Chemical Education Today
Book & Media Reviews Natural Product Chemistry at a Glance by Stephen P. Stanforth Blackwell, Oxford, UK, 2006. 152 pp, ISBN 978-1405145626. $ 35.99 reviewed by Alan M. Rosan
This sleek, purposeful, and authoritative book, part of the Blackwell “At-a-Glance” series of modular workbooks, is designed to present to undergraduates the structural variety and biosynthetic pathways of the main classes of natural products. It does this admirably by stating and continually reinforcing fundamental organic and bioorganic structural and functional principles. Starting with a dramatic molecular depiction of umbelliferone on the cover, it has much to offer at an affordable price and will reward the knowledgeable reader. The author, an expert in biosynthetic transformations, has thoughtfully and carefully assembled a useful workbook that provides, in nine chapters ranging from six to 29 pages, coverage of the foundations of natural product chemistry. After a brief introduction on primary and secondary metabolites and a succinct discussion of the key role played by acetyl coenzyme A, five core chapters detail the structural complexity and biosynthesis of fatty acids, polyketides, products of the shikimic acid pathway, terpenes and, lastly, natural compounds derived from amino acids. Within these chapters are found concise, well placed reminders of acid–base, keto–enol, redox, carbocation, transamination, acyl substitution, and carbonyl condensation chemistry along with authoritative descriptions of pathways to alkaloids, antibiotics, lignans, and amino acids. The book concludes with a short reading list citing some 20 major texts and primary journal reviews, provides the answers to all of the 54 in-chapter problems and has a 340-item index. This text presumes and requires considerable facility with organic bond-line drawing, iconic structure, stereochemistry, and reaction mechanisms but amply rewards those whose versatility with these fundamentals allows them to delve into the myriad pathways by which nature assembles an amazing variety of natural products. Based on the open-learning module approach and written with the defined purpose of linking fundamental organic reactions with their biological counterparts, each chapter begins with a short bulleted list of key learning objectives and ends with a bulleted summary of key points. These learning objects are active and require readers to develop skills at recognizing, identifying, describing, outlining, and proposing biosynthetic avenues. Drawings are numerous and crisp with all structures clearly numbered. When necessary, key structures and intermediates are reiterated throughout. This nicely avoids the problem of having to look back in the text. The five core chapters, each of which emphasizes a key biosynthetic unit,
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comprises short, bite-sized subsections and include from 3 to 20 in-chapter problems that amplify concepts. These are placed at strategic locations within the text and range from the simple to the very challenging. While the discussion is nearly error free, it does sometimes sacrifice clarity for brevity. For example, tautomeric equilibria are shown implying K =1. While occasionally structures and mechanisms are abbreviated or ambiguous as seen in aspects of calendic acid, the cis ring closure to 12oxophytodienoic acid, the anaerobic formation of oleic acid, the formation of thromboxane A2, the biosynthesis of penicillinic acid, and the Wagner–Meerwein rearrangement, in general the presentation is careful, concise and complete. Particularly insightful and clearly described are the remarkable biosyntheses of 6-deoxyerythronolide, the tetrahydrocannabinols, LSD, macrocyclic peptides, morphine, the penicillins, porphyrin, the taxanes, vancomycin, and the centrality of cinnamic acid. Similarly, the non equivalence of the enantiotopic hydrogens in NADPH is succinctly illustrated by reference to one’s hand. Building logically, the focus here is on learning the structures of and pathways available to key bioorganic building blocks and recognizing mechanistic themes common to organic transformations and biosynthetic natural product formation. Thus, for the most part, careful mechanistic drawings take center stage in this text. At the same time, it is somewhat unfortunate that little of the experimental evidence supporting these pathways is provided. For example, in the abbreviated but otherwise excellent discussion on the use of carbon labeling to determine the polyketide folding pattern leading to rubrofusarin, it would be useful to a student to present the actual isotopic labeling data. Similarly, the marvelously unexpected cyclopropyl to cyclobutyl carbocation rearrangement leading to squalene is offered without any accompanying evidence as to how this was elucidated. On the other hand, I found the presentation of polyketide cyclization and secondary modification particularly lucid. In the interests of concision, the biological origins, purposes, and utility of the many fascinating compounds discussed here are too often given short shrift. Thus it may appear that the examples chosen are more idiosyncratic than intended. It would certainly be illuminating to know where in nature these compounds arise and for what purpose. The real strength of this and other texts in the at-a-glance series lies in an exceedingly clear and patient exposition that leads to and explains molecular complexity from relatively simple modular units. The presentation here benefits enormously by having the drawings and figures generously spread out on the large pages with plenty of white space, often half a page or more, left for the reader’s notes and responses to questions. This format encourages active reading. With each chapter subsection seldom longer than two to four pages, and many titled with a question, one gains, upon reading this book, an appreciation for both nature’s and the author’s concise economy. A complemen-
© Division of Chemical Education • www.JCE.DivCHED.org • Vol. 85 No. 2 February 2008 • Journal of Chemical Education
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Chemical Education Today
Book & Media Reviews tary feeling of completion is enjoyed on working through the masterful presentation. This would be an excellent supplemental text in courses on natural product biosynthesis, bioorganic chemistry, or in an advanced organic chemistry/special topics offering. By incisively illuminating the diverse world of natural products chemistry it addresses the value and centrality of organic chemistry in nature’s handwork. I intend to refer to it often.
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http://www.jce.divched.org/Journal/Issues/2008/Feb/abs203.html Abstract and keywords Full text (HTML and PDF)
Alan M. Rosan is a member of the Department of Chemistry, Drew University, Madison, NJ 07940;
[email protected].
Journal of Chemical Education • Vol. 85 No. 2 February 2008 • www.JCE.DivCHED.org • © Division of Chemical Education
