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  • 2000-2004
  • 1985-1989  (1,855)
  • 1940-1944
  • 1988  (1,855)
  • General Chemistry  (1,050)
  • Organic Chemistry  (765)
  • MRI
  • breast cancer
Source
Material
Years
  • 2000-2004
  • 1985-1989  (1,855)
  • 1940-1944
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    The follow up study of intra-arterial infusion chemotherapy with local vein blocking as a surgical neo-adjuvant treatment for locally advanced breast cancer (1988)
    Springer
    Surgery today 18 (1988), S. 131-135 
    Details
    ISSN: 1436-2813
    Keywords: breast cancer ; intra-arterial infusion ; chemotherapy ; local vein blocking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Preoperative intra-arterial infusion neo-adjuvant chemotherapy, in combination with local vein blocking, was administered to thirtyone patients with locally advanced stage III breast cancer. The anti-cancer drugs and dosages used were 500 mg of 5-Fluorouracil (5FU), which was infused daily for 7–14 days, and 20 mg of Adriamycin (ADM), which was administered as a bolus dose twice into the subclavian and internal mammary arteries. The response rate of this method on the primary tumor was 48.4 per cent, and, histologically it was found to be as high as 90.3 per cent. The response rate of the clinical effects on the regional lymph nodes was 50.0 per cent, however, histologically, it was found to be lower than that of the primary tumor. In the long-term follow up study the 5-year survival rate was 72.2 per cent. Thus, this method seems to be effective as a combined modality in cases of locally advanced stage III breast cancer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02471420
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  • 2
    Electronic Resource
    Electronic Resource
    Immunocytochemical study on the variation in estrogen receptors of primary and nodal metastases of breast cancer (1988)
    Springer
    Surgery today 18 (1988), S. 228-231 
    Details
    ISSN: 1436-2813
    Keywords: breast cancer ; immunocytochemical assay ; estrogen receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The variation in estrogen receptors (ER) between primary and regional nodal metastatic lesions was examined by an estrogen receptor immunocytochemical assay (ER-ICA) in 25 mammary carcinoma patients. The ER status was evaluated in terms of the percentage of ER positive stained cells, staining intensity and distribution of those stained cells. The overall ER status was consistent in both sites, however, the percentage of ER positive cells and the staining intensity were not always consistent. A decrease in the percentage of ER positive cells and staining intensity was demonstrated in the nodal metastatic lesions of 4 and 3 cases out of a total 14 ER positive cases, respectively. The mean percentage of ER positive cells in the nodal metastatic lesions was 57 per cent compared with 73 per cent in primary lesions. Thus, a tendency of both the percentage of ER positive cells and the staining intensity to decrease in nodal metastases as when compared with primary lesions in breast cancer was demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02471436
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  • 3
    Electronic Resource
    Electronic Resource
    Chest wall resection and reconstruction for locoregionally advanced or recurrent breast cancer (1988)
    Springer
    Surgery today 18 (1988), S. 687-693 
    Details
    ISSN: 1436-2813
    Keywords: breast cancer ; chest wall reconstruction ; musculocutaneous flap
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Ten patients, including 7 with local recurrent breast cancer, 2 with primary advanced cancer and 1 with radionecrosis, underwent chest wall resection and immediate reconstruction, using large pedicled skin flaps or musculocutaneous flaps. A rectus abdominis musculocutaneous flap was used in 4 cases and a latissimus dorsi musculocutaneous flap was used in 1 case. The postoperative course of all the patients was uneventful and there was no incidence of flail chest or respiratory failure. The postoperative performance status and also the quality of life were improved in 9 of the 10 patients. Eight of the 10 patients are presently alive with or without disease, the longest survival time thus far being 8 years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02471531
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  • 4
    Electronic Resource
    Electronic Resource
    Cerebral micro arteriovenous malformations (mAVMs) (1988)
    Springer
    Acta neurochirurgica 91 (1988), S. 37-41 
    Details
    ISSN: 0942-0940
    Keywords: Cerebral arteriovenous malformation ; cerebral angiography ; intracerebral haemorrhage ; cryptic vascular lesions ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a personal series of 152 cerebral vascular malformations, 13 patients had small (less than 1 cm) parenchymal arteriovenous malformations (mAVMs) with small nidus or fistula and a single normalsized feeding artery and draining vein. All 13 patients presented with intracerebral haematomas (ICHs). The average age in this group was 31 years with no sex dominance; 8 patients had no antecedent symptoms. In 11 patients the small AMV could be demonstrated angiographically, with the remaining 2 malformations evident at surgery. In addition, all these mAVMs, being superficial (95% cortical), were surgically removable with no perioperative morbidity. They were not accessible by endovascular approach. This population group narrows the concept of occult vascular lesions if high quality angiographic studies are performed. mAVMs are by nature CT and MRI occult.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01400525
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  • 5
    Electronic Resource
    Electronic Resource
    The association of venous and cavernous malformations (1988)
    Springer
    Acta neurochirurgica 92 (1988), S. 100-105 
    Details
    ISSN: 0942-0940
    Keywords: Venous malformation ; cavernous malformation ; angioma ; angiographically occult AVM ; cryptic AVM ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four cases of venous malformation associated with a cavernous malformation are reported. Because cavernous malformations are often angiographically occult and do not have a characteristic appearance on computed tomography (CT), they are seldom recognized preoperatively and may be missed if the surgical specimen is not carefully reviewed. This association, however, may not be rare and may explain the presence of symptomatic venous malformations. Magnetic resonance (MR) imaging is particularly sensitive in detecting cavernous malformations and is highly specific. It is recommended that every symptomatic venous malformation be worked-up with a high field strength MR Unit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01401979
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  • 6
    Electronic Resource
    Electronic Resource
    Transcranial Dopplersonography of the vertebro-basilar system (1988)
    Springer
    Acta neurochirurgica 90 (1988), S. 136-138 
    Details
    ISSN: 0942-0940
    Keywords: TCD ; MRI ; anatomical measurements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This is the first investigation of distances, angles and locations of the vascular system in the posterior fossa. The distances from the skin surface of the neck, where a Doppler probe is positioned for transforaminal insonation, to the brainsystem have been measured in sagittal MRI pictures. The mean distance from the insonation point to the beginning of the basilar artery (BA) is 66.6 mm in males, 58.8 in femals. The distance to the end of the BA is 90.0 and 80.4, respectively. These distances are relevant for locating the vertebral and basilar arteries. The insonation angles to the VA and BA range from 20° to 30°. Correlations with Doppler findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01560568
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  • 7
    Electronic Resource
    Electronic Resource
    MR appearance of Rathke's cleft cysts (1988)
    Springer
    Neuroradiology 30 (1988), S. 155-159 
    Details
    ISSN: 1432-1920
    Keywords: MRI ; Rathke's cleft cysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two of three patients who proved to have symptomatic Rathke's cleft cysts presented with visual field deficit and all with diabetes insipidus. CT showed intra- and suprasellar cystic low density lesions with ring enhancement. MR showed intra-and suprasellar masses. On the T1-weighted images two of the three had hyperintense portions similar to fat and the other a hyperintense portion similar to white matter within the cysts. These portions were isointense to brain on the T2-weighted images in all cases. This characteristic intensity on MR images provides differentiation from cystic pituitary adenomas and cystic craniopharyngiomas, and leads to correct diagnosis of Rathke's cleft cyst.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395617
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  • 8
    Electronic Resource
    Electronic Resource
    Autopsy validation of MRI in central pontine myelinolysis (1988)
    Springer
    Neuroradiology 30 (1988), S. 175-177 
    Details
    ISSN: 1432-1920
    Keywords: Central pontine ; Myelinolysis ; Autopsy ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a fatal case of central pontine myelinolysis (CPM) a low field strength (0.08 Tesla) magnetic resonance image revealed reduction of image intensity in the pons with sparing of two central symmetrical areas in the ventral portion. The latter correlated with preservation of centrally located groups of longitudinal myelinated nerve fibres shown at autopsy. Although such sparing is well recognised in pathological studies of CPM it has never previously been demonstrated in life.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395621
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  • 9
    Electronic Resource
    Electronic Resource
    MR imaging in tumors of the pineal region (1988)
    Springer
    Neuroradiology 30 (1988), S. 224-231 
    Details
    ISSN: 1432-1920
    Keywords: CT ; MRI ; Germcell tumors ; Teratoma ; Pineocytoma ; Ependymoma ; Meningioma of the pineal region ; T2 calculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ten patients with tumors of the pineal region underwent CT and MRI investigations. There were 3 germinomas, 3 teratomas and 1 of each of the following: pineocytoma, PNET, ependymoma and meningioma. Not only were tumor size and growth compared to CT, but an attempt was made to obtain knowledge of the histology of the tumor by special T2 calculations. The investigations did not lead to an improvement in type specific diagnosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341833
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  • 10
    Electronic Resource
    Electronic Resource
    Bilateral anterior opercular syndrome: Localizing value of SPECT and MRI (1988)
    Springer
    Neuroradiology 30 (1988), S. 579-581 
    Details
    ISSN: 1432-1920
    Keywords: Operculum syndrome ; Anterior opercular syndrome ; Foix-Chavany-Marie syndrome ; SPECT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bilateral anterior opercular syndrome is clinically characterized by facio-pharyngo-glossomasticatory diplegia due to bilateral opercular lesions. Reported cases of the syndrome have been relatively rare probably because of difficulty in determining opercular damage on clinical symptoms alone. We report a case of this syndrome in whom bilateral opercular damage could be detected not by CT, but suggested by SPECT, and confirmed by MR imaging.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00339707
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  • 11
    Electronic Resource
    Electronic Resource
    The value of paramagnetic contrast agent gadolinium-DTPA in the diagnosis of pituitary adenomas (1988)
    Springer
    Neuroradiology 30 (1988), S. 481-486 
    Details
    ISSN: 1432-1920
    Keywords: MRI ; Pituitary adenoma ; Gd-DTPA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of this study was to assess the role of MR imaging and the paramagnetic contrast agent Gadolinium-DTPA(Gd-DTPA) in the diagnosis of pituitary macroadenomas. 44 macroadenomas were examined with MRI before and after intravenous application of Gd-DTPA. Gd-DTPA produced excellent enhancement of solid adenoma. The best contrast between adenoma and surrounding structures could be gained on post-Gd T1-weighted images. Post-Gd images were equivalent to pre-Gd images in the evaluation of supra-and infrasellar extensions of macroadenomas. Post-Gd images had advantages in the evaluation of cavernous sinus invasion by adenoma. The difference in degree of contrast enhancement between adenoma and cavernous sinus facilitated the exact evaluation of lateral extension by adenoma in 18 cases. Almost equal degree of enhancement of both structures impaired tumor-sinus contrast in 2 cases. In the other 24 cases the tumor filled the cavernous sinus completely. It is our opinion that Gd-DTPA can be used on a widespread basis because of its excellent capability to highlight and delineate pituitary adenomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00339687
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  • 12
    Electronic Resource
    Electronic Resource
    Respiratory depression due to MST (1988)
    Springer
    European journal of clinical pharmacology 35 (1988), S. 685-685 
    Details
    ISSN: 1432-1041
    Keywords: morphine slow release tablets ; breast cancer ; respiratory depression ; case report
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637609
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  • 13
    Electronic Resource
    Electronic Resource
    Measure theoretic imaging, with an example employing magnetic resonance input (1988)
    Springer
    Machine vision and applications 1 (1988), S. 169-174 
    Details
    ISSN: 1432-1769
    Keywords: measure theory ; computed tomography ; imaging ; NMR ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We present a new medical imaging principle which allows reconstruction of images (from the output of a general digital imaging technology) whose contrast is based on a fundamentally different mathematical mechanism than that of standard images. These images have the useful property that they are capable of exhibiting high contrast between tissues which in currently produced images necessarily have low contrast. The meaning of these images, and their general place in the context of present image generation techniques, is most naturally expressed in the formalism of measure theory. The property actually imaged is derived from a probability measure associated with the mapping which expresses the output of the imaging technology. It also has a nonprobabilistic interpretation as a generalization of the Jacobian, specifically, the Radon-Nikodym derivative. In particular, unlike standard images, contrast is independent of the metric in the space of physical signals that the imaging technology associates with points of the region to be imaged. Images based on this approach using magnetic resonance input are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01213004
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  • 14
    Electronic Resource
    Electronic Resource
    Phase II evaluation of teniposide (VM-26) in metastatic breast carcinoma (1988)
    Springer
    Investigational new drugs 6 (1988), S. 37-40 
    Details
    ISSN: 1573-0646
    Keywords: breast cancer ; breast carcinoma ; teniposide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The Southeastern Cancer Study Group performed a Phase II study of teniposide in previously treated patients with metastatic breast cancer. No responses were observed in 11 evaluable patients who received teniposide 60 mg/m2 by IV infusion for five consecutive days every three weeks. Toxicity was primarily gastrointestinal and hematologic and was frequently severe. This study demonstrated no therapeutic activity for teniposide when given in this dose and schedule to patients with heavily pretreated metastatic breast cancer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00170777
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  • 15
    Electronic Resource
    Electronic Resource
    Clinical trial of iproplatin (cis-dichloro-trans-dihydroxy-bis-isopropylamine platinum IV, CHIP) in patients with advanced breast cancer (1988)
    Springer
    Investigational new drugs 6 (1988), S. 87-91 
    Details
    ISSN: 1573-0646
    Keywords: breast cancer ; Iproplatin ; CHIP ; phase II study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Twenty-five women with advanced breast cancer were treated in a phase II trial of iproplatin 275 mg/m2 administered intravenously every 4 weeks. All patients had measurable or evaluable indicator lesions, and had undergone treatment with no more than one previous chemotherapy regimen, including adjuvant chemotherapy. Two of the twenty-four evaluable patients (8%) experienced major therapeutic responses. One patient had a complete regression of pulmonary nodules lasting 18 + months; another had a partial regression of metastatic disease in the liver (4 months). The inevaluable patient was ineligible for the study because of previous radiation to the indicator lesions on her chest wall; nonetheless, she experienced a 10 month partial regression of those nodules. Myelosuppression was generally dose limiting; thrombocytopenia was more profound, but leukopenia was more prolonged. Nausea, vomiting, diarrhea, and general malaise were prominent toxicities, and led to discontinuation of therapy in 4 patients. Iproplatin has limited activity in previously treated women with advanced breast cancer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195365
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  • 16
    Electronic Resource
    Electronic Resource
    Presence of antibodies reacting specifically with structural proteins of mouse mammary tumor virus (MMTV) among antibodies composing circulating immune complexes in breast cancer patients (1988)
    Springer
    Bulletin of experimental biology and medicine 105 (1988), S. 573-575 
    Details
    ISSN: 1573-8221
    Keywords: circulating immune complexes ; MMTV proteins ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00841209
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  • 17
    Electronic Resource
    Electronic Resource
    Characteristics of patients with short and long survivals after detection of intracranial metastases from breast cancer (1988)
    Springer
    Journal of neuro-oncology 6 (1988), S. 37-45 
    Details
    ISSN: 1573-7373
    Keywords: breast cancer ; brain metastasis ; patient characteristics ; survival after recurrence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The clinical course of 106 patients with brain metastases from breast cancer was retrospectively studied. Median time of survival after detection of intracranial metastases (SAR(ICM)) was 14 weeks (95% confidence limits: 10–19 weeks), and 25% of the patients survived for more than 37 weeks, while only 17% survived for one year. The occurrence of clinical, pathoanatomical and therapeutical variables in these patients were analyzed in a subgroup of 57 patients, who survived for less than 16 weeks, and compared with a subgroup of 49 patients, who survived for more than 16 weeks after detection of brain metastases. None of the variables studied were associated with either of the two prognostic groups. Patients with short SAR(ICM) had, however, a greater number of extra-cranial metastases at recurrence in the brain compared to patients with SAR(ICM) more than 16 weeks (p = 0.07). Patients with SAR(ICM) less than 16 weeks had a somewhat shorter recurrence-free interval (p = 0.22) and a significantly shorter time from primary diagnosis until detection of brain metastases (p = 0.04). Probably as a consequence of this, these patients had a shorter survival from primary diagnosis as well as from first recurrence. The findings may indicate that the differences in survival of patients with brain metastases are mainly due to differences in the rate of disease progression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00163539
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  • 18
    Electronic Resource
    Electronic Resource
    Influence of endocrine status on biochemical and immunocytochemical estrogen and progesterone receptor assays in breast cancer patients (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 67-73 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; estrogen receptor ; progesterone receptor ; menopausal status ; immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Breast cancer tissue from 190 patients was studied for immunocytochemically reactive estrogen and progesterone receptors (ER, PR). Parallel cytosol ER and PR assays were performed on 159 of these patients using the dextran-coated charcoal (DCC) method. For the immunocytochemical determination, monoclonal antibodies to ER (ER-ICA kit) and PR were used in an immunoperoxidase procedure. Agreement between the two techniques in postmenopausal patients was better than in the premenopausal group (ER, kappa = 0.597 vs. 0.398; PR, kappa = 0.460 vs. 0.329). The median ER cytosol concentration in receptor-positive postmenopausal patients was significantly higher than in receptor-positive premenopausal patients (87 vs. 31 fmol/mg cytosol protein, p〈0.001). A similar trend was also found in the immunocytochemical ER assay (270 vs. 207 histoscore units, p〉0.05). Significantly higher cytosol ER contents were found in patients with low serum estradiol concentration. The proportion of ER-negative tumors was slightly higher in the premenopausal patients by both methods. In the PR assays (biochemical or immunocytochemical) there were no significant differences between the two patient groups in the proportion of PR-negative tumors or in the median PR content in PR-positive tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805742
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  • 19
    Electronic Resource
    Electronic Resource
    Proliferative index of breast carcinoma by thymidine labeling: Prognostic power independent of stage, estrogen and progesterone receptors (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 191-204 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; cell kinetics ; estrogen receptor ; progesterone receptor ; prognosis ; proliferative index ; stage ; thymidine labeling index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied cellular proliferation by measuring the tritiated thymidine labeling index (TLI) in slices of primary invasive breast carcinomas. Estrogen receptor (ER) and progesterone receptor (PgR) were measured by ligand-binding assay. The TLI was a strong independent predictor of survival and relapse-free survival in women with or without axillary lymph nodal metastases and in American Joint Committee stage I. In operable node-negative women treated surgically, predicted survival at 5 years was 89 ± 4% (probability±standard error) for 81 patients with low TLI (⩽3%), 64 ± 7% for 101 with mid TLI (3.1 – 8%), and 66 ± 6% for 86 with high TLI (〉8%) (P = 0.001). Probabilities of survival for patients with positive axillary nodes were 79 ± 6% for 86 with low, 71 ± 7% for 71 with mid, and 52 ± 6% for 89 with high TLI (P = 0.0002). In stage I patients (tumor diameter not exceeding 2 cm), 5-year survival probabilities were 93 ± 4% in 70 with low, 72 ± 8% in 43 with mid, and 58 ± 10% in 35 with high TLI, (P = 0.0005). The TLI was predictive for survival and relapse-free survival within subgroups positive and negative for ER and positive for PgR (P〈0.05) in stage I patients, and a predictive trend was observed in the PgR-negative subgroup (P = 0.16). TLI also predicted within different categories of vascular invasion and nuclear grade. A stepwise Cox proportional hazards model selected TLI, number of positive axillary lymph nodes, and maximum diameter of the breast carcinoma as independent variables predictive of relapse, and added ER as a fourth variable for prediction of survival.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805940
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  • 20
    Electronic Resource
    Electronic Resource
    Measurement of a breast cancer associated antigen detected by monoclonal antibody SP-2 in sera of cancer patients (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 19-30 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; tumor-associated antigens ; monoclonal antibodies ; serum markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An enzyme-linked immuno-absorbent assay has been developed for the detection of a circulating tumorassociated antigen, 90K, recognized by murine monoclonal antibody SP-2 (Iacobelliet al., Cancer Res 46: 3005–3010, 1986). This assay was found to be simple and reproducible. Using this method, 6% of 165 apparently healthy individuals and 15% of 91 patients with benign breast disease showed 90K levels above 1.7 units/ml. Approximately 50% of 129 patients with advanced breast cancer demonstrated serum antigen levels above 1.7 units/ml. All histological types of breast cancer were positive, and no association between the incidence of elevated 90K levels and other prognostic variables could be detected. The titers of 90K were significantly higher in sera from advanced-stage (3 and 4) patients than in those from patients with limited-stage (1 and 2) disease. Elevated 90K levels were also observed in patients with carcinomas of other sites, including gastrointestinal, gynecological, and lung tumors. By means of the immune blotting technique, the antigenic components carrying the determinants in serum and extracts of breast cancer cells have been identified. The levels of 90K did not correlate with those of CA 15-3 or CEA. The measurement of 90K in sera appears to be a useful adjunct to other available assays for the detection and monitoring of breast cancer and other malignant tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01807554
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  • 21
    Electronic Resource
    Electronic Resource
    New lumps in the breast following conservation treatment for early breast cancer (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 51-58 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; conservative treatment ; mammography ; recurrent lumps
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A new lump in the breast following conservation treatment for early breast cancer may represent a recurrence of the disease or may be a benign lesion. Clinical evaluation of these lumps is often extremely difficult and, potentially, mammography would seem to be of great importance in the assessment. Between November 1981 and March 1986, 214 patients with operable breast cancers of 4 cm or less in diameter underwent conservative treatment. The conservation technique comprised synchronous excision of the primary tumour without a wide margin, axillary clearance, interstitial irradiation with iridium 192 (2000cGy), and subsequent external beam radiotherapy to the breast (4600cGy). After an average followup of 26 months, 17 patients developed a new lump in the treated breast necessitating further biopsy. Seven of these were malignant and 10 benign. In the latter category the most frequent finding was fat necrosis. Clinically, the lesions were indistinguishable from each other. The mammographic signs, which best predicted malignancy, were either of a mass or of a malignant type of microcalcification. This study illustrates the problems associated with deciding the nature of a new lump in the breast following conservation treatment. Mammography is complementary to physical examination, and a base-line mammogram six months after completion of therapy is helpful. Despite the use of mammography, biopsy is the only definitive way of excluding recurrence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01807558
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  • 22
    Electronic Resource
    Electronic Resource
    Secreted growth factors from estrogen receptor-negative human breast cancer do not support growth of estrogen receptor-positive breast cancer in the nude mouse model (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 211-219 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; autocrine growth regulation ; estrogen action ; growth factors ; nude mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Estrogen receptor (ER)-negative MDA-231 human breast cancer cells have been shown to secrete high concentrations of several growth factors including transforming growth factor-alpha and insulin-like growth factor I, which could have important autocrine or paracrine growth regulatory functions and, additionally, could explain the rapid autonomous growth of these cells. In contrast, the hormone-responsive, ER-positive MCF-7 cells secrete low levels of these factors constitutively. Since estrogen treatment increases secretion of these growth factors in MCF-7 cells, it has been postulated that these growth factors mediate estrogen's growth effects through an autocrine mechanism. To test this hypothesis we reasoned that growth factors supplied by MDA-231 cells should support growth of MCF-7 cells in an estrogen-depleted environment. Inoculation of castrated female athymic nude mice with MDA-231 cells resulted in rapid tumor growth. However, MDA-231 tumors did not support growth of MCF-7 cells inoculated on the opposite flank by an endocrine mechanism; MCF-7 tumors required estrogen supplementation for growth. To determine if MDA-231 cells could support MCF-7 growth by a paracrine mechanism, various mixtures of the two cell lines were coinoculated at the same site in castrated or in estrogen-supplemented mice. ER was not detectable in tumors derived from a mixed inoculum, indicating the absence of MCF-7 cell growth. Furthermore, DNA flow cytometry of these tumors revealed only a single G1 peak representative of MDA-231 cells in estrogen-deprived mice. On the other hand, two distinct G1 peaks representing both MDA-231 and MCF-7 cells were detected in tumors grown in estrogen-supplemented mice. These data demonstrate that growth factors from estrogen-independent MDA-231 cells are not capable of replacing estrogen for growth stimulation of MCF-7 cells. Either estrogen-stimulated growth of MCF-7 cells requires other secreted factors not supplied by MDA-231 cells, or it involves a different mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01807279
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  • 23
    Electronic Resource
    Electronic Resource
    Localization of human breast tumors grafted in nude mice with a monoclonal antibody directed against a defined cell surface antigen of human mammary epithelial cells (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 177-189 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; human tumor explants ; imaging ; mammary epithelial antigen ; monoclonal antibody ; nude mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A mouse monoclonal antibody (BLMRL-HMFG-Mc5) prepared against a defined cell surface antigen of human mammary epithelial cells, non-penetrating glycoprotein (NPGP), was used in imaging and distribution studies in athymic nude mice grafted with human breast tumors. Forin vivo tissue distribution studies,125I-labeled monoclonal antibody was injected into nude mice carrying simulated metastases of human tumors (breast and colon carcinomas). After 22–24 hr the amount of radioactivity per gram of tissue was 3–4 times higher in the breast tumor than in liver, brain, lung, muscle, or spleen. In contrast, colon carcinoma tissue, grafted and treated likewise, did not show higher accumulation of radioactivity relative to other tissues. At 4 days, the incorporation in breast tumors remained almost as high, while the circulating radioactive tracer and the incorporation in tissues other than breast had fallen significantly. In tumor imaging studies, breast tumor masses as small as 4 mm in diameter were clearly localized on a whole body scan using131I-labeled BLMRL-HMFG-Mc5 antibodies with a High-Purity germanium gamma camera. Normalization of131I-distribution to that of99mTc-pertechnetate increased the specificity of this imaging methodology. The quantitative density of131I-label was 2–3 fold higher over the breast tumor than over comparable areas of the mouse. No positive localization images were obtained for similar implants of colon and lung carcinomas or melanomas after injections of131I-labeled BLMRL-HMFG-Mc5. Localization of human breast tumors in this model can be achieved with131I-labeled anti-breast epithelial monoclonal antibodies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805939
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  • 24
    Electronic Resource
    Electronic Resource
    Effects of prednisolone on sex hormone binding globulin during primary endocrine treatment of advanced breast cancer (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 67-70 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; estradiol ; ovarian irradiation ; prednisolone ; sex hormone binding globulin ; tamoxifen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Serum sex hormone binding globulin (SHBG) was measured in 21 pre and 39 postmenopausal women with advanced breast cancer before treatment and 1, 3, 6, 9 and 12 months after ovarian irradiation or during continuous administration of tamoxifen at a dose of 10 mg twice daily, respectively; some patients received additional prednisolone at a dose of 5 mg twice a day. Ovarian irradiation was associated with a 25% reduction in serum SHBG levels 3 to 6 months after treatment whilst patients on tamoxifen experienced a rise of about 80% in serum SHBG levels after 1 to 3 months. In postmenopausal women prednisolone markedly dampened the effect of tamoxifen, reducing a 80% rise to about 20%. There was no relationship between SHBG levels and response to treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01807560
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  • 25
    Electronic Resource
    Electronic Resource
    Cisplatin and 5-fluorouracil in refractory breast cancer patients: A phase II study (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 269-271 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; chemotherapy ; cisplatin/5-fluorouracil synergism ; salvage therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 24 patients with a median of 3 prior chemotherapy regimens were treated in our department with cisplatin 20 mg/m2 (with pre- and posthydration) and 5-fluorouracil 200 mg/m2 i.v. on day 1–5, every three weeks. 23 patients are evaluable; one had early death. 4 patients (17%) achieved a partial response, 8 had stable disease, and 11 progressed. Toxicity observed was moderate and no renal toxicity was noted. This study therefore shows tolerable toxicity but limited usefulness of adding cisplatin to 5-fluorouracil according to this schedule in these highly pretreated patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01807286
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  • 26
    Electronic Resource
    Electronic Resource
    EGF binding is quantitatively related to growth in node-positive breast cancer (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 45-49 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; EGF binding ; growth rate ; mitoses ; nodal status
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Number of mitoses and EGF binding were determined in parallel in biopsies of 27 lymph-node positive and of 23 lymph-node negative breast cancer patients. For node-positive patients the parameters for cell growth and EGF binding were quantitatively correlated by the equation y = P3 + P1(1 − exp( − P2x)). For node-negative cases neither the non-linear model nor the linear approximation described the data unambiguously. The results strongly suggest that in node-positive patients, growth of breast cancer is related to an EGF-dependent acceleration of cell division.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805739
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  • 27
    Electronic Resource
    Electronic Resource
    Adjuvant trial for stage II receptor-positive breast cancer: CMF vs. CMF+ tamoxifen in a single centre (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 179-186 
    Details
    ISSN: 1573-7217
    Keywords: adjuvant chemotherapy ; breast cancer ; CMF ; randomized trial ; steroid receptors ; tamoxifen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of a randomized trial achieved in a single centre (Fondation Bergonié, Bordeaux, France) was to compare chemotherapy alone (intravenous CMF) versus chemotherapy and hormonotherapy (CMF plus tamoxifen — 30 mg per day during 2 years), for patients with stage II breast carcinoma and positive values of estrogen and/or progesterone receptor (EPR) (〉10 and 〉15 fmoles mg protein−1 respectively). Three hundred and thirty four women treated by surgery ± radiotherapy are included in this trial from 06.01.81 to 12.31.84. No patient is lost for follow-up. Eight are excluded. Three hundred and twenty six patients are evaluable with a 38 month median follow-up. For EPR assay, the dextran charcoal micromethod was used in the same centre. The two groups are identical as far as age, hormonal status, TNM, EPR values, and histological features are concerned. Analysis of results shows a significant improvement of relapse free survival (p = 0.018) and also overall survival (p = 0.04) for the CMF + tamoxifen group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805842
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  • 28
    Electronic Resource
    Electronic Resource
    Tamoxifen and fluoxymesterone versus tamoxifen and danazol in metastatic breast cancer — A randomized study (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 51-57 
    Details
    ISSN: 1573-7217
    Keywords: tamoxifen ; fluoxymesterone ; danazol ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A prospective randomized trial of tamoxifen and fluoxymesterone versus tamoxifen and danazol in metastatic breast cancer was conducted from December 1980 to September 1985. Patients were eligible regardless of site of disease, estrogen receptor status, or age. Sixty-two of sixty-three randomized patients were evaluable for response. Overall response for tamoxifen and fluoxymesterone was 11% with 61% stabilization of disease, versus 12% response rate for tamoxifen and danazol with 59% stabilization. Toxicities with tamoxifen and fluoxymesterone were greater with an increase in masculinization. We conclude that the response rates to the combinations of tamoxifen and fluoxymesterone or tamoxifen and danazol reported are equivalent in this study but that the increased toxicity with tamoxifen and fluoxymesterone would make tamoxifen and danazol the treatment of choice if a combination were to be used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805740
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  • 29
    Electronic Resource
    Electronic Resource
    Breast cancer: Young, old, and very old (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 205-211 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; tumour age ; tumour growth rate ; tumour stage ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A new method of characterizing breast carcinomas is presented that may help further our understanding of this disease. A tumour age coefficient is described, derived from tumour diameter and the mean nuclear area of the tumour cells, the latter a measure of tumour growth rate. On this basis a series of 213 operative infiltrating breast carcinomas is divided into 3 tumour age groups (young, old, and very old). These are then related to axillary nodal status and the patient's age at operation. The likelihood of nodal spread is shown to increase with tumour age. This is interpreted as an expression of a build-up of tumours that have spread with time. There was no set tumour age by which metastatic spread could be expected, but some indication of a lower age limit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805941
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  • 30
    Electronic Resource
    Electronic Resource
    Effects of the aromatase inhibitor 4-hydroxyandrostenedione and the antiandrogen flutamide on growth and steroid levels in DMBA-induced rat mammary tumors (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 287-296 
    Details
    ISSN: 1573-7217
    Keywords: aromatase inhibitor ; 4-hydroxyandrostenedione ; antiandrogen ; flutamide ; steroid metabolism ; DMBA-induced rat mammary tumors ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using dimethylbenz(a)anthracene (DMBA)-induced mammary tumors in the rat as model, comparison was made of the effect of treatment for 20 days with the aromatase inhibitor 4-hydroxyandrostenedione (4-OH-A) (7.5 mg, twice daily) or the antiandragen flutamide (5 mg, twice daily) on tumor growth as well as on plasma and tumor content of estrogens, androgens, and their precursors and metabolites. Tumor number and size were markedly decreased following treatment with either drug, the effect of treatment being more important on size than number, and on new tumors which developed during treatment than on tumors already present at start of treatment. Treatment with the aromatase inhibitor 4-OH-A caused a parallel decrease in plasma and tumor levels of pregnenolone (Preg), progesterone (P), and 17-OH P, while there was a marked increase in dehydroepiandrosterone (DHEA), androst-5-ene-3β,17β-diol (Δ5-diol), androstenedione (Δ4-dione), testosterone (T), androstane-3α, 17β-diol (3α-diol), and androstane-3β, 17β-diol (3β-diol), with no significant change in dihydrotestosterone (DHT) and 17β-estradiol levels. The marked increase in tissue T content coupled to a decrease in P levels could well contribute to the inhibition of tumor growth induced by 4-OH-A. Flutamide, on the other hand, caused a marked fall in plasma and tissue levels of Preg, 17-OH Preg, P, and 17-OH P, with no significant change in the concentration of the other steroids, thus suggesting a possible role of the fall in tissue P levels in the inhibition of tumor growth. Since both drugs are potent inhibitors of DMBA-induced tumor growth in intact animals, better knowledge of their mechanism of action should add to our understanding of the multiple endocrine factors controlling the growth of these tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01811241
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  • 31
    Electronic Resource
    Electronic Resource
    Relevance of cell kinetics to hormonal response of receptor-positive advanced breast cancer (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 31-36 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; cell kinetics ; hormone receptors ; hormonetherapy ; prognostic factors ; thymidine labelling index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relationship between cell kinetics and hormonal status and the relevance of the cell kinetic variable on success of hormonetherapy in estrogen receptor positive (ER+) breast tumors were analyzed in patients with advanced disease. Cell kinetics were evaluated as in vitro3H-thymidine labeling index (LI), and estrogen receptor (ER) and progesterone receptor (PgR) with the dextran-coated charcoal technique. The analyses performed on primary tumor or soft tissue metastases from 52 patients showed a general association between the presence of hormone receptors and low proliferative activity, or the absence of receptors and high proliferative activity (ER and L.I.: p〉0.05; PgR and L.I.: p = 0.05). However, hormonal status and cell kinetic status were unrelated in about 40% of the cases. Clinical response to additive hormonotherapy was analyzed in relation to pretreatment LI in 29 patients with ER+ tumors. Time to reach maximum response was significantly longer in slow than in fast proliferating tumors, but complete remission was reached in 88% of slow proliferating tumors compared to only 46% of fast proliferating tumors. These preliminary results show that ER+ fast proliferating tumors largely escape hormonal control, and if confirmed on larger series, could identify cell kinetics as an important tool to select patients who will benefit from hormonal treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01807555
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  • 32
    Electronic Resource
    Electronic Resource
    Tests for detecting recurrent disease in the follow-up of patients with breast cancer (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 249-254 
    Details
    ISSN: 1573-7217
    Keywords: biochemical markers ; recurrence ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In 141 postmenopausal node-positive patients with primary breast cancer, routine biochemical markers (alkaline phosphatase, gamma-glutamyl transpeptidase, carcinoembryonic antigen), and chest x-ray, in combination with history and clinical examination, have been performed at 3 monthly intervals for at least 2 years. Sixty one patients relapsed at a median time of 14 months. The recurrence was detected at routine follow-up in 40 (66%) patients. Of these 40 patients, 26 (65%) presented with symptoms, 11 (28%) were asymptomatic but were found to have relapsed on clinical examination, and only 3 (8%) had their relapse diagnosed on the basis of an abnormal chest x-ray. The remaining 21 patients presented early with symptoms. Therefore symptoms and clinical examination accounted for the detection of relapse in 58 of the 61 (95%) patients. Of the patients who had relapsed, 49% (30 of 61) had one or more abnormal markers/chest x-rays prior to relapse, rising to 79% (48 of 61) at the time of relapse. Of 80 patients with no evidence of recurrence, 36% (29) had no marker abnormality recorded, whereas in 64% (51) one or more abnormalities were found. These results suggest that history and examination are the important procedures in follow-up, and that abnormal markers are not always due to metastatic disease and may be misleading.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01807283
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  • 33
    Electronic Resource
    Electronic Resource
    Markers in breast cancer: Does CEA add to the detection by CA 15.3? (1988)
    Springer
    Breast cancer research and treatment 11 (1988), S. 273-276 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; CA 15.3 ; CEA ; circulating antigens ; sensitivity ; serum markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract 211 patients with various stages of breast cancer were studied by both the CA 15.3 and CEA markers to assess whether the latter may increase the screening sensitivity of the former. While both markers were equally specific, CA 15.3 was seen to be much more sensitive than CEA (p〈0.0001). Also, the addition of the CEA did not add appreciably (7%) to positive detection by CA 15.3. There appears to be no advantage to including CEA in a marker panel to follow the course of breast carcinoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01807287
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  • 34
    Electronic Resource
    Electronic Resource
    Influence of adjuvant tamoxifen on blood lymphocytes (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 75-79 
    Details
    ISSN: 1573-7217
    Keywords: adjuvant therapy ; breast cancer ; endocrine therapy ; lymphocytes ; tamoxifen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The blood lymphocyte population was studied in 23 breast cancer patients treated with adjuvant tamoxifen for 1.5–2 years, and in an equal number of control patients. The size and cellular composition of the blood lymphocyte population, as assessed by monoclonal antibodies directed against various subsets, did not differ between the two patient groups. However, lymphocytes from the tamoxifen-treated patients exhibited a significantly lower NK activity against K562 cells. In contrast, the proliferative response of lymphocytes to ConA was significantly higher. These results indicate that tamoxifen may modulate the immune system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805743
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  • 35
    Electronic Resource
    Electronic Resource
    Steroid hormone receptors and prognosis in breast cancer (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 267-273 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; steroid receptors ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The importance of steroid receptors for the prognosis of mammary carcinoma has been evaluated by investigating the course of disease in 163 patients for a median follow up time of 66 months after mastectomy. Multivariate analysis including estrogen receptor (ER), progesterone receptor (PgR), the presence of 8S and 4S ER together or 4S ER only, and the lymph node status revealed only the latter to have significant (p〈0.001) predictive potency. Lymph node positive (N-pos) patients had a 3.3 (1.7–6.2) fold risk of death and 2.8 (1.7–4.7) fold risk of recurrence relative to node negative (N-neg) patients. When we compared overall survival (OAS) and disease-free survival (DFS) in the various receptorpositive groups with the groups that displayed neither ER nor PgR, significant differences in prognosis were only seen in N-neg patients. PgR did not turn out to be a better prognostic factor than ER, nor was the 8S ER a sing of increased OAS and DFS compared to total ER. However, the number of patients in this group was too small to allow a definite statement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01811239
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  • 36
    Electronic Resource
    Electronic Resource
    Androgens inhibit basal and estrogen-induced cell proliferation in the ZR-75-1 human breast cancer cell line (1988)
    Springer
    Breast cancer research and treatment 12 (1988), S. 213-225 
    Details
    ISSN: 1573-7217
    Keywords: androgens ; antiestrogen ; antiandrogen ; androgen receptor ; estrogen receptor ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study describes the inhibitory effect of 5α-dihydrotestosterone (5α-DHT) and its precursors testosterone (T) and androst-4-ene-3,17-dione (Δ4-DIONE) on the growth of the estrogen-sensitive human breast cancer cell line ZR-75-1. In the absence of estrogens, cell proliferation measured after a 12-day incubation period was 50–60% inhibited by maximal concentrations of 5α-DHT, T, or Δ4-DIONE with half-maximal effects (IC50 values) observed at 0.10, 0.15 and 15 nM, respectively. This growth inhibition by androgens was due to an increase in generation time and a lowering of the saturation density of cell cultures. The antiestrogen LY156758 (300 nM) induced 25–30% inhibition of basal cell growth, its effect being additive to that of 5α-DHT. The mitogenic effect of 1 nM estradiol (E2) was completely inhibited by increasing concentrations of 5α-DHT with a potency (IC50 = 0.10 nM) similar to that measured when the androgen was used alone. E2 had a more repid effect on cell proliferation than 5α-DHT, the latter requiring at least 5 to 6 days to exert significant growth inhibition. As found in the absence of estrogens, maximal inhibition of cell proliferation in the presence of E2 was achieved by the combination of the antiestrogen and 5α-DHT. Supraphysiological concentrations of E2 (up to 1µM) were needed to completely reverse the growth inhibitory effect of a submaximal concentration of 5α-DHT (1 nM). The antiproliferative effect of androgens was competitively reversed by the antiandrogen hydroxyflutamide, thus indicating an androgen receptor-mediated mechanism. The present data suggest the potential benefits of an androgen-antiestrogen combination therapy in the endocrine management of breast cancer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01805942
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  • 37
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    Electronic Resource
    Die stereoisomeren Sinensiaxanthine und Sinensiachrome: Trennung und Bestimmung ihrer absoluten Konfiguration. 7. Mitteilung über Rosenfarbstoffe6. Mitteilung, s. [1]. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 24-30 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereoisomeric Sinensiaxanthins and Sinensiachromes: Separation and Absolute ConfigurationThe so-called sinensiaxanthins and sinensiachromes, important apocarotenols from various fruits, have been separated into 2 and 4 stereoisomers, respectively, and their absolute configurations have been determined: (3S,5R,6S)-5,6-epoxy-5,6-dihydro-10′-apo-β-carotene-3,10′-diol (2), its (9Z)-stereoisomer 7, the (8R)- and (8S)-epimers of (3S, 5R)-5,8-epoxy-5,8-dihydro- 10′ -apo-β-carotene-3, 10′-diol (4 and 5), and their (9Z)-stereoisomers 3 and probably 6. Thus, sinensiaxanthins are cleavage products from (Z/E)-isomeric antheraxanthins or violaxanthins (scission at C(9′)-C(10′)) and sinensiachromes analogously from mutatoxanthins or auroxanthins.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710103
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  • 38
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    Enantioselektive Verseifung der Diacetate von 2-Nitro-1,3-diolen mit Schweineleber-Esterase und Herstellung enantiomerenreiner Derivate von 2-Nitro-allylalkoholen (chirale Verknüpfungsreagenzien)Kurzmitteilung mit ausführlicher Beschreibung der Isolierung und Anwendung von Schweineleber-Esterase Rohpräparaten, s. [1].Teilweise erwähnt in einem Übersichtsartikel über EPC-Synthesen unter C,C-Verknüpfung mit Hilfe von Enamine, s. [2]. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1-23 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantioselective Saponification of Diacetates of 2-Nitro-1,3-propanediols by Pig-Liver Esterase and Preparation of Enantiomerically Pure Derivatives of 2-Nitro-allylic Alcohols (Chiral Multiple-Coupling Reagents)The reproducible enantioselective saponification of open-chain and cyclic diacetates of meso-2-nitro-1,3-propanediols (see 4b-13b) with pig-liver esterase (PLE) gives monoacetates (see 4c-l3c) of 〉 95% enantiomeric excess. The Re enantiotopic acetate group appears to be saponified preferentially, as proved by the X-ray crystal structure analysis of three camphanoates 4d, 6d, and 7d. Elimination of H2O or AcOH from the hydroxy acetates thus available gives derivatives of nitro-allylic alcohols (see 20-24, 27, and 29) which are subjected to diastereoselective Michael additions or SN2′ substitutions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710102
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  • 39
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    Electronic Resource
    New Pterocarpinoids from Dolichos marginata ssp. erecta (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 72-76 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four new pterocarpinoids, sphenostylin A, B, C, and D (1-4), have been isolated from the CHCl3 extract of the root bark of Dolichos marginata ssp. erecta (Leguminosae) by preparative liquid chromatography. The structures have been established by spectroscopic methods (UV, 1H-NMR, 13C-NMR, EI-MS, DCI-MS, CD) and chemical transformations. The isolated compounds showed weak antifungal activity against Cladosporium cucumerinum.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710109
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  • 40
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    Condensed Heterotricycles. Synthesis and Reactions of b-Fused 1(2H)-Isoquinolinones with unusual enaminic propertiesContribution No. 822 from Hindustan Ciba-Geigy Ltd., Research Centre. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 77-92 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homophthalic acid (1) undergoes reaction with 1,2-, 1,3-, and 1,4-diamines to give condensed 1(2H)-isoquinolinones like 2, 4, 13, and 25, which exhibit marked enamine character. These are attacked by electrophiles at the N or C terminus. Some notable reactions of imidazoisoquinolone 2 are those with maleic and acrylic acids to form the tetracycles 48 and 51, respectively. With propiolic acid, 5 underwent an interesting reaction to form the benzimidazonaphthyridine 53. An equally interesting behaviour was elicited from 2 in its reaction with formaldehyde, when in addition to the expected methylene-bridged molecule 59, the novel spiro derivative 60 was formed by the dimerisation of a presumed azadiene intermediate 63.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710110
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  • 41
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    The dimeric and polymeric anhydride of 2,3-O-isopropylidene-β-D-ribofuranose. An NMR study (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 120-123 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1H- and 13C-NMR data of the dimeric anhydride 1 of 2,3-O-isopropylidene-β-D-ribofuranose are reported together with the 1H-NOE values. The data show that the products of the polymerization of 1,5-anhydro-2,3-O-isopropylidene-β-D-ribofuranose are α- and β-D-ribofuranans and not an α-D-ribofuranan and a β-D-ribofuranan and a β D ribo-pyranan as claimed before [2] [3].
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710114
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  • 42
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    Complexes with a Pincers. 2,6-Diphenylpyridine as Twofold-Deprotonated (C ∧ N ∧ C) terdentate ligand in C,C-trans-, and as mono-deprotonated (C ∧ N) chelate ligand in chiral C,C-cis-complexes of platinum(II) and palladium(II). Preliminary communication (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 130-133 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,6-Diphenylpyridine forms, as twofold-deprotonated, terdentate ligand, complexes with Pt(II) and Pd(II), having two adjacent five-membered metallocycles. As mono-deprotonated, bidentate ligand, it forms cis-bis-complexes having a chirality axis. Pt(II) complexes undergo thermal and photochemical oxidative addition reactions, yielding stable Pt(IV) compounds. Pd(II) complexes yield substitued 2,6-diphenylpyridine in photochemical reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710116
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  • 43
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    Silicon-Directed Nazarov Cyclizations. Part V. Substituent and heteroatom effects on the reaction (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 168-194 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ability to incorporate alkyl, alkenyl, aryl, and heteroatomic groups into substrates for the silicon-directed Nazarov cyclization and their subsequent reactions has been investigated. In general, most of the groups are compatible with the conditions for the cyclization and do not interfere even when directly attached to the divinyl ketone. The influence of substituents on the rate of the cyclization has been addressed and is consistent with a simple mechanistic picture. O- and N-Containing functions are tolerated except when attached to the α-vinyl C-atom of the divinyl ketone. The diastereoface-directing effect of a fused cyclobutane is discussed.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710120
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  • 44
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    Synthesis of Aristotelia-Type Alkaloids. Part III.Part II: [1]. (3R,4R)- and (3R,4S)-1-p-menthene-3,8-diol and the corresponding racemates: Preparation and assignment of configuration (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 209-217 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A 1:1 mixture of the racemic trans- and cis-1-p-menthene-3,8-diols ((±)-3 and (±)-4, resp.) was readily prepared in 3 steps starting from 3-methyl-2-cyclohexen-1-one. The relative configuration of the diols, purified via the corresponding cyclocarbonates, was assigned by 1H-NMR spectroscopy and found to be at variance with tentative claims in the literature. Optically active samples of 3 and 4 were prepared by resolution of the racemates with (R)-1-phenylethylamine. The absolute configuration of the resulting diols was determined by chemical correlation with standards of known absolute configuration.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710122
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  • 45
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    Herstellung enantiomerenreiner, α-alkylierter Lysin-, Ornithin- und Tryptophan-Derivate (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 224-236 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Enantiomerically Pure, α-Alkylated Lysine, Ornithine, and Tryptophan DerivativesThe imidazolidinones 9 and 10 as well as the oxazolidinone 18a were prepared in several steps by known methods from lysine and ornithine with an overall yield of ca. 20%. After double deprotonation with LDA, the corresponding dianionic derivatives could be diastereoselectively alkylated with electrophiles (MeI, C6H5CH2Br, C6H5CHO, CH3CHO). Acid hydrolysis led to the two enantiomeric 2-methyl- and 2-benzyllysines and to the enzyme inhibitor (S)-2-methylornithine. Several α-alkylated tryptophan derivatives were obtained through alkylation of the heterocycles derived from various amino acids with 1-(tert-butyloxycarbonyl)-3-(bromomethyl)indole (26). Alkaline hydrolysis of the five-membered auxiliary ring of 30b followed by treatment with HCl afforded (S)-2-methyltryptophan (31).
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    URL: http://dx.doi.org/10.1002/hlca.19880710124
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  • 46
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    Hydrogénation de sels de flavylium: formation de composés heptacycliques; structure radiocristallographique du [tétrahydro-10b,10c,16,16a-diméthyl-16,16a-méthylène-10b,16-5aH-di(benzo[1]pyranno)[4,3-b:3′,4′,-c;2,3:2′,3′]-benz[1]oxépinyl-5a]-2-phénol (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 254-257 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrogenation of Flavylium Salts: Formation of Heptacyclic compounds; X-Ray Crystal Structure of 2-[10b,10c,16,16a-Tetrahydro-16,16a-dimethyl-10b,16-methylene-5aH-di[1]benzopyrano[4,3-b:3′,4′ -c; 2,3:2′,3′][1]benzoxepin-5a-yl]phenolThe hydrogenation of flavylium salts 1 either by catalytic reduction or by chemical reduction afforded the unexpected heptacyclic compound 2, the structure of which was determined by X-ray analysis. The latter was confirmed by 1H-NMR and mass spectra.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710128
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  • 47
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    Konformationsanalysen von Modell-Tripeptiden: Der Einfluss von α,α-disubstituierten α-Aminosäuren auf die Sekundärstruktur. Teil II. Röntgenstrukturanalyse und Konformationsenergie-Berechnungen (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 268-273 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational Analysis of Tripeptide Models: The Influence of α,α-disubstituted α-Amino Acids on the Secondary Structure. X-Ray Analysis and Conformational Energy CalculationsThe X-ray analysis of tripeptide Z-Ile-Val(2-Me)-benzocaine (1f) reveals the presence of a type-III β-turn. Moreover, MMP2 calculations on tripeptides, e.g. Z-Ile-Aib-benzocaine (1c), Z-Ile-D-Val(2-Me)-benzocaine (1g), Z-Ile-Gly(2,2-Pr2)-benzocaine (1h), Z-Ile-Gly-benzocaine (1a), and 1f, fit well into the frame of NMR and CD investigations. They allow considerations on the relative stability of different types of β-turns depending on the peptide sequence, e.g. the kind of α,α-disubstituted amino-acid moieties.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710130
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  • 48
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    Synthese von (-)-(R)-Nephthenol und (-)-(R)-Cembren A (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 292-297 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of (-)-(R)-Nephthenol and (-)-(R)-Cembren AStarting for L-serine,(-)-(R)-nephthenol((-)-2) and (-)-(R)-cembren A((-)-3) were synthesized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710133
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  • 49
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    Low-Temperature X-ray Crystal-Structure Analysis of the Thermally Unstable Lithiated 2-Butenyl tert-Butyl Sulfide: A comparison with model ab initio MO calculationsPart of the projected Dissertation of Th. M., ETH Zürich. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 299-311 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Single crystals of the N,N,N′,N′-tetramethylethylenediamine (TMEDA) complex 6 of the title compound have been isolated. Compound 6 decomposes in the crystalline state above -20°. From the bond lengths and angles obtained by X-ray crystal-structure analysis (data collected at -70°), compound 6 is best described as a (E)-1-(tert-butylthio)-1-lithio-2-butene with the double bond acting as an additional ligand on lithium (unsymmetrical allylic group). The S-atom is in a cisoid arrangement in a common plane with the four C-atoms of the butenyl system. The t-Bu group and the Li-atom are located above and below this plane. The structure is discussed with respect to the reactivity of 6 (α/γ reactivity). The gross structure is reproduced surprisingly well by an ab initio SCF MO calculation of the model lithiopropene-1-thiol 7(HS instead of t-BuS, CH2 instead of CHCH3, no solvation of Li). The prominent difference is the symmetry of the allyllic moiety in the calculated structure.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710202
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  • 50
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    Notiz zur Synthese Eines Optisch Aktiven Ace-Hemmers mit Amino-oxo-benzazepin-1-alkansäure-Struktur mittels enantiokonvergierender kristallisationsinduzierter Racemat-Trennung (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 337-343 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Note on the Synthesis of an Optically Active ACE Inhibitor with Amino-oxo-benzazepine-1-alkanoic-Acid Structure by Means of an Enantioconvergent Crystallization-Based ResolutionAn enantioselective synthesis of the potent angiotensin-converting enzyme inhibitor (1′S,3S)-3-[(1′-(ethoxy-carbonyl)-3′-phenylpropyl)amino]-2,3,4,5-tetrahydro-2-oxo-1H-1-benzazepine-1-acetic acid hydrochloride (3) is described which user a crystallization-based resolution of a racemic amino intermediate with concomitant racemization of the unwanted enantiomer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710205
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  • 51
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    Polycyclopentane Als Steroid-Analoga (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 363-368 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polycyclopentanes as Steroid AnalogaThe synthesis of linearly annellated pentaquinanes from a readily available triquinane is reported.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710209
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  • 52
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    Synthese Eines Optisch Aktiven Penem-Zwischenprodukts Mittels Asymmetrischer Amidoalkylierung (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 395-403 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of an Optically Active Penem Intermediate by Asymmetric AmidoalkylationThe amidoalkylation of an optically active, cationic glycine derivative with methyl acetoacetate furnishes an intermediate 10a (Scheme 2) that is transformed in six steps to the optically active, silyl-protected 4-acetoxy-3-(1-hydroxyenthyl)-2-azetidinon 18a, a well known intermediate in penem synthesis.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710213
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  • 53
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    Circular Dichroism of Planar, Exocyclic S-cis-Butadienes Remotely PerturbedInteraction between non-conjugated chromophores, Part 29. Part 28, see [1]. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 419-428 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optically pure 5,6-dimethylidenebicyclo[2.2.1]hept-2-yl derivatives have been prepared. The sign of the Cotton effects associated with lowest-energy transition of 2-(dicyanomethylidene)-((-)-(1S,4S)-15), (E)-2-(methoxyimino)-((+)-(1S,4S)-16), (Z)-2-(methoxyimino)-5,6-dimethylidenebicyclo[2.2.1]heptane ((-)(1S,4S)-17), and 2,3,5-trimethylidenebicyclo[2.2.1]heptane ((-)-(1R,4S)-18) is opposite to the chirality constituted by the coupling of the electric transition moments of the two homoconjugated π-chromophores (Kuhn-Kirkwood dipole-coupling mechanism). When the substituents at C(2) are not π-functions, no general rule can be retained for the chiroptical properties of the 5,6-dimethylidenebicyclo[2.2.1]hept-2-yl systems as shown for dimethyl acetal (-)-(1S,4S)-19, ethylene acetal (+)-(1R,4R)-20, exo and endo methyl ethers (+)-(1R,2S,4R)-21 and (+)-(1R,2R,4R)-22, and for spirol[5,6-dimethylidenebicyclo[2.2.1]heptane-2.2'-oxiranes](-)-(1S,2S,4S)-23 and (-)-(1S,2S,4S)-24.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710215
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  • 54
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    Ferroelectric Liquid Crystals. Part 2.‘Ferroelectric Liquid Crystals’, Part 1: [1]. Chiral phenyl benzoates incorporating a trans-1,4-disubstituted cyclohexane ring (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 451-460 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: About forty novel phenyl benzoates also incorporating a trans-1,4-disubstituted cyclohexane ring and a chiral centre have been prepared. The dependence of the liquid-crystal transition temperatures of this new class of compounds on lateral substituents, diverse central linkages, chain lengths, and position of the chiral centre has been studied systematically. The synthesis and liquid-crystal transition temperatures of these new compounds are described in detail.
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710218
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  • 55
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    [4 + 2]-Cycloadditionen von α,β-ungesättigten Hydrazonen. Teil 1. Pyridin-2,3-dicarboximide aus 1-(Dimethylamino)-1,4-dihydropyridin-Derivaten (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 486-492 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [4 + 2] Cycloadditions of α,β-Unsaturated Hydrazones to Pyridine-2,3-dicarboximides via 1-(Dimethylamino)-1,4-dihydropyridine DerivativesThe [4 + 2] Cycloaddition of α,β-unsaturated hydrazones of type 1 (1-aza-1,3-butadienes) with 2-halogenomaleimides 4 affords 1,4-dihydropyridines 6 which, after treatment with an acid, yield highly substituted pyridine-2,3-dicarboximide derivatives 7 (Scheme 1).
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710222
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    Photochemistry of 2,2-Dimethyl-2H-Furo[3,4-b]Pyran-4,7(3H, 5H)-Dione (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 498-501 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Irradiation (λ 〉 340 nm) of the title compound 2a in t-BuOH affords 3,3,10,10-tetramethyl-2,8-dioxatricyclo-[4.3.2.01,6]undecane-5,9-dione (3) via photoextrusion of 2-methylpropene and subsequent photocycloaddition of 2a to the alkene. The same regioisomer 3 is formed selectively and in much higher yields on irradiating 2a in the presence of excess 2-methylpropene. Irradiation of 3 (λ = 300 nm) in t-BuOH in the presence of the same alkene gives a 6:1 mixture of spirooxetanes 7a and 7b but not α-cleavage products. In 2-propanol, 2a is photoreduced to a 2:1 mixture of diastereoisomeric hydrodimers 9.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710224
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710301
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    Une synthèse générale des tétraazamacrocycles mono-C-fonctionnalisés (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 602-608 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A General Synthesis for Mono-C-Functionalized TetrazamacrocyclesA new synthesis, under usual conditions of concentration, medium, and temperature, of a series of mono-C-functionalized tetraazamacrocycles is given. The method may easily be generalized. The new procedure allows the modification of the length of the side-chain or the size of the cavity by choosing fitted staring materials. The key intermediate has a tosylated linear side-chain susceptible to be transformed into a large variety of functional groups.
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    URL: http://dx.doi.org/10.1002/hlca.19880710313
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  • 59
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    Enantiomerically pure 7-oxabicylo[2.2.1]hept-5-en-zyl derivatives as synthetic intermediates. Part IIIPart I, see [1]; Part II, see [2].. Total synthesis of D- and L-ribose derivativesFor a preliminary communication, see Y. Auberson, R. Bimwala, J. Wagner, P. Vogel, Société Suisse de Chimie, Berne, 16 Oct. 1987, Abstract p. 29. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 624-630 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantiomerically pure methyl 5-bromo-5-deoxy-2,3-O- isopropylidene-β-D- (D-5b) and -β-l-ribofuranoside (l-5b) have been derived from (-)-(1R,2S,4R)-2-exo-cyano-7-oxabicylo[2.2.1]hept-5-en-endo,-yl (1′S)-camphanate (1) and (+)-(1S,2R,4S)-2-exo-cyano-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl(1′R)-camphanate (2), respectively, in 5 synthetic steps and 28% overall yield. Hydrolysis of D-5b and L-5b afforded methyl 2,3-O isopropylidene-β-D-ribofuranoside (D-5a) and methyl 2,3-O-isopropylidene β-L-ribofuranoside (L-5a), respectively. The intermediate (+)-(1R,4R,5R,6R) 5-exo,6-exo-(isopropylidenedioxy)-7-oxabicyclo[2.2.1]heptan-2-one ((+)-7) and its enantiomer(-)-7 were also obtained enantiomerically pure by resolution of (=)-7 by the Johnson-Zeller method. In bothe approaches, the chiral auxiliaries ((-)- and (+)-camphanic acids, or (+)-(S)-N,S-dimethyl-S-phenylsulfoximide) were recovered at an early stage of the synthesis.
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    URL: http://dx.doi.org/10.1002/hlca.19880710316
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    Mécanisme de solvolyse des cis- et trans-(p-toluènesulfonates) d'aryl-2-cyclopentyle I. Etude de la première étape de la solvolyse: effets isotopiques de l' atone de deutérium en position 2, effets de sel basique et effet spécial de sel (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 648-657 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Solvolysis Mechanism of cis - and trans-2-Arylcylopentyl p-Toluenesulfonates. The Step: 1-Deuterium Isotope Effects, Basic Salt Effects, and Special Salt EffectWe have studied the first step of the solvolysis of cis and trans-2-arylcyclopentyl p-toluenesulfonates in HCOOH, AcOH, and EtOh. All substrates show a high kinetic 1-deuterium isotope effect (kH/kD(1) 〉1.15). This fact indicates that first step leads to classical intimate ion-pair Which dissociates to a solvet-separated ion-pair, without participation either of solvent, the 2-aryl group, or a H-atom at C(2). The slight influence of added basic ions on reaction rate allows us to exclude any direct solvent attack on the covalent substrate even in the most favorable case, i.e. ethanolysis of 2-(p-nitrophenyl)cylopentyl-p-toluenesulfonates. Furthermore, solvent-separated ion pair formation is indicated by the special salt effect induced by LiClO4.
    Notes: No abstract.
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    URL: http://dx.doi.org/10.1002/hlca.19880710319
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710401
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    Anion-receptor molecules: Synthesis of a chiral and functionalized binding subunit, a bicyclic guanidinium group derived from L- or D- asparaginePresented in part at the 11th International Congress of Heterocyclic Chemistry, Heidelberg, Federal Republic of Germany, August, 1987. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 685-693 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optically active (4S,8S)-4, 8-bis(hydroxymethyl)-1,5,7-triazabicyclo[4.4.0]dec-5-ene ((S,S)-1) has been synthesized in nine steps from L-asparagine with a total yield of 5.1%. Similarly, the enantiomer (R,R)-1 has been prepared from D-asparagine. (S,S)- and (S,S)-1 are representative examples of rigid and functionalized bicyclic guanidine systems and constitute useful intermediates in the construction of chiral selective anion-receptor molecules.
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    URL: http://dx.doi.org/10.1002/hlca.19880710402
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  • 63
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    Studies on Antifungal Agents. Part 22. 3-aryl-5-[(aryloxy)alkyl]-3-[(1H-imidazol-1-yl)methyl]-2-methylisoxazolidines and related derivatives (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 718-732 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and antifungal activity of a novel series of 3-aryl-5-[(aryloxy)alkyl]-3-[(1H-imidazol-1-yl)-methyl]-2-methylisoxazolidines and related compounds, are discussed. The synthesis of the title compounds was accomplished via a 1,3-dipolar cycloaddition of α-substituted ketonitrones with l-alkenyl phenyl ethers (Scheme 2 and 3). The compounds were evaluated for in vitro antifungal activity in solid agar cultures against a broad variety of yeast and systemic mycoses and dermatophytes. While antifungal activity was evident throughout the series, in general, derivatives having halogen atom(s) in either or both aryl rings demonstrated the highest potency, especially against Trichophyton rubrum and Candida albicans. The dichloro analog 20 (PR 967-248) was found to possess the most useful activity. Its minimum inhibitory concentration (MIC) values ranged between 0.2 and 2.0 μg/ml, as compared to 0.2-20.0 μg/ml for the standard drug ketoconazole (4).
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710406
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  • 64
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    Captodative olefins in normal and inverse Diels-Alder ReactionsPart 3 of Thermal Reactions of Donor-Acceptor Systems. Part 2: [1]. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 742-748 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Olefins with captodative substitution are reactive dienophiles in Diels-Alder reactions with normal and inverse electron demand. This is shown for reactions of 2-(tert-butylthio)acrylonitrile (1) with various dienes and heterodienes, e.g. 1,3-cyclohexadiene, hexachloro-1, 3-cyclopentadiene, acrolein, methacrolein, and methyl vinyl ketone (Schemes 2 and 3). In case of the hetrodienes, 3,4-dihydro-2H-pyrans are formed beside small amounts of tetrahydrothiophenes; however, with methyl vinyl ketone, both reaction pathways are equally followed. The high reactivity of captodative olefins in Diels-Alder reactions are rationalized on the basis of Sustmann's FMO model under consideration of Viehe's concept of captodative substitution of alkenes.
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  • 65
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    A novel rearrangement of 2(5H)-furanones (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 783-787 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel rearrangement of 2(5H)-furanones is described. When refluxed in aq. Ethanolic solution in the presence of excess KOH, the 2,5-dihydro-2-oxofuran-3-carboxamides 6 underwent a novel rearrangement to the corresponding 4,5-dihydro-4-oxo-2-(phenylamino)-3-furancarboxylic acids 1 in moderate-to-excellent yields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710413
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  • 66
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    Kurze Totalsynthesen von (±)-Sativen und (±)-cis-Sativendiol (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 788-807 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Short Total Syntheses of (±)-Sativene and (±)-cis-SativenediolOur approach to (±)-sativene (7) and (±)-cis-sdtivenediol (9) involves: (a) reaction of 3-methylbutanoyl chloride with Et3N/cyclopentadiene to give the endo-isopropyl-ketone 1 (here improved to 71%), (b) NBS bromination of 1 to a 5:1 mixture (87%) of the bromo-ketones 2 and 3, (c) NFD-reaction sequence initiated by the attack of 1,2-butadienyl titanate (complex of 15, obtained from 2-butine) on 2/3 to afford 52% of the brexenone derivative 4 (along with 8% of its epimer 16), (d) addition of dibromomethane to 4 forming 63% of the diene-alcohol 5 (along with 13% of the diene-carbaldehyde 38), and (e) carbenoid ring-expansion with MeLi applied to 5 resulting in 41% the diene-ketone 6 (along with 15% of a 1:3 mixture of the diene-ketones 32 and 33). Wolff-Kishner reduction of 6 led to 81% of (±)-sativene (7), when enough O2 was present, but to 97% of the diene 8 in the strict absence of O2. (±)-cis-Sativenediol (9) was obrained (86%) by OsO4 hydroxylation of 8. The brexenone derivatives 4 and 16 (6:1, 50%) were also produced when the NFD-reaction sequence was applied to the isomeric bromo-ketone mixture 13/13 (1:3). The latter was obtained by NBS bromination of 10, which in turn was available by base epimerization of 1, followed by destructive removal of unreacted 1 by repeated gas-flow thermolysis. An analogous (less convenient) route to (±)-sativene (7) passed through a series of dihydro compounds (the ene series) it started with the methylidene-ketone 36, which was the product (97%) of a partial hydrogenation of 4. Addition of dibromomethane to 36 led t 62% of the methylidene-alcohol 39 (along with a little tetracyclic ether 40). Carbenoid ring expansion of 39 with MeLi afforded ca. 42% of the methylidene-ketone 41 (along with 7% of the methylidene-ketone 43 or, under slightly different condition, along with 9% of the methylidene-ketone 42 and 10% of the methylidene-carabaldehyde 44). The methylidene-alcohol 39 and the methylidene-ketone 43 were also obtained by partial hydrogenation of 5 and 33, respectively. Wolff-Kisher reduction converted 41 into (±)-sativene (7 99%); the same conditons applied to 42 afforded only ca. 8% 7 (along with three other hydrocarbons, one of them (ca. 21%) probably being (±)-copacamphene (45)). In the diene series, the two succeeding reactions (4→5 and 5→6) competed with the same side reaction, a rearrangement leading to the brendene-aldehyde 38. In the ene series, the corresponding dihydro-by-product 44 was found in the reacton 39→41, but not during 36→39. These side reactons could largely be suppressed by keeping the reaction temperature low. An explanation is proposed.
    Additional Material: 1 Ill.
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    Reactions of Haloarenes with Thiolate Anions in Tetraglyme: Competition between electron transfer and SNAr mechanisms (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 859-866 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the bromo-substituted naphthalene 1 with the alkanethiolate anions 2a-b and arenethiolate 2c in tetraglyme gave the corresponding 1-naphythyl thio-ethers 3a-c. Thio-ethers 3a-c were oxidized to the corresponding sulfones 4a-c with m- chloroperoxybenzoic acid. The reaction of the dichloro-substituted anthracene 5a with 2b gave the disubstutution product 6a. The reaction of 9-bromoanthracene 5c with the alkanethiolate 2b gave 6b, whereas the reaction of 5c with the arenethiolate 2c gave a mixture of substitution product 6c and anthracene 7. The observation of the formation of both 6c and 7 is explained by the competition between substitution (SnAr) and electron-transfer (ET) mechanisms. Consistent with this interpretation, the reaction of the monochloro-substituted 5b, which has a higher-energy σ* orbital, with 2c gave 6c without the formation of 7. Zn/KOH in tetraglyme was shown to reduce the aryl halides 5b-c and thio-ether 6c to 7.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710421
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    Synthèse de l'acide décarboxythamnolique (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 876-880 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Decarboxythamnolic AcidThe total synthesis of the meta-depside decarboxythamnolic ( = 3-[(3-formyl-2-4-dihydroxy-6-methyl-phenyl)oxy]-2-hydroxy-6-methoxy-4-methylbenzoic acid; 25) by the biomimetic condensation of the substituted β-orcinol units 9 and 22 is described.
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    URL: http://dx.doi.org/10.1002/hlca.19880710424
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    Metabolism of Carotenoids in Salmonids. Part 3Part 1: [4]; Part 2:[1].. Metabolites of astaxanthin and canthaxanthin in the skin of atlantic salmon (salmo salar, L.) (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 887-896 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diets supplemented with astaxanthin and canthaxanthin, respectively, and a control diet without carotenoid additions, were fed to 1½-year-old Atlantic salmon (Salmo salar, L.) for one year. The integuments were investigated as to their quantitative and qualitative carotenoid composition. Astaxanthin and canthaxanthin deposited in the skin amounted to 20 and 14% of the total carotenoids only. Seventy % must be considered as metabolites of astaxanthin and canthaxanthin and 10% as basic xanthophylls also present in the control groups. Astaxanthin apparently underwent the following metabolic pathway: astaxanthin→idoxanthin→adonixanthin→zeaxanthin→zeaxanthin 5,6-epoxides. Reduction of the 4′-carbonyl group was stereospecific leading to the (4′R)-idoxanthin. Canthaxanthin was obviously converted to β,β-carotene via 4′-hydroxyechinenone, echinenone, and 4-hydroxy-β,β-carotene.
    Additional Material: 2 Ill.
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    Antifungal Polyphenols from Cordia goetzeiGürke (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1210-1219 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four highly oxygenated polyphenols 1-4, have been isolated from the stem bark of Cordia goetzei Gürke (Boraginaceae) and their structures elucidated by a combination of one- and two-dimensional (including COLOC) NMR spectroscopic techniques, mass spectroscopy, and chemical methods. The first new compound, cordigone (1), is a tetrahydrofuran derivative and the second one, cordigol (2), a furobenzopyran derivative. The benzofurans 3 and 4 are orange pigments, responsible for the coloration of the stem bark of the tree. All four polyphenols are fungicidal against cladosporium cucumerinum.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710532
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  • 71
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    8-Aza-7-deaza-2′-deoxyguanosine: Phosphoramidite synthesis and properties of octanucleotides (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1191-1198 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Base-modified octanucleotides derived from d(G1-G2-A-A-T-T-C-C-) (11) but containing 8-aza-7-deaza-2′-deoxyguanosine (2) instead of 2′-deoxyguanosine (1) have been prepared by solid-phase synthesis employing P(III) chemistry. Isobutyrylation of 2, followed by 4, 4′-dimethoxytritylation and subsequent phosphitylation yielded the methyl or the cyanoethyl phosphoramidites 6a or 6b, respectively. They were used as building blocks in automated DNA synthesis. The resulting octanucleotides 12-14 containing 2 showed increased Tm values compared to the parent oligomer 11. The oligomers 11-14 were employed as sequence-specific probes in endo-deoxyribonuclease Eco RI oligonucleotide recognition. Whereas displacement of dG-2 (enzymic cleavage site of 11) abolished phosphodiester hydrolysis, replacement of dG-1 enhanced the cleavage rate compared to 11.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710530
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    Synthesis of Optically Pure Tricarbonyliron Complexes of 5,6-Dimethylidenebicyclo[2.2.2.]oct-2-yl derivatives. Crystal structure and absolute configuration of (+)-tricarbonyl(1S,2S,4R,5R,6S)-C,5,6,C,-η-(5,6-dimethylidenebicyclo[2.2.2]oct-2-yl p-bromobenzoate)iron (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1349-1353 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title complexes have been derived from tricarbonyl [(1R,4S,5S,6R,)-C,5,6,C-η-(5,6-dimethylidenebicyclo[2.2.2]oct-2-ene)]iron (1.). The crystal structure and absoulte configuration of (+)-tricarbonyl (1S,2S,4R,5R,6S)-C,5,6,C,-η-(5,6-dimethylidenebicyclo[2.2.2]oct-2-yl p,-bromobenzoate)]iron ((+)-6) determined by X-ray diffrac-tion studies proved earlier attribution of the relative configuration (endo us. exo,) of the tricarbonyliron moieties in complexes 1 and 2 of 5,6-dimethylidenebicyclo[oct-2-ene. The structure of (+)-6 confirms the absolute configuration derived earlier from circular-dichroism spectra of 5,6-dimethylidenebicyclo[2.2.2]oct-2-yl esters and 5,6-dimethylidenebicyclo[2.2.2]octan-2-one.
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    Photocycloadditions of 2-(trimethylsilyloxy)-1,3-butadiene to 2-cycloalkenones. Access to the basic pentalenolactone skeletonPreliminary communication: [1]. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1392-1398 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The [2 + 2] Photocycloaddition of 2-(trimethylsilyloxy)-1,3-butadiene to a number of 2-cycloalkenones proved to be quite a general reaction leading to good yields of the cycloadducts (Table). This finding is surprising since dienes, in general, are better known as quenchers of enone triplets rather than as photochemical reactants. Both the high substrate concentrations, which can be employed in these cycloadditions, and the remarkable regio and stereoselectivity of the processes qualify them as valuable for syntheses. In a first application, the photoproducts 1a, b were transformed in three steps into a viable precursor 4 of the pentalenolactone-G and -H antibiotics.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710603
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    Transition-Metal Complexes with Bidentate Ligands Spanning trans-Positions. Part XVIIPart XVI: see [1].. Some platinum(II) complexes with anionic ligands such as methoxide, formate, carboxylate, hydride, and borohydride, and the X-ray crystal structure of [PtHCl()] (PP = 2,11-bis(diphenylphosphinomethyl)benzo[c]phenanthrene) (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1442-1457 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes trans-[PtXY(2] (X = H or Me; Y = OMe, OCHO, CO2H, and BH4; 2 = 2,11-bis{bis[3-(trifluoromethyl)phenyl]phosphinomethyl}benzo[c]phenanthrene) were prepared, and their decompositions to trans[PtHX(2)] were studied. Some binuclear hydrido-bridged complexes, e.g.[(2)HPt(μ-H)PtH(2)]+, were also obtained. The preparation of complexes trans-[PtHX(28)2] (X = H or Me, 28 = bis[3-(trifluoromethyl)phenyl]benzylphosphine) is also reported. The X-ray crystal structure of trans-[PtHCl1)] (1 = 2,11-bis(diphenylphosphinomethyl)benzo[c]phenanthrene) was carried out.
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    URL: http://dx.doi.org/10.1002/hlca.19880710608
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    Singlet-Oxygen Quenching by Carotenoids: Steady-state luminescence experiments (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1005-1010 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The near-infrared luminescence of singlet oxygen (1O2) has been measured in order to determine the efficiency of 1O2 quenching by two carotenoid compounds, β-carotene and canthaxanthin. 1H-Phenalen-1-one and rose bengal have been used as photosensitizers in those steady-state luminescence experiments. Stern-Volmer analysis of the 1O2 luminescence in solutions of CCl4 and CD3OD, containing different concentrations of the carotenoids, has shown a very efficient quenching by canthaxanthin. The rate constants are about a factor of 2 below the diffusion limited values for the given solvents, confirming earlier results in benzene. In comparison, the efficiency of 1O2 quenching by β-carotene is slightly lower than that by canthaxanthin in non-polar solvents and is reduced by an order of magnitude in CD3OD, due to the aggregation of this quencher.
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    Preparation of 3-Oxo- and 3-Ethylideneazetidine DerivativesThis work is part of the Ph. D. thesis of H. B. [1] (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1035-1041 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of 3-azetidinones with different N-substituents and their transformation to 3-ethylideneazetidines has been studied in relation with a projected synthesis of 3-ethylideneazetidine-2-carboxylic acid (= polyoximic acid; 1). The stable crystalline 3-azetidinone hydrochloride (18), obtained by hydrogenolysis of the known 1-(diphenylmethyl)-3-azetidenone (4), is described for the first time, From this key intermediate, 3-oxoazetidine-derived amides, exemplified by benzamide 12,urethanes (e.g. 17), and ureas (e.g. 20) can be prepared in good yield (Scheme 3). The olefination of 3-azetidinones with alkylidene(triphenyl)phosphoranes is a perparatively useful process only for derivatives with a pyramidal N-atom, e.g. the diphenylmethyl derivative 4, and not for the amide 12 or the urethane 17 (Scheme 4). 3-Alkylidene-azetidines with an amide N-atom should, therefore, be prepared by exchange of the N-substituent after the introduction of the double bond.
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    Absorption Spectra and Luminescence Properties of Isomeric Platinum (II) and Palladium (II) Complexes containing 1,1′-biphenyldiyl, 2-phenylpyridine, and 2,2′-bijpyridine as ligands (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1053-1059 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absorption spectra, luminescence spectra, and luminescence lifetimes of the isomeric [M(bph)(bpy)] and [M(phpy)2] complexes M = Pt(II) or Pd(II), bph2- = 1,1′-biphenyl-2,2′-diyl dianion, phpy- = 2-phenylpyridine-2′-yl anion, and bpy = 2,2′-bipyridine have been investigated and compared with those of [M(bpy)2]2+ complexes and of the free protonated ligands H2bph, Hbpy+, and Hphpy. In the absorption spectra, the region below 320 mm is dominated by ligand-centered (LC) transitions, whereas metal-to-ligand charge transfer (MLCT) transitions are responsible for the bands present in the near UV/VIS region. The MLCT bands move to higher energies on replacing Pt with Pd and in going from [M(bph)(bpy)] to the [M(phpy)2] isomer. For the mixed-ligand complexes, evidence for both M → bph2- (at higher energies) and M → bpy bands is found. The structured luminescence observed at 77 K shows lifetimes of 4.0 and 1.1 μs for [Pt(phpy)2] and [Pt(bph)(bpy)], respectively, and 480 and 250 μs for the analogous Pd complexes. On the basis of the energy and lifetime data, the luminescence of the Pt(II) complexes is assigned to the lowest triplet MLCT excited state, whereas for the Pd complexes the luminescent state is thought to result from a mixture of MLCT and LC triplet levels.
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    URL: http://dx.doi.org/10.1002/hlca.19880710516
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    Ruthenium(II) Complexes with Three Different Diimine Ligands (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1108-1115 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of tri-heteroleptic complex of Ru(II) with diimine ligands is describe. Ten compounds [Ru(R2bpy) (biq) (L)][PF6]2 (R = H, CH3); L = 2,2′-bipyridine (bpy), 4,4′-dimethyl-2,2′-bipyridine (Me2bpy), 2,2′-bipyrimidine (bpm), 2,2′-biisoquinoline (biiq), 1,10-phenanthroline (phen), dipyrido[3,2-c:2′,3′-e]pyridazine (taphen), 2,2′-biquinoline (biq), 6,7-dihydrodipyrido[2,3-b:3,2-j][1,10]-phenanthroline (dinapy), 2-(2[pyridyl)quinoline (pq), 1-(2-pyrimidyl)pyrazole] (pzpm), 2,2′-biimidazole (H2biim) are characterized by elemental analysis, electronic and 1H-NMR spectroscopy. The relative photosustitution rates of biq in MeCN are given at three temperatures.
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    URL: http://dx.doi.org/10.1002/hlca.19880710525
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  • 79
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    (Benzylthio)- und (Arylthio)-substituierte Nitril-ylide: Thermische Erzeugung und Reaktionen (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1177-1190 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal Generation and Reactions of (Benzylthio)-and (Arylthio)-Substituted Nitrile YlidesThermolysis of 4-(benzylthio)- and 4-(arylthio)-1,3-oxazol-5(2H)-ones 6, at 110-155° in the presence of dipolarophiles with activated C≡C, C=C, C=O, C=S, and N=N bonds, led to 5-membered cyclo-adducts and CO2 (cf. Schemes 3, 5-7). Heating 6a and 6c in the presence of ethyl propiolate yielded ethyl quinoline-3-carboxylate (19) and ethyl pyridine-3-carboxylate(22), respectively (cf. Scheme 8). These results are rationalized on the basis of the intermediate formation of thio-substituted nitrile ylides of type 7 (cf. Scheme 2), which undergo regioselective 1,3-dipolar cycloadditions with reactive dipolarophiles. In the absence of such a dipolarophile, the nitrile ylides isomerize via a [1,4]-H shift to give 2-aza-1,3-butadienes of type 20. The latter are trapped in a Diels-Alder reaction with ethyl propiolate (cf. Scheme 8).
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    URL: http://dx.doi.org/10.1002/hlca.19880710529
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  • 80
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    The Reversible Proxibarbal-Valofan Isomerisation. Part I. Kinetic and thermodynamic studies in aqueous solutions (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1220-1227 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tautomerisation between proxibarbal (I) and the two diastereoisomers of valofan, IIX and IIY, was investigated in aqueous solutions, and various rate and equilibrium caonstants were calculated by compartmental analysis. The proportion of I at equilibrium was found to increase with pH, and indeed, the two equilibrium constants are linear functions of pH. In contrast, the equilibrium-concentratio ratio of IIY/IIX was close to 63:37 and remained constant in the pH range investigated. The rate constants were also determined as a function of temperature, allowing calculation of the tehrmolynamic parameters. Under physiological conditions, the difference in free energy favouring I vs. IIX and IIY is 6.7 and 5.4KJ · mol-1, respectively.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710533
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  • 81
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    Tandem Diels-Alder Reactivity Controlled by Remote Substituents. Regioselective synthesis of linearly annellated six-membered ring systems from (1RS,5SR,6RS,7SR)-6,7-bis(chloromethyl)-8,9-dimethylidene-2-oxabicyclo[3.2.2]nonan-3-one. Crystal structure of (1RS,5RS,6SR,11RS)-6,7-bis(chloromethyl)-3-oxo-2-oxatricyclo[7.4.0.1,5]tridec-8-en-11-yl methyl ketoneFor a preliminary communication, see [1].Part of the planned Ph. D. thesis of Bernard Demarchi, University of Lausanne. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1249-1267 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthess of 6,7,8,9-tetramethylidene-2-oxabicyclo[3.2.2]nonan-3-one (12), 6,7,8,9-tetramethylidene-2-azatricyclo[3.2.2]nonan-3-one (13), and (1RS,5SR,6RS,7SR)-6,7-bis(chloromethyl)-8,9-dimethylidene-2-oxabicyclo-[3.2.2]nonan-3-one (14) are presented. The rate constants of the two successive Diels-Alder additions of a given dienophile to 12 and 13 were nearly the same. Lewis-acid-catalyzed Diels-Alder addition of methyl vinyl ketone to 14 gave adduct 39 with high regio- and stereoselectivity. Lewis acids isomerized 39 into(1RS,5RS,6SR,7SR,11RS)-6,7-bis(chloromethyl)-3-oxo-2-oxatricyclo[7.4.0.01,5]tridec-8-en-11-yl methyl ketone (40) whose structure was determined by single-crystal X-ray crystallography. Heating 39 with CsF/Cs2CO3 in DMF/HMPT gave (1RS,5RS,11RS)-6,7-dimethylidene-3-oxo-2-oxatricycl. [7.4.0.01,5]tridec-8-en-11-yl methyl ketone (42). The exocyclic butadiene moiety of triene 42 added to methyl propynoate and 2,3-didehydroanisole with good regioselectivity giving polysubstituted anthracenyl and naphthacenyl derivatives, respectively.
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  • 82
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    Präparative chromatographische Enantiomerentrennung von synthetisch nützlichen cyclischen AcetalenTeil der Doktorarbeiten von St. M. (Dissertation Nr. 8616, ETH Zürich, 1988), J. Z. (Dissertation Nr. 8518, ETH Zürich, 1988) und der geplanten Dissertation von U. G. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1303-1318 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparative Chromatographic Resolution of Synthetically Useful Cyclic AcetalsRacemic cyclic acetals derived from aldehydes and glycine, glycolic acid, thioglycolic acid, formylacetic acid, and acetoacetic acid (oxazolidinones 4-13, dioxolanones 14, 15, oxathiolanone 16, dioxinones 17-23) are resolved by preparative high-pressure liquid chromatography on silica gel coated with the polymer from N-acryloylphenylalanine ethyl ester (Chiraspher®). The separation factors α range from1,1 to 2,4. Use of a Prepbar®-chromatography system allows injection of several grams at a time. The enantiomeric acetals thus obtained are fully characterized. First application to amino-acid synthesis are mentioned.
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    URL: http://dx.doi.org/10.1002/hlca.19880710541
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  • 83
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    Stereoselectivity in Reactions of Metal Complexes. Part XPart IX: [1]. Kinetics and stereoselectivity of the inner-sphere electron-transfer reaction between [Co(bamap)H2O]+ (bamap = 2,6-bis(3-carboxy-1,2-dimethyl-2-azapropyl)pyridine) and optically active iron(II) complexes (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1339-1348 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the electron-transfer reaction between racemic or optically active [Co(bamap)H2O]+ and optically active Fe2+ complexes of the three new pentadentate ligands bamap, alamp, and valmp has been investigated. All the reacting species show C2 symmetry. With respect to aquo-Fe2+, the reaction rate for the Fe2+ complexes is enhanced by a factor of 104 to 105, and the observed kΔΛ/kΛΛ ratio is 1.0, 1,9, and 1.2, respectively. In all cases where stereoselectivity is observed, the reaction is faster between the complexes of opposite absolute configuration (ΔΛ or ΛΔ) than between species with the same configuration (ΛΛ or ΔΔ). The stereoselectivity effects are discussed of the basis of the structure of the transition state and the interatomic distances between the two metal centers at the moment of electron transfer.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710545
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  • 84
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710601
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  • 85
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    Synthesis of (+)-1,3:2,5-dianhydroviburnitol ((+)-(1R,2R,3S,5R,6S)-4,7-dioxatricyclo[3.2.1.03,6]octan-2-ol) (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1399-1405 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Epoxidation of (-)-(1R,2R,4R)-2-endo-cyano-7-oxabicyclo[2.2.1]hept-5-en-2-exo-yl acetate ((-)-5) followed by saponification afforded (+)-(1R,4R,5R,6R)-5,6-exo-epoxy-7-oxabicyclo[2.2.1]heptan-2-one ((+)-7). Reduction of (+)-7 with diisobutylaluminium hydride (DIBAH) gave (+)-1,3:2,5-dianhydroviburnitol ( = (+)-(1R,2R,3S,4R,6S)-4,7-dioxatricyclo[3.2.1.03,6]octan-2-ol; (+)-3). Hydride reductions of (±)-7 were less exo-face selective than reductions of bicyclo[2.2.1]heptan-2-one and its derivatives with NaBH4, AlH3, and LiAlH4 probably because of smaller steric hindrance to endo-face hydride attack when C(5) and C(6) of the bicyclo-[2.2.1]heptan-2-one are part of an exo oxirane ring.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19880710604
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  • 86
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    Lavandulifolioside: A New Phenylpropanoid Glycoside from Stachys lavandulifolia (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1483-1490 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new phenlypropanoid glycoside has been isolated from the methanolic extract of the aerial parts of Stachys lavandulifolia (Lamiaceae), lavandulifolioside (1). On the basis of chemical and spectral data the structure of the new compound 1 has been elucidated as β-(3,4-dihydroxyphenyl)ethyl O-α-L-arabinopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→3)-4-O-caffeoyl-β-D-glucopyranoside.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710612
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  • 87
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    Applications of ENDOR spectroscopy to radical cations in freon matrices. Part 2Part 1, see [1].. The radical cation of 2,3-diazabicyclo[2.2.2]oct-2-ene (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1498-1501 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical cation of 2,3-diazabicyclo[2.2.2]oct-2-ene (1), generated by γ-rays in a CF2ClCFCl2 matrix, has been fully characterized by its hyperfine data with the use of ESR, ENDOR, and TRIPLE resonance spectroscopy. The isotropic coupling constants for \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\scriptstyle {{\relbar}\kern-4pt {.} }}$\end{document} are +3.14 mT for the two 14N Nuclei in the azo group, -0.336 mT for the two protons at the bridgehead C atoms, and +151 and +0.135 mT for the sets of four exo- and four endo-protons, respectively. MO calculations indicate that these values are consistent with an electron removal from an orbital represented by the antibonding combination (n_) of the lone-pair atomic orbitals at the two N atoms. The corresponding radical anion \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\scriptstyle {{\relbar}\kern-4pt {.} }}$\end{document} is persistent in fluid solution and its hyperfine data, combined with MO calculations, point to an electron uptake into the antibonding π orbital (π*) of the azo group. It is, thus, reasonable to classify \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\scriptstyle {{+}\kern-4pt {.} }}$\end{document} as a σ and \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\scriptstyle {{\relbar}\kern-4pt {.} }}$\end{document} as a π radical.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710614
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  • 88
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    Semicorrin Metal Complexes as Enantioselective Catalysts. Part 1. Synthesis of chiral semicorrin ligands and general conceptsTaken in part from the Ph.d. thesis of H. F., ETH-Zürich (in preparation); for a preliminary communication, see [1]. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1541-1552 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An efficient synthesis of chiral semicorrin ligands is described (see 6-9, Schemes 2 and 3). Both enantiomers are readily obtained in enantiomerically pure form starting either from D-or L-pyroglutamic acid (1). Semicorrins of this type possess several features that make them attractive ligands for enantioselective control of metal-catalyzed reactions. Their structure is characterized by C2 symmetry, a conformationally rigid ligand system, and two stereogenic centers adjacent to the coordination sphere. In a metal complex, the two substituents at the stereogenic centers shield the metal atom from two opposite directions and, therefore, are expected to have a pronounced effect on the stereochemical course of a reaction occurring in the coordination sphere. The structure of these two substituents can be easily modified in a variety of ways. A series of (semicorrinato)copper(II) complexes (see 10-14, Scheme 4) has been prepared, and in one case (14), the three-dimensional structure has been determined by X-ray analysis (Fig. 1).
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19880710620
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  • 89
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    Stereoselective synthesis of pyrrolo[2,3-d]pyrimidine α- and β-D-ribonucleosides from anomerically pure D-ribofuranosyl chlorides: Solid-Liquid Phase-Transfer Glycosylation and 15N-NMR Spectra (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1573-1585 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solid-liquid phase-transfer glycosylation (KOH, tris[2-(2-methoxyethoxy)ethye]amine ( = TDA-1), MeCN) of pyrrolo[2,3-d]pyrimidines such as 3a and 3b with an equimolar amount of 5-O-[(1,1 -dimethylethyl)dimethylsilyl]-2,3-O-(1-methylethylidene)-α-D-ribofuranosyl chloride (1) [6] gave the protected β-D-nucleosides 4a and 4b, respectively, stereoselectively (Scheme). The β-D-anomer 2 [6] yielded the corresponding α-D-nucleosides 5a and 5b with traces of the β-D-compounds. The 6-substituted 7-deazapurine nucleosides 6a, 7a, and 8 were converted into tubercidin (10) or its α-D-anomer (11). Spin-lattice relaxation measurements of anomeric ribonucleosides revealed that T1 values of H—C(8) in the α-D-series are significantly increased compared to H—C(8) in the β-D-series while the opposite is true for T1 of H—C(1′). 15N-NMR data of 6-substituted 7-deazapurine D-ribofuranosides were assigned and compared with those of 2′-deoxy compounds. Furthermore, it was shown that 7-deaza-2′deoxyadenosine ( = 2′-deoxytubercidin; 12) is protonated at N(1), whereas the protonation site of 7-deaza-2′-deoxyguanosine (20) is N(3).
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    URL: http://dx.doi.org/10.1002/hlca.19880710623
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  • 90
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710701
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  • 91
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    Synthesis and Characterization of Crown-Ether-Containing Phthalocyanines with Group-IV-A Elements (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1616-1621 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Group-IV-A phthalocyanines with four crown ether substituents have been prepared from 4′,5′-dicyanobenzo(15-crown-5), 4′,5′-diiminoisoindolino(15-crown-5), or metal-free phthalocyanine and the corresponding metal salts. The axial ligands of dichloro[tetra(15-crown-5)phthalocyaninato]silicon or -tin have been converted into dihydroxy derivatives by hydrolysis in aqueous Et3N. The catalytic effect of H2O-free CaC12 in quinoline is used for the polycondensation of dihydroxysilicon-phthalocyanine to cofacially arrayed polymers. The thermal stability of group-IV-A-metal phthalocyanines is confirmed by the higher initial decomposition points (290-440°) compared to those of the corresponding transition-metal phthalocyanines.
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    URL: http://dx.doi.org/10.1002/hlca.19880710705
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  • 92
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    Facile Synthesis of Carbon Monoxide Isotopically Labelled at Oxygen from Enriched Water without Isotopic Dilution (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1659-1660 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: O-Labelled carbon monoxide was prepared on the gram scale from enriched water and acetals of norborn-2-en-7-one(= bicyclo[2.2.1]hept-2-en-7-one) in almost quantitative yields and without isotopic dilution.
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    URL: http://dx.doi.org/10.1002/hlca.19880710710
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    Syntheses of Amino-dideoxyallose and Amino-deoxyribose Derivatives Using Acylnitroso DienophilesDedicated to Professor Elias J. Corey on the occasion of his 60th birthday (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1642-1658 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dimethyl acetals 4 of (E)-2,4-pentadienal and of (E,E)- and (E,Z)-2,4-hexadienals undergo regio- and stereospecific cycloaddition reactions with in-situ-generated acylnitroso dienophiles 5a and 5b, leading thereby to the corresponding dihydrooxazines 7a-d and 8c-d. cis-Glycolization of these latter adducts stereospecifically gave the dihydro derivatives 9a-d and 10d which, after sequential hydrogenolysis, deacetalization, and instant cyclization, led to the aminodeoxyribose derivatives 17a, 17f, and 18, and to the amino-dideoxyallose compounds 17c and 17h. These piperidino-deoxysugar derivatives exhibit a strong anomeric effect, i.e. OH—C(1) is always axial, which is explained in terms of a nN(π)-σ*(C—OH) orbital compression, as compared to the less pronounced one in the more classical pyranose series.
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  • 94
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    1,3-Dipolare Cycloaddition aromatischer Nitril-ylide und Nitril-oxide an Dicyan und Diazocyanide (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1681-1688 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3 Dipolar Cycloaddition of Aromatic Nitrile Ylides and Nitrile Oxides with Cyanogen and DiazocyanidesNitril ylides 2 generated from the imidoyl chlorides 1 react with cyanogen and aryldiazocyanides to 2,5(4)-dia-ryl-1H-imidazole-4(5)-carbonitriles 3a,b or 5(4)-(arylazo)-2,4(5)-diaryl-1H-imidazoles 4a and 2,3,5-triaryl-2,3-dihydro-1H-1,2,4-triazole-1-carbonitriles 5a-f, respectively (Scheme 1). Reactions of benzonitrile oxides 7 with these dipolarophiles lead to 3,3′-diaryl-5,5′-bi[1,2,4]oxadiazoles 8a-c or 3-aryl-5-(arylazo)-1,2,4-oxadiazoles 9a-j (Scheme 2).
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    URL: http://dx.doi.org/10.1002/hlca.19880710714
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  • 95
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    Synthese der Spermidin-Alkaloide (±)-Inandenin-10-ol, Inandenin-10-on und (±)-OncinotinHerrn Prof. Dr. Duilio Arigoni zum 60. Geburtstag gewidmet. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1708-1718 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses of the Spermidine Alkaloids (±)-Inandenin-10-ol, Inandenin-10-one, and (±)-OncinotineNew syntheses of the title compounds using two-ring-enlargement reactions are described. Starting from the aldehyde 1, the corresponding 4′-aza derivative 15 could be obtained by reductive amination with the appropriate and protected spermidine derivative 14 (Scheme 4). Enlargement of the carbocyclic ring in 15 by five members gave, after further transformations, the hydroxylactam 18. Transamidation of 18, the second ring-enlargement step, led to (±)-inandenin-10-ol (7;22.9% overall yield) and, after oxidation, to inandenin-10-one (8; 22.5%, overall yield). (±)-Oncinotine 6 was synthesized by two pathways (Scheme 6): protection of the terminal NH2 group by treatment with the Nefkens reagent and replacement of the OH group by Cl gave 24, which by thermal transamidation followed by direct ring closure led to the oncinotine derivative 26. The same intermediate could be obtained in higher yield via 28 by oxidation and protection of 18 followed by transamidation and reductive ring closure. Treatment of 26 with hydrazine finally gave (±)-oncinotine 6 in 15.9% overall yield.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710718
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  • 96
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    Diastereoselektive Alkylierung von 3-Aminobutansäure in der 2-StellungSir Derek Barton, zum 70. Geburtstag gewidmet (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1824-1839 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diastereoselective Alkylation 3-Aminobutanoic Acid in the 2-PositionThe enantiomerically pure 3-aminobutanoic acids (R)- and (S)-6 are readily available by preparative HPLC separation of the two diastereoisomers 5 obtained from addition of (S)-phenethylamine to methyl crotonate and subsequent hydrogenolysis (Scheme 2). (S)-Methyl 3-(benzoylamino) butanoate ((S)-3) is also available by enzymatic kinetic resolution with pig-liver esterase. The N-benzyl- and N- benzyloxycarbonyl derivatives rac3,8, and 9 of 3-aminobutanoates are doubly deprotonated with LDA and alkylated or aminated in high selectivity (17 examples, relative topicity like; see Tables 1 and 2). The configuration of three of the products is assigned (Schemes 4-6), and in four cases, the free α-substituted β-amino acid is prepared by acidic hydrolysis (see Table 3). It is shown that the doubly lithiated β-amino-acid derivative is solubilized, and its reactivity may be strongly influenced by the presence of 3 equiv. of LiCl.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710724
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  • 97
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    Electronic Resource
    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710801
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  • 98
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    Electronic Resource
    Energy-Minimized Structures and Calculated and Experimental Isomer Distributions in the Hexaaminecobalt(III) system [Co(trap)2]3+ (trap = 1,2,3-propanetriamine) (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1875-1880 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The two isomers of [Co(trap)2]3+ (meso-[Co(trap)2]3+ and rac-[Co(trap)2]3+; trap = 1,2,3-propanetriamine) have been studied by strain-energy minimization. The two isomers have been separated preparatively by fractional crystallization, and fully characterized by 13C-NMR and electronic spectroscopy, and microanalyses. The calculated isomer distribution (rac/meso = 60%: 40%) is in good agreement with HPLC analysis of thermodynamic equilibrium mixtures at 298 K and 353 K (rac/meso = 55% : 45%). These results are discussed in relation to the approach of calculating isomer distributions of hexaaminecobalt(III) systems by strain-energy minimization neglecting the differences in environmental effects.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710805
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  • 99
    Electronic Resource
    Electronic Resource
    Synthesis of New unnatural Macrocyclic Trichothecenes: 4-epiverrucarin A. 47th Communication on verrucarins and roridins46th Commun.: [1]. (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1904-1913 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 4-epiverrucarin A (24), a new unnatural macrocyclic trichothecene, was synthesized starting from 4-epiverrucarol (20). The latter was obtained by metal-hydride reduction of the 4-oxo derivative 19. Subsequent conversion of 20 into the monoester 30 and then the diester 32 followed by macrolactonization of the latter yielded 4-epiverrucarin A (24). Attempts to invert the configuration of the naturally occuring 3α-OH group of a trichothecene were unsuccessful. The cytostatic (P-815) and immunosuppressive (MLR) activity of several natural and unnatural trichothecenes was determined in vitro.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710809
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  • 100
    Electronic Resource
    Electronic Resource
    Steric Crowding in Coordination Compounds: Electron-transfer kinetics of the [Co(tmen)3]3+/2+ couple (tmen = 2,3-dimethylbutane-2,3-diamine) (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1966-1970 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The [Co(tmen)3]3+ complex ion (tmen = 2,3-dimethylbutane-2,3-diamine) has been synthesized and its redox characteristics compared to those of its parent ion [Co(en)3]3+. The 12 peripheral Me groups significantly affect the properties of the [Co(tmen)3]3+ ion. The ligand-field bands are shifted to lower energies by about 1700 cm-1 compared to [Co(en)3]3+. The reduction potential for [Co(tmen)3]3+ is +0.28 V (vs. NHE) compared to -0.18 V for [Co(en)3]3+. The rate of the self-exchange reaction for the [Co(tmen)3]3+/2+ couple, k = 8.5 × 10-8 M-1·S-1 was determined by applying the Marcus cross-relation with the reductants Cr2+, V2+, Eu2+, Ru2+, and [Co(sepulchrate)]2+.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710814
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