| 摘要 |
L-Ascorbic acid, D-araboascorbic acid, and salts thereof, are prepared by esterifying a 2-keto-hexonic acid in the presence of a cation exchange resin, and enolizing and lactonizing the ester obtained. The 2-keto-hexonic acid may be 2-keto-gluconic acid or 2-keto-gulonic acid, and the acid may be esterified with methanol, ethanol, propanol or butanol. The enolization and lactonization may be carried out by heating in a neutral solvent, in the presence of a metal powder, sodium alcoholate, salt of a weak acid, or in an acidic solvent. Examples are given. |
