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  • 2000-2004  (518)
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  • breast cancer  (140)
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  • 101
    Electronic Resource
    Electronic Resource
    Microsatellite instability markers in breast cancer: A review and study showing MSI was not detected at ‘BAT 25’ and ‘BAT 26’ microsatellite markers in early-onset breast cancer (2000)
    Springer
    Breast cancer research and treatment 60 (2000), S. 135-142 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; microsatellite instability ; microsatellite markers ; review ; survey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Microsatellite markers may provide evidence of faulty DNA mismatch repair (MMR) via the detection of microsatellite instability (MSI). The choice of microsatellite markers may impact on the MSI detection rate. In hereditary non-polyposis colon cancer (HNPCC), several informative microsatellite markers have been recommended. Two of these, BAT 25 and BAT 26, are quasi-homozygous, enabling analysis of tumour DNA in the absence of paired normal DNA. Sixty-six breast cancer patients under 45 years of age at diagnosis were examined for MSI at BAT 25 and BAT 26. Tumour DNA was extracted from paraffin-embedded tissue. No MSI was detected at the BAT 25 or BAT 26 loci. An additional five microsatellite markers, known to be informative for HNPCC, were examined for MSI in these patients. Apparently-normal profiles were achieved. A tabulated survey of 306 microsatellite markers used to detect MSI in breast cancer revealed that only 35.5% of markers detected MSI at an average rate of 2.9%. The MSI detection rate at the specific HNPCC markers varied from 0% to 10% in breast cancer, with D175250 and TP53 being the HNPCC markers most suitable for analysis of breast cancer. The size of the microsatellite marker's repeat unit did not impact on MSI detection rates. Compiled data from large studies (n〉100) revealed D115988 as the marker with the highest MSI detection rate. Genomic instability pathways of carcinogenesis, characterised by MMR defects and MSI, appear to play a role in the genesis of some breast cancer types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006315315060
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  • 102
    Electronic Resource
    Electronic Resource
    EORTC 10941: A phase II study of liarozole in postmenopausal patients with ‘Chemotherapy-Resistant’ or ‘Potentially Hormone Sensitive’ metastatic breast cancer (2000)
    Springer
    Breast cancer research and treatment 60 (2000), S. 181-188 
    Details
    ISSN: 1573-7217
    Keywords: aromatase inhibitor ; breast cancer ; liarozole ; retinoic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Liarozole is an imidazole compound that inhibits enzymes involved in steroid hormone aromatisation and retinoid metabolism. The IDBBC branch of the EORTC has performed a series of phase II studies of the agent in four groups of postmenopausal women with metastatic breast cancer. This paper reports the results of the first two groups: ‘Chemotherapy Resistant’ (unrestricted ER status, 1 or 2 prior chemotherapy regimens, 0–2 prior hormonal therapies) and ‘Potentially Hormone Sensitive’ (ER positive or unknown, 1 or 2 prior hormonal therapies with a substantial disease free interval or progression free survival, and no history of chemotherapy for metastatic disease). Liarozole was administered at 150–300 mg orally bid. The objective response rate was 12% in the ‘Chemotherapy Resistant’ group (n=34), and 22% in the ‘Potentially Hormone Sensitive’ group (n=37), with median response durations of 9 and 14 months, respectively. Median time to treatment failure was only 2 months in both groups, due largely to the significant percentage (24%) of patients who ceased treatment following excessive mucocutaneous and gastrointestinal toxicity. This adverse event profile will limit its use in breast cancer. Results of the ‘ER negative’ and ‘Tamoxifen Refractory’ groups will be reported in a future paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006398518037
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  • 103
    Electronic Resource
    Electronic Resource
    Analysis of cathepsin D in human breast cancer: Usefulness of the processsed 31 kDa active form of the enzyme as a prognostic indicator in node-negative and node-positive patients (2000)
    Springer
    Breast cancer research and treatment 60 (2000), S. 173-179 
    Details
    ISSN: 1573-7217
    Keywords: active processed cathepsin D ; breast cancer ; prognostic indicator ; survival analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relative amounts of the precursor (52 kDa) and processed (31,27 kDa) forms of cathepsin D have been analyzed by Western blotting in biopsied breast tissue cytosols from 134 lesions from invasive breast cancer patients, 24 lesions from patients with ductal carcinoma in situ (DCIS), 227 lesions from benign breast disease patients, and 28 lesions from normal control subjects. The mean relative percentage amount of the 31 kDa form was significantly increased (p〈0.001) in the invasive breast cancer group compared to the other three groups. In addition, the mean relative percentage amount of the 31 kDa form was significantly increased (p〈0.05) in node-positive compared to node-negative breast cancer patients. In the benign breast disease group, patients with proliferative-type disease had a significantly increased (p=0.02) mean relative percentage amount of the 31 kDa form of cathepsin D compared to patients with nonproliferative-type disease. Invasive breast cancer patients were followed for up to 75 months to determine if the relative percentage amount of the 31 kDa form of cathepsin D was predictive of disease-free and overall survival. Although the amount of the 31 kDa form was not predictive of disease-free survival, patients in the ‘high’ 31 kDa group (〉18) were significantly (p〈0.05) more likely to die than patients in the ‘low’ 31 kDa group (≤18%). The 12 patients who died were all node-positive and in the high 31 kDa group. It thus appears that the relative amount of the processed, active 31 kDa form of cathepsin D is a useful prognostic indicator, at least in node-positive breast cancer patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006394401199
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  • 104
    Electronic Resource
    Electronic Resource
    Aberrant expression of TSG101 in Taiwan Chinese breast cancer (2000)
    Springer
    Breast cancer research and treatment 60 (2000), S. 259-266 
    Details
    ISSN: 1573-7217
    Keywords: TSG101 ; breast cancer ; tumor suppressor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Functional inactivation of the tsg101 gene in mouse fibroblasts results in cell transformation and the ability to form metastatic tumors in nude mice. The human tsg101 gene was mapped to chromosome 11q15.1-2 and found to mutate in some cancer patients. To test the expression pattern of the tsg101 gene in Chinese breast cancer patients, we analyzed the mRNA by RT-PCR in 51 breast cancer patients. The full-length tsg101 and 7 truncated transcripts were detected in both normal and matched tumor tissues. A short transcript with a deletion of nucleotides 154–1054 is frequently presented in late-stage breast cancers. TSG101 protein expression was also detected by Western blot analysis in 30 breast cancer patients. A predicted full-length 46 kDa and three proteins with smaller molecular weight were detected. The full-length 46 kDa protein was less expressed in tumor specimens. Immunohistochemical stains from 10 patients of each stage 0–4 revealed that TSG101 protein was predominantly present in the cytoplasm. Cell nuclei were occasionally immunopositive and the chromosomes were deeply stained during cell division. The intracellular location and the expression of TSG101 protein were both not stage-dependent in primary breast cancers. In addition, normal mammary glands were more homogenously immunopositive than invasive ductal carcinoma. These results support the notion that the aberrant expression of TSG101 in breast cancer is associated with altered cell growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006426400524
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  • 105
    Electronic Resource
    Electronic Resource
    The timing of treatment in breast cancer: gaps and delays in treatment can be harmful (2000)
    Springer
    Breast cancer research and treatment 60 (2000), S. 201-209 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; growth rates ; histological grade ; primary medical treatment ; radiotherapy fractionation ; ‘split-course’ radiotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract ‘Timing’ of treatment in breast cancer may refer to intervals within a single management or between different managements. Rates of shrinkage of breast cancers in response to treatment are related to histological grade and may be used as surrogates for growth rates. Histological grade should predict appropriate timing of treatment. Four cases of locally advanced breast cancer that illustrate a number of different types of interval are presented. Two tumours of differing histological grade (II and III) had been managed by historical ‘split-course’ radiotherapy and two similar grade III tumours were managed by primary medical treatment, followed at different intervals by radiotherapy. In the grade III tumours different radiotherapy fractionation régimes and effects of varying intervals between mangements are compared. The theoretical advantage of shrinkage (leading to reoxygenation) during the gap in ‘split-course’ radiotherapy is realized only in relatively slowly growing and shrinking tumours. Grade III tumours grow rapidly. They have the potential to shrink rapidly in response to appropriate treatment, namely intensive chemotherapy or radiotherapy but not hormones. Inadequate treatment leads to growth in intervals between individual doses, whether of drugs or radiation, and to failure of local control. The advantage of surgery or primary medical treatment will be lost if the interval between managements is too long in relation to the volume doubling time. Histological grade is a good guide of this parameter; the grade III tumours are particularly vulnerable to gaps in treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006441018271
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  • 106
    Electronic Resource
    Electronic Resource
    Relationship between in vivo drug exposure of the tumor interstitium and inhibition of tumor cell growth in vitro: a study in breast cancer patients (2000)
    Springer
    Breast cancer research and treatment 60 (2000), S. 211-217 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; 5-fluorouracil ; methotrexate ; pharmacodynamics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A novel approach is described to simulate effect site pharmacodynamics of anticancer drugs. This approach is based on (i) the in vivo measurement of unbound, interstitial drug pharmacokinetics (PK) in solid tumor lesions in patients and (ii) a subsequent pharmacodynamic (PD) simulation of the time versus drug concentration profile in an in vitro setting. For this purpose, breast cancer cells (MCF-7) were exposed in vitro to the time versus interstitial tumor concentration profiles of 5-fluorouracil (5-FU) and methotrexate (MTX) from primary breast cancer lesions in patients. This led to a maximal reduction in the viable cell count of 69 on day 4, and of 71 on day 7 for 5-FU and MTX, respectively. This effect was dependent on the initial cell count and was characterized by a high interindividual variability. For 5-FU there was a significant correlation between the maximum antitumor effect and the intratumoral AUC (r = 0.82, p = 0.0005), whereas no correlation could be shown for MTX (r = 0.05, p = 0.88). We conclude, that the in-vivo-PK / in-vitro-PD model presented in this study may provide a rational approach for describing and predicting pharmacodynamics of cytotoxic drugs at the target site. Data derived from this approach support the concept that tumor penetration of 5-FU may be a response-limiting event, while the response to MTX may be determined by events beyond interstitial fluid kinetics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006497202341
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  • 107
    Electronic Resource
    Electronic Resource
    Unique features of breast cancer in Taiwan (2000)
    Springer
    Breast cancer research and treatment 63 (2000), S. 213-223 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; database ; prognosis ; Taiwan ; young age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Between April 1990 and December 1997, 811 consecutive patients with 830 newly diagnosed breast cancers having their primary treatments in our institution were included in this study. Sixty three percent of breast cancer patients were premenopausal. The early-onset breast cancer (age ≤ 40) composed 29.3% of all patients. The five-year survival rate of all patients was 80.4% (95% confidence interval [CI], 76.2–84.6%). The five-year overall survival rate for stage 0 was 95.7% (95% CI, 87.3–100%), stage I, 93.9% (95% CI, 88.9–98.9%), stage II, 88.5% (95% CI, 82.0–95.1%), stage III, 65.0% (95% CI, 54.0–75.9%), and stage IV, 18.5% (95% CI, 3.4–33.7%). Multivariate analysis of primary operable breast cancer revealed that axillary lymph node involvement, high nuclear grade and early-onset breast cancer (age ≤ 40) were poor prognostic factors. The early-onset breast cancer had a more aggressive clinical behavior than that of the older age group, their five-year disease-free survival rates for stage I, stage II and stage III diseases being only 64.7%, 66.5%, and 43.3%, respectively. In these patients the only meaningful prognostic factor was extensive axillary lymph node metastasis (≥10). In summary, breast cancer patients in Taiwan tend to be younger than their counterpart in western countries. The early-onset breast cancer had poorer prognostic features for all stages comparing to the older age group. Standard pathologic factors are not good predictors of their outcome. For these patients new biologic markers need to be sought to distinguish between high and low risk and the treatment strategy for them should be guided by the aggressive characteristics of the disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006468514396
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  • 108
    Electronic Resource
    Electronic Resource
    Serum lipid levels during and after adjuvant toremifene or tamoxifen therapy for breast cancer (2000)
    Springer
    Breast cancer research and treatment 63 (2000), S. 225-234 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; cholesterol ; triglycerides ; tamoxifen ; toremifene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Tamoxifen decreases serum cholesterol (S-cholesterol) level about 10% and low-density lipoprotein cholesterol (S-LDL) 15–20%, but in most studies it has increased serum triglyceride levels and had little effect on serum high-density cholesterol (S-HDL). The effect of another antiestrogen, toremifene, on the serum lipid profile has not been completely studied. We monitored serum lipid levels longitudinally in 141 axillary node-positive postmenopausal breast cancer patients who received randomly either 40 mg toremifene or 20 mg tamoxifen as adjuvant therapy for 36 months, and in 34 postmenopausal women who received no adjuvant systemic therapy after surgery for axillary node-negative breast cancer. No significant differences were found between the drugs in their effects on S-cholesterol, LDL, HDL, or triglyceride levels, or on the cholesterol-to-HDL or LDL-to-HDL ratios. For both drugs the S-cholesterol and S-LDL absolute lowering effect was the greater the higher the pretreatment level. For a patient with a median pretreatment value, toremifene decreased S-cholesterol 6% and tamoxifen 13%, and S-LDL decreased by 13% and 23%, respectively, at 6 months of therapy. Six months after stopping three-year antiestrogen therapy S- cholesterol and S-LDL levels had returned to the pretreatment levels. In conclusion, we found no major differences between 40 mg toremifene and 20 mg of tamoxifen in their effect on the serum lipid levels, which return to the pretreatment levels within 6 months after cessation of therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006465732143
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  • 109
    Electronic Resource
    Electronic Resource
    Alcohol and Breast Cancer Mortality in a Cohort Study (2000)
    Springer
    Breast cancer research and treatment 64 (2000), S. 201-209 
    Details
    ISSN: 1573-7217
    Keywords: alcohol ; breast cancer ; cohort ; women
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Available epidemiological evidence indicates that alcohol intake is associated with a higher risk of developing breast cancer. Plausible biological pathways include its effect on levels of estrogens, cell membrane integrity and cell-to-cell communication, inhibition of DNA repair, and congener effect. The present study evaluated the impact of alcohol on mortality from breast cancer, an area with relatively few studies in the literature. The subjects were participants in a Canadian prospective cohort study, the National Breast Screening Study (NBSS). Women were enrolled in the cohort from 1980 to 1985 to evaluate the efficacy of mammographic screening. Information on usual diet and alcohol intake at enrolment and other epidemiological variables was collected by means of a mailed, self-administered questionnaire. Mortality from breast cancer during follow- up to 31 December, 1993 was ascertained by record linkage to the Canadian Mortality Data Base maintained by Statistics Canada. During the follow-up period of 1980–1993 (average 10.3 years), 223 deaths from breast cancer were identified for this analysis. The hazard ratios for the risk of death from breast cancer increased with intakes of total alcohol of 10–20 g/day (1.039, 1.009–1.071) and 〉 20 g/day (1.063, 1.029–1.098). This increase was contributed largely by the intake of wine, a 15% increase in risk at intakes higher than 10 g/day of alcohol from wine. Alcohol from spirits was associated with a small decrease in risk of death (hazard ratio at 10 g/day, 0.945, 0.915–0.976). The effect of alcohol from beer was not significant in the two categories studied. Although our results were statistically significant, the magnitude of the change in risk was small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006402323445
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  • 110
    Electronic Resource
    Electronic Resource
    PTP LAR Expression Compared to Prognostic Indices in Metastatic and Non-Metastatic Breast Cancer (2000)
    Springer
    Breast cancer research and treatment 64 (2000), S. 221-228 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; EGF receptor ; erbB2 ; estrogen receptor ; LAR ; 13762NF tumor ; tyrosine phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several prognostic indices in breast cancer, including c-erbB2, epithelial growth factor receptors (EGFR), estrogen and progesterone receptors are signal transduction molecules. Recently, expression of another signal transduction molecule, the protein tyrosine phosphatase LAR, has been suggested to be increased in breast cancer. The objective of the current investigation was to examine the relationship between LAR expression and prognostic parameters in breast cancer. LAR expression was associated with metastatic potential in the well-characterized 13762NF rat mammary adenocarcinoma clones. The metastatic MTLn3 and MTLn2 clones expressed sizable amounts of LAR. The essentially non-metastatic MTC clone had little LAR expression. C-erbB2 had highest expression in the highly metastatic MTLn3 clone, but c-erbB2 levels were sizeable in the weakly metastatic MTLn2 and non-metastatic MTC clone. EGFR expression had the strongest association with a clone's metastatic potential, being very high in MTLn3, weak in MTLn2, and undetectable in MTC. In human breast cancer specimens, LAR expression was strongly positive in 50% of metastatic cases but in only 21% of ‘non-metastatic’ cases. As with the 13762NF-derived clones, c-erbB2 expression was strongly positive independent of metastatic phenotype. However, 46% (6/13) of cases that were strongly positive for c-erbB2 were strongly positive for LAR. Only 17% (2/11) of negative or weakly c-erbB2 positive samples were strongly positive for LAR. All ER+ positive tumors (n = 15) were positive for LAR and 53% of these tumors were strongly positive for LAR. In ER− negative cases, only 1 of 11 was strongly positive for LAR. While the current data indicate a strong association between ER and LAR expression in breast cancer tissue (p = 0.003), additional studies are warranted to further explore the relationship between LAR and prognostic indices of breast cancer progression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006410509740
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  • 111
    Electronic Resource
    Electronic Resource
    p21WAF1/CIP1 Expression in breast cancers: associations with p53 and outcome (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 33-43 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; p21WAF1/CIP1 ; p53 ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract p21WAF1/CIP1 is transcriptionally activated by wt p53 and inhibits G1 associated cyclins, a major mechanism by which p53 inhibits cellular proliferation. Archival breast cancers (798) with a median follow-up of 16.3 years were used to explore the prognostic value of p2l immunohistochemical analyses. p21 immunostaining was detected in the majority (726/798: 91%) of breast cancers as well as adjacent in situ carcinomas (125/170: 74%), hyperplastic lesions (140/349: 40%) and normal breast epithelium adjacent to carcinoma (3/89: 3%). Complete immunonegativity was observed in only 9% of invasive cancers and was associated with p53 immunopositivity (p〈0.05). Univariate analysis of all patients showed that p21 negativity was associated with a longer disease specific survival (relative risk (RR) 1.5). Node positive p21 – patients also showed a longer disease free and disease specific survival as compared to tumor p21+ patients. In node negative patients, p53 positivity but not p21 alone, was significantly associated with a shortened disease free survival (RR = 1.6). Node negative patients who were p53 + p21−, in particular had the shortest disease free survival compared to other p53, p21 subgroups (i.e., p21 negativity was associated with a worse outcome). Multivariate analysis of lymph node negative patients (n〉300) demonstrated that tumor size and tumor grade were independently predictive of outcome, whereas neither p53 nor p21 were significant. For node positive patients, p21 positivity (p=0.05), p53 positivity (p=0.03), a higher number of positive nodes, larger tumor size, steroid receptor negativity, high proliferation rate, and erbB-2 expression were each independently associated with poor outcome. In summary, p21 negativity was inversely correlated with p53 immunopositivity in the majority of cases. p21 negative tumor patients had an improved outcome if they were node positive, whereas p21 status was not significantly associated with survival in node negative patients. This observation may be due to the reported ‘uncoupling of S phase and mitosis’ associated with a loss of p21 expression which may result in enhanced sensitivity to chemotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006455526894
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  • 112
    Electronic Resource
    Electronic Resource
    ATM heterozygosity and breast cancer: screening of 37 breast cancer patients for ATM mutations using a non-isotopic RNase cleavage-based assay (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 79-85 
    Details
    ISSN: 1573-7217
    Keywords: ataxia telangiectasia ; ATM ; breast cancer ; mutation screening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Based upon the results of several epidemiologic studies, it has been suggested that women who are carriers for a mutation in the ataxia telangiectasia-mutated (ATM) gene are susceptible for the development of breast cancer. Therefore, 37 consecutive breast cancer patients were screened for the presence of a germline ATM mutation using a non-isotopic RNase cleavage-based assay (NIRCA). This paper reports the first use of NIRCA for detection of ATM mutations in breast cancer patients. Using this assay, no ATM mutations were found in our patient population. This result is similar to the findings of other studies that have employed approaches complementary to NIRCA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006463730337
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  • 113
    Electronic Resource
    Electronic Resource
    Sex hormone-induced mammary carcinogenesis in the female Noble rats: Expression of Bcl-2 and Bax in hormonal mammary carcinogenesis (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 45-57 
    Details
    ISSN: 1573-7217
    Keywords: androgen receptor ; apoptosis ; Bax ; Bcl-2 ; breast cancer ; estrogen receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have established a Noble rat model to explore the mechanisms of hormonal mammary carcinogenesis, in which the role of androgen in promoting mammary carcinogenesis was highlighted. We have also established that stromal-epithelial interactions may be responsible for the promotional effects of testosterone in mammary carcinogenesis. Based on these understandings, in the present study we examined the expression of Bcl-2 and Bax in pre-malignant mammary glands from rats treated with different protocols of sex hormones for 7 weeks as well as sex hormone induced mammary tumours. We observed that Bcl-2 was strongly expressed in most of mammary tumour cells, whereas weak or negative in adjacent normal or hyperplastic ductal structures. On the contrary, Bax immunoreactivity was weak in mammary tumour cells while strongly expressed in adjacent normal or hyperplastic ductal structures. More importantly, the results from comparative study of ‘pre-malignant’ glands further showed that when animals were treated with 17β-oestradiol, the mammary epithelial cells expressed high levels of Bcl-2. The results from rats treated with testosterone, either alone or in combination with oestrogen, give rise to high levels of Bax expression in ‘pre-malignant’ mammary glands. These observations indicate that in ‘pre-malignant’ mammary glands, treatment with testosterone, either alone or in combination with 17β-oestradiol, may induce high apoptotic activities. However, in fully developed mammary tumours, the apoptotic activities apparently decrease in tumour cells. TUNEL assay provides further data to support this conclusion. Our study, thus, suggests that androgens may play a promoting role in mammary carcinogenesis by upregulation of Bax expression and induction of high apoptotic activities in ‘pre-malignant’ stage, which would provide a selective pressure favouring the expansion of the initiated cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006400732154
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  • 114
    Electronic Resource
    Electronic Resource
    Breast cancer incidence in relation to smoking cessation (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 121-129 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; ex-smokers ; smoking ; smoking cessation ; tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract High plasma levels of oestrogens are associated with increased breast cancer risk. If smoking, as has been suggested, have both a tumour initiating mutagenic effect and a protective anti-oestrogenic effect, one would assume that smokers who give up smoking have the highest incidence of breast cancer. This was evaluated in the follow-up of a cohort of 10,902 women of whom 4,359 were premenopausal. Record-linkage with official cancer registries yielded 416 incident cases during an average follow-up of 13.6 years. The adjusted relative risk in all ex-smokers was 1.31 (1.02–1.69), as compared to never smokers, and in premenopausal ex-smokers it was 1.57 (1.07–2.30). Breast cancer incidence in premenopausal ex-smokers was inversely related to time since cessation, (p for trend = 0.01), and was highest among the women who had given-up smoking less than 12 months before screening: 2.76 (1.55–4.91). There was no significant association between current smoking and breast cancer risk. We conclude that incidence of breast cancer in premenopausal women who have given up smoking is higher than it is in smokers and never smokers. To what extent this may be related to endocrine effects associated with smoking cessation remains to be evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006448611952
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  • 115
    Electronic Resource
    Electronic Resource
    Improving discussion of surgical treatment options for patients with breast cancer: local medical opinion leaders versus audit and performance feedback (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 171-175 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; breast conserving surgery ; hospital practices ; mastectomy ; physician behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied whether a hospital intervention utilizing medical opinion leaders and performance feedback reduced the proportion of women who reported that surgeons did not discuss options prior to surgery for early stage breast cancer. Opinion leaders provided clinical education to their peers using a variety of strategies and were selected for their ability to influence their peers. Performance feedback involved distributing performance reports that contained data on the outcomes of interest as well as on other treatment patterns. Twenty-eight hospitals in Minnesota were randomized to the intervention or to a control group that received performance feedback only. The proportion of patients at intervention hospitals who said that their surgeon did not discuss options decreased significantly (p〈0.001) from 33% to 17%, but a similar decrease was observed among control hospitals. Using medical opinion leaders to intervene in hospitals appeared as effective as performance feedback.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006475012861
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  • 116
    Electronic Resource
    Electronic Resource
    Breast cancer prognostic significance of a single nucleotide polymorphism in the proximal androgen response element of the prostate specific antigen gene promoter (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 111-119 
    Details
    ISSN: 1573-7217
    Keywords: androgen receptor ; breast cancer ; mutation ; polymorphism ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Prostate Specific Antigen (PSA) expression by breast epithelial cells is associated with favorable breast cancer prognosis. In preliminary studies, we found that a nucleotide variation (G → A) at position −158 in the androgen response element (ARE-1) of the PSA promoter was present in four out of 9 breast tumors examined and in a breast carcinoma cell line. We have now determined the nucleotide composition at position −158 of DNA extracted from 148 well-characterized breast tumors and compared tumor genotype with that of controls without cancer, with tumor PSA concentration and with clinicopathological variables, overall survival and disease free survival. The G → A base change at position −158 is a polymorphism. Allelotypes were similarly distributed in breast cancer patients and controls. The Mann–Whitney U Test showed a significantly higher tumor PSA concentration in tumors that presented a homozygous G as opposed to homozygous A genotype. Genotype at position −158 was not associated with clinicopathological variables in contingency table analysis. Univariate Cox regression models showed a 28% reduction in risk for death in patients with homozygous G genotype compared to those with homozygous A genotype (P=0.03). However, ARE-I genotype did not significantly add to the prognostic power in the multivariate model of overall survival. In summary, the base change at position −158 is a polymorphism that may affect breast cancer prognosis, but further studies are required to confirm this possibility and to investigate the relevance of this polymorphism in terms of breast cancer susceptibility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006459613498
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  • 117
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    Pilot studies on the p53 gene in nipple aspirate fluid from patients with breast cancer (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 139-143 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; mutation ; nipple aspirate fluid ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nipple Aspirate Fluid (NAF) from patients with breast cancer is a potential source of exfoliated tumour material amenable to molecular biological study, but few such data have been reported. In this study we demonstrate that polymerase chain reaction (PCR) amplification of p53 gene DNA is achievable in a proportion of NAF samples from breast cancer patients. Subsequently four NAF samples from patients whose primary tumours were identified as having a defined p53 mutation were studied by single stranded conformational polymorphism analysis (SSCP). Two samples yielded PCR product indistinguishable from wild type and two yielded no product. Whilst no cancer-related genetic mutations were demonstrated in NAF samples, further study is warranted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006487315587
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  • 118
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    Psychological distress following first recurrence of disease in patients with breast cancer: prevalence and risk factors (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 145-150 
    Details
    ISSN: 1573-7217
    Keywords: adjustment disorders ; breast cancer ; first recurrence ; major depressive disorder ; psychological distress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives: To investigate the prevalence of, and risk factors for psychological distress following first recurrences of breast cancer. Patients and methods: The sample was drawn consecutively from the inpatient and outpatient populations of the National Cancer Center Hospital in Japan during an 18-month period from July 1996 to December 1997. Of the 56 eligible patients, 55 women aged 30–73 year with recurrent breast cancer participated in the study. The prevalence of psychological distress, including major depressive disorder and adjustment disorders was evaluated according to the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Third edition-revised (DSM-III-R). Risk factors for psychological distress were analyzed with a logistic regression model. Results: Of the 55 subjects, 42 met the DSM-III-R criteria for major depressive disorder or adjustment disorders. Major depressive disorder was seen in 4 (7%), and adjustment disorders in 19 (35%). Logistic regression analysis showed that a disease-free interval of less than 24 months significantly predicted a diagnosis of major depressive disorder or adjustment disorders (odds ratio 5.28, 95% confidence interval; 1.28–21.8, p=0.02). Conclusions: These results suggest that it is important for all oncology staff to pay careful attention to the psychological health of patients who have been informed of their cancer recurrence, and that some psychosocial intervention is necessary for preventing distress in patients facing early recurrence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006483214678
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  • 119
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    A comparison of cell cycle markers in well-differentiated lobular and ductal carcinomas (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 161-170 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; cell cycle ; ductal ; histologic subtypes ; lobular
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Infiltrating lobular carcinoma (ILC) and infiltrating ductal carcinoma (IDC) are similar in many respects and their histologic features occasionally overlap. Despite the many similarities, some clinical follow-up data and the patterns of metastasis suggest that ILC and IDC are biologically distinct. Unfortunately, most breast cancer research has focused almost exclusively on the ductal subtype or has not stressed the biologic or molecular genetic distinctions between breast carcinoma subtypes. Several reports have suggested the possibility that ILCs and IDCs differ with respect to expression of antigens involved in proliferation and cell cycle regulation. Therefore, we undertook an immunohistochemical evaluation of cell cycle related antigens in ILCs, including histologic variants thought to represent aggressive neoplasms, and IDCs matched for histologic grade (Modified Bloom–Richardson Grade I). We believe that different antigent expression profiles could elucidate the biological distinctiveness of breast carcinoma subtypes and possibly provide diagnostically relevant information. We studied the expression of the following antigents in 28 archived, formalin-fixed ILCs and 34 well-differentiated IDCs: estrogen receptor (ER), progesterone receptor (PR), Her 2-neu, mib-1, cyclin D1, p27, p53, mdm-2 and bcl-2. 94% of ILCs and 100% of IDCs expressed ER; 75% of ILCs and 76% of IDCs expressed PR; 4% of ILCs and 13% of IDCs expressed c cerb B-2; ILCs and IDCs both expressed mib-1 in approximately 10% of lesional cells; 82% of ILCs and 54% of IDCs expressed cyclin D1; 90% of ILCs and 83% IDCs expressed p27 strongly; 4% of ILCs and 4% of IDCs expressed p53, 25% of ILCs and 33% of IDCs expressed mdm-2; 96% of ILCs and 100% of IDCs expressed bcl-2. None of the apparent differences were statistically significant. The ILC variants demonstrated immunophenotypes that were essentially similar to ILCs of the usual type. We conclude that ILCs and well-differentiated IDCs show similar proliferation and cell cycle control antigen profiles. Despite their unusual histologic features, most ILC variants appear to maintain a characteristic ILC immunophenotype.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006479113769
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  • 120
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    The growth and metastasis of human, HER-2/neu-overexpressing tumor cell lines in male SCID mice (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 217-228 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; in vivo tumor models ; Her-2/neu ; metastasis ; SCID mice ; soluble Her-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract HER-2/neu is overexpressed on a variety of human adenocarcinomas and overexpression has been associated with a poor prognosis. For this reason, HER-2 has become an attractive target for immunotherapy. To facilitate testing of anti-HER-2-monoclonal antibodies (MAbs) and immunotoxins (ITs), we have evaluated the in vivo growth and metastatic spread of three HER-2-overexpressing human breast cancer cell lines (BT474, MDA-MB-453 and HCC1954) and one ovarian cancer cell line (SKOV3.ip1) in pre-irradiated male SCID mice using subcutaneous (s.c.), intravenous (i.v.) and intraperitoneal (i.p.) routes of injection. All the cell lines tested grew as s.c. tumors and the growth of BT474 and MDA-MB-453 cells after s.c. injection was improved by co-inoculation with Matrigel. Metastases to the lungs were detectable by PCR or histopathology after s.c. injection of BT474 and to a much lesser extent after s.c. injection of HCC1954, MD-MB-453 and SKOV3.ip1cells. I.P. injection of HCC1954 and SKOV3.ip1 cells produced fatal ascites while i.v. injection of SKOV3.ip1, but not BT474 or MDA-MB-453 cells, resulted in infiltration of lungs and death within 9–11 weeks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006494001861
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  • 121
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    Increased risk of second cancers following breast cancer: Role of the initial treatment (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 183-195 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; chemotherapy ; cohort study ; radiotherapy ; second primary cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives and methods.The risk of second primary malignancies (SMN) was studied in a cohort of 4,416 one-year survivors of a breast cancer. The role of the menopausal status and of the initial treatment modalities (surgery, radiotherapy, and chemotherapy) was investigated. Results.Excluding second primary breast cancer and non-melanoma skin cancer, a total of 193 (4.4%) patients developed a SMN between 1973 and 1992, compared with 136 expected (Standardised Incidence Ratio, SIR = 1.4, 95% CI (1.2–1.6)). No trend towards either an increase or a decrease was noted in the SIR with time after treatment (p = 0.2). The greatest increase in the relative risk concerned soft tissue cancers (SIR = 13.0, 95% CI: 6.8–22.3), followed by leukaemia (SIR = 3.1, 95% CI: 1.7–5.0), melanoma (SIR  =  2.7, 95% CI: 1.4–4.8), kidney (SIR = 2.5, 95% CI: 1.2–4.5), ovary (SIR = 2.0, 95% CI: 1.2–3.1) and uterine tumours (SIR = 1.9, 95% CI: 1.4–2.5). The SIR was 3.0 (95% CI 1.8–4.7) in women under 40 at the time of the breast cancer, 1.9 (95% CI : 1.4 – 2.4) in those aged 40–49 and 1.2 (95% CI 1.0–1.4) in those aged 50 or more. In the 2,514 women who had received radiotherapy as initial treatment without chemotherapy, the SIR for all SMN was 1.6 (95% CI: 1.1–2.3) fold higher than in those who had not received radiotherapy as initial treatment. Conclusion.In conclusion, this study confirms the increased risk of second malignancies in women treated for a breast cancer, and particularly in those who were younger at the time of treatment for breast cancer. Our results also suggest that radiotherapy may play a role in the onset of these second lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006489918700
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  • 122
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    Pathways through which a regimen of melatonin and retinoic acid induces apoptosis in MCF-7 human breast cancer cells (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 229-239 
    Details
    ISSN: 1573-7217
    Keywords: apoptosis ; breast cancer ; melatonin ; retinoic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It has been established that melatonin (Mlt) and retinoic acid, individually, inhibit the proliferation of the estrogen receptor-alpha (ERα)-positive MCF-7 breast cancer cell line. Our laboratory has previously demonstrated that Mlt and all-trans-retinoic acid (atRA) not only inhibit the proliferation, but also induce apoptosis of MCF-7 cells when used in a sequential regimen of Mlt followed 24 h later by atRA. Using this same MCF-7 breast cancer cell line, we investigated the potential pathways through which apoptosis is being induced. We found that treatment of MCF-7 cells with Mlt for 24 h before the addition of atRA decreased the protein levels of the death suppressor, Bcl-2, and increased, although with different time courses, the levels of the death promoters, Bax and Bak; however, there was no change in the levels of the tumor suppressor gene, p53. MCF-7 cells treated sequentially with Mlt and atRA also demonstrated an enhanced sensitivity to the apoptotic effects of atRA, which did not appear to be due to increased expression of the retinoic acid receptors, RARα or RXRα, but rather to enhanced transcriptional activity of the RARα. These data suggest that the sequential treatment regimen of Mlt and atRA may induce apoptosis by modulation of members of the Bcl-2 family of proteins. Thus, this combinatorial regimen, which reduces the concentration of atRA needed for clinical efficacy while enhancing its anti-tumorigenic activity, could be of great therapeutic benefit, and may, in fact, specifically induce the regression of established breast tumors due to its apoptosis-promoting effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006442017658
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  • 123
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    Predication of axillary lymph node metastasis by intravenous digital subtraction angiography in breast cancer, its correlation with microvascular density (2000)
    Springer
    Breast cancer research and treatment 61 (2000), S. 261-269 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; intravenous digital subtraction angiography ; axillary lymph node metastasis ; neovascularization of lymph nodes ; microvascular density ; antibody to platelet/endothelial cell adhesion molecule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Accurate predication of axillary node status by non-invasive diagnostic method would be of great value in cases of breast cancer. There have been few reports advocating digital subtraction angiography (DSA) as specifically advantageous for the detection of lymph node metastasis. IV (intravenous)-DSA was carried out on 42 patients with breast carcinoma using a DSA system with a matrix of 1024 × 1024×pixels. When a mass became stained in the axilla, it was considered to be metastatic. An immunohistochemical technique with JC70 antibody to platelet/endothelial cell adhesion molecules was used to evaluate the microvascular density (MVD) of the axillary lymph nodes. IV-DSA achieved a 76.2% sensitivity, 85.7% specificity, and 81.0% accuracy. The average MVD with JC70 antibody was 97.7 ± 44.4 in metastatic and 62.9 ± 23.6 in nonmetastatic nodes. MVD was significantly higher in the cancerous than in the noncancerous regions within lymph nodes. The MVD was 105 ± 38.4 in DSA-N(+) cases and was 57.8 ± 21.9 in DSA-N(−) cases, and the difference was statistically significant. In conclusion, IV-DSA is a useful diagnostic modality for detection of axillary lymph node metastasis. This new modality predicts lymph node status by assessing the neovascularization of the lymph node.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006449619475
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  • 124
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    Cancer Risk Associated with Subfertility and Ovulation Induction: A Review (2000)
    Springer
    Cancer causes & control 11 (2000), S. 319-344 
    Details
    ISSN: 1573-7225
    Keywords: breast cancer ; endometrial cancer ; fertility drugs ; infertility ; melanoma ; ovarian cancer ; thyroid cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: Over the past decades the use of fertility drugs (FDs) has greatly increased. Recently, the possible association between the use of FDs and risk of cancer has aroused great concern. In this paper, we critically review the available epidemiologic studies. Methods: We identified papers published between 1966 and 1999 that examined FDs and specific causes of subfertility in relation to the risks of cancers of the ovary, breast, endometrium and thyroid, and melanoma. Results: Although present insights into the pathogenesis of hormone-related malignancies suggest a possible association between the use of FDs and the risk of specific cancers, this has not been convincingly demonstrated in epidemiologic studies. With regard to cancer risk in relation to the cause of subfertility, the only consistent association observed is an increased risk of endometrial cancer for women with subfertility due to hormonal disorders. While positive findings in some studies on FDs and ovarian cancer risk have aroused serious concern, the associations observed in most of these reports appear to be due to bias or chance rather than being causal. The most important sources of bias are inadequate confounder control for both parity and causes of subfertility. Conclusions: To discriminate between the possible carcinogenic effects of various ovulation induction regimens, subfertility disorders, and reproductive characteristics associated with subfertility, future studies should include large populations of subfertile women with sufficient follow-up time. In such cohort studies the cause of subfertility should be measured adequately (based on medical records) and information about reproductive characteristics should be collected for all cohort members. Such studies should also include a group of subfertile women with an indication for FD use but not so treated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008921211309
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  • 125
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    Hydatidiform moles and the long-term risk of breast cancer (Sweden) (2000)
    Springer
    Cancer causes & control 11 (2000), S. 117-120 
    Details
    ISSN: 1573-7225
    Keywords: breast cancer ; cohort ; hydatidiform
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives: The etiology of breast cancer is only partially understood. Based on the findings that pregnancies reduce breast cancer risk, a possible inverse association between exposure to the placental hormone human chorionic gonadotropin (hCG) and the risk of breast cancer has been suggested. Hydatidiform mole, a gestational trophoblastic disease, is associated with a high expression of hCG. We performed a population-based cohort study in which women with a history of hydatidiform mole were followed up for future cancer outcomes. Methods: All 3371 women with a notification of hydatidiform mole in the Swedish Cancer Registry between 1958 and 1993 were followed up for future cancer outcomes by record linkages within the registry. Results: In a total of 57,075 person-years of follow-up, 59 women had a diagnosis of breast cancer during follow-up, yielding an overall standardized incidence ratio of 1.3 (95% CI 1.0–1.7). Conclusion: This finding is not consistent with the hypothesis of a protective effect of hCG exposure on breast cancer risk, but rather suggests an adverse association.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008915217389
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  • 126
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    Isolation of genes overexpressed in freshly isolated breast cancer specimens (2000)
    Springer
    Breast cancer research and treatment 59 (2000), S. 41-48 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; bcg-1 ; L19 ; L34 ; MAGE-like ; MLN70 ; subtractive hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A number of approaches have been used to identify genes important in breast cancer. In one approach the genes already shown to be involved in other tumors, such as p53 and Her2neu, were examined. A second approach examined genes detected through genetic screening of families with a high incidence of breast cancer, for example, BRCA-1 and BRCA-2. We used a third approach, subtractive hybridization, to identify and clone genes that were preferentially expressed in breast cancer cells compared to normal mammary epithelium. Instead of analyzing breast cancer cell lines, we examined fresh human breast cancer specimens. By subtracting normal mammary epithelial cDNA from breast cancer cDNA, we were able to clone several genes overexpressed in breast cancer. Two of these genes, L19 and MLN70, were previously reported to be overexpressed in breast cancer. Three of these genes, L19, L34, and MLN70, were localized to a region on chromosome 17 where Her2/neu and BRCA-1 are found. In addition, we isolated a gene we call breast cancer associated gene-1 that was expressed almost exclusively in fresh breast cancer tissue and not in normal mammary epithelium or breast cancer cell lines. We were unable to detect expression of breast cancer associated gene-1 in cell lines from melanoma, renal cell carcinoma, lymphoma, or leukemia. The full-length sequence from two separate breast cancer specimens revealed one amino acid difference compared to the sequence from normal breast epithelial tissue. Further studies are necessary to determine whether these genes contribute to breast cancer development or can be used as therapeutic targets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006315919985
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  • 127
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    The influence of infiltrating lobular carcinoma on the outcome of patients treated with breast-conserving surgery and radiation therapy (2000)
    Springer
    Breast cancer research and treatment 59 (2000), S. 49-54 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; lobular ; ductal ; conservative surgery ; radiation therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: The role of conservative surgery and radiation therapy (CS and RT) in the treatment of patients with infiltrating ductal carcinoma is well established. However, the efficacy of CS and RT for patients with infiltrating lobular carcinoma is less well documented. The goal of this study was to examine treatment outcome after CS and RT for patients with infiltrating lobular carcinoma and to compare the results to those of patients with infiltrating ductal carcinoma and patients with mixed ductal–lobular histology. Methods: Between 1970 and 1986, 1624 patients with Stage I or II invasive breast cancer were treated with CS and RT consisting of a complete gross excision of the tumor and ≥6000 cGy to the primary site. Slides were available for review for 1337 of these patients (82%). Of these, 93 had infiltrating lobular carcinoma, 1089 had infiltrating ductal carcinoma, and 59 had tumors with mixed ductal and lobular feature these patients constitute the study population. The median follow-up time for surviving patients was 133 months. A comprehensive list of clinical and pathologic features was evaluated for all patients. Additional histologic features assessed for patients with infiltrating lobular carcinoma included histologic subtype, multifocal invasion, stromal desmoplasia, and the presence of signet ring cells. Results: Five and 10-year crude results by site of first failure were similar for patients with infiltrating lobular, infiltrating ductal, and mixed histology. In particular, the 10-year crude local recurrence rates were 15%, 13%, and l3% for patients with infiltrating lobular, infiltrating ductal, and mixed histology, respectively. Ten-year distant/regional recurrence rates were 22%, 23%, and 20% for the three groups, respectively. In addition, the 10-year crude contralateral breast cancer rates were 4%, 13% and 6% for patients with infiltrating lobular, infiltrating ductal and mixed histology, respectively. In a multiple regression analysis which included established prognostic factors, histologic type was not significantly associated with either survival or time to recurrence. Conclusions: Patients with infiltrating lobular carcinoma have a similar outcome following CS and RT to patients with infiltrating ductal carcinoma and to patients with tumors that have mixed ductal and lobular features. We conclude that the presence of infiltrating lobular histology should not influence decisions regarding local therapy in patients with Stage I and II breast cancer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006384407690
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  • 128
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    The diagnostic and prognostic utility of prostate-specific antigen for diseases of the breast (2000)
    Springer
    Breast cancer research and treatment 59 (2000), S. 1-14 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; prostate-specific antigen ; prognostic indicators ; tumor markers ; breast cyst ; benign breast disease ; molecular forms of prostate-specific antigen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Although prostate-specific antigen (PSA) is the most valuable tumor marker for the diagnosis and management of prostate carcinoma, it is widely accepted that PSA is not prostate specific. Numerous studies have shown that PSA is present in some female hormonally regulated tissues, principally the breast and its secretions. In this review, we summarize the findings of PSA in the breast, and focus on its potential for clinical applications in breast disease. PSA is produced by the majority of breast tumors and is a favorable indicator of prognosis in breast cancer. Low levels of PSA are released into the female circulation, and while the level of serum PSA is elevated in both benign and malignant breast disease, the molecular form of circulating PSA differs between women with and without breast cancer. These findings indicate that PSA may have potential diagnostic utility in breast cancer. PSA may also have a clinical application in benign breast disease, as both the level and molecular form of PSA differ between Type I and II breast cysts. High levels of PSA have been reported in nipple aspirate fluid (NAF) and recent studies have shown that the concentration of PSA in NAF is inversely related to breast cancer risk, indicating that NAF PSA may represent a clinical tool for breast cancer risk assessment. Thus, PSA represents a marker with numerous potential clinical applications as a diagnostic and/or prognostic tool in breast disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006380306781
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  • 129
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    Results of two or five years of adjuvant tamoxifen correlated to steroid receptor and S-phase levels (2000)
    Springer
    Breast cancer research and treatment 59 (2000), S. 69-76 
    Details
    ISSN: 1573-7217
    Keywords: estrogen and progesterone receptor ; S-phase fraction ; tamoxifen ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A Swedish cooperative trial demonstrated that 5 years of adjuvant tamoxifen was more beneficial than 2 years of tamoxifen in the treatment of postmenopausal women with estrogen receptor (ER) positive, early stage, invasive breast cancer. The main aim of the present study was to investigate the importance of progesterone receptor (PgR) and ER concentration levels for patients participating in the trial and still distant recurrence free two years after the primary operation. Subgroup analyses revealed that only patients with ER positive and PgR positive breast cancer had improved distant recurrence free survival (DRFS) by prolonged tamoxifen therapy (p=0.0016). Patients with ER negative and PgR negative as well as ER positive and PgR negative tumors showed no significant effect of prolonged tamoxifen (p=0.53 and p=0.80, respectively). The percentage of ER negative and PgR positive breast cancers was too small (2.2%) for any meaningful subgroup analysis. There was a significant positive trend that the concentration level of PgR (high positive vs. low positive vs. negative) decreased the recurrence rate for those with prolonged therapy. No corresponding pattern was found for the ER content. S-phase fraction did not correlate to the recurrence rate of PgR positive breast cancers. Patients recurring during tamoxifen therapy had receptor negative tumors to a greater extent than those recurring after tamoxifen treatment. In conclusion, prolonged tamoxifen therapy for 5 years instead of 2 years was found to be beneficial for patients with ER positive and PgR positive breast cancer, whereas three extra years of tamoxifen had little or no effect for patients with ER positive but PgR negative tumors as well as for steroid receptor negative patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006332423620
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  • 130
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    Influence of chemically modified tetracyclines on proliferation, invasion and migration properties of MDA-MB-468 human breast cancer cells (2000)
    Springer
    Clinical & experimental metastasis 18 (2000), S. 139-146 
    Details
    ISSN: 1573-7276
    Keywords: BRCA1 ; breast cancer ; chemically modified tetracycline ; E-cadherin/catenin ; invasion ; migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Chemically modified tetracyclines (CMTs) are promising anti-cancer agents. In this study, we found that CMT-3 and CMT-8 showed dose-dependent cytotoxicities in MDA-MB-468 human breast cancer cells. Moreover, both CMT-3 and CMT-8 significantly inhibited in vitro cell migration and invasion at non-cytotoxic concentrations. Anti-invasion and migration potentials of the CMTs were associated with an increased expression of E-cadherin/catenins (α, β and γ-catenin) and tumor suppressor BRCA1. In addition, CMT-3 and CMT-8 abolished or reduced spontaneous and HGF/SF-induced cell invasion and migration in U-373 MG human glioblastoma cells. Our current finding is the first demonstration that CMT-3 and CMT-8 can activate the function of invasion suppressor molecules associated with the suppression of breast cancer cell invasion and migration. Thus, clinical application of CMTs may provide potential benefit for suppression of breast cancer growth, invasion and metastasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006732424102
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  • 131
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    Mannose 6-Phosphate/Insulin-Like Growth Factor 2 Receptor, a Bona Fide Tumor Suppressor Gene or Just a Promising Candidate? (2000)
    Springer
    Journal of mammary gland biology and neoplasia 5 (2000), S. 85-94 
    Details
    ISSN: 1573-7039
    Keywords: Mannose 6-phosphate/insulin-like growth factor 2 receptor ; tumor suppressor gene ; breast cancer ; loss of heterozygosity ; somatic mutation ; microsatellite instability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R)3 is considereda “candidate” tumor suppressor gene. This hypothesis has been provoked by the identificationof loss of heterozygosity (LOH) at the M6P/IGF2R locus on chromosome 6q26 in breast andliver cancer, accompanied by point mutations in the remaining allele. Somatic mutations incoding region microsatellites have also been described in replication error positive (RER+)tumors of the gastrointestinal tract, endometrium and brain. These genetic data are compelling,but a tumor suppressor gene candidate has to meet functional as well as genetic criteria. Thisreview weighs the evidence and discusses the observations that are necessary to promoteM6P/IGF2R from candidate to bona fide tumor suppressor gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009571417429
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    Mammary Cancer in Humans and Mice: A Tutorial for Comparative Pathology. The CD-ROM (2000)
    Springer
    Journal of mammary gland biology and neoplasia 5 (2000), S. 243-244 
    Details
    ISSN: 1573-7039
    Keywords: mouse mammary gland ; human breast ; oncogenes ; breast cancer ; CD-ROM ; histopathology ; ammary development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This article introduces a CD-ROM containing whole-mount and histological images of normal growth and development of both the mouse mammary gland and the human breast. It also covers nonneoplastic lesions and neoplasias in both species including a catalog of lesions in genetically engineered mice. Instructions, with examples, on techniques such as whole-mount preparation, immunohistochemistry, in situ hybridization, and common histological stains are provided. The images are based on full-scale 1996 × 1640 pixel images at 300 pixels/inch and are annotated. Every genetically engineered model has one or more accompanying citations. Tables are provided for orientation and organization. The CD includes zoom capabilities, a search engine, and a help mode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026451607575
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    Estrogen Metabolism as a Regulator of Estrogen Action in the Mammary Gland (2000)
    Springer
    Journal of mammary gland biology and neoplasia 5 (2000), S. 259-270 
    Details
    ISSN: 1573-7039
    Keywords: estrogens ; 17β-hydroxysteroid dehydrogenase (17HSD) ; mammary gland ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Estrogen action in the target cells is dependent on estrogen receptor activity and intracellular estrogen concentration, which, in turn, is affected by the serum concentration and local metabolism in these cells. During the reproductive years the main source of estrogens is the ovarian follicles, but in postmenopausal women most of the estrogens are formed in peripheral tissues. 17β-hydroxysteroid dehydrogenases (17HSDs)6 catalyze the reaction between 17β-hydroxysteroids and 17-ketosteroids, and several distinct 17HSD isoenzymes have been characterized. 17HSD type 1 catalyzes the reaction from low-activity estrone to high-activity estradiol. The type 2 enzyme has an opposite activity, thereby reducing the exposure of tissues to estrogen action. 17HSD type 1 is expressed both in steroidogenic tissues and in the target tissues of steroid action, such as normal and malignant breast tissue, where it may be responsible for maintaining the high intracellular estradiol concentration seen in breast cancer specimens. Therefore, 17HSD type 1 inhibitors may be useful in the treatment and/or prevention of estrogen-dependent malignancies, such as breast cancer. This article deals mainly with 17HSD types 1 and 2 and their role in estrogen action in breast tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009542710520
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    Estrogen Receptor Alpha in Human Breast Cancer: Occurrence and Significance (2000)
    Springer
    Journal of mammary gland biology and neoplasia 5 (2000), S. 271-281 
    Details
    ISSN: 1573-7039
    Keywords: breast cancer ; estrogen receptor ; endocrine therapies ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Estrogens have long been recognized as being important for stimulating the growth of a large proportion of breast cancers. Now it is recognized that estrogen action is mediated by two receptors, and the presence of estrogen receptor α (ERα)3 correlates with better prognosis and the likelihood of response to hormonal therapy. Over half of all breast cancers overexpress ERα and around 70% of these respond to anti-estrogen (for example tamoxifen) therapy. In addition, the presence of elevated levels of ERα in benign breast epithelium appears to indicate an increased risk of breast cancer, suggesting a role for ERα in breast cancer initiation, as well as progression. However, a proportion of ERα-positive tumors does not respond to endocrine therapy and the majority of those that do respond eventually become resistant. Most resistant tumors remain ERα-positive and frequently respond to alternative endocrine treatment, indicative of a continued role for ERα in breast cancer cell proliferation. The problem of resistance has resulted in the search for and the development of diverse hormonal therapies designed to inhibit ERα action, while research on the mechanisms which underlie resistance has shed light on the cellular mechanisms, other than ligand binding, which control ERα function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009594727358
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    Symptom Structure of PTSD Following Breast Cancer (2000)
    Springer
    Journal of traumatic stress 13 (2000), S. 301-319 
    Details
    ISSN: 1573-6598
    Keywords: PTSD ; breast cancer ; symptom structure ; confirmatory factor analysis ; PCL-C
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Abstract Identification of posttraumatic stress disorder (PTSD) symptoms and diagnoses in survivors of cancer is a growing area of research, but no published data exist regarding the symptom structure of PTSD in survivors of malignant disease. Findings from investigations of the PTSD symptom structure in other trauma populations have been inconsistent and have not been concordant with the reexperiencing, avoidance/numbing, and arousal symptom clusters specified in DSM-IV. The present study employed confirmatory factor analysis to evaluate the extent to which the implied second-order factor structure of PTSD was replicated in a sample of 142 breast cancer survivors. PTSD symptoms were measured using the PTSD Checklist—Civilian Version (PCL-C). Fit indices reflected a moderate fit of the symptom structure implied by the DSM-IV. These findings provide some tentative support for the DSM-IV clustering of PTSD symptoms and for the validity of cancer-related PTSD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007762812848
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    Knowledge About Genetic Risk for Breast Cancer and Perceptions of Genetic Testing in a Sociodemographically Diverse Sample (2000)
    Springer
    Journal of behavioral medicine 23 (2000), S. 15-36 
    Details
    ISSN: 1573-3521
    Keywords: genetic risk ; breast cancer ; knowledge ; genetic testing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Psychology
    Notes: Abstract Informed consent for genetic testing for breast–ovarian cancer susceptibility requires that women understand basic concepts about the inheritance of cancer susceptibility and the benefits and risks associated with genetic testing. Women awaiting routine medical services (N = 220) were surveyed about their knowledge of breast cancer and cancer genetics and their perceptions of genetic testing and personal risk. There were no racial differences in median income or mean level of education. Compared to Caucasian women, African American women knew significantly less about breast cancer and about genetic risk for breast cancer. African American women had different psychological, social, and economic concerns as evidenced by how they weighted the benefits and risks of genetic testing. This study is the first to assess several dimensions of informed consent for genetic testing among a sociodemographically diverse group. The findings should enable health professionals to target the African American and lower-income populations with the appropriate education and counseling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005416203239
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    Unrealistic Optimism and the Health Belief Model (2000)
    Springer
    Journal of behavioral medicine 23 (2000), S. 367-376 
    Details
    ISSN: 1573-3521
    Keywords: optimistic bias ; Health Belief Model ; breast cancer ; prostate cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Psychology
    Notes: Abstract Why do people fail to engage in positive behaviors which will promote their health and well-being? Researchers addressing this question adopt primarily one of two perspectives, drawing either on theories of health behavior, such as the Health Belief Model (HBM), or on theories of risk perception, such as unrealistic optimism. To overcome this compartmentalization, two studies of cancer screening behavior assessed the extent to which unrealistic optimism occurred in relation to each of the elements of the HBM: severity and curability of cancer and the benefits of, and barriers to, having a screening test. Data were collected using telephone interviews, dialing numbers randomly selected from the telephone directory. In the first study 164 women aged 50 to 70 years responded to questions about breast cancer and screening mammography, while in the second study 200 men aged 45 to 60 years responded to questions about prostate cancer and screening using the prostate specific antigen test. Women had an optimistic bias in relation to breast cancer risk and severity and barriers to having a screening mammogram but not in relation to the benefits of screening. For prostate cancer, there was an optimistic bias for all HBM variables: risk and severity of prostate cancer and barriers to and benefits of screening. It was concluded that unrealistic optimism is broader than perceived risk, being evident for all elements of the HBM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005500917875
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    Patient Motivation, Satisfaction, and Coping in Genetic Counseling and Testing for BRCA1 and BRCA2 (2000)
    Springer
    Journal of genetic counseling 9 (2000), S. 219-235 
    Details
    ISSN: 1573-3599
    Keywords: BRCA1 ; motivation ; satisfaction ; coping, genetic counseling ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Psychology
    Notes: Abstract Women with a strong family history of breast and/or ovarian cancer can now have genetic testing, that may identify mutations associated with increased cancer predisposition. Within the context of a clinical trial evaluating printed educational materials, we examined motivation, satisfaction, coping, and perceptions of genetic counseling and testing among 159 women who underwent pretest counseling and made a testing decision. Ninety-six percent of the participants elected to have BRCA1/2 testing. When making a decision about genetic testing, study participants were concerned less about the potential negative effects that could result from testing than the potential benefits. After counseling, participants said that they felt better able to make decisions that were right for them and that their questions and concerns were adequately addressed during the session. Ninety-five percent of the women were satisfied with their test decision. Participants used a range of strategies to cope with thoughts and feelings about cancer and/or genetic testing immediately following test decision. Results suggest that the genetic counseling session helped women make decisions about testing for BRCA1 and BRCA2, even in the setting of a trial in which all women also received detailed educational materials. Further, the results indicate that future research focusing on perceptions of risks and benefits of testing and of coping strategies immediately following test decision may be warranted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009463905057
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    Breast Cancer in Men: Emasculation by Association? (2000)
    Springer
    Journal of clinical psychology in medical settings 7 (2000), S. 91-97 
    Details
    ISSN: 1573-3572
    Keywords: breast cancer ; breast cancer in men ; male breast carcinoma ; breast cancer treatment ; psychological effects of cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The occurrence of breast cancer in men is rare in comparison to women. Public knowledge that men can get breast cancer and of male breast self-examination are lacking. Research in the course and treatment of breast cancer in men is needed. Men generally present in more advanced stages of breast cancer than women, and have a poorer prognosis. In this article, the epidemiology, common symptoms, diagnostic methods, and current treatment of breast cancer in men are described. Gender differences in presentation and course of illness are discussed. Additionally, the psychological implications of breast cancer for male gender roles and masculine identity are explored. Directions for further investigation are given. Treatment providers are encouraged to educate themselves and their male patients on breast cancer in men and male breast examination techniques so that this disease may be identified earlier in its course and survival rates improved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009553613564
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    Adolescent Daughters of Mothers with Breast Cancer: Impact and Implications (2000)
    Springer
    Clinical social work journal 28 (2000), S. 183-195 
    Details
    ISSN: 1573-3343
    Keywords: adolescent ; mother ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract While the literature supports the view that a parent's illness will have an impact on a child, less specific attention has been given to the impact of a mother's breast cancer on her adolescent daughter. In this paper, clinical vignettes derived from interviews with adolescent daughters (ages 12–19) living with mothers who have breast cancer are presented to illustrate some of the concerns daughters have about themselves and their mother's illness. The daughters express anxiety about changes in family roles, but seem more concerned about the potential loss of the mother/daughter relationship. They describe their fears of recurrence of the disease as well as getting the disease themselves. The girls also demonstrate great strength; resilience and hope in the face of the challenges presented by the changes in their lives. Girls who had mothers die of the disease are not included in this article. Implications for treatment are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005106301713
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    Triphenylpyrylium Tetrafluoroborate-Sensitized Photochemistry of the Terpenes Sabinene, α-Phellandrene, and α- and γ-Terpinene (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1563-1567 
    Details
    ISSN: 1434-193X
    Keywords: Triplet recombination ; Electron transfer ; Radical ions ; Photochemistry ; Terpenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The triphenypyrylium tetrafluoroborate (TPT)-sensitized reactions of several terpene donor molecules, including sabinene (1), α-phellandrene (4), α-terpinene (5) and γ-terpinene (6) give rise to significantly different products than reactions induced by other electron-transfer sensitizers, such as 1,4-dicyanobenzene (DCB). The divergent reactions require decidedly different key intermediates; the products obtained with TPT can be explained by dissociative recombination of the intermediate radical-radical cation pair in the triplet state, generating donor-derived biradicals.
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    Ring Expansion of 2-Alkylidenedihydroquinazolines to Iminodihydro-1,4-benzodiazepines by Methanesulfonyl and Trifluoromethanesulfonyl Azide (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1577-1587 
    Details
    ISSN: 1434-193X
    Keywords: Azides ; Cleavage reactions ; Cycloadditions ; Nitrogen heterocycles ; Polycycles ; Ring expansion ; Synthetic methods ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---2-Alkyl-1-methylquinazolinium hexafluorophosphates 9 are deprotonated by sodium or potassium hydride to afford solutions of 2-alkylidenedihydroquinazolines 10, which were investigated by NMR spectroscopy. Trapping with methanesulfonyl azide (5a) of 10 in situ or subsequent treatment with trifluoromethanesulfonyl azide (5b) gives mixtures of colourless (15) and intensely yellow N-sulfonylimino-1,4-benzodiazepines 16 along with products due to cleavage of the exocyclic double bond of 10, viz. 11 and 13. The ethylidene compound 10b yields the bicyclic products 18 and 19, apparently by complex sequences of reactions that are triggered by removal of the acidic proton at C-2 of 16b and 16f. The structures of the products are based on spectroscopic evidence and X-ray diffraction analyses performed on 15b, 16d, 16e, and 19.
    Additional Material: 6 Ill.
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    Electrophilic Reactivity of a 2-Azaallenium and of a 2-Azaallylium Ion (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1589-1593 
    Details
    ISSN: 1434-193X
    Keywords: Azaallenium ions ; Azaallylium ions ; Iminium ion ; Kinetics ; Linear Free Energy Relationships ; Ab initio calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The rate constants for the reactions of the 2-azaallenium ion 1b+, the 2-azaallylium ion 2a+ and the iminium ion 3+ with different nucleophiles were determined by 1H NMR spectroscopy. By correlation with the Linear Free Enthalpy Relationship (LFER) lg k20°C = s (E + N), developed by Mayr and Patz, the electrophilicity parameters E(1b+) = -3.7, E(2a+) ≍ -16 and E(3+) = -10.43 were obtained. They show that the relative reactivities of these ions are approximately 1012:1:106. Quantum chemical calculations (ab initio, DFT) of the methyl anion affinities for the ions 1b+,2a+ and3+ are in agreement with the experimental E values. The X-ray structure of 3+·CF3SO3- is reported for the first time; it shows no strong interaction between the cation and the anion.
    Additional Material: 2 Ill.
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    Oxazoline N-Oxide Mediated [3+2] Cycloadditions: Application to a Formal Synthesis of a (+)-β-Methylcarbapenem (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1595-1601 
    Details
    ISSN: 1434-193X
    Keywords: Oxazoline N-oxide ; Cycloadditions ; Cycloadditions ; Lactams ; Thienamycin ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---[3+2] Cycloaddition between a camphor-derived oxazoline N-oxide 9 and the γ,δ-unsaturated enamino ester 11 afforded the single adduct 6. A stereoselective reduction of the enamino ester side chain allowed the control of the absolute configuration of the two additional asymmetric centres. Nitrogen protection and oxidative hydrolysis of the resulting product 13, followed by further functional group manipulations, led to the β-lactam derivative 1, a known precursor of the β-methylthienamycin derivative2a.
    Additional Material: 1 Ill.
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    A New Substitution Pattern in Subphthalocyanines: Regioselective Synthesis and Separation of “ortho” Derivatives (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1603-1607 
    Details
    ISSN: 1434-193X
    Keywords: Boron ; Cyclotrimerizations ; Nitrogen heterocycles ; Macrocycles ; Subphthalocyanines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The regioselective preparation of ortho-substituted subphthalocyanides was achieved employing 3-substituted phthalonitrile derivatives as starting materials. A mechanistic proposal has been outlined.Supporting information for this article is available on the WWW under //http://www.wiley-vch.de/contents/jc_2046/2000/99525_s.pdf or from the author.
    Additional Material: 2 Ill.
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    A New Route to 2,7- and 7-Functionalized Labdanes (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1609-1615 
    Details
    ISSN: 1434-193X
    Keywords: Terpenoids ; Natural products ; Total synthesis ; Cyclizations ; Rearrangements ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new route for the synthesis of 2,7- and 7-functionalized labdanes starts from (R)-carvone (1). 11-Nordrim-7-en-9-one (15) is an appropriate starting material for the total synthesis of hispanone (21), a biologically active furolabdane isolated from the Mediterranean medicinal plant Ballota saxatilis.
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    Preparation of Kingiside from Aucubin (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1623-1626 
    Details
    ISSN: 1434-193X
    Keywords: Iridoid glucoside ; (8S)-Kingiside ; (8S)-Loganin ; (8S)-7-Ketologanin ; Asymmetric synthesis ; Natural products ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The tetraacetyl derivative 8 of the naturally occurring kingiside (8a) was prepared from aucubin (1). Intermediates in the synthesis were (8S)-tetraacetyl loganin (6) and (8S)-tetraacetyl-7-ketologanin (7), whose free (8R)-epimers occur in many different plants (Caprifoliaceae, Loganiaceae). The 13C NMR spectrum allows the structure to be unequivocally identified.
    Additional Material: 1 Tab.
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    Isomeric Tetrakis(dimethylamino)naphthalenes: Syntheses, Structure-Dependence of Basicities, Crystal Structures, and Physical Properties (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1617-1622 
    Details
    ISSN: 1434-193X
    Keywords: Tetrakis(dimethylamino)naphthalenes ; Basicity ; Hydrogen bonds ; Cyclicvoltammetry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---For comparison to the recently described 2,3,6,7-tetrakis(dimethylamino)naphthalene (1) the three isomers 2,3, and 4 were synthesized. The basicities of this group of isomers are strongly dependent upon the different mutual orientations of the pairs of dimethylamino substituents: only the isomers 3 and, partially, 4, both with dimethylamino groups in adjacent peri-positions of the naphthalene, are strong “proton sponges”. For the isomers 1 and 2 with the same number and kind of twofold dimethylamino substituents in neighbouring ortho-positions, however, no significant basicity increase is observed. To explain this difference between the two groups of isomers it is suggested that in the ortho-pairs of 1 and 2 the C-N bonds diverge considerably, leading to an increased N···N distance and consequently to less stable [N···H···N]+ hydrogen bonds in contrast to the parallel C-N bonds in the peri-substituted isomers 3 and 4. X-ray crystal structure analyses of the bases and of some of the salts derived therefrom were solved and are discussed. Cyclic voltammetry indicates that 1 to 4 are strong electron donors, reacting easily to radical cations or dications which with suitable acids have been obtained as salts.
    Additional Material: 3 Ill.
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    Ring Closure Reactions of Disubstituted 4-Penten-1-oxyl Radicals - Towards a Stereoselective Synthesis of allo-Muscarine (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1677-1683 
    Details
    ISSN: 1434-193X
    Keywords: Radicals ; Cyclizations ; Pyridinethione ; Tetrahydrofurans ; Asymmetric synthesis ; Thiazolethione ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The trisubstituted functionalized tetrahydrofurans 10, 11, 16, 18, and 19 were photochemically prepared from 2,3-syn- and 2,3-anti-configuredN-(3-benzoyloxy-5-hexen-2-oxy)thiazole-2(3H)-thione anti-6, pyridinethiones 7, anti-8, and BrCCl3. The formation of tetrahydrofurans was achieved by an efficient and highly regioselective alkoxyl radical cyclization (5-exo-trig). The 2,3-anti substituted intermediates 9 and 12 cyclize stereoselectively whereas a 2,3-syn-configured O-radical affords both possible diastereomeric addition products in equal amounts. The cyclized tetrahydrofuryl methyl radicals were trapped with the bromine atom donor BrCCl3 to afford the bromomethyl-substituted cyclic ethers 10, 11, 18, and 19 in excellent yields. The utility of this reaction was stressed by conversion of one of the newly prepared tetrahydrofurans in a two-step synthesis into (+)-allo-muscarine (+)-20.Supporting information for this article is available on the WWW under //http://www.wiley-vch.de/contents/jc_2046/2000/99590_s.pdf or from the author.
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    The Formation of 1,3-Dithiolanes from Aromatic Thioketones and Diazomethane - The Mechanism of the Schönberg Reaction (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1685-1694 
    Details
    ISSN: 1434-193X
    Keywords: Thioketones ; Thiocarbonyl ylides ; Cycloadditions ; Cycloreversions ; Sulfur heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Reactions of diaryl thioketones with diazomethane at room temperature afford 4,4,5,5-tetraaryl-1,3-dithiolanes; the scope of this surprising 2:1 interaction has been studied for decades (Schönberg Reaction). The clue to the mechanism was our observation that the stoichiometry is 1:1 at -78 °C, and 2,5-dihydro-2,2-diaryl-1,3,4-thiadiazoles are formed as primary [2+3] cycloadducts. They lose N2 at -45 °C in first-order reactions generating diaryl thioketone S-methylides which can be intercepted by thioketones (→1,3-dithiolanes), multiple CC bonds, or acids HX. In the absence of trapping reagents, the elusive intermediates either dimerize furnishing 2,2,3,3-tetraaryl-1,4-dithianes or give rise to 2,2-diarylthiiranes by electrocyclization. Beyond thiobenzophenone and diazomethane, our main model reaction, the studies involve fluorene-9-thione, 4,4-dimethoxy- and 4,4-dichlorothiobenzophenone. The ring of 2,5-dihydro-2,2-diphenyl-1,3,4-thiadiazole (8) is opened by LDA at -78 °C and derivatives of anion 12 are obtained. - In summa: The Schönberg reaction consists of two 1,3-dipolar cycloadditions, linked by a 1,3-dipolar cycloreversion.
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    New Boronic-Acid- and Boronate-Substituted Aromatic Compounds as Precursors of Fluoride-Responsive Conjugated Polymer Films (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1703-1710 
    Details
    ISSN: 1434-193X
    Keywords: Conjugation ; Boron ; Sensors ; Cyclic voltammetry ; Polymers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---New electropolymerizable aromatic compounds (i.e. pyrrole, thiophene, aniline) bearing boronic acid and ester substituents have been synthesized and their electrochemical behavior has been investigated. Functionalized polythiophene and polypyrrole films could be anodically generated in acetonitrile, whereas the polyaniline derivative was electroformed in an acidic aqueous solution. The electrochemical responses of some of these materials were changed when fluoride ions were added to the electrolytic solutions. The strongest modifications, caused by binding of fluoride by the immobilized boron, were observed for the polypyrrole derivative in hydroorganic media.
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    The Effect of the Carbon Ligand on the Reaction of Organozinc Reagents in the Synthesis of Substituted 2,5-Dihydrofurans: A Rare Example of An Uncatalysed Allylic-Substitution Reaction Involving Alkyl Zinc Halides (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1711-1718 
    Details
    ISSN: 1434-193X
    Keywords: Heterocycles ; Zinc ; Palladium ; Catalysts ; Sulfur ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Organozinc halides derived from Grignard reagents behave differently in their reaction with ethyl (±±)-(2RS,3SR)-tetrahydro-4-methylene-2-phenyl-3-(phenylsulfonyl)furan-3-carboxylate (3) according to the hybridisation of the carbon ligand. During the development of short multi-component reactions for the synthesis of diverse functionalized ethyl 2,5-dihydrofuran-3-carboxylates it was discovered that aryl and vinyl zinc halides undergo clean reaction with 3 in the presence of Pd(PPh3)4. In contrast, when alkyl zinc halides are reacted with 3 in the presence of Pd(PPh3)4, reductive desulfonation of 3 is observed. Remarkably, in the absence of a transition metal catalyst, the allylic substitution of 3 with alkyl zinc halides proceeds cleanly and in moderate to good yield.
    Additional Material: 2 Ill.
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  • 153
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    Stable Heterotopic Noncovalent Resorcin[4]arene Assemblies (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1727-1734 
    Details
    ISSN: 1434-193X
    Keywords: Self-assembly ; Vapor-pressure osmometry ; Resorcin[4]arenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Resorcin[4]arene tetracarboxylic acids 5,6 (A) and resorcin[4]arene tetrapyridines 2,3 (P) self-assemble in chloroform solution to form stable heterotopic AP dimers. Data from NMR titration and dilution experiments, as well as from vapor-pressure osmometry (VPO), indicate that the AP dimer is formed with an association constant greater than 107 M-1. Solid-solution extraction experiments are indicative of the formation of a 2:1 trimer (A2P), while self-associated homotopic species (A2 and A3) can be detected by NMR and VPO. Analysis of the heterotopic noncovalent assembly process over a range of compositions shows that these other species are much less stable than the AP heterodimer, which is the exclusive species at an A/P concentration ratio of 1:1 (〉 99.7% of the total at 10 mM).
    Additional Material: 6 Ill.
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  • 154
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    The LiClO4-Mediated Synthesis of β-(Dialkylamino) Sulfoxides and β-(Dialkylamino) Sulfones by Addition of α-Lithiated Salts of Sulfoxides and Sulfones to Aldehydes and (Trimethylsilyl)dialkylamines (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1735-1739 
    Details
    ISSN: 1434-193X
    Keywords: Sulfoxides ; β-Amino sulfones ; Mannich type reaction ; Lithium perchlorate ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The LiClO4-mediated one-pot reaction of aldehydes with (trimethylsilyl)dialkyl amines and the lithium salt of sulfoxides or sulfones, affords the corresponding β-(dialkylamino) sulfoxides and β-(dialkylamino) sulfones in high yields. The aminosulfoxidation reaction of aliphatic or aromatic aldehydes lacks diastereoselectivity, but the diastereomeric sulfoxides can be separated by HPLC or column chromatography for further use.
    Additional Material: 1 Ill.
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  • 155
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    Electronic Resource
    Synthesis of Heptano Bridged Pyranoside Derivatives (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1741-1744 
    Details
    ISSN: 1434-193X
    Keywords: Bridged pyranose derivatives ; Ring enlargement ; Carbenes ; Glycosides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Addition of dichlorocarbene to the glycal (±±)-2 followed by cyclopropyl-allyl rearrangement leads to the chloro-2H-pyran (±±)-4. Oxidation of (±±)-4 and reduction of the obtained hydroxypyranone (±±)-5 gave the methyl pyranoside (±±)-6. The relative configuration of (±±)-6 was established by X-ray structural analysis of the corresponding acetate (±±)-7. The synthesis of the optically active starting materials (+)-2 and (-)-2 is also reported.
    Additional Material: 1 Ill.
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  • 156
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    Sialyltransferase Inhibitors Based on CMP-Quinic Acid (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1745-1758 
    Details
    ISSN: 1434-193X
    Keywords: CMP-Neu5Ac analogues ; Enzyme inhibitors ; Substrate analogues ; Transition state analogues ; Transferases ; Carbohydrates ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Quinic acid was transformed into phosphitamides 16, 25, and 36, which could be readily linked to 5′-O-unprotected cytidine derivative 17. Ensuing oxidation of the obtained phosphite triesters with tBuO2H and hydrogenolytic de-O-benzylation furnished the corresponding phosphate diesters 18, 26, and 38. Base catalyzed removal of acetyl protecting groups, and methyl ester hydrolysis furnished CMP-Neu5Ac analogues 1d, 1e, and 2. Quinic acid was also transformed into 1,2-unsaturated diallyl α-hydroxymethyl-phosphate derivatives (R)- and (S)-46, which on reaction with cytidine phosphitamide 47 afforded the phosphite triesters. Subsequent oxidation with tBuO2H and then treatment with NEt3 gave phosphate diester derivatives (R)- and (S)-48. Deallylation, acetyl group removal, and methyl ester hydrolysis furnished (R)- and (S)-3, respectively. Treatment of (R)- and (S)-48 with DBU as a base led to acetic acid elimination, thus yielding, after de-O-allylation, acetyl group cleavage, and ester hydrolysis, diene derivative (E)-4. Donor substrate analogues 1d and 1e exhibited good α(2-6)-sialyltransferase inhibition (Ki: 2.0·10-4 and 2.0·10-5 M). However, transition state analogues (R)-, and particularly (S)-3 showed excellent inhibition properties (Ki: 1.6·10-6 and 2.7·10-7 M).
    Additional Material: 1 Tab.
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  • 157
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    Synthesis and α-Mannosidase Inhibitory Activity of Three Deoxy Derivatives of Mannostatin A (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1759-1765 
    Details
    ISSN: 1434-193X
    Keywords: Cyclitols ; Aminocyclitols ; Glycosidase inhibitors ; α-Mannosidase inhibitors ; Deoxygenation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Three deoxy derivatives 2-4 of the α-mannosidase inhibitor mannostatin A (1) were synthesized, and their inhibition of Jack bean α-mannosidase was evaluated in order to elucidate the roles of each of the three hydroxyl groups of the inhibitor. The 1- and 2-deoxy derivatives 2 and 3 retained some inhibitory activity, although reduced by a factor of about 100 relative to the parent, whereas it was completely lost with the 3-deoxy derivative 4. Structure and activity relationships are discussed in the light of these findings.
    Additional Material: 1 Tab.
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  • 158
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    A Circular Dichroism Approach to the Conformation of 1-Arylethylamino-Substituted 1,3,5-Triazine Derivatives (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1767-1772 
    Details
    ISSN: 1434-193X
    Keywords: Circular dichroism ; Conformation analysis ; s-Triazines ; Chiral auxiliaries ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---CD data of the optically pure 2-[(R)-1-(9-anthryl)ethylamino]-4-chloro-6-[(R)-1-(1-naphthyl)ethylamino]-1,3,5-triazine, 2[(R)-1-(9-anthryl)ethylamino]-4,6-bis[(R)-1-(1-naphthyl)ethylamino]-1,3,5-triazine, 2,4-bis[(R)-1-(9-anthryl)ethylamino]-6-chloro-1,3,5-triazine are presented. The analysis of the CD spectra by means of the nonempirical DeVoe approach has afforded the complete conformational characterisation of the three s-triazine derivatives, allowing us to establish how the conformation of these derivatives depends on the nature of the substituent 1-arylethylamino groups.
    Additional Material: 6 Ill.
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  • 159
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    α,β-Unsaturated Fischer Carbene Complexes vs. 1,3-Dipoles: Reactions with Nitrones and Nitrilimines (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1773-1783 
    Details
    ISSN: 1434-193X
    Keywords: Cycloadditions ; Carbenes ; Nitrones ; Nitrilimines ; Pyrazolines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The reaction of tert-butylalkynyl chromium Fischer carbene complex 1 with nitrones 2 affords β-enamino-ketoaldehydes 4 by the light-promoted rearrangement of the corresponding [3+2] cycloadduct carbene complexes 3. On the other hand, [3+2] cycloaddition of chiral nonracemic Fischer alkenyl carbene complexes 19 with nitrilimines 10 yields enantiomerically pure Δ2-pyrazolines with high regio- and diastereoselectivity.
    Additional Material: 3 Ill.
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  • 160
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    Increasing Enantioselectivities and Reactivities by Stereochemical Tuning: Fenchone-Based Catalysts in Dialkylzinc Additions to Benzaldehyde (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1785-1792 
    Details
    ISSN: 1434-193X
    Keywords: Asymmetric synthesis ; Zinc ; Transition structures ; QM/MM computations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Trimethylsilyl substitutions of the fenchyl alcohols [(1R,2R,4S)-exo-(2-Ar)-1,3,3-trimethylbicyclo[2.2.1]heptan-2-ol, Ar = 2-methoxyphenyl (1) and Ar = 2-(dimethylaminomethyl)phenyl (2)] yield the chiral ligands 3 [Ar = 2-methoxy-3-(trimethylsilyl)phenyl] and 4 [Ar = 2-(dimethylaminomethyl)3-(trimethylsilyl)phenyl]. Increased reactivities and enantioselectivities in diethylzinc additions to benzaldehyde are obtained from 3 (63% ee R) and 4 (93% ee S), relative to 1 (26% ee S) and 2 (73% ee S). X-ray crystal structures of 3 and of its methylzinc complex 3-Zn reveal out-of-plane bending of the methoxy groups as major geometrical consequences of the trimethylsilyl substitutions. Analyses of QM/MM ONIOM μ-O transition-structure models for 1, 2, 3, and 4 show that trimethylsilyl-induced distortions of methoxy and of dimethylaminomethyl groups explain the observed increased enantioselectivities.
    Additional Material: 10 Ill.
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  • 161
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    Evidence of Formation of an exo-π-Allyl Complex Intermediate in the Pd0-Catalyzed Alkylation of a Bicyclic Allylic Diacetate with Stabilized Carbon Nucleophiles (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1799-1803 
    Details
    ISSN: 1434-193X
    Keywords: Palladium ; exo-π-Allylpalladium complexes ; Allylic alkylation ; Spiro compounds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The palladium(0)-catalyzed alkylation of 2,3-bis(acetoxymethyl)bicyclo[2.2.1]hepta-2,5-diene 1 with malonate-type enolates as nucleophiles is investigated. A monoalkylated product is formed first, and undergoes (depending on the nucleophile used) a second intramolecular reaction leading to spirocyclopropane-annulated bicyclo[2.2.1]heptene derivatives 5. The formation of endo spirobicyclic cyclopropanes adducts as major isomer is rationalized by assuming formation of an intermediate exo-(π-allyl)palladium complex.
    Additional Material: 2 Ill.
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  • 162
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    Reductions of α,β-Unsaturated Ketones by NaBH4 or NaBH4 + CoCl2: Selectivity Control by Water or by Aqueous Micellar Solutions (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1793-1797 
    Details
    ISSN: 1434-193X
    Keywords: Ketones ; Reductions ; Micelles ; Cobalt ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Operationally simple and environmentally benign procedures have been developed to selectively reduce different α,β-unsaturated ketones, 4,4-dimethylcyclohex-2-ene-1-one (1), isophorone (2), benzylideneacetone (3), chalcone (4) by NaBH4 or by the system NaBH4 + CoCl2. Alternative reaction media to the extensively used MeOH have been explored, and new procedures take advantage of the acceleration and chemoselectivity induced by water or by aqueous micellar solutions. It was possible to selectively and quantitatively afford pure products of 1,2 and of 1,4 reduction as well as the totally reduced compounds (yield and selectivity 〉 90%) by simple changes in the experimental conditions.
    Additional Material: 4 Ill.
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  • 163
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    Conformational Behavior of C-Glycosyl Analogues of Sialyl-α-(2→3)-Galactose (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1805-1813 
    Details
    ISSN: 1434-193X
    Keywords: C-Glycosides ; Conformation analysis ; Molecular dynamics ; Selectins ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The conformational behavior of the C-glycosyl analogue of sialyl-α-(2→3)-galactose, synthesized as a glycosidase inhibitor, has been studied using a combination of NMR spectroscopy (J and NOE data) and molecular dynamics calculations. The obtained results show that the population distribution of conformers with respect to the orientation about the pseudo-glycosidic linkages is mainly controlled by steric interactions. This is in contrast to findings made for O-glycosides. In these natural compounds, the conformational behavior about the glycosidic linkage Φ is mainly governed by the exo-anomeric effect.
    Additional Material: 5 Ill.
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  • 164
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    Enantioselective Preparation of 2,4-Disubstituted Azetidines (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1815-1820 
    Details
    ISSN: 1434-193X
    Keywords: Asymmetric synthesis ; Palladium-catalysed couplings ; Palladacycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Chiral C2-symmetric N-benzylazetidines have been conveniently prepared from optically pure anti-1,3-diols without loss of enantiomeric purity. N-Debenzylation led to the corresponding N-unsubstituted azetidines, which were then subjected to palladium-catalysed coupling reactions with aryl bromides to afford chiral N-arylazetidines. (R,R)-N-Benzyl-2,4-dimethylazetidine has been employed in the synthesis of a new cyclopalladated complex, which can be used, for instance, as a chiral recognition agent for phosphorus ligands.
    Additional Material: 1 Tab.
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  • 165
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    Deoxyhydantocidin: Synthesis by Base-Catalyzed Spiro Cyclization and Interconversion with the 1′-Epimer (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1831-1840 
    Details
    ISSN: 1434-193X
    Keywords: Cyclizations ; Spiro compounds ; Nucleosides ; Isomerizations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Syntheses of the spiro nucleosides 2′-deoxyhydantocidin 3a and its 1′-epimer 3b are described. The newly developed route involves a Horner-Wadsworth-Emmons condensation of the phosphonate 16 with the erythrose derivative 15 affording a mixture of six isomers which was fully assigned by NMR spectroscopy. The mixture was directly converted into the final compounds in an efficient base-catalyzed cyclization reaction. A base-catalyzed interconversion between the two isomers was observed.
    Additional Material: 2 Ill.
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  • 166
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    1-Alkyl- and Azeto[1,2-a][1,5]benzodiazepine Derivatives in the Reaction of o-Phenylenediamine with 3-(Dimethylamino)propiophenones (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1973-1976 
    Details
    ISSN: 1434-193X
    Keywords: Benzodiazepines ; Heterocycles ; Azeto[1,2-a]-1,5-benzodiazepines ; Cyclizations ; Cycloadditions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The reaction of o-phenylenediamine (4) with one, two or three equivalents of p-substituted 3-dimethylaminopropiophenone hydrochlorides 5a-e was studied. 4-Aryl-2,3-dihydro-1H-1,5-benzodiazepine derivatives 6a-e were obtained in good yields, along with the 1:2-adducts 7c-e and the unexpected 1:3-adducts rac-8c-e. The type of adduct formed is determined by the molar ratio of the reactants 4 and 5 and by the nature of the substituent in the para position of the propiophenone 5.
    Additional Material: 1 Ill.
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  • 167
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    Synthesis of Benzotri(benzonorbornadienes) (BTBNDs): Rigid, Cup-Shaped Molecules with High Electron Density within the Cavity (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1965-1971 
    Details
    ISSN: 1434-193X
    Keywords: Cup-shaped PAHs ; Host-guest compounds ; Host-guest chemistry ; Cyclizations ; Semiempirical calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Cyclotrimerisation of benzo-polycyclic bromostannylalkenes 8a-d with Cu(NO3)2·3H2O in THF affords benzotri(benzonorbornadienes) 3a-d as a mixture of the syn and anti isomers. The ratio of syn to anti is close to the 1:3 statistical value in most cases (i.e. in cyclotrimers 3a,b,d), but highly in favour of the anti isomer in 3c, where steric hindrance by the methoxy groups plays an important role in the stereochemistry of the cyclotrimerisation. The substrates for the cyclotrimerisation, i.e. the bromostannyl alkenes 8a-d, were prepared from bromoalkenes 7a-d by treatment with base (LDA) and quenching with trimethyltin chloride. In turn, bromoalkenes 7a-d were prepared from alkenes 5a-d by radical bromination-elimination. The reaction conditions used were designed to minimise Wagner-Meerwein rearrangements that would lead to unwanted bromo isomers. The cup-shaped syn cyclotrimers 3a-d exhibit high electron density within the cavity as determined by AM1 semiempirical calculations of their electrostatic potential surfaces and are valuable substrates for supramolecular chemistry. As an example, it is shown that fullerene C60 is drawn into solution in acetonitrile by complexation with both the syn and anti trimer of benzonorbornadiene 3a.
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  • 168
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    Uncovering Reaction Pathways of 1-Aminocyclohexenes with [(1-Alkynyl)carbene]tungsten Complexes Leading to Cyclopentadienes and Dihydropyrroles (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 37-49 
    Details
    ISSN: 1434-193X
    Keywords: Carbene complexes ; Enamines ; Metallatrienes ; Cyclopentadienes ; Dihydropyrroles ; spiro-Tetrahydropyrroles ; Iminium carbonylmetalates ; Dimetallapolyenes ; Tungsten ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Reactions of the [(1-alkynyl)carbene]tungsten complex (CO)5W=C(OEt)C≡CPh (1) with 1-aminocyclohexenes 2a-c and 7a-c afford different types of products depending on the amino substituents and the reaction conditions. (4-Aminocyclobutenyl)carbene complexes B have been shown to be generated in the first reaction step through a [2+2] cycloaddition. These are key intermediates and afford cross-conjugated tungstatrienes E, (conjugated) 1-tungsta-1,3,5-hexatrienes G, or (non-conjugated) 1-tungsta-1,3,6-heptatrienes F by following competing reaction pathways. Cross-conjugated 1-tungstatrienes 3 have been isolated in 52-74% yield by performing the reactions of 1-aminobenzocyclohexenes 2a-c with compound 1 in pentane. In dichloromethane instead of pentane, (conjugated) 1-tungsta-1,3,5-hexatrienes 4 are obtained, which subse-quently undergo fragmentation to give cyclopentadienes 6 (by π-cyclization) and dihydropyrroles (by α-cyclization) in a molar ratio dependent on the nature of the amino substituents. (Non-conjugated) 1-tungsta-1,3,6-heptatrienes 10 are generated upon reaction of 1-aminocyclohexenes 7a-c with compounds 1, which are transformed into cyclopentadienes 12 via conjugated 1-tungsta-1,3,5-hexatrienes 9 as intermediates. Reactions of 1-tungsta-1,3,6-heptatrienes 10 with the (1-alkynyl)carbene complex 1 afford dinuclear compounds 14, which subsequently yield indenes 15 (by two successive π-cyclization steps) and spiro-tetrahydropyrroles 16 (by both a π-cyclization and an α-cyclization step), depending on the steric bulk of the amino substituent.
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  • 169
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    Mechanism and Extensibility of the Reaction (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 99-104 
    Details
    ISSN: 1434-193X
    Keywords: Allyl alcohols ; Organocerium reagents ; Alkenes ; Addition reactions ; Cerium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Alkylcerium reagents add to the multiple bonds of allyl and propargyl alcohols in good yields and under mild conditions. The double bond can be reduced with lithium aluminum hydride in the presence of cerium trichloride. The regiochemistry of the attack depends on electronic factors.
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  • 170
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    (S)-Pyroglutamic Acid, (S)-Malic Acid, and (S)-Serine as Useful Starting Materials in the Synthesis of Enantiopure Hydroxyamidines (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 115-124 
    Details
    ISSN: 1434-193X
    Keywords: Amidines ; Chiral bases ; N-Acyliminium ions ; Enantioselective catalysis ; Chiral pool ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The synthesis of four enantiopure hydroxyamidines is described. One amidine was obtained from (S)-pyroglutamic acid. Its key step involved the addition of phenylmagnesium bromide to the corresponding ester, affording the tertiary alcohol without detectable racemization. The second amidine was obtained by coupling of an (S)-malic acid derived N-acyliminium ion with β-naphthol. The other amidines were obtained from an (S)-serine-derived imide which was reduced to two diastereomeric lactams that were eventually transformed into the corresponding amidines.
    Additional Material: 1 Ill.
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  • 171
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    Efficient Preparation of a Highly Strained Eleven-Membered Ring (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 155-163 
    Details
    ISSN: 1434-193X
    Keywords: Macrocycles ; Cyclizations ; Strained compounds ; Ketophosphonate ; Iodoalkyne ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Two strategies have been explored to build the highly strained eleven-membered ring 2, a potential precursor for the biosynthetic key intermediate of the protoilludane family: an intramolecular Horner-Wadsworth-Emmons olefination and an intramolecular Nozaki-Hiyama-Kishi type-ring closure.
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  • 172
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    Neutral Anion Receptors with Multiple Urea-Binding Sites (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 165-170 
    Details
    ISSN: 1434-193X
    Keywords: Neutral anion receptor ; Hydrogen bonds ; Urea moieties ; Donor-acceptor systems ; Macrocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The synthesis of macrocyclic and acyclic cleft-like anion receptors in which four hydrogen bond donating urea moieties are present in a preorganized fashion is described. NMR spectroscopy shows the complex formation with H2PO4- and Cl -. Cleft-like receptors bind H2PO4- in a 2:1 guest-host stoichiometry (Ka = 107M-2) in DMSO, whereas Cl - is bound in a 1:1 stoichiometry (Ka = 103M-1). The macrocyclic receptors form a 1:1 complex with H2PO4- (Ka = 103M-1 in DMSO) with a 100-fold selectivity for H2PO4- over Cl -.
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  • 173
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    Hydroxylation and Amination of Azulenes by Vicarious Nucleophilic Substitution of Hydrogen (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 193-198 
    Details
    ISSN: 1434-193X
    Keywords: Nucleophilic substitutions ; Azulenes ; Hydroxylation ; Amination ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Hydroxylation of azulenes with tert-butylhydroperoxide proceeds efficiently at the 6-position when the former contain electron-withdrawing substituents in the five-membered ring. Similarly, VNS amination of azulenes proceeds with 4-amino-1,2,4-triazole; its anion, being an active nucleophile, also reacts with unsubstituted azulene. A variety of transformations of 6-hydroxyazulenes, such as substitution of the corresponding sulfonates with nitrogen, oxygen, sulfur, carbon nucleophiles and halogens, and the Claisen rearrangement of allylic ethers, is reported.
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  • 174
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    Reaction of 1,3-Disubstituted Acetone Derivatives with Pseudohalides: A Simple Approach to Spiro[4.4]nonane-Type Bis-Oxazolidines and -Imidazolidines (Bicyclic Carbamates, Thiocarbamates, Ureas, and Thioureas) (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 205-209 
    Details
    ISSN: 1434-193X
    Keywords: Heterocycles ; Carbohydrates ; Imidazolidines ; Oxazolidines ; Spiro compounds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Prochiral 1,3-dihydroxyacetone forms racemic oxazolidine- and oxazoline-type spiro[4.4]nonanes upon reactions with potassium (thio)cyanate and cyanamide. In contrast, 1,3-diaminoacetone yields only the corresponding spiro-bisimidazolidinethione under similar conditions together with monocyclic by-products, but the spiro-bisimidazolidinone is accessible by reaction of 1,3-dichloroacetone with urea. The resolution of the racemic spiro-bisoxazolidinethione 2a was achieved by using brucine as the resolving agent.
    Additional Material: 1 Ill.
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  • 175
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    Evidence for the Intermediacy of (η3-Allyl)palladium Complexes in the Palladium-Catalyzed Acryloxylation of Cycloalkenes: Unexpected Oxidation of 1,5-Cyclooctadiene (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 219-224 
    Details
    ISSN: 1434-193X
    Keywords: Homogeneous catalysis ; Palladium ; Acetoxylation ; Acryloxylation ; Addition reactions ; Cyclooctadiene ; Cyclooct-4-enone ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Palladium-catalyzed acryloxylation of several cycloalkenes in the presence of the Pd(OAc)2/p-benzoquinone/MnO2 catalytic system is reported. This oxidation reaction yields allylic acrylates as the sole products through the intermediacy of an η3-allyl complex. However, with 1,5-cyclooctadiene (3), cyclooct-4-enone (4) is the major reaction product. Its formation results from oxidation, which is also observed in the palladium-catalyzed acetoxylation of 3. It has been shown that this is the result of a 1,2-trans addition (acryloxy-palladation), followed by a β-hydride elimination, which yields an enol acrylate or acetate. A second Markovnikov-oriented 1,2-trans-acryloxy-palladation on the latter yields a palladium complex, rearrangement of which gives 4.
    Additional Material: 1 Ill.
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  • 176
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    Synthesis of New Seven-Membered Ring Cyclic Dipeptides From Functionalized β-Amino Acids (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 251-255 
    Details
    ISSN: 1434-193X
    Keywords: Amino acids ; coupling ; N-Substituted amide ; Cyclizations ; Cyclic dipeptides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A short synthesis of new, functionalized seven-membered ring cyclic dipeptides is described. After the coupling of N-protected β-amino acids to N-substituted α-amino tert-butyl esters, the protective groups of the terminal functions were removed and the cyclization took place diastereoselectively in the presence of the coupling agent BOP. Amide substitution was found to be effective in promoting the cyclization of linear dipeptides.
    Additional Material: 1 Ill.
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  • 177
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    Tin-Mediated Free-Radical Cyclization of β-Allenylbenzoyloximes (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 275-280 
    Details
    ISSN: 1434-193X
    Keywords: Radical reactions ; Substituent effects ; Nitrogen heterocycles ; Dihydropyridines ; Pyrrolines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A set of allene-tethered benzoyloximes (5) has been treated with nBu3SnH. Depending on their substitution pattern, a wide range of compounds has been obtained. If the stannyl radical adds on the allene, the C-centred radical thus formed undergoes either a 5-exo ring closure to give the cyclopentene derivatives 7 or a 6-endo ring closure onto the N atom to give the dihydropyridines 8. If the stannyl radical adds on the benzoyl moiety, an iminyl radical is formed which leads to the 3H-pyrroles 9 and the alkylidene-pyrrolines 10. Steric effects as well as polar effects are the factors governing the reaction course.Supporting information for this article is available on the WWW under //http://www.wiley-vch.de/contents/jc_2046/2000/99373_s.pdf or from the author.
    Additional Material: 1 Ill.
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  • 178
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    Synthesis and Absolute Configuration of Hongoquercin A, an Antibacterial Sesquiterpene-Substituted Orsellinic Acid Isolated as a Fungal Metabolite (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 297-302 
    Details
    ISSN: 1434-193X
    Keywords: Antibiotics ; Configuration determination ; Heterocycles ; Hongoquercin A ; Terpenoids ; Total synthesis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---(±)-Hongoquercin A (1), the racemate of an antibacterial fungal metabolite, has been synthesized starting from geranylacetone (2) and ethyl orsellinate (ethyl 2,4-dihydroxy-6-methylbenzoate, 5). The structure (±)-1 has been confirmed by X-ray analysis of its ethyl ester (±)-10. Synthesis of the naturally occurring (+)-hongoquercin A from (-)-sclareol (11) established its configuration as depicted in 1.
    Additional Material: 1 Ill.
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  • 179
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    Synthesis of Lacto-N-neohexaose and Lacto-N-neooctaose Using the Dimethylmaleoyl Moiety as an Amino Protective Group (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 319-326 
    Details
    ISSN: 1434-193X
    Keywords: Carbohydrates ; Amino sugars ; Protecting groups ; Glycosylations ; Trichloroacetimidates ; Oligosaccharides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The N-DMM-Protected lactosamine derivative 2 was readily transformed into the corresponding glycosyl donor 4 and into acceptor 5. A TMSOTf-catalyzed glycosidation afforded the derived tetrasaccharide 6 which led to glycosyl donor 9. Reaction of 9 with lactose derivative 10 as acceptor gave the desired hexasaccharide 11. Cleavage of all protective groups and N-acetylation afforded the target molecule 1b (lacto-N-neohexaose). Glycosylation of acceptor 10 with donor 4 furnished tetrasaccharide 16 which, employing standard procedures, gave acceptor 18. Glycosylation of 18 with donor 9 furnished, under standard conditions, octasaccharide 19. Cleavage of all protective groups and N-acetylation afforded the target molecule 1c (lacto-N-neooctaose). Both 1b and 1c were obtained in good overall yields.
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  • 180
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    A Facile Route to Bulladecin-Type Acetogenins - Total Synthesis of Asimilobinand Correction of the Configuration of Its Tetrahydrofuran Segment (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 349-356 
    Details
    ISSN: 1434-193X
    Keywords: Sharpless asymmetric dihydroxylation ; Asimilobin ; Tetrahydrofuran ring ; Wittig reactions ; Annonaceous acetogenins ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The most efficient method for the synthesis of the trans/threo/trans-bis(tetrahydrofuran) (THF) ring unit was established, and the first total synthesis of (-)-asimilobin and its diastereomer was then accomplished in twelve and fourteen steps, respectively, from trans-1,5,9-decatriene, by a convergent route with a Wittig reaction as the key step. By virtue of these synthetic results, the absolute configuration of the bis(THF) unit in naturally occurring asimilobin should be corrected.
    Additional Material: 3 Ill.
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  • 181
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    Changing the Reactivity of Enediynes by Metal-Ion Coordination (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 381-385 
    Details
    ISSN: 1434-193X
    Keywords: Enynes ; Macrocycles ; Coordination chemistry ; Crown compounds ; Radicals ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The complex molecular structure and interesting activation mechanisms of naturally occurring enediynes have inspired the synthesis of a variety of simpler model systems to mimic their properties. While in most model compounds nucleophilic attack, isomerization or bioreduction are used to activate the unsaturated system for diradical cyclization, some attempts have been made to employ metal-ion coordination for this purpose. Significant enhancement of the thermal reactivity has been achieved by metal-ion induced conformational and electronic changes of suitably substituted enediynes, such as 1, 5, 6, 17 and 18. Enediyne activation by stoichiometric or catalytic formation of vinylidene complexes, such as 22, from terminal alkynes has also been investigated. This paper summarizes recent results pursuing the activation of enediyne diradical cyclization by metal ions.
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  • 182
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    Synthesis of Enantiomerically Pure (-)-Wine Lactone Based on a Palladium-Catalyzed Enantioselective Allylic Substitution (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 419-423 
    Details
    ISSN: 1434-193X
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The first enantioselective synthesis of enantiomerically pure (-)-wine lactone, (-)-1a, a fragrance constituent of various white wines, and its epimer (+)-1b, was carried out. The key steps are allylic substitution of (±)-2-cyclohexen-1-yl acetate (2) with dimethylmalonate using palladium complexes of phosphanyldihydrooxazol L1 or of the phosphanylcarboxylic acid L2 as catalyst, subsequent decarboxylation, iodolactonization and elimination, furnishing enantiomerically pure bicyclic lactone (+)-7 in 47% overall yield. The diastereoselective introduction of methyl groups by SN2′-type substitution with an organocopper compound and by enolate alkylation gave lactone (-)-1a in 43% overall yield from (+)-7.
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  • 183
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    Studies Towards the Synthesis of Aplykurodins - Synthesis of 17,18-Dihydro-3,9-di-epi-aplykurodinone B (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 439-448 
    Details
    ISSN: 1434-193X
    Keywords: Aplykurodins ; Marine steroids ; C-C coupling ; Cyclic peroxides ; Lactonization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---An approach to the synthesis of aplykurodins, ichthyotoxic marine lactones, is presented. The carbon framework was derived from vitamin D3 by conversion of the readily accessible allyl alcohol 13 to the protected Grundmann's hydroxy ketone 22 and subsequent introduction of the C2 side chain through a Pd0-promoted coupling. Highly stereoselective hetero Diels-Alder reaction with O21 produced the key intermediate peroxide 25. Functional group transformations, coupled with a series of chemo- and stereoselective reactions, finally resulted in the synthesis of the unnatural analogue 17,18-dihydro-3,9-di-epi-aplykurodinone B (6).
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  • 184
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    Oxidation of Aryl- and Diarylcyclopropanes in a Pentasil Zeolite: Ring Opening with Deprotonation or Net Hydrogen Migration (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 467-472 
    Details
    ISSN: 1434-193X
    Keywords: Zeolites ; Radical ions ; Ring opening ; Electron transfer ; Oxidations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Incorporation of trans-1,2-diphenylcyclopropane (1) and its 3,3-D2-isotopomer into the channels of a redox-active pentasil zeolite (Na-ZSM-5) resulted in the formation of exo,exo-1,3-diphenylallyl radical (2•) and its 2-D1 isotopomer, respectively. This conversion requires oxidation, ring opening, and deprotonation, in an unspecified sequence. The allyl radical 2• is also formed upon incorporation of trans-1,3-diphenylpropene (3). A comparison with the solution photochemistry, in the presence or absence of added base, shows the conversion of 1 into 2• to be a zeolite-specific reaction. Incorporation of arylcyclopropanes 9 (R = H, OCH3) into ZSM-5 generated trans-propenylbenzene radical cations 10•+ (R = H, OCH3); the 2,2-D2 isotopomer of 9 (R = OCH3) gave rise to three different isotopomers of 10•+ (R = OCH3).
    Additional Material: 2 Ill.
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  • 185
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    Syntheses of Novel Tripodal Calix[n]cryptands (n = 4, 6) and Their Extraction Abilities toward Cations (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 485-490 
    Details
    ISSN: 1434-193X
    Keywords: Calixarenes ; Tripodal cryptand ; Extraction abilities ; Cations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The tripodal calixcryptands have been one of the scarcely explored fields in calixarene chemistry due to the difficulties in their preparation. The strategy presented in this paper shows that novel tripodal calixcryptands can be conveniently prepared by directly treacing p-tert-butylcalix[n]arenes (n = 4, 6) with a multi-functional polypode reagent, e.g. 1,1,1-tris(tosyloxyethoxyethoxymethyl)propane or tetrakis(tosyloxyethoxyethoxymethyl)methane, under selected conditions. The first example of 1,2,4-tripodal calix[6]cryptands has been prepared. Novel calix[6]crown and doublecalix[4]arenes were co-prepared. The extraction abilities of these novel calixcryptands toward several alkali metal ions, ammonium and alkylammonium ions are presented.
    Additional Material: 4 Ill.
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  • 186
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    Synthesis of 4-Arylsulfonylquinolines by Double Condensation of Allyl Aryl Sulfones with Nitroarenes (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 521-525 
    Details
    ISSN: 1434-193X
    Keywords: Allyl aryl sulfones ; Nitroarenes ; Condensation reaction ; Lewis acids ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Allyl aryl sulfones 2 react with aryl nitrocompounds 1 in a DBU/MgCl2 system giving the 4-arylsulfonyl quinolines 3. Some mechanistic aspects of the reaction are discussed. Application of this reaction to the formal total synthesis of the natural product (-)Eupolauramine is described.
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  • 187
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    Anionic Cyclizations of Pentynones and Hexynones: Access to Furan and Pyran Derivatives (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 527-538 
    Details
    ISSN: 1434-193X
    Keywords: Furans ; Pyrans ; Dihydropyran-2-ylidenes ; Ring closure ; Addition reaction ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---On treatment with base the pentynones 8a-f undergo anionic addition reactions of the resulting enolate species to the alkyne moiety and afford the 2,5-disubstituted furans 10a-f in yields ranging from 10-91%. The proposed mechanism involves the 2-methylene-dihydrofurans 11 as intermediates which tautomerize to yield the observed products. In the case of the α-picolyl derivative 8g both possible enolates 12 and 13 are formed which are subsequently transformed to the products 10g and 14g, respectively. Starting with the hexynones 9a-e an analogous reaction takes place with the formation of the pyran derivatives 15 and 16 in comparable yields. Under the same reaction conditions the n-butyl ketone 9f gives rise to two isomeric compounds, namely the 4H-pyran 16f and the cyclohexenone 17. This result is explained by assuming initial formation of two isomeric enolates which react either by O- or C-attack on the carbon-carbon triple bond.
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  • 188
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    Efficient Synthesis of S-Adenosyl-L-Homocysteine Natural Product Analogues and Their Use to Elucidate the Structural Determinant for Cofactor Binding of the DNA Methyltransferase M·HhaI (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 549-555 
    Details
    ISSN: 1434-193X
    Keywords: Alkylations ; Deaminated AdoHcy ; Decarboxylated AdoHcy ; Mitsunobu reaction ; Nucleosides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---5′-Acetylthio-5′-deoxy-2′,3′-O-isopropylideneadenosine (8) was directly prepared from commercially available 2′,3′-O-isopropylideneadenosine (7) and thioacetic acid under Mitsunobu conditions in almost quantitative yield. In situ cleavage of the acetylthio function of 8 followed by coupling with different alkyl bromides proceeded with high yields. Deprotection of the obtained 5′-thionucleosides yielded the S-adenosyl-L-homocysteine analogues decarboxylated AdoHcy (11), deaminated AdoHcy (14) and 5′-[3-(cyano)propylthio]-5′-deoxyadenosine (16) in good overall yields. Direct deprotection of the thionucleoside 8 delivered 5′-thio-5′-deoxyadenosine (18) in excellent yield. In addition, binding constants of these AdoHcy analogues and the DNA methyltransferase M·HhaI were determined in a fluorescence assay.
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  • 189
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    Catalytic Asymmetric Aziridination of Enol Derivatives in the Presence of Chiral Copper Complexes to give Optically Active α-Amino Ketones (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 557-561 
    Details
    ISSN: 1434-193X
    Keywords: Amino ketones ; Homogeneous catalysis ; Aziridination ; Copper ; Enols ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A series of acyclic and cyclic enol derivatives 1 has been transformed into the corresponding α-amino-functionalized ketones 2 by means of enantioselective catalytic aziridination with chiral Cu complexes, prepared in situ from [Cu(MeCN)4]PF6 and the optically active ligands 3, by using (N-tosylimino)iodobenzene (PhINTs) as a nitrogen source. The best enantioselectivities (ee values of up to 52%) have been achieved for the electronically deactivated enol acetate 1aδ, but the incorporation of steric bulk and the substitution pattern at the enol double bond do not improve the ee values. The cyclic substrates react considerably less readily (only up to 45% conversion) compared to their acyclic counterparts (complete consumption). A transition structure is suggested for the asymmetric Cu-catalyzed aziridination of the enol acetate 1aδ in the presence of the chiral ligand 3b that could account for the sense of the (R)-configured product 2a.
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  • 190
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    D2-Symmetric Chiroporphyrins Derived from (1R)-cis-Hemicaronaldehydic Acid: Preparation and Spectral Characterization (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 583-589 
    Details
    ISSN: 1434-193X
    Keywords: Porphyrins ; Chiral auxiliaries ; Macrocycles ; Pyrethroids ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Esters, N,N-disubstituted amides, and a N-acylurea derived from the enantiopure industrial intermediate (1R)-cis-hemicaronaldehydic acid (or biocartol) are convenient synthons for the preparation of a series of chiroporphyrins by condensation with pyrrole. These chiral meso-tetracyclopropylporphyrins are obtained exclusively as the D2-symmetric α,β,α,β atropisomer, generally in low to moderate yields (2-20%), and in the urea case in excellent yield (60%). Hydrolysis of the urea substituents affords a chiroporphyrin with mono-N-substituted amide groups. 1H-NMR spectroscopy indicates that the ester, amide, and urea stereogenic groups sit on the porphyrin close to the metal binding site and restrict substrate or ligand access along a C2-symmetric groove. This structural feature of chiroporphyrins and of their metal complexes is of high potential interest in asymmetric catalysis and chiral recognition.
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  • 191
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    Anthracene-Containing [2]Rotaxanes: Synthesis, Spectroscopic, and Electrochemical Properties (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 591-602 
    Details
    ISSN: 1434-193X
    Keywords: Cyclophanes ; Molecular recognition ; Molecular shuttles ; Rotaxanes ; Template-directed synthesis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Two dumbbell-shaped compounds (8 and 11), each composed of two polyether chains intercepted by a 1,4-dioxybenzene recognition site, terminated by tetraarylmethane-based stoppers, and emanating from a central 9,10- or a 2,6-dioxyanthracene unit, have been synthesized. Two [2]rotaxanes (9 · 4 PF6 and 12 · 4 PF6) have been prepared by interlocking these dumbbell-shaped compounds (8 and 11) with a bipyridinium-based tetracationic cyclophane (15 · 4 PF6) - namely, cyclobis(paraquat-p-phenylene). A [3]rotaxane (10 · 8 PF6) incorporating two cyclophane components (15 · 4 PF6) was also obtained when the 9,10-dioxyanthracene-containing dumbbell-shaped compound (8) incorporating two 1,4-dioxybenzene recognition sites was employed. The 1H-NMR spectroscopic investigation of the [2]rotaxanes (9 · 4 PF6 and 12 · 4PF6) revealed that the cyclophane component encircles one of the two 1,4-dioxybenzene recognition sites in the 9,10-dioxyanthracene-containing [2]rotaxane (9 · 4 PF6) and the 2,6-dioxyanthracene unit in the other [2]rotaxane (12 · 4 PF6). These structures have been confirmed by UV/Vis and electrochemical experiments. Comparison with the spectroscopic properties of simple model compounds shows the presence of electronic interactions which lead to (i) the occurrence of very efficient energy transfer processes in the dumbbell-shaped components and (ii) perturbations in the absorption spectra with appearance of two charge-transfer absorption bands and complete luminescence quenching in the [2]rotaxanes. For the 2,6-dioxyanthracene-containing [2]rotaxane (12 · 4 PF6), it has been demonstrated that the cyclophane can be displaced from the dioxyanthracene to the 1,4-dioxybenzene station upon electrochemical oxidation.
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  • 192
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    A Radical-Based Strategy for the Synthesis of Higher Homologues of Sinefungin (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 627-631 
    Details
    ISSN: 1434-193X
    Keywords: Complex nucleoside ; Antibiotics ; Radicals ; Zn-Cu couple ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Homosinefungin 5, which can be considered as an analogue of S-adenosylmethionine (SAM) and of S-adenosylhomocysteine (SAH), has been synthesized by means of a sequence in which the key step was the addition of a radical, produced by the simple treatment of an iodide precursor with a zinc-copper couple, to suitably activated olefins.
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  • 193
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    Replacement of the Cleavable Phosphodiester Bond of a Hammerhead Ribozyme Substrate by an Amide Linkage (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 633-638 
    Details
    ISSN: 1434-193X
    Keywords: Amide linkage ; Phosphodiester ; Hammerhead ribozyme ; Oligonucleotides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A nucleoside dimer in which the natural phosphodiester bond is replaced by an isosteric amide linkage has been prepared. This dimer analogue was subsequently incorporated chemically at the cleavage position of a hammerhead ribozyme substrate. Although the resulting substrate analogue exhibited a high affinity for the ribozyme as shown by gel retardation assays, the amide bond proved to be fully resistant to cleavage under standard conditions of ribozyme cleavage activity.
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  • 194
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    Solid-Phase Synthesis of Dihydropyrans by Eu(fod)3-Catalysed [4+2] Heterocycloaddition of Vinyl Ethers with Benzylidenepyruvic Acid Esters. Comparison with Conventional Homogeneous Liquid Phase Conditions (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 639-643 
    Details
    ISSN: 1434-193X
    Keywords: Solid-phase synthesis ; Wang resin ; Hetero Diels-Alder reactions ; Dihydropyrans ; Reductive reactions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The OH groups of Wang resin were esterified with benzylidenepyruvic acid (1) to give the immobilized 1-oxabutadiene 2. The latter reacted with vinyl ethers 3a-h (dienophiles) in the presence of Eu(fod)3, and the resulting adducts 4a-h underwent reductive cleavage with LiAlH4 to afford the dihydropyrans 5a-h in high (62 to 100%) overall yields. A similar sequence carried out under conventional homogeneous liquid phase conditions led to significantly lower yields. The endo/exo selectivity of the cycloaddition reaction was the same in both cases.
    Additional Material: 2 Tab.
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  • 195
    Electronic Resource
    Electronic Resource
    Synthesis of Pyridinium Amphiphiles Used for Transfection and Some Characteristics of Amphiphile/DNA Complex Formation (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 665-673 
    Details
    ISSN: 1434-193X
    Keywords: Cationic amphiphiles ; Transfection ; Pyridinium salts ; Vesicles ; Lipoplex ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Pyridinium amphiphiles have found practical use for the delivery of DNA into cells. Starting from 4-methylpyridine, a general synthesis has been devised for the production of pyridinium amphiphiles which allows variation in both the hydrophobic part and in the headgroup area of the compounds. By means of differential scanning microcalorimetry, zeta potential, particle size measurements and cryo electron microscopy, some characteristics of the pyridinium amphiphile/DNA complexes have been determined.
    Additional Material: 2 Ill.
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  • 196
    Electronic Resource
    Electronic Resource
    Evaluation of the Regioselectivity in Pauson-Khand Reactions of Substituted Norbornenes and Diazabicyclo[2.2.1]heptanes with Terminal Alkynes (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 681-689 
    Details
    ISSN: 1434-193X
    Keywords: Pauson-Khand reaction ; Cyclopentenones ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---1-Methyl-norbornene ester 9 and 1-methyl-2,3-diazabicyclo[2.2.1]heptene ester 10 were employed in intermolecular Pauson-Khand reactions with various terminal alkynes 11a-f to give the dimethyl 1-methyltricyclo[5.2.1.05,9]dec-7-en-6-one 2,3-dicarboxylates 12 and 13, and diethyl 2,3-diaza-1-methyltricyclo[5.2.1.05,9]dec-7-en-6-one 2,3-dicarboxylates 14 and 15, respectively. Whereas the co-cyclization of norbornene 9 with alkynes 11 bearing small substituents R resulted in the preferred formation of 12 (12:13 ≤ 85:15), regioisomer 13 was obtained as the major product when sterically bulky alkynes were employed (12:13 ≥ 6:94). For 2-methyl-3-butyn-2-ol 11e a strong temperature dependency of the regioselectivity was found. The ratio of regioisomers (12e:13e) changed from 95:5 at -25 °C to 12:88 at 120 °C in toluene. In contrast, reactions with 2,3-diazanorbornene 10 showed only moderate regioselectivities in favour of 14 (14:15 ≤ 69:31), regardless of the temperature and the size of R. The observed regioselectivities support a mechanism for the Pauson-Khand reaction in which the apical rather than the basal anti oriented carbon monoxide ligand of cobalt alkyne complex 1 is replaced by the alkene.
    Additional Material: 1 Ill.
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  • 197
    Electronic Resource
    Electronic Resource
    Rationally Designed Bicyclic Lactams Control Different Turn Motifs and Folding Patterns in Hexapeptide Mimics (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 695-699 
    Details
    ISSN: 1434-193X
    Keywords: Reverse-turn mimics ; γ-Turns ; β-Turns ; β-Hairpins ; Peptides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Conformational analysis of N-acetylated hexapeptide mimics incorporating a bicyclic lactam (1-4) was carried out by a combination of 1H-NMR spectroscopy, IR spectroscopy, and computer modeling. The nature of the bicyclic lactam determines the turn motifs and the folding patterns of these constrained peptides. The (5,6)-bicyclic lactam derivatives 1 and 2, characterized by a type-II' β-turn (C=O3···H6-N), are very compact intramolecularly H-bonded structures. The (5,7)-bicyclic lactam derivative 3, characterized by an inverse γ-turn (C=O4···H6-N), is a quite flexible “tweezer-like” structure.
    Additional Material: 4 Ill.
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  • 198
    Electronic Resource
    Electronic Resource
    On the Regioselectivity of Imidoyl Radical Cyclisations (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 707-711 
    Details
    ISSN: 1434-193X
    Keywords: Radical reactions ; Photolysis ; X-ray scattering ; Rearrangements ; Semiempirical calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The previously reported tandem cyclisation of N-aryl α-(2-cyanophenyl)sulfanyl imidoyl radicals affords one quinoxaline derivative arising from exclusive 1,6-cyclisation of the final iminyl radical onto the N-aryl ring. When the imidoyl radicals are generated by addition of photolytically generated (2-cyanophenyl)sulfanyl radicals to isocyanides, the reaction also gives small amounts of a by-product that is formed by an analogous route and whose X-ray crystallographic data are reported here. The formation of this product entails a rare ortho-selective photo-Fries rearrangement of the starting disulfide, followed by addition to the isocyanide and regioselective 1,5-cyclisation of the resulting imidoyl onto only one of the two available radical acceptors, i.e. the cyano group and the sulfide moiety. Semiempirical MNDO-d calculations were performed in order to throw some light on the factors affecting these competitive cyclisations.
    Additional Material: 2 Ill.
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  • 199
    Electronic Resource
    Electronic Resource
    Single Electron Transfer vs. SN2 Reaction (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 713-721 
    Details
    ISSN: 1434-193X
    Keywords: Reductive alkylation ; Acenaphthylenes ; Carbanions ; Polycycles ; Single-electron transfer ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Reaction of the 5-hydroacenaphthylene anion with benzyl halides proceeds at carbon atom 1 as well as at carbon atom 2a, in the latter case creating a quaternary centre. The hardness-softness of the electrophiles was shown to play only a minor role in determining the regioselectivity of the reaction of the hydroanion with several benzyl and alkyl halides: the leaving group hardly affects the ratio of 1- and 2a-substituted products. This indicates that the alkylation might proceed by an electron transfer (SET) instead of an SN2 mechanism. Further evidence for SET was obtained by the use of free radical and electron scavengers. The substitution products 1-benzylacenaphthene and 2a-benzyl-2a,5-dihydroacenaphthylene could be isolated and purified.
    Additional Material: 3 Ill.
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  • 200
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    Electronic Resource
    Synthesis of [3-D3]-, [3-13C]-, and [1,2-13C2]Propynes and Their Use for the Synthesis of [5-D3-Methyl]-, [5-13C-Methyl]-, and [5,6-13C2-2,5-Cyclohexadienyl]ubiquinones 3 (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 723-727 
    Details
    ISSN: 1434-193X
    Keywords: Isotopic labeling ; Isotopic labeling ; Isotopic labeling ; Deuterium ; Carbon-13 ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Three selectively labeled propynes were prepared either with deuterium or carbon-13 at position 3 and doubly labeled with carbon-13 at positions 1 and 2 by an alkylation reaction from the corresponding labeled or unlabeled monolithio acetylides and dimethylsulfates. Their lithiation with nBuLi gave the corresponding propynyllithium derivatives which reacted with dimethyl squarate to afford the corresponding propargylic alcohols. These were thermolysed in p-xylene to furnish [5-D3-methyl]-, [5-13C-methyl]-, and [5,6-13C2-2,5-cyclohexadienyl]ubiquinone. The farnesyl side chain was introduced onto the labeled quinones with farnesyl trimethyltin under BF3 catalysis to provide [5-D3-methyl]-, [5-13C-methyl]-, and [5,6-13C2-2,5-cyclohexadienyl]ubiquinone 3 (6c, 6b, 6a, respectively).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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