The Chemistry Of Free Radicals

Free radicals constitute the most frequently used class of reaction intermediates in organic chemistry. This study describes the structure and reactivity of free radicals, and explores their role in both natural phenomena and in the design of new reaction pathways.

The past twenty years has seen an explosion of interest in free radicals, as their pivotal role in both chemistry and biology has come to light. This introductory textbook aims to capture this excitement for advanced level undergraduates, with particular emphasis on the importance of radical reactions in organic synthesis. The book provides a gentle, stepwise introduction to the subject, taking the student from the basic principles of radical reactions through to their applications in industry and their role in biological and environmental processes, allowing the relevance of the subject to be grasped more easily. Suitable for advanced level undergraduates and postgraduates in chemistry and biochemistry, the book will also be invaluable for research level scientists requiring an update in the area.

This book describes the experience over 25 years of the senior author with the chemistry of organic free radicals. It begins with a mechanistic study of industrial importance on the pyrolysis of chlorinated alkanes. It continues with a theory on the biosynthesis of phenolate derived alkaloids involving phenolate radical coupling. There follows 20 years of practical work to prove the theory correct, especially in the case of morphine alkaloids. The book then describes the work on nitrile photolysis (Barton reaction) which involved the invention of new radical chemistry leading to a simple synthesis of the important hormone, aldosterone. There follows a description of the invention of an important new method for the deoxygenation of biologically important molecules, especially sugars and nucleosides, using radical chemistry applied to thiocarbonyl derivatives. Some years later, in a logical extension to carboxylic acids, another new reaction was invented which provides carbon, nitrogen, oxygen and other radicals under mild conditions. A final chapter summarizes recent applications of thiocarbonyl group derived radical reactions by other authors.

The free-radical chemistry of DNA had been discussed in some detail in 1987 in my book The Chemical Basis of Radiation Biology. Obviously, the more recent developments and the concomitant higher level of understanding of mechanistic details are missing. Moreover, in the living cell, free-radical DNA damage is not only induced by ionizing radiation, but free-radical-induced DNA damage is a much more general phenomenon. It was, therefore, felt that it is now timely to review our present knowledge of free-radical-induced DNA damage induced by all conceivable free-radical-generating sources. Originally, it had been thought to include also a very important aspect, the repair of DNA damage by the cell’s various repair enzymes. Kevin Prise (Cancer Campaign, Gray Laboratory, L- don) was so kind to agree to write this part. However, an adequate description of this strongly expanding area would have exceeded the allocated space by much, and this section had to be omitted. The directors of the Max-Planck-Institut für Strahlenchemie (now MPI für Bioanorganische Chemie), Karl Wieghardt and Wolfgang Lubitz, kindly allowed me to continue to use its facilities after my retirement in 2001. Notably, our - brarian, Mrs. Jutta Theurich, and her right-hand help, Mrs. Rosemarie Schr- er, were most helpful in getting hold of the literature. I thank them very much. Without their constant help, this would have been very difficult indeed.

Covers the most advanced computational and experimental methods for studying carbon-centered radical intermediates With its focus on the chemistry of carbon-centered radicals and radical cations, this book helps readers fully exploit the synthetic utility of these intermediates in order to prepare fine chemicals and pharmaceutical products. Moreover, it helps readers better understand their role in complex atmospheric reactions and biological systems. Thoroughly up to date, the book highlights the most advanced computational and experimental methods available for studying and using these critically important intermediates. Carbon-Centered Free Radicals and Radical Cations begins with a short history of the field of free radical chemistry, and then covers: A discussion of the relevant theory Mechanistic chemistry, with an emphasis on synthetic utility Molecular structure and mechanism, focusing on computational methods Spectroscopic investigations of radical structure and kinetics, including demonstrations of spin chemistry techniques such as CIDNP and magnetic field effects Free radical chemistry in macromolecules Each chapter, written by one or more leading experts, explains difficult concepts clearly and concisely, with references to facilitate further investigation of individual topics. The authors were selected in order to provide insight into a broad range of topics, including small molecule synthesis, polymer degradation, computational chemistry as well as highly detailed experimental work in the solid, liquid, and gaseous states. This volume is essential for students or researchers interested in building their understanding of the role of carbon-centered radical intermediates in complex systems and how they may be used to develop a broad range of useful products.