Halogen halogenated carbohydrates

Halogen oxidation. See Oxidation, halogen. Halogenated carbohydrates, 22, 177-227 Haworth, Walter Norman, obituary of, 6, 1-9 HemiceUuloses,... 

A recent chapter on halogenated carbohydrates contains a comprehensive review of the subject (see J. E. C. Barnett, Advan. Carbohydrate. Chem. 22, 177 (1967)). 

The search for new methods of synthesis of halogenated carbohydrates continues to be an active area of investigation. The compounds are of utility as synthetic intermediates, and many of them are of intrinsic value in biochemistry and pharmacology. In the present Chapter methods for the synthesis of deoxyfluoro sugars and glycosyl fluorides are discussed. 

Several halogenated carbohydrates have been studied. One example is methyl 6-bromo-6-deoxy-a-D-galactopyranoside.48 Bromine... 

S. Hanessian, M. M. Pompipom, and P. Lavallde, Procedures for the direct replacement of primary hydroxyl groups in carbohydrates by halogen, Carbohydr. Res. 24 45 (1972). 

Despite the wide spread use of the artificial sweetener, Splenda , which is a synthetic chlorinated carbohydrate, Nature has provided very few halogenated carbohydrates. The antitumor metabolite FR 901463 (1598) was isolated from a Pseudomonas sp. along with two nonchlorinated epoxides. FR 901463 is not an isolation artifact, being present in the culture medium prior to extraction and isolation (1542-1544). 

Lemmes R, von Sonntag C (1982) On the formation of deoxy sugars from halogenated carbohydrates by a-hydroxyalkyl radicals considerations for the optimisation of reaction conditions. Carbohydr Res 105 276-282... 

Unsaturated carbohydrates may be prepared by the removal of hydrogen halide from certain halogenated carbohydrates which, in turn, are available from trityl ethers. Thus far this reaction has been successfully carried out only with compounds containing a primary halogen atom. 

Sulfonate displacement has been well established as a common method for introducing halogen atoms into carbohydrates. The high reactivity and easy preparation of sulfonic esters contribute to their use in carbohydrate chemistry. Triflate displacements are popular for the preparation of secondary halogenated carbohydrates and often give satisfactory results when mesylates and tosylates fail to give products. 

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