Bases in the Chemistry of Natural Products

Lee, M.L. Schneider, G. (2001) Scaffold Architecture and Pharmacophoric Properties of Natural Products and Trade Drugs Application in the Design of Natural Product-Based Combinatorial Libraries. Journal of Combinatorial Chemistry, 3, 284-289. 

Man-Ling Lee, Schneider G. (2001). Scaffold architecture and pharmacophoric properties of natural products and trade drugs appUcation in the design of natural product-based combinatorial libraries./owrnflZ of Combinatorial Chemistry, 3,284-9. 

This chapter shows how radical chemistry based on thiocarbonyl derivatives of secondary alcohols can be useful in the manipulation of natural products and especially in the deoxygenation of carbohydrates. From the original conception in 1975, the variety of thiocarbonyl derivatives used has increased, but the methyl xanthate function still remains the simplest and cheapest, when other functionality in the molecule does not interfere. Otherwise, selective acylation with aryloxythiocarbonyl reagents is important. Many of the functional groups present in carbohydrates and other natural products do not interfere with radical reactions. 

An understanding of what an alkaloid is will be mentioned in the first section, and in the second section, the aspects of classifying alkaloids on the basis of their biosynthetic origin will be presented. This method will be compared with a classification based on their carbon or heterocyclic skeleton, such as indole, isoquinoline alkaloids, or a classification of the alkaloids based on a chemotaxonomic approach, such as Rutaceae and Apocynaceae alkaloids. A short history of the study of alkaloids and the crude drugs as the origin of various alkaloids, and their relevance in the history of natural products chemistry will be described. Through these discussions, it will be established that the natural products classified as alkaloids relate to our life deeply, and on an everyday basis, as medicines, as dyestuffs, as flavors, as stimulants, and as toxic substances. 

In Chapter 1, Boldi and Dragoli provide an overview of the fields of natural products research and combinatorial chemistry. The latter half of the chapter examines several areas of research in the synthesis of natural-product-based libraries. 

The transition metal based catalytic species derived from hydrogen peroxide or alkyl hydroperoxides are currently regarded as the most active oxidants for the majority of inorganic and organic substrates " An understanding of the mechanism of these processes is therefore a crucial point in the chemistry of catalytic oxidations. This knowledge allows one to predict not only the nature of the products in a given process, but also the stereochemical outcome in asymmetric reactions. 

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