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本文报道了L-抗坏血酸(1)的两种新合成法。利用内酯环已经形成的L-古罗糖酸-1,4内酯(3)以合成L-抗坏血酸。3的直接化学氧化未能得到较高收率的1。因为1比3更易于被氧化。因而在大多数氧化条件下,1将不能残留下来。因此,3的氧化必须在一个氧化条件下能保持较稳定的衍生物上进行。进而在温和的水解条件下得到1。这就是本文所报道的新方法。经由一个新的被特殊基团保护了的L-古罗糖酸衍生物以制备1的另一方法,亦同样能够成功地得到L-抗坏血酸。
This paper reports two new synthetic methods of L-ascorbic acid (1). L-gulonic acid-1,4-lactone (3) that has been formed by a lactone ring is used to synthesize L-ascorbic acid. Direct chemical oxidation of 3 failed to give higher yields. Because 1 to 3 more easily oxidized. Therefore, in most oxidation conditions, 1 will not remain. Therefore, 3 oxidation must be able to maintain a relatively stable oxidation of the derivative. This gives 1 under mild hydrolysis conditions. This is the new method reported in this article. L-ascorbic acid is likewise successfully obtained via a new L-gulonic acid derivative protected by a special group by another method for preparing 1.