Structure and Reactivity Patterns in Natural Compounds

The classic sequence of experiments with natural compounds in the twentieth century has been as follows isolation from biological sources, purification, elucidation of molecular structure, and finally total synthesis. These tasks of organic chemistry were fulfilled by the end of the century as far as the major components of higher organisms are concerned. Only compounds that are central to the growth of their tissues are the subject of this book. Many individual compounds of this kind of natural product, namely lipids, steroids, carbohydrates, carotenoids, porphyrins, vitamins, nucleic acids, and proteins, are today commercially available, and their structural and dynamic analysis has reached an accuracy and diversity that leaves little to be desired (Karrer, 1954 Fieser and Feiser, 1960 Tedder et al., 1972 Nuhn, 1981 Fuhrhop, 1982 Beyer and Walter 1988 Fuhrhop and Penzlin, 1994 Mann et al., 1994). 

The most important by-product of the analytic and synthetic work accomplished so far is knowledge about the stereochemistry and reactivity of natural compounds. There is an enormous potential for the chemists of the twenty-first century lying in the mastery and application of this knowledge in order to produce organized and finally functional materials. Typical contemporary examples include surface monolayers on metals and colloids made of fatty acid and steroid derivatives, the regio- and stereoselective assembly reactions between steroids and carbohydrates, coupled redox chains of metalloporphyrins and vitamins, noncovalent fibers made of amino acids, nucleotides, and saccharides, and the functionalization of proteins by incorporation of reactive molecules. The field of supramolecular or noncovalent natural compound chemistry has been scientifically fruitful for several decades and is presently exploited for the development of useful molecular devices and machines as well as for medical applications. 

The pathway of the book as a whole leads from less reactive, chiral molecules, which are useful as membrane components (lipids steroids, carbohydrates), to molecules that react reversibly with light and electrons and are helpful in energy conversion (carotenes, porphyrins, redoxactive vitamins), and finally to helical and reactive biopolymers (nucleic acids, proteins), which are used as frameworks for molecular machinery. Natural compounds that do not form important supramolecular assemblies or have not been used extensively as model compounds (e.g., alkaloids, antibiotics, metabolites) are not treated in separate chapters, but appear occasionally. 

All chapters are subdivided into at least four sections  

A monolayer section and some special sections are then occasionally added (e.g., catalysis in the case of porphyrins). 

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