Nature sugars

Primitive people very likely encountered vinegar-like Hquids in hoUows in rocks or downed timber into which berries or fmit had fallen. Wild yeasts and bacteria would convert the natural sugars to alcohol and acetic acid. Later, when eady peoples had learned to make wines and beers, they certainly would have found that these Hquids, unprotected from air, would turn to vinegar. One can postulate that such eady vinegars were frequendy sweet, because the fmit sugars would have been acted on simultaneously by both bacteria and yeast. Only since the middle 1800s has it been known that yeast and bacteria are the cause of fermentation and vinegar formation. 

When you crack open a can of Coca Cola or Pepsi, you are tasting some of the fruits of bioohemioal engineering Most nondiet soft drinks sold in the United States are sweetened with high-fruotose oorn syrup (MFCS), a substitute for the natural sugar that oomes from cane and beets. MFCS, produced by an enzymatic reaction, is an example of the suooessful application of chemical engineering principles to bioohemioal synthesis. So successful, in fact, that more than 1.5 billion of MFCS was sold in the United States last year. 

The molecules of natural sugars are almost all classified as being right handed (R configuration), including the sugar that occurs in DNA. 

The Selective Fermentation of Natural Sugars by Pure Yeasts... 

Since chirality means "handness" it is quite pertinent to talk of homochiral molecules when referring to enantiomerically pure substances. Any natural sugar or amino acid is a homochiral product which belongs to the D or L-series, respectively. 

From his time at the Squibb research laboratories, he was interested in the chemistry of antibiotics, and in this area, he elucidated the partial structure of curamycin, an antibiotic produced by Streptomyces curacoi. From curamycin, he isolated and characterized the new natural sugar derivatives D-curacose (4-O-methyl-D-fucose), curacin [4-0-(dichlo-roisoeveminyl)-2,6-dideoxy-D-araW/io-hexose], and curamycose (2,6-di-O-methyl-D-mannose). 

A vast range of natural sugars exempMly these cyclic addition products. A typical sugar exists predominantly in the form of a hemiacetal or hemiketal in solution, although this is an equilibrium reaction, and the open chain carbonyl form is always present to a small extent (<1%). The formation of a six-membered cyclic hemiacetal from glucose is achieved by attack of the C-5 hydroxyl onto the protonated carbonyl (conjugate acid). 

The second section of the book, entitled Total Synthesis of Carbohydrates , focuses on strategies for the generation of monomeric carbohydrates, with major emphasis on the use of nonchiral, acyclic precursors. The contributors do not reinvent the wheel by providing tedious synthetic access to abundant natural sugars. Rather, they show... 

However, there are also many important biological catalytic systems. Fermentation of sugars into ethanol has been practiced since the Stone Age, and we stiU have not improved these catalysts much from the naturally occurring enzymes that exist in the yeasts that are found naturally growing in natural sugar sources. 

Synthesis and Applications of Ionic Liquids Derived from Natural Sugars... 

Tranter, G. E., MacDermott, A. J., Overill, R. E., and Speers, P. (1992). Computational studies of the electroweak origin of biomolecular handedness in natural sugars. Proc. Royal Soc., London A, 436, 603-15. 

Derivatives of uridine 5 -pyrophosphate are the most common natural sugar nucleotides, and about forty of them have been isolated. 

According to this site, the Sugar Association is proud to provide reliable, science-based information about pure, natural sugar. Furthermore, reliance on sound science has positioned the association as a leader in communicating accurate information about the nutritional and functional uses of sugar to consumers, professionah, and the media. 

Glucose and fructose are the predominant natural sugars in V. vini-fera grapes. A number of investigators have reported the proportions of these sugars, and generally at maturity the ratio is close to 1 1 although wide variation has been noted (19, 20). 

Natural sugar frameworks offer unique platforms for chemical manipulation and conversion into sugar or nonsugar target molecules. The following six chapters offer some of the most useful methods for functionalizing sugar molecules. 

C. Fouquey, J. Polonsky, and E. Lederer, Synthesis of three 3,6-dideoxyhexoses. Determination of the structure of the natural sugars tyvelose, ascarylose, and paratose, Bull. Soc. Chim. Fr. p. 803 (1959). 

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