Deoxy sugars sulfonates

If an appropriately situated, unsubstituted hydroxyl group is available, anhydro-ring formation usually takes precedence over substitution or elimination. Thus, with alkali, the bromo-, chloro-, and iodo-deoxy sugars react analogously to sulfonic ester derivatives148 to afford epoxides in good yield.22,169 It has been established170 that l,2 5,6-dianhydro-D-mannitol is formed in aqueous solutions of... 

The sugar sulfonic acid is l-0-(6-deoxy-6-sulfo-a-D-glucopyranosyl)-glycerol isolated from a plant sulfolipid.46 The plant sulfolipid... 

As mentioned above, there is particular need for p-stereospecific glycosylation in the 2-deoxy sugar series. Wiesner et al. [17] have developed a method which starts with 4-(p-methoxy)-benzoyl-3-methylurethane digitoxose 31. On treatment with the agly-con and p-toluene sulfonic acid, the P-glycoside 32 is obtained in 83% with an P a-ratio of 7 1. 

The reduction of halides or sulfonates is one of the most conventional methods for the synthesis of deoxy sugars. This method is particularly useful for the deoxygenation of primary hydroxyls of carbohydrates. Reduction has been accomplished employing one of the following three methods. 

Treatment of halides or sulfonates with hydride donors such as tetrabutylammonium borohydride,38 lithium aluminium hydride,39 lithium triethylborohydride46 or sodium borohydride generate deoxy sugar derivatives (Scheme 3.8c).41 When sodium borohydride is employed, a transition metal catalyst (PdCk or NiC-b) may be added. 

Application of mass spectrometry to carbohydrate derivatives has been reviewed in this Series. Although no example of its application to sugar sulfonates was cited, such experiments have undoubtedly been performed samples having very low volatility may be examined after direct introduction into the ion-source chamber. Sulfonates of 6-chloro-6-deoxy sugars were first identified in this way, and interpretation of the mass spectra was aided by the presence of fragments containing C1 and C1. 

However, reduction of primary sulfonic esters of D-galactopyrano-sides with lithium aluminum hydride in tetrahydrofmran can also result in formation of deoxy sugars. Heyns and coworkers reduced methyl 3-0-methyl-6-0-p-tolylsulfonyl- 8-D-galactopyranoside in this... 

This Sml2-induced C-glycosylation was extended to the s)mthesis of C-linked glycosides of 2-acetamido-2-deoxy sugars [88,89,90]. Reductive samariation of the 2-pyridyl sulfone of A-acetylglucosamine 184 in the presence of aldehyde 167 leads selectively to the a-C-gly-cosyl dimer 185 [90] (O Scheme 38). 

Perhaps the earliest report of the replacement of a sulfonate ester attached to a secondary carbon atom in a sugar derivative was that of Helferich (53). Under quite drastic conditions (sodium iodide in acetone, 105°C., 72 hours, sealed system) the 4-mesylate derivative 9 was converted into a crystalline 4-deoxy-4-iodo sugar derivative 10 in 46% yield. Although the position of the iodine atom was established, the configuration at C-4 was not known. 

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