bluuebunny/crossref_metadata_2025 huggingface dataset:
Randomized Phase II Study of Gemcitabine and Docetaxel Compared With Gemcitabine Alone in Patients With Metastatic Soft Tissue Sarcomas: Results of Sarcoma Alliance for Research Through Collaboration Study 002
Authors: Maki Robert G. , Wathen J. Kyle , Patel Shreyaskumar R. , Priebat Dennis A. , Okuno Scott H. , Samuels Brian , Fanucchi Michael , Harmon David C. , Schuetze Scott M. , Reinke Denise , Thall Peter F. , Benjamin Robert S. , Baker Laurence H. , Hensley Martee L.
Published: June 2007

Purpose

Gemcitabine as a single agent and the combination of gemcitabine and docetaxel have activity in patients with metastatic soft tissue sarcoma. To determine if the addition of docetaxel to gemcitabine improved clinical outcome of patients with metastatic soft tissue sarcomas, we compared a fixed dose rate infusion of gemcitabine versus a lower dose of gemcitabine with docetaxel.

Patients and Methods

In this open-label phase II clinical trial, the primary end point was tumor response, defined as complete or partial response or stable disease lasting at least 24 weeks. A Bayesian adaptive randomization procedure was used to produce an imbalance in the randomization in favor of the superior treatment, accounting for treatment-subgroup interactions.

Results

One hundred nineteen of 122 randomly assigned patients had assessable outcomes. The adaptive randomization assigned 73 patients (60%) to gemcitabine-docetaxel and 49 patients (40%) to gemcitabine alone, indicating gemcitabine-docetaxel was superior. The objective Response Evaluation Criteria in Solid Tumors response rates were 16% (gemcitabine-docetaxel) and 8% (gemcitabine). Given the data, the posterior probabilities that gemcitabine-docetaxel was superior for progression-free and overall survival were 0.98 and 0.97, respectively. Median progression-free survival was 6.2 months for gemcitabine-docetaxel and 3.0 months for gemcitabine alone; median overall survival was 17.9 months for gemcitabine-docetaxel and 11.5 months for gemcitabine. The posterior probability that patients receiving gemcitabine-docetaxel had a shorter time to discontinuation for toxicity compared with gemcitabine alone was .999.

Conclusion

Gemcitabine-docetaxel yielded superior progression-free and overall survival to gemcitabine alone, but with increased toxicity. Adaptive randomization is an effective method to reduce the number of patients receiving inferior therapy.
Intermittent hypoxia in eggs ofAmbystoma maculatum: embryonic development and egg capsule conductance
Authors: Valls J. Hunter , Mills Nathan E.
Published: June 2007

The spotted salamander Ambystoma maculatum breeds in shallow freshwater pools and imbeds its eggs within a common outer jelly matrix that can limit oxygen availability. The eggs are impregnated with the unicellular alga Oophilia amblystomatis, which produces oxygen during the day but consumes oxygen at night. This daily cycle of algal oxygen production drives a diurnal fluctuation of oxygen partial pressure(PO2) within the eggs, the magnitude of which depends on the distance of an egg from the exterior of the jelly matrix and on the ambient PO2 of the pond. We subjected A. maculatum eggs to fluctuating oxygen levels with a variable minimum PO2 and an invariable maximum, to simulate natural conditions, and measured differences in developmental rate,day and stage at hatching, and egg capsule conductance(GO2). Lower minimum PO2 slowed development and resulted in delayed,yet developmentally premature hatching. GO2increased in all treatments throughout development, but PO2 had no detectable effect on the increase. Intermittent hypoxia caused comparable but less pronounced developmental delays than chronic hypoxia and failed to elicit the measurable change in GO2 seen in ambystomatid salamander eggs exposed to chronic hypoxia.
Cardiac remodelling in rainbow troutOncorhynchus mykissWalbaum in response to phenylhydrazine-induced anaemia
Authors: Simonot Danielle L. , Farrell Anthony P.
Published: June 2007

We examined the nature, extent and timing of cardiac ventricular remodelling in response to chronic, chemically induced anaemia in warm- and cold-acclimated rainbow trout Oncorhynchus mykiss. Chronic anaemia was induced by bi-weekly injections of phenylhydrazine hydrochloride (PHZ) and resulted in transient but large decreases in haematocrit (Hct) and haemoglobin concentration. After 2 weeks of anaemia, relative ventricular mass(rMV) in warm-acclimated rainbow trout had already increased significantly and, by the eighth week of anaemia,rMV was 58% greater than in the sham-injected control fish. Temperature modulated the anaemia-induced ventricular remodelling and erythropoietic responses, as indicated by cold-acclimation reducing the extent of the cardiac remodelling and slowing erythropoietic recovery. For example,in cold-acclimated fish, PHZ reduced Hct to 8.8±1.9% (ranging from 4–16%) and increased rMV by 15% over a 4-week period, whereas the same treatment in warm-acclimated fish reduced Hct to only 17.4±2.1% (ranging from 6–29%) and yet increased rMV by 28%. Cold-acclimated fish also recovered more slowly from anaemia. In addition, warm-acclimated fish maintained compact myocardium between 32% and 37% during anaemia, while cold-acclimated fish responded with an increase in compact myocardium (from 29% to 37%). Routine cardiac output (Q̇) was continuously monitored following a single PHZ injection to examine the initial cardiac response to anaemia. Contrary to expectations, acute anaemia did not produce an immediate, proportionate increase in routine Q̇. In fact, Q̇ did not increase significantly until Hct had decreased to 10%, suggesting that rainbow trout may initially rely on venous oxygen stores to compensate for a reduced arterial oxygen-carrying capacity. Thus, we conclude that myocardial oxygenation, acclimation temperature and cardiac work load could all influence anaemia-induced cardiac remodelling in rainbow trout.
Properties and possible function of a hyperpolarisation-activated chloride current in Drosophila
Authors: Rose Uwe , Derst Christian , Wanischeck Mario , Marinc Christiane , Walther Christian
Published: June 2007

A chloride current, ICl,H, slowly activating on hyperpolarisation was investigated in Drosophila melanogaster larval muscles using the two-electrode voltage clamp. Sizeable currents were observed after the intracellular chloride concentration([Cl–]i) had been elevated by diffusion of Cl– from the electrodes. The time course of ICl,H was rather variable and required two exponentials to be accurately described. The reversal potential, –40 to –20 mV in Cl–-loaded fires, shifted on lowering external[Cl–] in the positive direction. Steady-state activation of ICl,H was characterised by V0.5 of≈–120 mV and a slope factor, k, of ≈10 mV at a[Cl–]i ≈35 mmol l–1. Raising[Cl–]i to ≈50 mmol l–1 caused a negative shift of V0.5 equivalent to the change of ECl and led to a nearly threefold increase in maximal steady-state conductance. ICl,H was resistant to 10 mmol l–1 Zn2+ and 1 mmol l–1Cd2+ but was greatly reduced by 1 mmol l–19-anthracenecarboxylic acid (9-AC). ICl,H was affected by changes of extracellular pH and increased on lowering extracellular osmolality. 9-AC also decreased muscle fibre resting conductance by approximately 20% and increased muscle contractions. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis confirmed the expression of all three ClC genes in muscle, and immunohistochemistry indicated location of Drosophila melanogaster chloride channel-2(DmClC-2) at the Z-lines. We conclude that DmClC-2 accounts for the channels underlying ICl,H, and in part for the resting chloride conductance. DmClC-2 may serve general homeostatic mechanisms such as pH- and osmo-regulation or may support muscle function on high motor activity or during a particular neurohormonal state of the animal.
Representation and Inference of Lexicographic Preference Models and Their Variants
Authors: Kohli Rajeev , Jedidi Kamel
Published: June 2007

The authors propose two variants of lexicographic preference rules. They obtain the necessary and sufficient conditions under which a linear utility function represents a standard lexicographic rule, and each of the proposed variants, over a set of discrete attributes. They then: (i) characterize the measurement properties of the parameters in the representations; (ii) propose a nonmetric procedure for inferring each lexicographic rule from pairwise comparisons of multiattribute alternatives; (iii) describe a method for distinguishing among different lexicographic rules, and between lexicographic and linear preference models; and (iv) suggest how individual lexicographic rules can be combined to describe hierarchical market structures. The authors illustrate each of these aspects using data on personal-computer preferences. They find that two-thirds of the subjects in the sample use some kind of lexicographic rule. In contrast, only one in five subjects use a standard lexicographic rule. This suggests that lexicographic rules are more widely used by consumers than one might have thought in the absence of the lexicographic variants described in the paper. The authors report a simulation assessing the ability of the proposed inference procedure to distinguish among alternative lexicographic models, and between linear-compensatory and lexicographic models.
Myopic Marketing Management: Evidence of the Phenomenon and Its Long-Term Performance Consequences in the SEO Context
Authors: Mizik Natalie , Jacobson Robert
Published: June 2007

Managers often have incentives to artificially inflate current-term earnings by cutting marketing expenditures, even if it comes at the expense of long-term profits. Because investors rely on current-term accounting measures to form expectations of future-term profits, inflating current-term results can lead to enhanced current-term stock price. We present evidence that some firms engage in this type of “myopic marketing management” at the time of a seasoned equity offering (SEO). In particular, a greater proportion of firms than is typical report earnings higher than normal and marketing expenditures lower than normal at the time of their SEO. Although they realize that firms might be undertaking strategies to artificially inflate current-term earnings, the financial markets are not adequately identifying and properly valuing the firms doing so. Our results indicate that myopic firms are able to temporarily inflate their stock market valuation, but in the long run, as the consequences of cutting marketing spending become manifest, they have inferior stock market performance. We propose some actions that might reduce the incentives for myopic behavior.
Mean-Centering Does Not Alleviate Collinearity Problems in Moderated Multiple Regression Models
Authors: Echambadi Raj , Hess James D.
Published: June 2007

The cross-product term in moderated regression may be collinear with its constituent parts, making it difficult to detect main, simple, and interaction effects. The literature shows that mean-centering can reduce the covariance between the linear and the interaction terms, thereby suggesting that it reduces collinearity. We analytically prove that mean-centering neither changes the computational precision of parameters, the sampling accuracy of main effects, simple effects, interaction effects, nor the R2. We also show that the determinants of the cross product matrix X′ X are identical for uncentered and mean-centered data, so the collinearity problem in the moderated regression is unchanged by mean-centering. Many empirical marketing researchers commonly mean-center their moderated regression data hoping that this will improve the precision of estimates from ill conditioned, collinear data, but unfortunately, this hope is futile. Therefore, researchers using moderated regression models should not mean-center in a specious attempt to mitigate collinearity between the linear and the interaction terms. Of course, researchers may wish to mean-center for interpretive purposes and other reasons.
Development and Clinical Utility of a 21-Gene Recurrence Score Prognostic Assay in Patients with Early Breast Cancer Treated with Tamoxifen
Authors: Paik Soonmyung
Published: June 2007

Learning Objectives

After completing this course, the reader will be able to: List the strengths and limitations of the recurrence score and discuss how the TAILORx trial is trying to further the utility of the recurrence score.Describe the need for robust prognostic factors for estrogen receptor–positive and node-negative breast cancer treated with tamoxifen.Discuss the basic statistical requirements in prognostic marker development.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Improved Insight into Resistance Mechanisms to Imatinib in Gastrointestinal Stromal Tumors: A Basis for Novel Approaches and Individualization of Treatment
Authors: Sleijfer Stefan , Wiemer Erik , Seynaeve Caroline , Verweij Jaap
Published: June 2007

Learning Objectives

After completing this course, the reader will be able to: Describe the most important resistance mechanisms to imatinib that are responsible for early and late progression.Discuss the most important systemic treatment options for managing progressive disease under imatinib treatment.Explain how insight into mechanisms conferring sensitivity to imatinib may be used to individualize treatment of patients presenting with GIST.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Prediction of the Responsiveness to Treatment with Erythropoiesis-Stimulating Factors: A Prospective Clinical Study in Patients with Solid Tumors
Authors: Steinmetz Tilman , Hellmich Martin , Neise Michael , Aldaud Ali , Lerchenmüller Christian , Tsamaloukas Antonis , Fandel Francoise , Weiligmann Christoph , Totzke Uwe , Schmitz Stephan
Published: June 2007

Objective.

Treatment with erythropoiesis-stimulating factors (ESFs) can ameliorate anemia associated with cancer and chemotherapy. However, half of anemic cancer patients do not respond even to high doses. To determine factors that are predictive of a treatment response, a multicenter, prospective study was performed.

Patients and Methods.

Investigated factors were baseline erythropoietin, reticulocytes and soluble transferrin receptor (sTfR) after 2 weeks, and reticulocytes and hemoglobin after 4 weeks. Anemic patients with solid tumors received 150 μg/week of darbepoetin concomitantly with chemotherapy. The dose was doubled if hemoglobin did not increase by >1 g/dl after 4 weeks. Patients were considered responders if hemoglobin increased by ≥2 g/dl or reached a level ≥12 g/dl within 8–12 weeks.

Results.

In total, 196 patients were enrolled; 61% of the intention-to-treat (ITT) and 68% of the per-protocol population were responders. In the ITT population, the hemoglobin increase after 4 weeks indicated an 11-fold higher chance of response (odds ratio, 11.0; 95% confidence interval [CI], 5.1–23.6; sensitivity, 88%; specificity, 60%). In a multiple logistic regression model including all factors, the area under the receiver operating characteristic curve was 0.78 (95% CI, 0.71–0.84). The combination of sTfR after 2 weeks and hemoglobin after 4 weeks was as predictive as the combination of all five tested factors.

Conclusion.

So far, an early hemoglobin increase remains the single most predictive factor for response to ESF treatment. In contrast to anemic patients with lymphoproliferative malignancies, serum erythropoietin had little predictive value in patients with solid tumors.
Intimate Partner Violence and Cigarette Smoking: Association Between Smoking Risk and Psychological Abuse With and Without Co-Occurrence of Physical and Sexual Abuse
Authors: Jun Hee-Jin , Rich-Edwards Janet W. , Boynton-Jarrett Renée , Wright Rosalind J.
Published: June 2007

Objectives. We examined the association between psychological abuse in a current relationship and current cigarette smoking among women, with and without the co-occurrence of physical or sexual abuse.

Methods. Women’s experience of psychological abuse, experience of physical or sexual abuse, and smoking status were ascertained through a survey of female nurses. A score of 20 or more on the Women’s Experience With Battering scale defined psychological abuse. We used logistic regression to predict current smoking, adjusting for demographic and social covariates. Analyses included women in a current relationship (n=54200).

Results. Adjusted analyses demonstrated that women experiencing only psychological abuse alone were 33% (95% confidence interval [CI]=13%, 57%) more likely to smoke than nonabused women. Compared with nonabused women, psychologically abused women’s risk of smoking was greater if they reported a single co-occurrence of physical or sexual abuse (odds ratio [OR]=1.5; 95% CI=1.3, 1.8) or multiple co-occurrences (OR=1.9; 95% CI=1.7, 2.3).

Conclusions. Psychological abuse in a current relationship was associated with an increased risk of smoking in this cohort of largely White, well-educated, and employed women. The co-occurrence of physical or sexual abuse enhanced that risk. Further research is needed to see if these associations hold for other groups.
Educational Disparities in Rates of Smoking Among Diabetic Adults: The Translating Research Into Action for Diabetes Study
Authors: Karter Andrew J. , Stevens Mark R. , Gregg Edward W. , Brown Arleen F. , Tseng Chien-Wen , Marrero David G. , Duru O. Kenrik , Gary Tiffany L. , Piette John D. , Waitzfelder Beth , Herman William H. , Beckles Gloria L. , Safford Monika M. , Ettner Susan L.
Published: June 2007

Objectives. We assessed educational disparities in smoking rates among adults with diabetes in managed care settings.

Methods. We used a cross-sectional, survey-based (2002–2003) observational study among 6538 diabetic patients older than 25 years across multiple managed care health plans and states. For smoking at each level of self-reported educational attainment, predicted probabilities were estimated by means of hierarchical logistic regression models with random intercepts for health plan, adjusted for potential confounders.

Results. Overall, 15% the participants reported current smoking. An educational gradient in smoking was observed that varied significantly (P<.003) across age groups, with the educational gradient being strong in those aged 25 to 44 years, modest in those aged 45 to 64 years, and nonexistent in those aged 65 years or older. Of particular note, the prevalence of smoking observed in adults aged 25–44 years with less than a high school education was 50% (95% confidence interval: 36% to 63%).

Conclusions. Approximately half of poorly educated young adults with diabetes smoke, magnifying the health risk associated with early-onset diabetes. Targeted public health interventions for smoking prevention and cessation among young, poorly educated people with diabetes are needed.
The Effect of Support for Action Against the Tobacco Industry on Smoking Among Young Adults
Authors: Ling Pamela M. , Neilands Torsten B. , Glantz Stanton A.
Published: June 2007

Objectives. We investigated associations between tobacco industry denormalization attitudes and the smoking behavior of young adults (aged 18 to 29 years).

Methods. We analyzed data from 9455 young adults in the 2002 California Tobacco Survey.

Results. The data showed that 27.4% of young adults were “ever smokers” (smoked ≥ 100 cigarettes in their lifetime), of whom 66.9% were current smokers (18.3% of young adults). Denormalization attitudes formed 2 major factors: support for anti–tobacco industry action and mistrust of tobacco companies. In multivariate logistic regression, support for action against the tobacco industry was negatively associated with current smoking (odds ratio [OR] = 0.16; 95% confidence interval [CI]=0.13, 0.19) and susceptibility to smoking, after we controlled for demographics, exposure to smokers, and advertising receptivity. Mistrust of tobacco companies was associated with smoking behavior, with anti-industry support acting as a mediating variable. Among current smokers, support for anti–tobacco industry action was strongly associated with intentions to quit (OR=4.64; 95% CI=3.15, 6.84) after we controlled for demographics, exposure to smokers, and advertising receptivity.

Conclusions. Support for anti–tobacco industry action protects against smoking and is associated with intentions to quit among young adults. Encouraging involvement in tobacco control and against the tobacco industry may decrease smoking among young adults.
Knowledge Synthesis of Smoking Cessation Among Employed and Unemployed Young Adults
Authors: Bader Pearl , Travis Heather E. , Skinner Harvey A.
Published: June 2007

Objectives. We synthesized evidence regarding effective strategies for smoking cessation among employed or unemployed young adults aged 18 to 24 years.

Methods. For this knowledge synthesis, we used (1) a systematic review of the scientific literature, (2) a Delphi panel of experts, and (3) 6 focus groups of employed and unemployed young adult smokers.

Results. Of 51 related studies, only 4 included employed and unemployed young adults in their samples (as opposed to students), and none focused solely on them. Using the Delphi process, 27 experts reached consensus on priorities for research, practice, and policy, emphasizing population engagement, recruitment, and innovative interventions. Key themes from focus groups were that interventions should be relevant to young adults, individual choice should be respected, and the positive aspects of quitting should be stressed. Despite having negative views on traditional smoking cessation methods, participants expressed optimism about being able to quit and proposed creative recommendations.

Conclusions. Our findings set an agenda for targeting research, improving practice, and informing policy for smoking cessation among young adults. We also demonstrate the value of using 3 complementary approaches: literature review, expert opinion, and target population perspectives.
Barriers to Smoking Cessation in Inner-City African American Young Adults
Authors: Stillman Frances A. , Bone Lee , Avila-Tang Erika , Smith Katherine , Yancey Norman , Street Calvin , Owings Kerry
Published: June 2007

The prevalence of tobacco use among urban African American persons aged 18 to 24 years not enrolled in college is alarmingly high and a challenge for smoking cessation initiatives. Recent data from inner-city neighborhoods in Baltimore, Md, indicate that more than 60% of young adults smoke cigarettes. We sought to describe community-level factors contributing to this problem. Data from focus groups and surveys indicate that the sale and acquisition of “loosies” are ubiquitous and normative and may contribute to the high usage and low cessation rates.
Use of Tobacco Cessation Treatments Among Young Adult Smokers: 2005 National Health Interview Survey
Authors: Curry Susan J. , Sporer Amy K. , Pugach Oksana , Campbell Richard T. , Emery Sherry
Published: June 2007

Objectives. We compared use of smoking cessation treatments and factors associated with treatment use among young adult smokers and other adult smokers.

Methods. We used data from the 2005 National Health Interview Survey core and cancer control supplement. The sample consisted of 6511 current smokers, of whom 759 were aged 18–24 years. Our analyses were weighted to account for differential sampling probabilities and nonresponse rates. We compared continuous measures using the t test; logistic regression was used to obtain odds ratios and confidence intervals. Multiple logistic regression was used to identify correlates of treatment use.

Results. Behavioral treatment use was infrequent among all smokers (4%–5%). Young adult smokers were less likely than other smokers to use pharmacotherapy (18% vs 32%). Correlates of pharmacotherapy use for young adult smokers were receiving advice from a health care provider, heavier smoking, and higher educational attainment. Compared with other smokers, young adult smokers were less likely to have received advice to quit from a health care provider (49% vs 60%).

Conclusions. Evidence-based tobacco cessation treatments are underused by young adult smokers.
Possible selves: An adult education perspective
Authors: Rossiter Marsha
Published: June 2007

The possible selves construct is presented as a useful and largely untapped perspective on adult learning. Special attention is given to the role of educational helping relationships in fostering positive possible selves among adult learners.
Gender and possible selves
Authors: Lips Hilary M.
Published: June 2007

This chapter discusses the ways in which societies' gendered expectations may affect the possible selves that women and men develop.
Synthesis of (Z)‐3‐hexen‐1‐yl acetate by lipase immobilized in polyvinyl alcohol nanofibers
Authors: Nakane Koji , Hotta Toshiki , Ogihara Takashi , Ogata Nobuo , Yamaguchi Shinji
Published: June 2007

Polyvinyl alcohol (PVA)‐nanofibers‐immobilized lipase were formed by electrospinning. The specific surface area of the nanofiber (5.96 m2/g) was about 250 times larger than that of PVA‐film‐immobilized lipase (0.024 m2/g). The PVA‐nanofibers‐immobilized lipase were used as the catalyst for the esterification of (Z)‐3‐hexen‐1‐ol (leaf alcohol) with acetic acid in hexane. The activity of the nanofiber is equivalent to that of commercially available immobilized lipase (Novozym‐435). The ester conversions of the nanofibers, Novozym‐435, the film and lipase powder reached 99.5% at 5 h, 100% at 5 h, 11.5% at 6 h, and 81.1% at 5.75 h, respectively. The nanofibers‐immobilized lipase showed higher activity for the esterification than the film‐immobilized lipase and lipase powder, probably because it has high specific surface area and high dispersion state of lipase molecules in PVA matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
The duality concept in subject analysis
Authors: Morris Jack C.
Published: June 2007

Any comprehensive survey of the principles, structure and methodology of subject analysis would require a treatise of great length to do even partial justice to the subject. Such is here neither contemplated nor intended. Scope has been restricted to problems concerning library cataloging through subject headings. Observations herein concern American practices in devising subject headings for alphabetic card catalogs, irrespective of whether the finished products are assembled as portions of dictionary catalogs or are filed to form the subject sections of “divided” catalogs. The form of card used is assumed to be the “unit” type wherein each card includes identical and reasonably full descriptive and informative data for the communication covered. The term general catalog is taken to mean one designed for many users, to be inclusive of one or selected disciplines intensively or covering portions of all fields of knowledge rather than to connote any particular degree of specificity or level of analysis for individual communications. A searching criticism is directed to current tendencies in subject heading construction which are presently denoted as “direct and specific” in the hope that the full import and significance of the duality concept will emerge. It is suggested that the duality concept is applicable to all forms of subject analysis for all kinds of communications. It is recommended that research and experimental investigations be directed to effecting a marriage of the best features of subject‐headed unit cards with those of marginal punched cards. The “Uniterm” specie of coordinate indexing is reviewed critically because of its purported challenge to the major modes of subject analysis.
Reversed‐phase high‐performance liquid chromatographic, size exclusion chromatographic and polyacrylamide gel electrophoretic studies of glycinin: evidence for molecular species and their association–dissociation
Authors: Bhushan Ravi , Arya Upasana
Published: June 2007

Isolation and purification of glycinin and its molecular species from an Indian soybean variety (JS‐335) was achieved using polyacrylamide gel electrophoresis (PAGE), size exclusion chromatography (SEC) and reversed‐phase high‐performance liquid chromatography (RP‐HPLC). Glycinin was found to have two molecular species (glycinin I and II), and only glycinin I underwent reversible dissociation–association system intoαandβspecies. Glycinin I and II were not found to constitute a dissociation–association system. Glycinin II also did not dissociate under varying conditions of time, pH and ionic strength of buffer. Various species so dissociated were isolated, purified and characterized. Copyright © 2007 John Wiley & Sons, Ltd.
Assay of tyrosine hydroxylase based on high‐performance liquid chromatography separation and quantification of l‐dopa and l‐tyrosine
Authors: Olšovská Jana , Novotná Jitka , Flieger Miroslav , Spížek Jaroslav
Published: June 2007

An assay of l‐tyrosine (Tyr) hydroxylating activity operating in lincomycin biosynthesis is described. The assay development consisted of HPLC procedure development, assessing the effect of reaction mixture components on non‐enzymatic Dopa and Tyr oxidation, and sample stability evaluation. The HPLC procedure with isocratic elution and fluorescence detection was developed and validated. The method showed a wide linear range of Dopa determination of 0.125–25 µmol/L with lower limit of quantification (LLOQ) of 0.125 µmol/L, RSD of 7.2% and accuracy of 101.7%. The studied linear range of Tyr was 15.625 mmol/L to 500 mmol/L with LLOQ of 15.625 mmol/L, RSD of 1.1%, and accuracy of 98.1%. Recoveries for Dopa and Tyr were 100.66 ± 0.89% and 94.76 ± 0.94%, respectively. The inter‐ and intra‐day accuracies and precisions were all within 10%. Samples of the reaction mixture were stable for at least 24 h at room temperature (RT) and 28 days at −20°C. The method was tested for the enzyme activity monitoring in purified as well as crude preparations and enabled micro preparation of the enzyme product during confirmation of its identity. The influence of pH and ascorbic acid content in reaction mixture was studied with respect to non‐enzymatic Tyr oxidation. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of faropenem in human plasma and urine by liquid chromatography–tandem mass spectrometry
Authors: Gao Shouhong , Chen Wansheng , Tao Xia , Miao Haijun , Yang Shaolin , Wu Rong
Published: June 2007

A simple, rapid and sensitive liquid chromatography/electrospray tandem mass spectrometry (LC‐MS/MS) quantitative detection method, using cefalexin as internal standard, was developed for the analysis of faropenem in human plasma and urine. After precipitation of the plasma proteins with acetonitrile, the analytes were separated on a C18 reversed‐phase column with 0.1% formic acid–methanol (45:55, v/v) and detected by electrospray ionization mass spectrometry in positive multiple reaction monitoring mode. Calibration curves with good linearities (r = 0.9991 for plasma sample and r = 0.9993 for urine sample) were obtained in the range 5–4000 ng/mL for faropenem. The limit of detection was 5 ng/mL. Recoveries were around 90% for the extraction from human plasma, and good precision and accuracy were achieved. This method is feasible for the evaluation of pharmacokinetic profiles of faropenem in humans, and to our knowledge, it is the first time the pharmacokinetic of faropenem has been elucidated in vivo using LC‐MS/MS. Copyright © 2007 John Wiley & Sons, Ltd.
Lithio‐1,3,5‐trithiane Erzeugung, Umsetzung mit Elektrophilen und Verwendung als nucleophile Acylierungsmittel
Authors: Seebach Dieter , Corey Elias J. , Beck Albert K.
Published: June 2007

1,3,5‐Trithian selbst sowie 2‐mono‐ und 2,4,6‐ trisubstituierte Trithiane lassen sich mit n‐Butyllithium in Tetrahydrofuran metallieren. Umsetzung der Lithiumderivate mit Elektrophilen führt zu höher substituierten Trithianen, die teilweise in reiner Form isoliert werden können. Die NMR‐Spektren der erhaltenen Produkte bei Raumtemperatur werden beschrieben. Quecksilber(II)‐assistierte Solvolyse von alkylierten Trithianen führt zu Carbonyl‐verbindungen oder deren O‐Acetalen unter „Herauslösung”︁ des höchstsubstituierten C‐Atoms, was die Verwendung von Lithiotrithianen als nucleophile Acylierungsmittel ermöglicht. Vor‐ und Nachteile gegenüber der Dithian‐Methode werden diskutiert.
Darstellung, Struktur und radikalischer Zerfall von zwei bicyclischen Phosphortrischwefelpentanitrid‐Ringverbindungen
Authors: Appel Rolf , Ruppert Ingo , Milker Roland , Bastian Volker
Published: June 2007

Das disilylierte Schwefel(IV)‐diimid 1 kondensiert mit Fluorphosphoranen PhnPF5–n (n = 0, 1) unter Trimethylfluorsilan‐Abspaltung zu den bicyclischen Phosphortrischwefelpenta‐nitrid‐Ringsystemen 3a, b. Ihre thermische Zersetzung liefert u.a. Tetraschwefeltetranitrid und SN2. ‐Anionoradikale in hoher Konzentration. Es wird versucht, durch NMR‐, ESR‐ und massenspektroskopische Methoden Voraussagen über die Struktur der neuen Heterocyclen zu machen.
Über die Abhängigkeit der Bindungslängen in einigen N,O‐Dibenzoylhydroxylaminen von der Verdrillung der Carboxyl‐ und Hydroxamsäuregruppen gegen die Benzolkerne Die Kristallstrukturen von N,O‐Dibenzoyl‐(C14H11NO3), N,O‐Bis(2‐ chlorbenzoyl)‐(C14H9Cl2NO3), N‐Benzoyl‐O‐p‐toluoyl‐ (C15H13NO3) und N‐Benzoyl‐O‐o‐toluoylhydroxylamin (C15H13NO3)
Authors: Göttlicher Siegfried , Ochsenreiter Peter
Published: June 2007

Die Kristallstrukturen von vier N,O‐ Dibenzoylhydroxylaminen – 1: N,O‐Dibenzoylhydroxylamin (C14H11NO3), 2: N,O ‐Bis(2‐chlorbenzoyl)hyroxylamin (C14H9Cl2NO3), 3: N‐Benzoyl‐O‐p‐toluoylhydroxylamin (C15H13NO3), 4: N‐ Benzoyl‐O‐o‐toluoylhydroxylamin (C15H13NO3) – wurden röntgenographisch unter Anwendung direkter Methoden zur Lösung des Phasenproblems bestimmt. Die CC‐ Bindungslängen zwischen den Phenylgruppen einerseits und den Hydroxamsäure‐ bzw. Carboxylatgruppen andererseits lassen sich als Funktion der Verdrillungswinkel φ dieser Bindung durch eine Gerade darstellen, wenn man die Bindungslängen gegen cos2 φ aufträgt. Der reine sp2–sp2‐CC‐ Einfachbindungsabstand (φ = 90°) ist danach 1.513 Å.
Thiophosphinsäureamid‐Komplexe des Rheniums
Authors: Lindner Ekkehard , Ebinger Hans‐Martin
Published: June 2007

Bei der Einwirkung der Thiophosphinsäureamide (C6H5)PNH2S (1 a) oder (CH3)2PNH2S (1 b) auf [BrRe(CO) 4]2 (2 a) erhält man gemäß Gl. (I) die monomeren Substitutionsprodukte R2PNH 2SRe(CO)4Br (RC6H5 (3 a), CH3 (3 b) mit einzähniger PSRe‐Verknüpfung. 3 a und b spalten beim Erwärmen in C6H6 gemäß Gl. (2) CO ab unter Bildung der wahrscheinlich polymeren Tricarbonylrhenium‐Komplexe R2PNH2SRe(CO)3Br (RC6H5 (4a), CH3 (4b). In 4a, b sind 1a bzw. b zweizähnig über Stickstoff und Schwefel an das Rhenium gebunden. 4a und b bilden sich auch aus 1 a und b und BrRe(cO)5 (2b). Die neu dargestellten Komplexe 3a, b und 4a, b werden IR‐, Raman‐ und 1H‐NMR‐spektroskopisch charakterisiert.
Über die Eignung von 5‐Imino‐Δ1‐1,2,4‐triazolin‐3‐onen und 3,5‐Bisimino‐Δ11,2,4‐triazolinen als Dienophile
Authors: Sunderdiek Rainer , Zinner Gerewalt
Published: June 2007

Die Triazoline 5 und 8 sowie das Triazol 14 reagieren im Gegensatz zu 1 mit 1,3‐Dienen nicht spontan zu 1,4‐Addukten, sondern erst in Gegenwart von 2 Moläquivv. Bortrifluorid ätherat. Die Triazoline 8 geben mit Cyclopentadien keine 1,4‐Addukte.
Monosubstituierte [16] Annulene
Authors: Schröder Gerhard , Kirsch Gerald , Oth Jean F. M.
Published: June 2007

Die Synthesen von Methoxycarbonyl‐ (4a ⇌ 4a), Phenyl‐ (4b ⇌ 5b), Chlor‐(4c ⇌ 5c) und Fluor[16]annulenen (4d ⇌ 5d) werden beschrieben. Ihre temperaturabhängigen NMR‐ Spektren werden mitgeteilt und im Lichte des für [16] Annulen entwickelten Austauschmechanismus diskutiert.
Perfluoralkansulfinsäure‐ester, ‐amide und ‐isocyanate
Authors: Roesky Herbert W. , Tutkunkardes Senol
Published: June 2007

Perfluormethan‐ und Perfluorbutansulfinsäure reagieren mit PCl3, PCl5 und SOCl2 zu den Sulfinylchloriden 1a und b. Als Nebenprodukt dieser Reaktion konnte das Anhydrid 2 isoliert werden. ester von Sulfinsäuren 3–6 lassen sich aus der Säure und (CH3)3SiCl oder (CH3)3SnCl herstellen. Sulfinylchloride reagieren mit Silicium‐Stickstoff‐Verbindungen oder aminen zu den Sulfinamiden 7–12. Es sind reaktive Zwischenprodukte, die mit Trichlormethansulfenylchlorid und Phosphorpentachlorid 13–16 ergeben. 15 und 16 werden thermisch zu den Sulfinylchloriden und dem trimeren Phosphornitridchlorid gespalten. Zu den Isocyanaten 17 und 18 gelangt man durch Reaktion des Säurechlorids mit AgNCO oder durch Reaktion der Amide mit Chlorsulfonylisocyanat. Die Massen‐ und NMR‐Spektren der neuen Verbindungen werden diskutiert.
Verdazyle, 22. Darstellung und Reaktionen amino‐substituierter Verdazyle
Authors: Neugebauer Franz Alfred , Bernhardt Ralph
Published: June 2007

Die Synthese der nitro‐substituierten (7–13, 16) und amino‐substituierten Verdazyle (14,15,17) wird beschrieben. Die Aminoverdazyle lassen sich unter Beibehaltung der Radikalnatur mit Säurechloriden acylieren und mit Aldehyden zu Aldiminen umsetzen. Bifunktionelle Säurechloride oder Aldehyde ergeben Bisverdazyle: deren ESR‐Spektren werden diskutiert.
Stabile Methylnickelverbindungen, V. Das Methyltetrakis(trimethylphosphin)nickel‐Kation
Authors: Klein Hans‐Friedrich , Karsch Hans H. , Buchner Wolfgang
Published: June 2007

Methylnickelverbindungen des Typs L2(CH3)NiX [L(CH3)3P; XCl, Br, J. NCS, O2P(CH3)2] nehmen zwei äquivalente Trimethylphosphin auf und bilden Komplexe der Zusammensetzung L4(CH3)NiX. NMR‐Spektroskopische Untersuchungen bei tiefen Temperaturen zeigen die Existenz des Methyltertrakis(trimethylphosphin)nickel‐Kations in Lösung. Seine trigonal‐bipyramidale Struktur mit axialer NiCH3‐Gruppe ist beweglich. Durch Computersimulation der NiCH3‐Protonenresonanz für den Bereich von −50 bis –80°C wird die Aktivierungsenergie der intramolekularen Bewegung zu 11.6 kcal/mol bestimmt. In verdünnten CH2Cl2‐Lösungen ist dieser Wert unabhängig vom Gegenion X‐. Trimethylphosphit substituiert nur einen Phosphinliganden und besetzt die zweite axiale Position im starren Komplexion.
N‐Boryl‐ und N‐Silylketimine als Komplexliganden
Authors: Schmid Günter , Weber Lothar
Published: June 2007

N‐(Diäthylborly)‐ und N (Trimethylsilyl)diphenylketimin reagieren mit Bis(benzonitril)‐palladiumdichlorid in guten Ausbeuten zu den gelben N‐Boryl‐ bzw. N‐Silylketimin Komplexen [(C6H5)2CNB(C2H5)2]2PdCl2 und [(C6H 5)2CNSi(CH3)3]2PdCl2. Triphenylphosphin substituiert die Ketimine unter Bildung von trans‐[(C6H5)3P]2PdCl2. Wie 11B‐NMR‐ und IR‐spektroskopische Untersuchungen zeigen, scheinen in beiden Komplexen die Ketimini‐Moleküle durch die CN‐Gruppe an das Palladium koordiniert zu sein. Eine mögliche Bindung des N‐Borylketimins über das BN‐π‐System kann ausgeschlossen werden.
Polyhalogenierte Bicyclo[4.2.0]octa‐1,5,7‐triene, IV. Das Prinzip der aromatisierenden nucleophilen Substitution am Perchlorbicyclo[4.2.0]octa‐1,5,7‐trien
Authors: Roedig Alfred , Bauer Hans‐Hermann , Bonse Gerhard , Ganns Rainer
Published: June 2007

Durch nucleophile Agenzien wird die Titelverbindung 1 sehr leicht in die Benzocyclobuten‐derivate 4 umgewandelt. Das LiAlH4‐Produkt 5 besitzt cis‐Konfiguration, wie seine Synthese aus 2,3,4,5 ‐Tetrachlor‐1,1‐dimethoxycyclopentadien und cis‐3,4‐Dichlor‐1‐cyclobuten über die Zwischenstufen 7, 8, 6 beweist. Das Diazid 9 (wahrscheinlich cis)‐spaltet in siedendem Xylol Stickstoff ab zum Perchlorchinoxalin (10). Mit Phenolaten und Thiophenolaten werden aus 1 die Verbindungen 11a‐h erhalten. Die Anwendung bifunktioneller Nucleophile wie Brenzcatechin und Glyclo führt zur Angliederung eines weiteren Ringes (12 bzw. 15a). In den Thiophenol‐Derivaten 11e, f lassen sich auf cis‐Konfiguration hinweisend die beiden Chloratome leicht durch eine Äthylendioxy‐Brücke ersetzen. Es wird ein allgemeiner Mechanismus vorgeschlagen, der die Stereospezifität berücksichtigt und in einer SN2″‐Substitution im ersten und einer modifizierten Reaktion vom SNl‐Typ im zweiten Schritt besteht.
Reaktionen des 3,3‐Dichlor‐1,5,2,4,6,3‐dithiatriazaphosphor(V)‐in‐S,S′‐bis(oxidfluorids), eines cyclischen Phosphornitrilsulfanurhalogenids
Authors: Heider Walter , Klingebiel Uwe , Lin Teh‐Pei , Glemser Oskar
Published: June 2007

(NSOF)2NPCl21 reagiert mit Ammoniak im Molverhältnis 1:2 zu 1, mit Silylaminen (CH3)3SiNHR (RCH3, C2H5) im Molverhältnis 1:1 zu 2 und 3, mit (CH3)3SiNR2 (RCH3, C2H5) zu 4 und 5. Schließlich konnten aus (NSOF)2NPCl 2 und Disilylaminen [(CH3)3Si]2NR (RH, CH3, C2H5) die Verbindungen 6, 7 und 8 isoliert werden. Die IR‐, Massen‐ und 1H‐, 19F‐und 31P‐NMR‐Spektren dieser Verbindungen werden mitgeteilt.
Kinetik der Schutzgruppenabspaltung an Nucleosiden mittels 1H‐NMR‐Spektroskopie
Authors: Regel Walter , Stengele Eberhard , Seliger Hartmut
Published: June 2007

Die Lage des Basenprotons 6‐H im 1H‐NMR‐Spektrum von Pyrimidin‐Nucleosiden ist beim ungeschützten Nucleosid verschieden von derjenigen eines in 3′‐ oder 5′‐Stellung geschützten Nucleosids. Durch Integration beider Peaks in Abhängigkeit von Zeit, Konzentration und pH‐wert konnte erstmals eine quantitative Hydrolysekinetik durchgeführt werden.‐Verbesserte und z. T. neue Vorschriften zur Darstellung von tritylierten Pyrimidin‐Nucleosiden werden beschrieben.
Heteropolycyclen vom Triangulen‐Typ, II. Zur Stereochemie verbrückter Triarylamine
Authors: Hellwinkel Dieter , Melan Michael
Published: June 2007

Nach Aussage der 1H‐NMR‐Spektrometrie liegt 5,5,9,9‐ Tetramethyl‐5H, 9 H‐chino[3,2,1‐de]‐acridin (4b), in einer C2‐Konformation mit planarem Stickstoff vor, in der die beiden Acridcan‐Untereinheiten entgegengesetzt gefaltet sind. Die auch bei Temperaturen von + 160°C noch nicht verbreiterten zwei Methylresonanzen beweisen eine überraschend hohe konformative Stabilität (ΔG≠ > 22 kcal/mol). Die entsprechenden NMR‐Daten von 4,4,8,8,12,12‐Hexamethyl‐4H, 8H, 12H‐ benzol[1,9]chinolizino[3,4,5,6,7‐defg]acridin (5 b) sprechen für eine planare, oder rasch invertierende (ΔG≠ < 9 kcal/mol) flach pyramidale Struktur.
Natürlich vorkommende Terpen‐Derivate, XXVIII. Über ein neues Sesquiterpen‐Derivat aus Artemisia pontica L.
Authors: Bohlmann Ferdinand , Schumann Dieter , Zdero Christa
Published: June 2007

Die polaren Anteile des Wurzelextrakts von Artemisia pontica L. enthalten ein neues Sesquiterpen‐diol, das mit Isofraxidin verknüpft ist. Die Struktur 2 wird durch die spektroskopischen Daten des Naturstoffs und einiger Derivate geklärt.
Natürlich vorkommende Terpen‐Derivate, XXIX. Über zwei neue Sesquiterpene aus Ptilostemon chamaepeuce (L.) Less
Authors: Bohlmann Ferdinand , Rao Nagabhushan , Schwarz Helmut
Published: June 2007

Die Wurzeln von Ptilostemon chamaepeuce (L.) Less. enthalten zwei Sesquiterpene (2 und 3), deren Strukturen durch ihre spektroskopischen Daten sowie durch einige chemische Reaktionen geklärt werden. Das massenspektroskopische Verhalten wird diskutiert.
Polyacetylenverbindungen, 224. Synthese des Ichthyotherol‐acetats
Authors: Bohlmann Ferdinand , Vogel Dieter
Published: June 2007

Ausgehend von dem Trindien 3 erhält man über das Epoxid 4 das Tetrahydropyranderivat 6, das nach Veresterung 7, liefert. Das Acetat ist in allen spektroskopischen Eigenschaften identisch mit dem Naturstoff. Die Struktur des Epoxids 5 wird ebenfalls durch Synthese des Racemats sichergestellt.
Alkaloide aus Rhamnaceen, XVIII. Amphiin‐F, ‐G und ‐H, weitere Peptidalkaloide aus Ziziphus amphibia A. Cheval
Authors: Tschesche Rudolf , Spilles Christain , Eckhardt Gert
Published: June 2007

Aus dem komplexen Rohbasengemisch von Ziziphus amphibia A. Cheval. wurden neben den bereits beschriebenen Amphibinen‐A, ‐B, ‐C, ‐D und ‐E drei weitere Peptidalkaloide Amphibin‐F, ‐G und ‐H isoliert und in der Struktur geklärt (1‐3). Die Amphibine‐F und ‐G (1, 2) zählen zu den Cyclopeptidalkaloiden mit 14 gliedrigem Ringsystem aus trans‐3‐Hydroxyprolin, p‐Hydroxystyrylamin und einer α‐Aminosäure. Das Amphibin‐H (3) weist ein 13 gliedriges Ringsystem auf, das aus den Aminosäuren trans‐3‐Hydroxyprolin und Phenylatanin sowie aus 5‐Hydroxy‐2‐methoxystyrylamin gebildet wird5).
Pteridine, LX. Synthese und Oxidationsverhalten von 7,8‐Dihydroxanthopterinen
Authors: Pfleiderer Wolfgang
Published: June 2007

Die Synthese des 7,8‐Dihydroxanthopterins (18) und verschiedener N‐ und C‐Methyl‐Derivate (19–27, 30) wird beschrieben. Ihre pKa‐Werte und UV‐Spektren werden bestimmt und ihr Autoxidationsverhalten untersucht. Die Monoanionen unterliegen der Autoxidation, welche durch Ammoniak und primäre Amine stark katalysiert wird. Ein Mechanismus wird diskutiert und verschiedene Zwischenprodukte anhand von blockierten N‐ und C‐Methyl‐Derivaten wahrscheinlich gemacht.
Offene und verbrückte Zwischenstufen, 1. Bestimmung der sterischen Wechselwirkung in offenen und verbrückten Norbornanderivaten
Authors: Giese Bernd
Published: June 2007

Die Regioselektivität der Bromlactonbildung aus 1‐Alkyl‐5,6‐exo,cis dibrom‐2,3‐endo,cis‐norbornandicarbonsäuren (6) steigt mit der Größe des Brückenkopfsubstituenten R1 an. Das Bromatom an C‐6 wird bei R1 = CH3 2mal und bei R1 = C2H5 5 mal rascher substituiert als das entferntere Brom an C 5. Dagegen entstehen in der säurekatalysierten Ringöffnung des 5,6‐exo‐Epoxy‐1‐methyl‐2,2‐endo,cis‐norbornandicarbonsäure‐anhydrids (12a) die Hydroxylactone 13a und 14a mit gleicher Geschwindigkeit. Ein Äthylsubstituent verschiebt hier das Verhältnis der Isomeren 13d und 14d auf den Wert 3. — Diese unterschiedliche sterische Abstoßung zwischen den Alkylgruppen und dem Bromatom bzw. Epoxidsauerstoff gewährt Einblick in die verschiedene sterische Weschselwirkung in offenen und verbrückten Zwischenstufen.
Offene und verbrückte Zwischenstufen, 2. Zum Auftreten überbrückter Zwischenstufen bei der Bromierung von Norbornenderivaten
Authors: Giese Bernd
Published: June 2007

Bei der exo‐Bromierung der Norbornen‐endo,cis‐dicarbonsäurederivate 3 treten der geschwindigkeitsbestimmende und der produktbestimmende Schritt zeitlich nacheinander auf. Für die Zwischenstufe wird aus kinetischen und stereochemischen Daten das nicht‐klassische Ion 6 wahrscheinlich gemacht. Verhindern 7‐ständige Methylgruppen die Ausbildung des dreigliedrigen Ringes, dann konkurriert die radikalische Bromanlagerung an die Olefine erfolgreich mit dem Ionenangriff.
Synthese von Di‐ und Trihalogen‐1,3‐dimethylcyclobutanen
Authors: Griesbaum Karl , Chu Yingli
Published: June 2007

Dehydrobromierung von 1,3‐Dibrom‐1,3‐dimethylcyclobutan (5) mit Kalium‐tert‐butylat gab 1‐Methyl‐3‐methylen‐1‐cyclobuten (1). Addition von Brom‐ bzw. von Chlorwasserstoff an 1 lieferte 3‐Brom‐(2) bzw. 3‐Chlor‐1,3‐dimethyl‐1‐cyclobuten (3). Weitere Halogen‐wasserstoffadditionen an 2 und 3 führten zu den stereoisomeren 1,3‐Dibrom‐ (5), 1,3‐Dichlor‐(7) und 1‐Brom‐3‐chlor‐1,3‐dimethylcyclobutanen (6). Die Bromierung von 2 bzw. von 3 lieferte die stereoisomeren 1,2,3‐Tribrom‐ (4) bzw. 1,2‐Dibrom‐3‐chlor‐1,3‐dimethyl‐cyclobutane (8).
Eine neue Methode zur reduktiven Entfernung phenolischer Hydroxygruppen
Authors: Vowinkel Erich , Wolff Christian
Published: June 2007

Phenole können in einem zweistufigen Verfahren über ihre Isoharnstoffderivate dehydroxyliert werden. Die Phenole werden zunächst an Carbodiimide addiert und die dabei gebildeten O‐Arylisoharnstoffe sodann bei Raumtemperatur hydrogenolytisch in die aromatischen Kohlenwasserstoffe und disubstituierte Harnstoffe gespalten. Die reduktive Spaltung ist gegen sterische Faktoren empfindlich. Der Prozeß kann auch in einem Eintopfverfahren durchgeführt werden.
Plyhalogenierte Bicyclo[4.2.0]octa‐1,5,7‐triene, V. Aromatisierende nucleophile Substitutionen mit aliphatischen Aminen und Ammoniak
Authors: Roedig Alfred , Bonse Gerhard , Helm Rudolf , Ganns Rainer , Kühnel Ute
Published: June 2007

Die bicyclische Perchlorverbindung 1 liefert mit primären aliphatischen Aminen die Diimine 3a–d. Mit Äthylenimin lassen sich vier Aziridinreste unter Bildung von 4 einführen. Offenkettige sekundäre Amine spalten dagegen den Cyclobutenring und liefern o‐dichlormethylsubstituierte Benzamide 6. Hierbei wechselt ein Halogenatom seinen Platz am Vierring, wie die Umwandlung der Bromverbindung 16 in das Amid 17 veranschaulicht. Auch durch Ammoniak erfährt 1 eine Ringöffnung. Dabei wird ein C‐Atom als Formamid abgespalten und das Benzonitril 18c gebildet. Durch Variation der Reaktionsbedingungen ist das Diimin 3f faßbar, das ebenso wie 3a–d mit Basen in 18c übergeführt werden kann. Mögliche Mechanismen für die Ringspaltung von 1 werden diskutiert.