Amides, carbohydrate, reaction with

In all forms of digestion (whether of proteins, carbohydrates, or fats), larger molecules are broken down into smaller molecules by a reaction with water in which a water molecule is split in two, each part joining a different product molecule. This type of reaction is called hydrolysis. Remember that proteins are long chains of amino acids linked together by amide functional groups called peptide bonds. When protein molecules are digested, a series of hydrolysis reactions convert them into separate amino acids. 

By contrast, the use of allyltins /3-substituted by an electron-withdrawing group represents a particularly attractive option, due to their enhanced reactivity towards nucleophilic carbon radicals. For this purpose several allyltins were prepared with amide, ester, chloride, nitrile, trimethylsilyl and sulfones functionalities [292]. They have been used for the synthesis of 1,4-dienes [293] or 10-15 membered a-methylene lactones [294], in aminoacids [295] or carbohydrate chemistry [296]. The /3-functionalization by nonactivating alkyl groups is tolerated as well and was used in the synthesis of prostaglandins [297] or /3-lactams [298]. This was also applied to radical cascade reactions with up to four elementary steps with an excellent diastereoselectivity control (Scheme 6.34) [299]. 

The conversion of some carbohydrate chlorosulfates into the corresponding fluorosulfates with silver fluoride in methanol,31 and the formation of a mono(azi-dosulfate) derivative on treatment of methyl 4,6-dichIoro-4,6-dideoxy-a-D-galac-topyranoside 2,3-di(chlorosulfate) (8) with sodium azide in N,N-dimethylform-amide at room temperature,32 are two other examples of reactions involving sulfur-chlorine scission. 

The lactams 2-pyrrolidinone and lV-methyl-2-pyrrolidinone may be used to increase the solubility of carbohydrates in alcoholic reaction media. However, they cannot be used in the preparation of metal halide adducts, because of their tendency to associate, perhaps by complexing, with metal halide adducts.1 Amides are known to form complexes with metal halides. For example, sodium iodide combines with N, N-dimethylformamide to give Nal 3 N,N-dimethylformamide. Acetamide can form NaBr 2 acetamide and NaI-2 acetamide. 7... 

IV. Alcoholates from Reactions, in Liquid Ammonia, of Carbohydrates with Alkali Metals, Alkaline-earth Metals, and Alkali Metal Amides... 

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