perbenzoic acid

Methods:After protection of the hydroxyl at C-3 and C-23 and carboxyl at C-28 of 23-hydroxy betulinic acid,the oxidation of compounds 5a-e was processed with m-chloroperoxybenzoic acid in chloroform by refluxing for 6 h.

方法:将23-羟基白桦脂酸3,23位羟基经乙酰化保护以及28位酯化得23-羟基白桦脂酸酯,再与间氯过氧苯甲酸进行环氧化反应,开环及脱保护得到目标化合物。