151377-73-0 2-Keto-L-gulonic acid methyl ester 3031-98-9 Gulonic acid, 2-keto-, methyl ester, L- L-xylo-2-Hexulosonic acid, methyl ester Methyl 2-keto-L-gulonate Methyl L-xylo-hexulosonate NSC 163924 Xylohexulosonic acid, methyl ester