Chemistry complex sugars

Intrigued as much by its complex nature as by its outsider status in traditional organic chemistry, the editors of The Organic Chemistry of Sugars compile a groundbreaking resource in carbohydrate chemistry that illustrates the ease at which sugars can be manipulated in a variety of organic reactions. 

Several major research directions on hyaluronic acid were identified in the first half of the twentieth century. Lately, they have developed into independent branches within different fields of science including polymer chemistry, radiochemistry, biochemistry, molecular biology, medicine and glycobiology. The latter term was accepted in 1988 to describe a branch of science that combines a traditional biochemistry of hydrocarbons with a modem understanding of the role of complex sugars in cell and molecular biology. 

A major trend in organic synthesis, however, is the move towards complex systems. It may happen that one needs to combine a steroid and a sugar molecule, a porphyrin and a carotenoid, a penicillin and a peptide. Also the specialists in a field have developed reactions and concepts that may, with or without modifications, be applied in other fields. If one needs to protect an amino group in a steroid, it is advisable not only to search the steroid literature but also to look into publications on peptide synthesis. In the synthesis of corrin chromophores with chiral centres, special knowledge of steroid, porphyrin, and alkaloid chemistry has been very helpful (R.B. Woodward, 1967 A. Eschenmoser, 1970). 

Burger, K. Nagy, L. Metal complexes of carbohydrates and sugar-type ligands. In Burger, K. (Ed.), Biocoordination Chemistry, Chichester, Ellis Horwood, 1990 Chapter VI, p. 236. 

With the death of the bean, cellular structure is lost, allowing the mixing of water-soluble components that normally would not come into contact with each other. The complex chemistry that occurs during fermentation is not fully understood, but certain cocoa enzymes such as glycosidase, protease, and polyphenol oxidase are active. In general, proteins are hydrolyzed to smaller proteins and amino acids, complex glycosides are split, polyphenols are partially transformed, sugars are hydrolyzed, volatile acids are formed, and purine alkaloids diffuse into the bean shell. The chemical composition of both unfermented and fermented cocoa beans is compared in Table 1. 

In the study of the origin of life on earth, the element carbon is essential. Carbon is a required component of the fundamental molecules of life amino acids, bases, and sugars. In addition, a large variety of carbon compounds is necessary in the complex biochemical cycles of living organisms. The physical and chemical nature and geometry of the carbon atom make it well suited to form the vast array of molecules involved in the chemistry of life. 

By the second half of the nineteenth century German chemists had established a dominant position in analytical and synthetic organic chemistry. Various simple sugars and aminoacids were being isolated and characterized, as well as more complex plant products. Studies on the composition of blood and the properties of hemoglobin were also well under way. The composition of lipid-rich components and the order of the different units within complex macromolecules, such as proteins and nucleic acids, could not however be resolved by techniques then available. 

---