作者:T. Fujii、Y. Hatanaka
DOI:10.1016/0040-4020(73)80202-9
日期:1973.1
and benzohydroxamic acid (3b) using PdC as a catalyst has disclosed that 2a·HCl smoothly undergoes the hydrogenolytic cleavage at both the benzyl—O and NO bonds, whereas 2b almost selectively suffers benzyl—O cleavage. The use of the benzyl group for protecting a hydroxamic acid function, suggested by the hydrogenolysis study, was embodied in the synthesis of rhodotorulic acid (1) starting with the
以PdC为催化剂对苄氧胺盐酸盐(2a ·HCl),苄基苯氧肟酸酯(2b)和苯并异羟肟酸(3b)进行催化加氢的比较研究表明,2a ·HCl顺利地在两个苄基上进行了氢解-O和N = O键,而2b几乎选择性地遭受苄基-O裂解。用于保护异羟肟酸的功能,通过氢解研究建议使用苄基的,体现在rhodotorulic酸(合成1)与反应起始2A与溴化物5,得到8。关键中间l- 9通过使用Taka-淀粉酶选择性地,不对称地脱乙酰化8,可以方便地制备糖基。1-转化9成氨基酯1- 13通过N α -保护的氨基酸(1- 11)和酯1- 12和1-耦合11与1- 13得到的二肽11- 14。从ll- 14中除去叔丁氧基羰基并将所得的氨基酯环化,生成倒数第二个异羟肟酸苄酯(ll- 15),将其用PdC和氢气选择性地脱苄基,得到1。