反应详情

Ingenol can be converted to ingenol-3,4-acetonide by treatment with 4-toluenesulphonic acid hydrate and acetone to give ingenol-3,4:5,20-diacetonide followed by treatment with perchloric acid in methanol or zinc bromide in dichloromethane and methanol according to the method of Opferkuch et al. (1981). Ingenol-3,4-acetonide could be converted to ingenol-3,4-acetonide-20-trityl ether by treatment with trityl chloride and 4-(N,N-dimethylamino)pyridine in dry pyridine, acylated in an analogous manner to that described in Example 1 or Example 3 to give the ingenol-3,4-acetonide-20-trityl ether 5-acylate then treated with methanolic perchloric acid according to the method of Example 15 or Example 18 to give the ingenol 5-acylate. The ingenol 5-acylate could then be converted to the ingenol-3,4-acetonide 5-acylate by treatment with 4-toluenesulphonic acid hydrate and acetone according to the method of Opferkuch et al. (1981). The ingenol-3,4-acetonide 5-acylate could be converted to the 20-chloro-20-deoxy-3,4-acetonide 5-acylate by the method of Example 15.