Sugars as Precursors

There has been further activity in the use of sugars as precursors for the A ring of anthracyclinones. The aldehyde (3), previously reported (Vol. 18, p, 248), has been prepared by an improved procedure and converted into (4), a suitable intermediate for an AB + CD approach to the tetracycle. Similar routes to those described earlier (Vol. 18, p. 248) have been used in the synthesis of (5), containing the key tertiary carbinol function, from diiso-propylidene glucose via a Marschalk reaction, and earlier work has... 

Low-fat food prepared from urmatural sugars 1 will have a zero calorie value and might contribute to battling obesity. The availability of 2 as precursor compoimd for the synthesis of 1, however, is a current bottleneck. Sugar substrates... 

This review summarizes recent approaches towards the selective formation of anomeric aldose and aldulosonic acid phosphates of biological relevance, in particular as precursors for the synthesis of nucleotide-activated sugars. 

Nitro sugars have been broadly used as precursors of the corresponding amino sugars, most of them naturally occurring and biologically relevant compounds. The standard procedure involves a catalytic hydrogenation and several catalysts have been used for this purpose. 

S. G. Carmella, S. S. Hecht, T C. Tso, and D. Hoffmann, Roles of tobacco cellulose, sugars, and chlorogenic acid as precursors to catechol in cigarette smoke, J. Agric. Food Chem. 32(2), 267—273 (1984). 

Many new sugar based products present the advantage of being non-toxic and biodegradable. The products resulting from the telomerization of 1 with appropriate nucleophiles such as alcohols, amines, water, or carbon dioxide serve generally as useful intermediates in the synthesis of various natural products and fine chemicals [60-63], as precursors for plasticizer alcohols [56, 64], components of diesel fuels [65], surfactants [11, 66], corrosions inhibitors, and non-volatile herbicides [67]. 

The increased availability of methods for the preparation of unsaturated sugars107 has stimulated interest in addition reactions of these compounds the use of unsaturated carbohydrate derivatives as precursors for specifically halogenated sugars has been widely exploited. 

For the application of alkenes as precursors in the synthesis of carbohydrates, knowledge of their stereochemistry is essential. Fortunately, several alkenic compounds having a defined configuration of the double bond and proper functional groups are readily available, making them convenient substrates in the synthesis of sugars. 

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