There is disclosed an improved process for substitution of the hydroxy group at 2-position of an ascorbic acid derivative according to the following reaction scheme:
wherein R⁰ is hydrogen, alkyl having 1 to 6 carbon atoms, phenyl or a group of the formula
(wherein X is two hydrogen atoms, or acetal or ketal residue); R¹ is an alkyl or alkenyl group having up to 22 carbon atoms which may be substituted with phenyl or alkoxy having 1 to 22 carbon atoms; Y is halogen or optionally substituted sulfonyloxy; R is hydrogen, or primary, secondary or tertiary alkyl having 1 to 10 carbon atoms; and Z is an alkali metal or an alkali earth metal. There is also disclosed hydrolysis of the following scheme:
wherein R¹ is as defined above; and X is acetal or ketal residue.
根据以下反应方案,公开了一种
抗坏血酸衍
生物 2-位羟基取代的改进工艺:
其中 R⁰ 是氢、具有 1 至 6 个碳原子的烷基、苯基或式中的基团
(其中 X 是两个氢原子,或
缩醛或
缩酮残基);R¹ 是具有最多 22 个碳原子的烷基或烯基,可被具有 1 至 22 个碳原子的苯基或烷氧基取代;Y 是卤素或任选取代的磺酰氧基;R 是氢,或具有 1 至 10 个碳原子的伯、仲或叔烷基;Z 是碱
金属或碱土
金属。还公开了以下方案的
水解:
其中 R¹ 如上定义;X 为
缩醛或
缩酮残基。