Analogs of L-Ascorbic Acid Containing One Enolic Hydroxyl Group

Analogs of l-Ascorbic Acid Containing One Enolic Hydroxyl Group 

When the enol (XCVII) of 5-keto-4-desoxy-mannosaccharo-3,6-lactone is subjected to ozonolysis, cleavage occurs at the double bond with the formation of oxalic acid and D-erythuronic acid (XCVIII), the latter being identified by the fact that upon oxidation with bromine it yields meso-tartaric acid (XCIX). The formation of oxalic acid and erythu-ronic acid locates the double bond in XCVII between C4 and C5 and demonstrates that C4 carries a hydrogen atom while C5 has attached to 

The isomerization of D-mannosaccharodilactone which proceeds under the influence of alkaline reagents can also be brought about by diazomethane and by silver oxide and methyl iodide. In both cases isomerization is accompanied by methylation and there results 2,5-dimethyl-A -D-mannosaccharo-3,6-lactone methyl ester (CI).  

HCOH 1 HCOH HCOH HCOH HCOH HCOH 1 HCOH  

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V. Analogs of l-Ascorbic Acid Containing One Enolic Hydroxyl Group. 101... 

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