Structure elucidation by NMR in organic chemistry

Structure elucidation by NMR in organic chemistry

831 Literature Studies in Natural Products Chemistry, edited by AU Rahman, 1993, Dfl 570.00, p 694 The discovery and study of natural substances of ...

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Literature

Studies in Natural Products Chemistry, edited by AU Rahman, 1993, Dfl 570.00, p 694 The discovery and study of natural substances of both terrestrial and marine plants and animals have, for a long time, marked important progress not only in chemistry but also in biology and medecine. Recent examples of such progress, usually the result of fortuitous discoveries, include the avermectins, which are presently the best arms against certain cattle parasitic diseases; mevinic acids; inhibitors of cholesterol biosynthesis, which have radically changed the prognosis of severe hypercholesterolemia; cyclosporin, FKS06, and rapamycin etc, which have opened up a new chapter in the domain of immunology and, finally, the taxoids (taxol and more recently taxot~re), isolated or prepared from the yew tree, which no doubt represents the most important acquisition in cancer chemotherapy in many years. These are but a few of tile examples of recent discoveries based on compounds of natural origin. This series, edited by Professor Atta-ur-Rahman (Karachi) is already, with the appearance of volume 13, a monument in the area of natural products chemistry. As in the preceding volumes, it is composed of ! 3 chapters (totaling almost 700 pages) devoted to the synthesis (or biosynthesis) of complex natural molecules including terpenes, propane-l,3-diol derivatives, cytochalasans, antibiotics derived from erythromycin, carbocylic sugars, 'anti-sense' oligonucleotides, the biosynthetic preparation of perfumes and flavones, antitumor alkaloids of the acridone family, macroline-related indole alkaloids, mitomycin, the use of organosilicon derivatives as nucleophiles in the synthesis of bioactive natural products via N-acyliminium intermediates, trichothecene mycotoxins and mevinic acids. One chapter deals entirely with the renaissance of pharmacognosy, that is, the use of natural products for their biological and, particularly, therapeutic properties. All these articles have been written by competent research scientists directly implicated (and sometimes at the origin) of the progress described throughout the 14 chapters. This being a 'camera-ready' book, the typography varies from chapter to chapter. However, it is generally pleasant to read and the small number of errors, always benign, is under the sole responsibility of the authors. It is certain that this work in conjunction with the preceding volumes, has a useful and valuable place on any good chemistry library and is especially accessible to biologists desirering to understand the chemical nature of the substances they are often brought to handle.

P Potier

Amiloride and its analogs, edited by EJ Cragoe Jr, TR Kleyman, L Simchowitz, VCH, 1993, DM, 189.00, p 388 The book entitled Amiloride and its analogs edited by Drs EJ Cragoe Jr, TR Kleyman, and L Simchowitz summarises the

historical discovery and various utilizations of an important class of reagents, all derived from amiloride, which/u'e able to specifically inhibit a broad category of specific ion transport systems in a variety of different cell types. This book of 387 pages is divided in 22 sections which have been written by most of the investigators which have contributed to a better understanding of ionic cotransporter molecules. The book resumes the pharmacological properties of amiloride and its analogs, their physiological and molecular actions on ionic transporters such as sodium-proton exchanger, sodium-calcium exchanger, or their effects on voltage dependent C a 2+ channels in various epithelia. Some sections are also devoted to the biological application and immunological utilization of amiloride and to molecular biology of the sodium-proton exchanger. Also of interest are the last sections which concern the use of amiloride for clinical aplications. This book provides and resumes most of the important studies over the last decade, devoted to the specific action of amiloride and its derivatives which have permitted a better understanding of action of many ionic transport exchangers. This book should offer a useful tool for researcher or physicians involved in the field of ionic transport processes. Although specialized, this book provides a good overview of the different strategy used with these specific hocking agents specifically directed against membranous exchangers in a variety of non-epithelial and epithelial cells. A Vandewalle

Structure Elucidation by NMR in Organic Chemistry, edited by Eberhard Breitmaier, John Wiley & Sons, 1993, $15.95, p 265 This book provides a descriptive approach to structure determination using modern NMR spectroscopy, ie the strategy, the techniques and the methodology by which molecular structures are deduced from NMR spectra. The book does not set out to explain the areas usually covered in most textbooks such as the basic principles of NMR, pulse sequences or theoretical aspects but the emphasis is on practical side in solving the structure of unknown synthetic and natural compounds. It is designed for those, who, without deep knowledge of theoretical NMR, want to use the technique. Of course this cannot be achieved with efficiency without an understanding of theoretical bases. Thus, it starts with a short introduction to basic principles and methods, then the main parameters and techniques as well as basic terms are presented. In chapter 2 follows an introduction to tactics and strategies of structure elucidation of structural fragments by' one- and two-dimensional NMR. These include the atom connectivities, relative configuration and conformation, absolute configuration, intra- and intermolecular interaction and molecular dynamics. Chapter 3 presents a series of case studies providing spectroscopic details for 50 compounds that illustrate typical appli-

832 cations of the NMR technique in the structural characterisation of both synthetic and natural products. The presentation of the problems is particularly clear as for example chemical shift and coupling constant values do not have to be read off from scales but are presented numerically avoiding the need of tedious work. More interestingly the solutions of the problems are presented at the end of the book with detailed and full explanations which is a great advantage as compared to some other textbooks. The book will be of great interest for both students and professional scientists of chemistry, pharmacology and biochemistry engaged in the synthesis or the isolation and characterization of natural products. M Delepierre

Advances in Enzymology, voi 65, edited by Alton Meister, Wiley lnterscience, 1992, £ 67, p 436 A series like Advances in En:ymoiogy delivers every year a collection of review articles on many different topics. Eight areas were covered in 1992 and it would be impossible for a single referee to go in detail through all subjects. Ohe can remark however that scientists interested in nucleotides would learn relevant data from the article on traffic ATPases, by G Ferro-Luzzi Ames ,'rod coworkers, from the paper on the redox centers of ribonucleotide reductase by Fontecave et al and from the article on the calcium transport ATPase by lnesi ct al. One could also relate these subjects to methylation of mRNA (Nar,'lyan ,'rod Rottman) and even to mammali,'m nitric oxide synthases (by Stuehr ,'m Griflith) if one remembers that the target of nitric oxide is a GTP enzyme, soluble guanylyl cyclase! Generally speaking the articles range from detailed microscopic studies to studies in cell biology. The article by Ferro-Luzzi Ames et al is, in this respect, a integrated model: one learns about cells, membrane localization of traffic ATPases (especially in Gram-negative bacteria), membrane organization of the multiple components of the transporters, multidomain organization of the subtmits, and amino acid sequences of relevant portions of the polypeptides (in particular there is an interesting discussion about the role of glutamine residues in the formation of hinges in the polypeptide chain). One knows theretbre that, this year again, it is useful to have Advances in En-ymology in a library, located not too far from the laboratory. AL Lecocq

CIBA Foundation Symposium 172. Corticotropin.releasing Factor. edited by A Wiley-lnterscience Publication, John Wiley & Sons, 1993, £ 45, p 357

covered and identified. One of the key effector in this system is the hypothalamic neuropeptide corticotropin-releasing factor (CRF), isolated in 1981 from bovine hypothalamus (Vale et al) and isolated from the rat in 1983. All the experiments achieved in the last 10 years support the key role of this 41-amino acid straight polypeptide in the regulation of the pituitary-adrenal axis during basal and many stressfull circumstances. CRF neurons located in the paraventricular nucleus of the hypothalamus are triggered during stress. CRF is released and delivered to the hypophysial portal vasculature and to the pituitary corticotropes. ACTH is released following processing of a precursor, pro-opiomelanocortin that includes other biologically active peptides. ACTH finally triggers glucocorticoid production in the adrenal. However it became apparent that CRF has a variety of additional effects on reproductive hormones: fever, apetite, anxiety, depression, autonomic nervous system and inflammation. The book was put together following a symposium which brought together scientists working on CRF in a variety of systems. Among them were the pioneers in the field as well as experts in various other fields. The aim of the symposium and of the book is to provide a coherent picture of the role CRF plays in the control and coordination of the response to stress inducing situations. The first part of the books is dealing with 'classical' aspects of CRF: neuroanatomy, secretion in response to stress, CRF gene activation, CRF receptors and binding proteins. Each chapter is up to date, well documented and followed by a discussion about the most controversial or yet unpublished data. The second part of the book is dealing with recent data in which the role CRF is integrated in the regulation of other major biological functions. Two chapters are concerning the effects of cytokines and infection on CRF and ACTH release and one on the peripheral paradoxical anti-inflammatory action of CRE At the brain level CRF has also been shown to control the autonomic nervous system, cardiovascular functions and behavioral response to stress. Finally, on the clinical aspect, two chapters are dealing with the physiopathology of affective and anxiety disorders as well as the role of CRF in pregnancy and endocrine diseases. These chapters demonstrate that CRF is a key integrator of interactions between the neuroendocrine and the immune systems and that the same regulator may interact at many levels. For example interleukin I modulate hypothalamic CRF production, CRF can modulate peripheral interleukin I production and Glucocorticoids regulate CRF production and its action at the level of the pituitary or on inflammatory processes. The dicussions on these topics are particularly interesting since the data are new and sometimes still controversial, such as the possibility that lymphocytes might produce CRF in sufficient amount for biological action. In conclusion this is an excellent book for specialists in the field but also for scientists and clinicians from other field, in need of up-to-date informations on the various aspects of CRF biological activities. For this last population of readers it would have been interesting to have one or two introductory chapters on the neuroendocrinology of stress and on CRF itself. However this book is clearly not designed for teaching and has the quality and limits of symposium series. F Haour

Since 'stress' has been characterized by H Selye in the '40s, the biochemical mediators of this condition have been dis-