D-manno analogs

Treatment of methyl 2-azido-4,6-0-benzylidene-2-deoxy-a-D-altro-pyranoside (128) (42) with 121 followed by refluxing and processing afforded a chloro derivative as a sirup in 70% yield (46, 49). Reduction of this product with an excess of Raney-nickel in methanol containing acetic anhydride afforded a crystalline product, m.p. 179°C., which is formulated as the d-manno analog 131. The actual product is most likely methyl azido-4,6-0-benzylidene-3-chloro-2,3-dideodxy - a - d - mannopyran-oside (130) resulting from attack of chloride ion at C-3 with inversion of configuration in the intermediate 129. Had the chlorination proceeded... 

Yoshimura, J, Hara, K, Sato, T, Hashimoto, H, The highly stereoselective synthesis of perhenzylated a,a-trehalose and its Tt-galacto and D-manno analogs, Chem. Lett., 319-320, 1983. 

Following the synthesis by Comforth and his associates18 of NeuAc from oxalacetate and 2-acetamido-2-deoxy-D-mannose, Ghalambor and Heath29,31 prepared KDO (isolated as the crystalline methyl 2,4,5,7,8-penta-0-acetyl-3-deoxy-D-manno-2-octulopyranosonate, 70) from D-arabinose and oxalacetate by an analogous reaction (see Scheme 20). 

The occurrence of 3-deoxy-D-manno-octulosonic acid in lipopoly-saccharides has prompted its synthesis,537 together with the D-gal-octo158 and the D-gluco analogs.157 Although gas-liquid chromatography was successfully used to analyze the products of these syntheses, it has been reported that methanolysis of a bacterial endotoxin lipopolysaccharide failed to yield 3-deoxy-D-manno-octulosonic acid, presumably because of the lability of the latter to acid.381 However, Kasai and Nowotny have reported four peaks for the O-trimethylsilyl derivatives of 3-deoxy-D-manno-octulosonic acid obtained by methanolysis of the glycolipid from a Salmonella minnesota mutant.538 Reduced 3-deoxy-D-manno-octulosonic acid and its methyl ester have also been analyzed successfully as their acetates.339,539... 

Among nucleoside glycosyl monophosphates, the primary derivatives include cytidine (N-acetyl neuraminic monophosphate) (CMP-NeuAc),51 in which the n-glycero-fi-n-galacto configuration of the monosaccharide group has been confirmed,52 and the analogous derivative of 3-deoxy-D-manno-2-octulosonic acid.53,54... 

This methodology is valuable for similar derivatives in the D-manno [68], L-ara-bino [69] and 2-deoxy or 2,3-deoxy [70] series. Parallel work [71] on the O-formyl and O-acetyl phenyl P-D-glucopyranoside 70 and its a-anomer 71 yield compounds 72 and 73. The epimerization of 72 in acidic conditions leads to the more stable compound 73 by anomeric effect. Stereoelectronic effects can explain the twist-boat conformations of 69 and the chair conformation for the manno analog established by x-ray cristallography [72-73]. 

Reductive denitration was also investigated in the furanose series,45,252 using diethyl (2,3 5,6-di-0-isopropylidene-l-nitro-a-D-mannofuranosyl)phosphonate (158), an anomeric mixture of the analogous phenyl sulfone (159), (4R)-4,7-anhydro-2,3,4-trideoxy-5,6 8,9-di-0-isopropylidene-4-C-nitro-D-manno-nono-... 

In the years since the last review of sulfonic esters of carbohydrates, there have been many developments in physical methods for isolation of organic compounds and for their structural elucidation. Column chromatography on a variety of adsorbents has found wide application in the separation and isolation of esters of carbohydrates. Caution should be exercised in the use of alumina as the adsorbent for primary sulfonates on neutral or basic alumina of activity I, selective hydrolysis of the primary sulfonate group occurred with methyl 3,4 - di - O - methyl - 2,6 - di - O - (methylsulfonyl) - a - D - glucopyranoside, methyl 2,3-di-0-methyl-4,6-di-0-(methylsulfonyl)-/3-D-glucopyrano-side, and methyl 4-0-methyl-2,3,6-tri-0-(methylsulfonyl)-a-D-manno-pyranoside in benzene or ethanol-free chloroform. Analogous results... 

T. Sugai, G.-J. Shen, Y. Ichikawa, and C.-H. Wong, Synthesis of 3-deoxy-D-manno-2-octulosonic acid (KDO) and its analogs based on KDO aldolase-catalyzed reactions, J. Am. Chem. Soc. 775 413 (1993). 

Tadanier, J., Lee, C. M., Whittern, D., Wideburg, N. Synthesis of some C-8-modified 3-deoxy-]3-D-manno-2-octulosonic acid analogs as inhibitors of CMP-Kdo synthetase. Carbohydr. Res. 1990, 201, 185-207. 

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