Lyxose 5-deoxy-3-

Deoxy-D-(2-2H)lyxose (substituted) or (2S)-2-deoxy-D-fhreo-(2-zH)pentose... 

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-... 

D-Lyxose yielded a D-lyxosyl chloride 2,3,4-tri(chlorosulfate) which, on treatment with chloride ion, led to a dichlorodideoxy compound, most probably 2,4-dichloro-2,4-dideoxy-L-arabinose.353 D-Glucose gave a compound presumed to be 4,6-dichloro-4,6-dideoxy-a,/3-D-galactosyl chloride 2,3-di(chlorosulfate),360 and D-xylose afforded a monochloromonodeoxy derivative formulated, on indirect evidence, as 4-chloro-4-deoxy-L-arabinopyranosyl chloride 2,3-di(chlorosulfate).360 3,4-Dichloro-3,4-dideoxy-/3-D-ribopyranosyl chloride 2-(chlorosulfate) was the major, and 4-chloro-4-deoxy-a-D-xylopyranosyl chloride 2,3-di(chlorosulfate) the minor, product from the reaction of L-arabinose with sulfuryl chloride at room temperature for 24 hours.357,361 It has been established that, on reaction with sulfuryl chloride at low temperature, crystalline a-D-xylopyranose and /3-D-lyxopyranose afford, respectively, the 2,4,6-tri(chlorosul-fate)s of /3-D-xylopyranosyl chloride and a-D-lyxopyranosyl chloride,362 363 confirming that substitution at C-l occurs by an Sn2 process on a l-(chlorosulfuric) ester intermediate. 

In the pentose series, attack has also been observed to occur mainly from the less-hindered side of the double bond, as in the addition of trifluoro(fluoroxy)methane to di-O-acetyl-D-arabinal. Trifluoromethyl 3,4-di-0-acetyl-2-deoxy-2-fluoro-/3-D-arabinopyranoside and 3,4-di-0-acetyl-2-deoxy-2-fluoro-/J-D-arabinopyranosyl fluoride were obtained,72,74 together with a very small proportion of 3,4-di-0-acetyl-2-deoxy-2-fluoro-a-D-ribopyranosyl fluoride.74 With di-O-acetyl-D-xylal, however, the lyxose derivatives were mainly obtained.72,73 The suggestion has been made73 that the greater conformational mobility of pentopyranoses results in a preponderance of the C d) conformer of the D-lyxose derivatives,72,73 such that F-l and CFsO-l are axially disposed. For further reactions of unsaturated carbohydrates with tri-fluoro(fluoroxy)methane, see Section 11,9. 

Fucosidase inhibiting l,4,5-trideoxy-l,4-imino-L-lyxitol (78) was prepared [124] from D-ribose via protected 5-amino-5-deoxy-L-lyxose (79) by a chemical route. This compound, as well as the 1-aminomethyl homologue (80), obtained by Kiliani-Fischer chain extension of (79), inhibited a-L-fucosidase with K around 2 pmol/1. l,4-Dideoxy-l,4-imino-D-iditol (81) [71] was found to be a moderate inhibitor of the enzyme. 

An elegant, stereospecific synthesis of two 2-chloro-2-deoxy-pentoses was achieved during the course of a study of the anomerization of chlorosulfated glycosyl chlorides.40 It had been found37 that attempts to anomerize /3-D-xylopyranosyl chloride 2,3,4-tri(chloro-sulfate) (14) with 0.25 mol-equivalent of aluminum chloride afforded the crystalline a-D anomer only in low yield formed also was another compound whose structure has been established40 to be that of 2-chloro-2-deoxy-a-D-lyxopyranosyl chloride 3,4-di(chlorosulfate) (16). The dichloro derivative 16 became the exclusive product when 1.5 mol-equivalents of aluminum chloride were used treatment of 16 with sodium iodide yielded crystalline 2-chloro-2-deoxy-D-lyxose. Similarly, a-D-lyxopyranosyl chloride 2,3,4-tri(chlorosulfate) (15) afforded 2-chloro-2-deoxy-a-D-xylopyranosyl chloride 3,4-di(chlorosuI-fate) (17). 

Anhydrides of sugars1723 have also been obtained by intramolecular displacement of halide ions. Thus, for example, treatment of 3,4-di-0-acetyl-2-bromo-2-deoxy-D-xylopyranose (133) with (p-ni-trophenyl)hydrazine affords173 3,4-di-0-acetyl-2,5-anhydro-D-lyxose (p-nitrophenyl)hydrazone (135) and 3,4-di-0-acetyl-2,5-anhydro-D-xylose (p-nitrophenyl)hydrazone (136). The formation of two (p-nitrophenyl)hydrazones can be explained by an initial displacement of the bromine atom at C-2 by 0-5, to give 3,4-di-0-acetyl-2,5-... 

Barium D-ribose 5-phosphate pentahydrate75 2-Deoxy-D-cry[Pg.363]

The Wohl degradation214 of suitably acetylated aldononitriles was used for the synthesis of 5-deoxy-L-arabinose,216 5-deoxy-D-lyxose,2W and 5-deoxy-D-ribose.217... 

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