4- deoxy branched-chain sugar

Deoxy sugars showed an inhibitory effect on the biosynthesis of heparan sulphate [47], and a 4-deoxy branched-chain sugar is a structural feature of amipurimycin, isolated from Streptomyces novoguineensis, that presented a strong antifungal activity against Pyricularia oryzae [48],... 

Deoxy-branched chain sugars are also referred to as precursors for alkaloid and polyketide synthesis in Chapter 24, and branched-chain sugar nucleosides are mentioned in Chapter 20. 

A variety of approaches to deoxy branched-chain sugars have been reported. 

Before 1983, branched-chain sugars had not been found in bacterial polysaccharides, but there are now five examples belonging to this class. The LPS from Coxiella burned phase I contains both 6-deoxy-3-C-methyl-L-gulose (L-virenose) as pyranoside (12) and 3-C-(hydroxymethyl)-L-lyxose as furan-oside (13). Another 6-deoxy-3-C-methylhexose, having the manno configuration, is a component of the Nitrobacter hamburgiensis 0-antigen. ... 

Streptose is the first branched-chain sugar to have been identified as a component of a biological compound produced by a microorganism. This dicarbonyl sugar is known only in its derivatives. The chemistry of streptose and streptomycin has been lucidly reviewed by Lemieux and Wolfrom.1 In this article, it was noted that streptose must be either 5-deoxy-3-C -formyl-L-ribose or 5-deoxy-3-C-formyl-L-lyxose. Since then, the presence of the latter configuration (XXXIV) has been definitely established by Wolfrom and DeWalt,66 who found that N-acetyltetrahydrostreptobi-... 

M. L. Wolffom and S. Hanessian, Reaction of free carbonyl sugar derivatives with organo-metallics reagents. II 6-Deoxy-L-idose and a branched-chain sugar, J. Org. Chem. 27 2107 (1962). 

Carbohydrate chemistry is engaged in the synthesis and variation of deoxy sugar chains, where a wide set of protective groups and stereoselective glycosylation techniques are required. This contribution centers on stereoselective syntheses of mono-and oligosaccharides in the field of 2,6-dideoxy- and, in particular cases, branched-chain sugars, and summarizes modem synthetic glycosylation reactions which have been developed for this special kind of carbohydrate chemistry. 

I. I. Cubero and M. T. P. Lopez-Espinosa, Branched-chain sugars. 12. Synthesis of 3,4-anhydro-l-deoxy-3-C-methyl-D-hexulose derivatives, Carbohydr. Res., 154 (1986) 71-80. 

A. A. J. Feast, W. G. Overend and N. D. Williams, Branched chain sugars.V. Structure and reactivity of anhydro sugars. VI. The synthesis of branched-chain deoxy sugars, J. Chem. Soc., (1965) 7378-7388. 

Williams N, Wander J (1980) Deoxy and branched-chain sugars. In Pigman W, Horton D (eds) The Carbohydrates Chemistry, Biochemistry Vol IB. Academic Press, New York, p 761... 

Synthesis of 6-Chloro-9-(6 -deoxy-3 -C-methyl-2, 3, 4 -tri-0-methyl-/3-D-allopyrano-syl)purine A Branched-chain Sugar Nucleoside, G. B. Howarth, W. A. Szarek, and J. 

An analogous methyl 2,3-dideoxy-3-C-methylene-a-L-en/thro-hexopyranoside (20) was obtained10 from methyl 4,6-O-benzylidene-2-deoxy-a-L-eri/t/iro-hexopyranosid-3-ulose (19) it was used in the synthesis of olivomycose (see p. 242). There was also reported32,34 the preparation of 3-deoxy-l,2 5,6-di-0-isopropylidene-3-C-methyl-ene-a-D-rifco-hexofuranose (22) from 1,2 5,6-di-0-isopropylidene-a-D-nfeo-hexofuranos-3-ulose (21) in about 60% yield, followed by transformations into branched-chain sugar derivatives, including... 

More than a dozen branched-chain, deoxy sugars have now been discovered as components of antibiotics. One review on their biosynthesis4 and two5,6 on the chemistry and biochemistry of branched-chain sugars have appeared. These sugars can be divided into two groups according to their biosynthesis. 

In their extensive studies of branched-chain sugars. Overend and coworkers have examined the reaction of several tertiary p-tol-uenesulfonic esters with lithium aluminum hydride in ether, as a method of obtaining branched-chain deoxy sugars. Methyl 3,4-0-isopropylidene-2-C-methyl-2-0-p-tolylsulfonyl-/8-L-arabinopyrano-side (3, R = CHs, R = OTs) afforded methyl 2-deoxy-3,4-0-isopropyli-dene-2-C-methyl-j8-L-erythro-pentopyranoside (3, R = CH3, R = H) in 50 % yield. Extension of this method to the 2-C-(phenylethynyl) and... 

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