TRANSFORMATION OF ASCORBIGEN INTO 1-DEOXY-1-(INDOL-3-YL)-ALPHA-L-SORBOPYRANOSE AND 1-DEOXY-1-(INDOL-3-YL)-ALPHA-L-TAGATOPYRANOSE

Ascorbigen, ndol-3-yl)methyl]-alpha-L-xylo-3-hexulofuranosonic acid ga mma-lactone 1a results from the interaction of 3-hydroxymethylindole a nd L-ascorbic acid in mild conditions. In alkaline media ascorbigen op ens the lactone and furanose cycles and decarboxylates to yield a mixt ure of 1-deoxy-1-(indol-3-yl)-alpha-L-sorbopyranose 5a and 1-deoxy-1-( indol-3-yl)-alpha-L-tagatopyranose 6a. Formation of ascorbigen 3-O-met hylfuranoside 1e stabilizes furanose ring and prevents spontaneous dec arboxylation. Diphenylmethyl esters of ndol-3-yl)methyl]-alpha-1-xylo- 3-hexulofuranosonic acid and the corresponding 3-O-methylglycoside 4a and 4c were synthesized. A similar study was performed for N-methylasc orbigen 1b.