The preparation of the pure enantiomers of LIFIBROL and its alkyl esters is achieved with surprisingly good yield by reacting the pure enantiomeric forms of S(-) R(+)-4-(4-tert.butylphenyl)-1,2-epoxy butane with 4-hydroxybenzoic acid alkyl ester at elevated temperature in DMF and in the presence of 4-hydroxybenzoic acid alkyl ester sodium salt. Thereafter, the raw reaction product is separated. Either the stereochemically pure LIFIBROL ester is then recovered by recrystallization or the precipitated LIFIBROL enantiomer is made in pure crystalline form by mild alkaline saponification and subsequent acidification.
通过在
DMF中,在
4-羟基
苯甲酸烷基酯和
4-羟基
苯甲酸烷基酯钠盐的存在下,以纯对映体的S(-)R(+)-4-(4-
叔丁基苯基)-
1,2-环氧丁烷的对映体形式反应,以惊人的良好产率制备了LIFIBROL及其烷基酯的纯对映体。然后,分离原始反应产物。通过再结晶可以回收立体
化学纯的LIFIBROL酯,或通过轻微的碱性皂化和随后的酸化制备纯晶态的沉淀LIFIBROL对映体。