmatropic rearrangement, and produces a mixture of the four cycloadducts 1-4. The cycloaddition of 1122 with enantioenriched tBMA produces one cycloadduct (3) in which ca 91% of the enantiomeric excess (ee) of the tBMA is transferred to the cycloadduct. The other three cycloadducts are formed retaining much less of the ee of the starting tBMA. The results are interpreted on the basis of molecular modeling calculations carried out on the 1122-1,3-dimethylallene system reported previously. It is suggested that cycloadduct 3 is formed by essentially only one continuous minimum-energy reaction pathway, while cycloadducts 2 and 4 are formed by two competitive minimum-energy reaction pathways which result in the formation of cycloadducts possessing opposite absolute configurations. The combined contributions of the two competitive pathways result in much lower overall degrees of transfer of the ee of the tBMA to the diradical intermediates and cycloadducts.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610060205
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    Erratum (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 132-132 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060211
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    Nucleophilic solvent intervention in the solvolysis of 2-aryl-2-Chloropropanes. An example to demonstrate the advantage of using the YBnCl scale in correlation analysis (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 122-125 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The advantage of using the YBnCl scale over the YCl scale in Grunwald-Winstein-type correlation analysis was demonstrated by the kinetic evidence of a significant nucleophilic solvent intervention in the solvolysis of 2-aryl-2-chloropropanes. A depression of log k values measured in ethanol-trifluoroethanol mixtures and a positive azide salt effect were observed.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060209
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    Multinuclear NMR and ab initio MO studies of 7-methyl-7H-pyrrolo [2,3-b]pyridine and related compounds (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 139-144 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The contribution of the polarized resonance structures to 7-methyl-7H-pyrrolo[2,3,-b]pyridine and 4-methyl-4H-pyrrolo [3,2-b] pyridine, which have recently attracted much attention in physico-chemical studies, was considered based on multinuclear (1H, 13C and 15N) NMR spectroscopy and MO calculation. Comparison of the chemical shifts of the compounds with those of other relevant compounds and the effects of concentration and solvents observed by multinuclear NMR suggested that the contribution of the non-polarized structures to both compounds predominates over that of the polarized structures. This result was also supported by ab initio MO calculations using the 6-31G basis set.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060303
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    Stern-Volmer quenching kinetics for use of a dualistic quencher (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 160-162 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Stern-Volmer quenching equation for use of a dualistic quencher, which serves not only as the quencher for an excited starting molecule but also as the promoting agent for product formation, was obtained by applying the steady-state approximation to the photoreaction system. The equation was applied to the kinetic analysis of the Norrish type II photoreaction of valerophenone using triethylamine, which serves as the excited-state quencher and as the promoting agent for product formation.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060306
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    Versatile packing modes of 9-substituted 9-fluorenols. X-ray crystal structures of 9-methyl-, 9-phenyl-, 9-(1-naphthyl)- and 9-(2-biphenylyl)fluoren-9-ol (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 171-178 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The four studied semi-rigid fluorenol derivatives differ only in the size of the 9-substituents. All four compounds crystallize with two molecules per asymmetric unit and with relatively low crystallographic symmetry [P1 for the 9-methyl derivative (1) and P21/n for the 9-(1-naphthyl) (3) and 9-(2-biphenylyl) (4) derivatives]. Crystal data: 1, a = 8·779(1), b = 11·570(1), c = 11·747(1), α = 91·197(5), β = 104·345(4), γ = 105·848(6)° 2, a = 8·425(1), b = 13·819(1), c = 23·902(2)Å, β = 95·87(1)° 3, a = 15·679(4), b = 8·567(2); c = 23·884(17)Å, β = 92·60(6)° 4, a = 7·770(6), b = 33·766(10), c = 13·649(4)Å, β = 95·30(1)°. Nevertheless, the packing modes are different. The 9-methylfluoren-9-ol molecules, forming H-bonded tetramers with full H-bond saturation, give rise to the lowest packing coefficient among the four compounds. The crystals of the 9-phenyl derivative are built up of H-bonded dimers, whereas those of the bulky 9-naphthyl and 9-diphenylyl derivatives consist of single molecules only. The latter two compounds, however, have a denser packing than the two that contain H-bonded aggregates. The crystal structures are held together mainly by ordinary Van der Waals forces. In the case of 9-biphenylyfluoren-9-ol, the structure seems to be stabilized also by weak H-bond-type interactions from the alcoholic hydroxyl group to the π-electron cloud of an aromatic ring in the neighbouring molecule the O…centroid distances are 3·182(3) and 3·248(4)Å, and in the 9-naphthyl derivative the OH groups are involved in some short (˜3·3Å) intermolecular approach, possibly indicating an electrostatically favourable packing for the compound.
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    Ring-opening reactions. 6.For part 5, see ref. 1. eliminative ring fission of aziridinium and azetidinium ions (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 187-192 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reactivity ratio between the three- and four-membered cyclic ammonium ions in ring-opening elimination reactions was measured. The comparison with the analogous ratio obtained in a previous study on ring-opening substitution reactions suggests a substantial difference in the effect of the stereochemical factors governing the two ring-opening reactions and confirms the anomalous behaviour of small rings in the ring-opening substitution reaction.
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    Substituent effects on the kinetic solvent isotope effect in solvolyses of arenesulphonyl chloridesLimitation of the Transition State Variation Model, Part 6. (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 223-227 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Hammett type plot of kinetic solvent isotope effect (KSIE = kSOH/kSOD), log(KSIE) vs σ, can be a useful mechanistic tool for solvoltic reactions. The slopes of such straight line plots for para-substituted benzenesulphonyl chlorides in methanol (0·15), water (0·05) and methanol-water (0·05) are interpreted in terms of different reaction channels (general base-catalysed and SN2), in contrast to simple Hammett plots, log kSOH (or log kSOD) vs σ, invariably exhibiting non-linear concave curves.
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    URL: http://dx.doi.org/10.1002/poc.610060405
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    Ab initio studies of the reaction between diazonium ions and water (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 243-250 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Ab initio calculations, using the 6-31G* basis set, were performed in order to study the energetics of the electrophilic attack on water by such diazonium ions as methyl-, ethyl- and fluroethyldiazonium. For the first case, an indication of a transition state appears at the Hartree-Fock level, whereas for the other two, the energy is continuously decreasing from reactants to products. When correlation energy was taken into account via single-point MP2/6-31G* calculations, a deep ion-dipole energy minimum was observed for the methyldiazonium ion followed by a low transition state, whereas the other two did not change their energy pattern. On performing the MP2/6-31G* optimization for the methyl species, the Hartree-Fock results were confirmed, with a slight displacement of the transition state toward a shorter CO distance.
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    Photochemical and radiolytic cleavage of 10-methylacridine dimer in solutions and cryogenic glasses (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 254-256 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 10-Methylacridine dimer [(AcrH)2] dissociates into a pair of 10-methylacridyl radicals (AcrH·) on laser excitation (308 nm) in solvents of various polarities. Exposure of (AcrH)2 in methylcyclohexane glass at 77 K to γ-rays of 60Co generates the radical cation (AcrH)2+·. Thermal annealing of the matrix to 90 K results in dissociation of (AcrH)2+· into AcrH· and 10-methylacridinium cation (AcrH+).
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    Hydrogen bonding of aromatic amines in hydroxylic solvents. Part 1. Absorption spectroscopy of substituted anilines and hydrogen bond-induced rehybridization of trivalent nitrogen atoms.This paper is dedicated to Professor Jiro Tanaka on the occasion of his 63rd birthday. (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 261-272 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The longest wavelength absorption band of substituted anilines containing electron-accepting groups is characterized as an intramolecular charge-transfer (ICT) transition. Dual absorption peaks observed for the ICT transition of some para-substituted anilines in a strongly hydrogen-bonding solvent, hexafluoropropan-2-ol (HFP) can be attributed to two inequivalently hydrogen-bonded species with differently hybridized aniline nitrogens in HFP. The hydrogen bond-induced rehybridization causes appreciable changes in the ICT absorption spectra of highly polar aromatic amines. Rehybridization of aromatic amino nitrogens depends on the OH acidity in the solvent molecule and the basicity of the substituted anilines. The geometry of trivalent nitrogens in aryl amines is critically dependent upon the ionization potential of the amino group, the electron affinity of the electron-accepting substituent and the substitution site of the electron-withdrawing group with respect to the amino moiety.
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    URL: http://dx.doi.org/10.1002/poc.610060503
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    Acid-catalysed solvolysis of optically active 1-Phenyl-1-methoxythane. The role of ion- molecule pair intermediates (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 287-292 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The acid-catalysed solvolysis of (R)-1-phenyl-1-methoxyethane was studied in mixtures of dilute aqueous perchloric acid and acetonitrile at 50°C. The rate of loss of optical activity (kα) was found to be the same as the rate of solvolysis (ksolv) at both low and high water contents of the solvent. These results are not in accord with literature data on racemization and oxygen exchange of 1-phenylethanol in water, which has been discussed in terms of interconversion of chiral ion-dipole pair intermediates. The mechanistic implications of the results are discussed.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060506
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    Substituent effects in carbon-13 NMR spectra of aminopyridines (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 307-315 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 13C NMR spectra of 45 vicinally substituted 2-, 3- and 4-aminopyridines were investigated. The substituent effects are evidently sensitive to the position of both the substituent and the fixed amino group. In the para position with respect to the substituent, long-range electronic effects are expressed by the dual substituent parameter treatment (DSP), and the resonance contribution is more important than the inductive contribution. Correlation results for the ipso and ortho carbon atoms using the more sophisticated extended DSP equation suggest non-electronic effects of unknown origin.
    Additional Material: 9 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610060509
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  • 65
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    Stereochemistry of aminolysis of N-pentafluorophenylcarbonimidoyl dichloride. Crystal and molecular structures of N2-pentafluorophenyl-N1,N1-dibenzylchloroformamidine (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 319-325 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It has been established that the product of the reaction of N-pentafluorophenylcarbonimidoyl dichloride (1) with dibenzylamine, viz. N2-pentafluorophenyl-N1,N1-dibenzylchloroformamidine (4a) is a Z-isomer, whereas according to the concept of stereoelectronic control one might have expected a product with E-configuration. The heat of formation and the geometry of Z- and E isomer of N2-pentafluorophenyl-N1,N1-diethylchloroformamidine (4b) (the latter is a product of the reaction of 1 with diethylamine) were calculated with the semi-empirical MNDO method. The calculated geometry of (Z)-4b was found to be in a good agreement with the experimentally determined structure of 4a. The formation of (Z)-4b is more preferable energetically than that of (E)-4b; the calculated difference in the heats of formation is 2·8 kcal mol-1. Thermodynamic control of the reaction stereochemistry is proposed.
    Additional Material: 1 Ill.
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    Conformational analysis of substituted perhydro-1,2-oxazolo[3,2-c] [1,4]oxazines by NMR spectroscopy (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 326-332 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The 13C NMR spectra of most of the substituted perhydro-1,2-oxazolo[3,2-c] [1,4]oxazines (3) at low temperature showed the presence of two isomers of unequal populations. The major isomer is shown to be the cis isomer {except in 2-hydroxymethyl-2-methylperhydro-1,2-oxazolo[3,2-c] [1,4] oxazine (3e)}, which is in equilibrium with the minor isomer (trans conformer) by a relatively slow nitrogen inversion. Intramolecular hydrogen bonding in oxazines, having 2-hydroxymethyl substituents, is shown to be an important factor in determining the population ratio of the two isomers. The barrier to nitrogen inversion was determined by detailed band-shape analysis of proton and carbon NMR spectra and were in the range 66·3-72·9 kJ mol-1. The chair inversion had been slowed down, in one case, trans-dimethylperhydro-1,2-oxazol[3,2-c] [1,4]oxazine-2,3-dicarboxylate (3j), to show the presence of the two forms of the cis isomers. The barrier to chair inversion is 41·5 kJ mol-1 as determined by proton NMR band-shape analysis of 3j.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060603
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    Kinetic studies of solvent and pressure effects on thermal isomerizations of N-phenyl- and N-methylrhodaminelactams (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 478-482 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Solvent and pressure effects were examined for the isomerization rates of N-phenyl- and N-methylrhodaminelactams (RL-Ph and RL-CH3) from their zwitterionic to the spiro forms. From the pressure dependence of the reaction rate, the activation volumes were estimated to be about 5 cm3 mol-1 for RL-Ph and 3-10 cm3 mol-1 for RL-CH3. It is proposed that there are two rotameric isomers for the coloured zwitterionic forms, and the role of these rotamers in the kinetic effects of solvent and pressure is discussed. The results are consistent with a reaction mechanism involving heterolytic ring closure on activation.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060806
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    Zero-field splitting versus interelectronic distance in triplet electron spin resonance spectra of localized dinitrenes (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 483-487 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Triplet zero-field splitting parameters were obtained in 2-methyltetrahydrofuran glass at 77 K for phenylene-1,4-dinitrene (1), biphenyl-4,4′-dinitrene (2), (E)-1,2-bis(4′-nitrenophenyl)ethene (3), 1,4-bis(4′-nitrenophenyl)buta-1,3-diene (4) and 1,8-bis(4′-nitrenophenyl)octa-1,3,5,7-tetraene (5). The results were (1) |D/hc| = 0·169 cm-1 |E/hc| = 0·004 cm-1, (2) |D/hc| = 0·189 cm-1, |E/hc| = 0·00 cm-1, (3) |D/hc| = 0·122 cm-1, |E/hc| = 0·00 cm-1, (4) |D/hc| = 0·0865 cm-1, |E/hc| = 0·00 cm-1 and (5) |D/hc| = 0·0442 cm-1, |E/hc| = 0·00 cm-1. All these biradicals are ground-state singlets. Based on the observed decrease in triplet signal intensities as temperature decreases. The substantial magnitudes of |D/hc| for 3-5, despite the large distance between localized nitrene electrons, is much more than can be explained by a simple dipolar interaction between localized electrons, and is attributed at least partly to spin polarization effects on the π-electron clouds of these systems.
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    Solvation and metal ion effects on structure and reactivity of phosphoryl compounds. 2. β,γ-Substituted alkylphosphonic esters (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 523-530 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: NMR spectroscopic and conformation analyses ware carried out for five dimethyl β,γ-disubstituted propylphosphonates, YCH2CHXCH2PO3Me2, in five solvents and in acetone containing sodium and magnesium ions. Conformational preferences observed for the rotation about the C1—C2 bond are determined by the attractive interactions between the oxygen containing substituents X (X = OH, OMe) and the phosphoryl group, and are enhanced by the metal ions, presumably via chelation effects. The rotation about the C2—C3 bond yields statistical distribution of the rotamers. For Y = benzoyl, there was no evidence for a competition of the carbonyl group for the intramolecular interactions with X or with a metal ion.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060907
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    Efficient formation of some amidines by the reactions of aryliminodimagnesium with weakly electron-accepting benzonitrile, N,N-dimethylformamide and related compounds. Features of reactions governed by σ-complexationAryliminodimagnesium Reagents, Part XXIII. For Part XXII, see Ref. 1. (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 509-519 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In many reactions of magnesium reagents, including Grignard and aryliminodimagnesium [ArN(MgBr)2, IDMg], the formation of abnormal products via reactions such as radical dimerization, hydrogen abstraction and conjugate 1,4-addition orginating from efficient single electron transfer (SET) is not excluded. In IDMg reactions with benzonitrile and N,N-dimethylformamide in tetrahydrofuran, however, clean reactions took place affording N-arylbenzamidine and N,N′-diarylformamidine via exclusive 1,2-addition and condensation plus replacement, respectively. Some alkyl and arylvinyl cyanides gave the corresponding amidines without 1,4-addition or hydrogen abstraction. These results are the first observation of such reactions of magnesium reagents, and are attributed to a combination of the weak electron-donating ability (EDA) of IDMg with the weak electron-accepting ability (EAA) of nitriles. Although ESR is therefore inapplicable, factors governing the product yields were studied on the basis of effects caused by the addition of strongly coordinating hexamethylphosphoramide and pyridine to the reagent solution, and by addition of nitrobenzenes having a strong EAA. From the results, a large participation of σ-complexation followed by implicit SET in the inner sphere of the complex is proposed.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610060905
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    Masthead (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061001
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    Using theoretical descriptors in structure-activity relationships: Solubility in supercritical CO2 (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 539-544 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The use of quantitative structure-activity relationships (QSAR) in correlating biological phenomena to chemical structure, and the use of linear free energy relationships (LFER) and linear solvation energy relationships (LSER) for correlating physical phenomena are becoming standard occurrences. In this work the empirical LSER solvatochromic descriptors were replaced with a computationally derived set to aid in a priori property prediction. This paper deals with the application of this descriptor set to correlating the solubilities of 22 compounds in super critical CO2. A reasonable correlation, consistent with previous correlations by other researchers, was found.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610061002
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    Nucleophilic catalysis in deoxymercuration: The beta effect of mercury (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 555-560 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Deoxymercuration was examined in the antiperiplanar stereochemistry of trans-2-acetoxycyclohexylmercury(II) acetate (6). The presence of the mercury group accelerates the departure of the beta leaving group by a factor of about 1010. This beta effect is larger than that of silicon and comparable to that of germanium. In contrast to these latter cases, the rate for 6 was found to increase with the nucleophilicity of the solvent. It is concluded that a molecule of solvent is coordinated with mercury in the transition state. This nucleophilic assistance raises the polarizability and nucleophilicity of the mercury group, enhancing its ability to stabilize the developing positive charge or to form a bridged intermediate.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610061005
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    Studies on the thermal decarboxylation of 1-alkoxycarbonylbenzotriazoles (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 567-573 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1-Alkoxycarbonylbenzotriazoles on thermolysis lose carbon dioxide; the decarboxylation is accompanied by the formation of a mixture of 1- and 2-alkylbenzotriazoles, with the N-1 isomer predominating over the N-2 isomer in all cases. A cross-over experiment, in which heating equimolar amounts of 1-benzyloxycarbonylbenzotriazole and 1-(4-methylbenzyloxycarbonyl)-5,6-dimethylbenzotriazole gave almost all the cross-over products, supports the proposed intermolecular mechanism for this decarboxylation and the formation of 1- and 2-alkylbenzotriazoles. No decarboxylation was observed for 1-phenoxycarbonylbenzotriazole.
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610061007
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    Stereochemical structures of (8,8-ethylenedioxy-2-oxo-)- and (8,8-ethylenedioxy-2-hydroxy-)-6-phenylsulphonylbicyclo[3·3·0]octanes (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 583-589 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cyclopentannulation of 4-tert-butyldimethylsilyloxy-2-cyclopenten-1-one from a β-metallated dioxolane-type orthoester affords 4-tert-butyldimethylsilyloxy-8,8-ethylenedioxy-6-phenylsuiphonyl-2-oxobicyclo [3·3·0] octanes as a mixture of two diastereoisomers. Their stereochemical structures were established by NMR and x-ray analysis. The minor product possesses a cis ring fusion, the sulphonyl and the tert-butyldimethylsilyloxy groups being endo and exo, respectively. The major isomer also has a cis ring fusion but an exo position for both dimethylsilyloxy and sulphonyl groups. Both cyclopentannulation products result from an anti addition with respect to the 4-tert-butyldimethylsilyloxy group on the enone.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610061009
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    Attractive interactions between negative charges and polarizable aryl parts of host-guest systemsSupramolecular Chemistry, Part 40. Part 39: A. V. Eliseev and H.-J. Schneider, Angew. Chem., in press. (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 590-594 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: NMR measurements of associations between simple organic host and guest molecules bearing alternatively negatively charged groups and electroneutral π-moieties show in aqueous solutions weak but distinct attractions reaching approximately 2 kJ mol-1 and X-/arene unit. A similar value is observed for the complex between a calixarene with 4-sulfonato groups and toluene, for which the NMR shifts indicate an orientation with the guest methyl substituent upwards. The conformational fit of the selected complexes is checked by molecular mechanics simulations.
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    URL: http://dx.doi.org/10.1002/poc.610061010
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    A comparison of the relative magnitudes of the interaction energies between functional groups with zero, one and two intervening 2p AOs on Carbon, and substituent effects on the relative ground-state energies of E-1,2-disubstituted ethenes (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 621-626 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Ab initio theoretical calculations have been carried out on directly bonded donor-acceptor (Ẍ-Y) species and on variously substituted E-1,2-disubstituted ethanes, and π interaction energies have been estimated. In conjunction with the previously calculated radical stabilization energies of mono- and disubstituted methyl radicals, a comparison is made of the relative magnitudes of the π interaction energies between groups with zero, one and two intervening 2p AOs on carbon atoms. It is concluded that the stabilizing effect of the π interaction between directly bonded donor Ẍ and acceptor Y groups (zero intervening 2p AOs) is approximately 2·1 times that in the disubstituted methyl radicals (one intervening 2p AO), while in the E-1,2-disubstituted ethenes (two intervening 2p AOs) the stabilizing effect is ˜ 0·7 of that calculated for the disubstituted methyl radicals for both acceptor-donor and acceptor-acceptor disubstituted systems. No correlation is observed with the π stabilization energies of the ‘cross-conjugated’ 1,1-disubstituted ethenes.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610061105
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    Theoretical solute parameters and correlations of log P and pKa. A comment on a recent development and statistical protocol (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 634-636 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Physical-chemical properties can be correlated and predicted using linear free energy or linear solvation energy relationships (LSER). Procedures to obtain theoretical parameters from calculated molecular structures that can be used in LSER have recently been evaluated [G R. Famini, C. A. Penski and L. Y. Wilson, J. Phys. Org. Chem. 5, 395-408 (1992)]. Among other applications, these procedures were applied to correlate octanol-water partition coefficients and pKa values for two groups of structurally diverse solutes with very good reported results. In this paper, the statistical results of those studies are re-examined. The corrected statistical parameters do not provide tenability for the appropriateness of the methodology in these applications. However, valid multilinear relationships of the theoretical LSER parameters with the experimental properties are found which do substantiate the original conclusions of Famini et al.
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    URL: http://dx.doi.org/10.1002/poc.610061107
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    Masthead (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061201
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    Nucleophilic participation in the solvolyses of 2-aryl-2-halopropanes and the previously claimed advantage of using YBnX scales (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 642-644 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Contrary to a recent report, the specific rates of solvolyses of five 2-aryl-2-chloropropanes give only marginally (not significantly) better correlations with use of the YBnCl scale rather than the YCl scale. With the use of the extended (two-term) Grunwald-Winstein equation, some evidence for a weak nucleophilic solvation is obtained, but at a low confidence level. The specific rates of 2-bromo-2(p-trifluoromethylphenyl)propane solvolysis are significantly better correlated using YBr (rather than YBnBr) values and, indeed, the use of NT values in conjunction with YBr values leads to an l value of 0·17 ± 0·06 and evidence for a weak nucleophilic participation at a 98·7% confidence level.
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    URL: http://dx.doi.org/10.1002/poc.610061109
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    σ-π Energy diagrams for substituted rings (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 645-650 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The recently developed σ-π energy separation technique was applied to substituted monocyclic ring systems. Modified correlation diagrams are presented which allow the influence of the substituent on the σ and π energies to be assessed. The slopes of the σ and π electron energy curves can be used to classify aromatic, non-aromatic and anti-aromatic compounds. A two-dimensional resonance coordinate representation shows a clustering of compounds of the three classes in distinctly different regions of this plane.
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    URL: http://dx.doi.org/10.1002/poc.610061202
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    Classification of the solubility behaviour of β-cyclodextrin in aqueous-CO-solvent mixtures (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 651-659 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The solubility behaviour of β-cyclodextrin in aqueous mixtures was studied by determining the interactions between the co-solvent and water. Three clear classes of co-solvent are evident. In the first, including ethanol, tetrahydrofuran and acetone, there is formation of clathrate hydrates by the co-solvent. In these systems the solubilization is a maximum at the mole fraction corresponding to the minimum in the partial excess molar volume. The second class, including such solvents as dimethyl sulphoxide and pyridine, forms strong molecular complexes with water, and here a valley and a plateau region occur in the solubility values. In the third class, including formamide and urea, a steady increase in the solubility is observed. For these highly polar solvents no maxima are observed in intrinsic solvent properties such as the partial excess molar volume.
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    URL: http://dx.doi.org/10.1002/poc.610061203
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    Hydrogen bonding. 31. Construction of a scale of solute effective or summation hydrogen-bond basicity (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 660-684 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The β2H scale of solute hydrogen-bond basicity, formulated from 1:1 hydrogen-bond complexation constants in tetrachloromethane, has been used to set up a scale of effective or summation hydrogen-bond basicity, appropriate for the situation in which a solute is surrounded by solvent molecules. The method is based on the equation, \documentclass{article}\pagestyle{empty}\begin{document}$$ \log SP = c + rR_2 + s\pi _2^{\rm H} + a\sum {\alpha _2^{\rm H}} + b\sum {\beta _2 + vVx} $$\end{document} where SP is, in this work, a set of solute water-solvent partition coefficients in a given system. The explanatory variables are solute parameters as follows: R2 is an excess molar refraction, π2H is the solute dipolarity/polarizability, Σα2H and Σβ2 are the effective solute hydrogen-bond acidity and basicity and Vx is McGowan's characteristic volume. Various equations are established using β2H in the equation, and then amended β2H values are back-calculated and new Σβ2H values obtained. It is found that for most solutes, the effective basicity Σβ2H is invariant over the systems used to within an experimental error of around 0·03 units. About 350 Σβ2H values obtained from two or more experimental log P values are listed, together with values for homologous series and a number of singly determined values. For some specific solutes, such as sulphoxides, alkylanilines and alkylpyridines, Σβ2 is not constant, and an additional solute basicity denoted as Σβ2O is needed in order to deal with partitions from water to solvents that are partially miscible with water, such as isobutanol and octanol. Values of Σβ2O, and where possible Σβ2H also, are listed for 80 additional solutes.
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    URL: http://dx.doi.org/10.1002/poc.610061204
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    Acidities of 4-substituted benzoic, bicyclo[2.2.2]oct-1-yl and bicyclo[2.2.2]oct-2-enyl carboxylic acids (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 685-689 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Experimental gas-phase acidities are reported for a series of 4-substituted bicyclo [2.2.2] oct-1-yl carboxylic acids and for a limited number of the corresponding bicyclo [2.2.2] oct-2-enyl carboxylic acids. Similar acidities are also reported for additional 4-substituted benzoic acids, allowing a comparison of field and resonance effects between the three series. Ab initio molecular orbital calculations for these series of acids confirm the conclusion that the aromatic acids display direct field and resonance effects, whereas the acidities in the aliphatic series acids are largely determined by direct field effects.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061205
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  • 85
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    AM1 and polarized-π frontier molecular orbital (PPFMO) studies of facial selectivity in hydrogen transfer to substituted adamantyl radicals (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 690-695 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fully optimized transition states for hydrogen transfer from methane and propene to substituted 2-adamantyl radicals were calculated using the AM1 molecular orbital method. Methane and propene were chosen to provide an early (propene) and a late (methane) transition state. For 5-substituted radicals (F, Cl, Ph, CH3, CF3) the enthalpic differences between syn and anti reactions was found to be small [〈0·1 kcal mol-1 (1 kcal = 4·184 kJ)]. Other radicals with nitrogen or boron included directly in the adamantyl fragment showed greater selectivities, with aza substitution favoring syn and bora substitution favouring anti attack, as did the 4,9-difluoro derivative. The calculated selectivities are all in qualitative agreement with experimental results (where available) on bromine atom transfer. PPFMO calculations showed the polarization of the SOMO to be generally in accord with the AM1 results, whereas the polarization of the LUMO's was less indicative. The bond orders for the bonds syn and anti to the incipient C—H bond in the adamantyl fragments indicated that the anti bonds were always weaker than those syn, in agreement with the suggestion by Cieplak that has been used to explain the experimental selectivities. However, the bond lengths of the incipient C—H bonds are always shorter for the side of preferred attack, in apparent agreement with the suggestion by Anh.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061206
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  • 86
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    First determination of an absolute rate constant for a 1,2-phenyl migration to a carbene (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 696-698 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The first determination of a 1,2-phenyl shift in α,α-dimethylbenzylchlorocarbene was achieved by nanosecond laser flash photolysis, τ = 50 ns.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061207
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  • 87
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    Electronic Resource
    Kinetics and mechanism of the oxidation of substituted benzaldehydes by ethyl N-chlorocarbamate (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 1-6 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the oxidation of a number of para- and meta-monosubstituted benzaldehydes by ethyl N-chlorocarbamate (ECC) were studied in aqueous acetic acid solution in the presence of perchloric acid. The main product of the oxidation is the corresponding benzoic acid. The reaction is first order with respect to the aldehyde, ECC and hydrogen ions. The oxidation of benzaldehyde exhibits a substantial primary kinetic isotope effect (kH/kD = 5·20 ± 0·10). Addition of ethyl carbamate has no effect on the rate. [EtOC(OH)NHCI]+ is postulated as the reactive oxidizing species. The rates of oxidation of para-substituted benzaldehydes exhibit an excellent correlation with Taft's σ1 and σR+ values whereas those of the meta-substituted compounds compounds correlate best with σ1 and σR0 values. The reaction constants are large and negative. A mechanism involving transfer of a hydride ion from the aldehyde to the oxidant, in the rate-determining step, is proposed.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060102
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  • 88
    Electronic Resource
    Electronic Resource
    Alkaline hydrolysis of substituted benzyl substituted benzoates (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 23-28 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics and mechanism of the alkaline hydrolysis of both acyl- and aryl-substituted benzyl benzoates were studied in 80% (v/v) aqueous acetone at 20, 34, and 40 °C. Each of the substituted benzyl alcohols generated an independent σ-ρ plot which was correlated well with the Hammett equation (R = 0·996-0·999). The values of ρ for the acyl moiety showed no tendency either to increase or to decrease with the intrinsic reactivity of the parent benzyl alcohol and were all within ±0·098 of the mean of 2·236. However, the Hammett ρ values for the leaving groups decreased from H to p-NO2 substituents of the acyl part, in which the values were smaller than those of acyl moieties and fairly accurately obeyed the σ0 values rather than the σ values. The rate data for benzyl-substituted benzoates were correlated by the Yukawa-Tsuno equation, log k/k0 = 1·72(σ0 + 0·49ΔσR-) - 0·020, R = 0·996. The results suggested that the alkaline hydrolysis of benzyl benzoates showed a greater sensitivity to acyl than aryl activation, and the rates and activation parameters were largely determined by the addition step. The results are attributed to the preferential partitioning of an unstable tetrahedral intermediate to the products.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060105
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  • 89
    Electronic Resource
    Electronic Resource
    Precipitation of strong uncharged organic acids with various crown ethers or with acyclic polyethers from aqueous medium. Characterization of adducts in the solid state (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 47-53 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It was found that substituted picric acids form slightly soluble 1 : 2 : 2 adducts with several simple crown ethers or with tri-, tetra-, or pentaethylene glycol dimethyl ether (glymes 4, 5 and 6) in water, whereas 2,4,6-trinitrobenzenesulfonic acid forms a 1 : 1 : 1 adduct with dicyclohexano-18-crown-6 (cis-syn-cis). The ability of a crown ether to precipitate a given acid follows the order dicyclohexano-18-crown-6 (cis-syn-cis) 〉 benzo-15-crown-5 〉 dicyclohexano-24-crown-8 〉 18-crown-6 〉 21-crown-7, 15-crown-5 ≫ 12-crown-4, roughly in the order of its base strength. Precipitation can occur even when the concentration(s) of one or more of the components are 〈 10-4 M. The solubility products of the 18-crown-6 complexes with dichloro- or dimethylpicric acids were estimated. In the solid state the 1 : 2 : 2 dicyclohexano-18-crown-6 (cis-anti-cis)-dichloropicric acid-water complex, which reportedly has two pseudohydronium ions lacking C3v symmetry of H3O+, exhibits an IR spectrum in the OH stretching region characteristic of an aqua complex.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060108
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  • 90
    Electronic Resource
    Electronic Resource
    Elimination kinetics and mechanism of primary, secondary and tertiary α-hydroxycarboxylic acids in the gas phase (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 54-58 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rates of elimination of primary, secondary and tertiary α-hydroxycarboxylic acids were determined in a seasoned, static reaction vessel over the temperature range 280-390°C and the pressure range 30-201 Torr. The reactions, in the presence of a free radical inhibitor, are homogeneous, unimolecular and follow a first-order rate law. The rate coefficients are given by the following equations: for glycolic acid, log k1 (s-1) = (14·03 ± 0·24) - (209·3 ± 1·5) kJ mol-1 (2·303RT)-1; for lactic acid, log k1 (s-1) = (12·24 ± 0·11) - (182·8 ± 1·3) kJ mol-1 (2·303RT)-1; and for 2-hydroxyisobutyric acid, log k1 (s-1) = (12·91 ± 0·13) - (174·7 ± 1·5) kJ mol-1 (2·303RT)-1. The basicity and the ease with which the hydroxy group is removed from primary to tertiary α-hydroxycarboxylic acids are reflected in rate enhancement. The mechanism of these eliminations appears to proceed through a semi-polar five-membered cyclic transition state.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060109
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  • 91
    Electronic Resource
    Electronic Resource
    Interaction of dichlorocarbene with imines (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 83-84 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The interaction of dichlorocarbene with imines and ketene imines was studied by means of the MNDO method. The results indicate that the lack of ylide cyclization products in the reactions of dichlorocarbene with ketene imines is due to a high reactivity of ketene imine ylides in intermolecular reactions, rather than stereoelectronic factors preventing cyclization. It was shown that the dichlorocarbene reaction with N-benzylideneaniline resulting in gem-dichloraziridine proceeds through transient formation of ylide.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060203
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  • 92
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    Conformational interconversion of [1.1] ferrocenophane: A molecular mechanics study (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 107-112 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A molecular mechanics scheme developed for bridged ferrocene derivatives was applied to study the conformational energy surface of [1.1] ferrocenophane (1). The mechanism of the intramolecular interconversion of 1 is shown to be different from the mechanism of the syn-syn exchange proposed earlier for this ‘molecular acrobat’.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060207
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  • 93
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    Electronic Resource
    Acidity constants of benzamide and some Ortho-substituted derivatives (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 101-106 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acidity constants of benzamide and seven ortho-substituted derivatives were determined. Except for o-nitrobenzamide, all the amides exhibit medium effects. The data were treated by vector analysis. o-Aminobenzamide displays two protonation equilibria. The second acidity constant was determined by vector analysis and by the excess acidity function, since the acid strength provided by perchloric acid is insufficient for complete protonation. Different acidity functions and the ortho substituent effect on ionization of the amide group are compared.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060206
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  • 94
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    Catalytic activity of polypodands and glymes under solid-liquid phase-transfer catalysis conditions. Amolecular mechanics study (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 113-121 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A molecular mechanics study of cyclophosphazenic polypodands and of glymes, of their complexes with ion pairs (IPs) M+ I- (M+ = Li+, Na+, K+, Rb+) and IP aggregates (M+ I-)n was carried out to investigate the catalytic activity of these ligands in solid-liquid phase-transfer reaction. This activity is explained by their ability to bind IP aggregates effectively and to activate the anion by increasing the interionic distance in the single IP.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060208
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  • 95
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    Study of initial- and transition-state solvation in the solvolysis of tert-butyl halides in alcohols from infinite dilution activity coefficients (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 133-138 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Gibbs energies of activation of the solvolytic reactions of tert-butyl halides (chloride, bromide and iodide) in eight mono-alcohols and eight di-alcohols were dissected into contributions from the initial state and transition state. The unified approach proposed by Abraham was applied and the various factors making up the overall solvent effect in both states were identified and compared. To perform this study, the Gibbs energies of transfer of the initial state were calculated using the infinite dilution activity coefficient values of the solutes in the solvents, γ∞. These values were determined from the UNIFAC group-contribution method, with the modified Flory-Huggins equation in the combinatorial term and with group interaction parameters from the Parameter Table exclusively based on experimental γ∞ data reported in the literature. It is concluded that solvent polarizability and polarity-HBD acidity and cavity effects during the activated process are mainly due to transition-state contributions.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060302
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  • 96
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    [4] Metacyclophane: STO-3G molecular structure, strain energy and CNDO/S—Cl electronic transition energies (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 163-170 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The molecular structure of [4] metacyclophane is optimized at the ab initio STO-3G SCF level and a genuine minimum is located. In the STO-3G structure the benzene ring is less bent and geometrically distorted than in the previously reported MNDO structure. Although some bond alternation is calculated for the carbon-carbon bond lengths of the bent benzene ring, their values still fall in the range of highly delocalized compounds. Despite the fact that the STO-3G strain energy [SE(tot.)] is larger than the corresponding MNDO strain energy, the distribution of SE(tot.) over the bent benzene ring [SE(bb.)] and the oligomethylene bridge [SE(br.)] is similar. To facilitate the hitherto unsuccesful identification of [4] metacyclophane, its electronic transition energies were calculated with CNDO/S-CI using the STO-3G geometry as input geometry. The reliability of the CNDO/S-CI results was assessed by a comparison of calculated and experimental electronic transition energies for p- and, m-xylene, [5] para- and [5] metacyclophane and [4] paracyclophane following the same approach.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060307
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  • 97
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    Kinetics and mechanism of electron transfer reactions of aquo-thallium(III) and coordinated thallium(III). Reduction of thallium(III) and chlorothallium(III) complexes by L-ascorbic acid in aqueous acid medium (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 179-186 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stoichiometry of the reaction of TIIII with ascorbic acid (H2A) in the presence and absence of chloride ion conforms to TIIII + H2A 〉 TII + 2H+ + A. where A is dehydroascorbic acid. The reaction exhibits complex kinetics and the reactivity of various chlorothallium (III) species decreases in the order of [TIOH]2+ 〉 TI3+ 〉 [TICI]2+ 〉 [TICI2]+ 〉 TICI3 〉 [TICI4]-. The mass balance relationship was employed to calculate the equilibrium concentration of the chloride ion for evaluation of the rate constants.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060309
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  • 98
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    IUPAC Commission on Physical Organic Chemistry (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 193-194 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060311
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  • 99
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    Theoretical studies of substituent effects on thermal eliminations of aryl ethyl carbonates and S-aryl O-ethyl thiocarbonatesDetermination of Reactivity by MO Theory. Part 82. (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 215-222 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Substituent effects on the thermal elimination reactions of carbonates and thiocarbonates were investigated MO theoretically using the AM1 method. For both substrates, an electron-withdrawing group is found to facilitate the decomposition. A two-step process is favoured by carbonates, whereas one- and two-step processes can compete in the pyrolysis of thiocarbonates. The ability to transmit substituent effect is greater with oxygen (carbonates) than with sulphur (thicarbonates) in contrast to the experimental results of Taylor and co-workers. Modelling studies with replacement of the phenyl ring with a vinyl group are found to be justified in this type of work.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060404
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  • 100
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    Radical reactions of epoxides. 2.For Part 1, see Ref. 1. intramolecular competition between cyclopropylmethyl and oxiranylmethyl radical ring-opening rearrangementsInitial results presented at the 46th Northwest Regional Meeting of the American Chemical Society, LaGrande, OR, 1991. Taken from the Thesis of K. W. Krosley.2 (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 228-232 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The erythro-thioimidazole precursor to the cyclopropyloxiranylmethyl radical has been prepared. Treatment with 7-19 equiv. of triphenyltin hydride at 70°C gave only 3-cyclopropylprop-2-en-1-ol, the product of epoxide ring opening. No product in which the cyclopropyl ring had opened was observed. Kinetic analysis allowed the assignment of a lower limit for the rate of oxiranylcarbinyl radical rearrangements of 1 × 1010 s-1 at this temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060406
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