product. Purification via column chromatography yielded the pure diastereoisomers in approximately 25% overall yield. The two diastereoisomers were resolved on thin-layer chromatography and high-performance liquid chromatography. When the bile of A mississippiensis was hydrolyzed with rat fecal bacteria, the 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid isolated via chromatographic purification
描述了由3α,7α,12α-三羟基-5β-
胆甾醇-26-酸合成3α,7α-二羟基-5β-
胆甾醇-26-酸的25R-和25S-非对映异构体。通过剧烈地
水解密西西比短吻鳄的胆汁,然后反复结晶
水解物,获得3α,7α,12α-三羟基-5β-胆甾烷-26-oo酸的25S-非对映异构体,且25R-非对映异构体为通过
水解密西西比河胆汁中的胆汁盐与大鼠粪便分离。在控制条件下,甲基3α,7α,12α-三羟基-5β-胆甾烷-26-
油酸的25R-或25S-非对映异构体的乙酰化产生相应的3α,7α-二
乙酸酯。将二
乙酸酯定量氧化为甲基3α,7α-
二乙酰氧基-12-氧代-5β-胆甾烷-26-酸酯,其以约58%的产率转化为12-
甲苯磺酰zone。用
硼氢化钠在
乙酸中还原
甲苯磺酰zone,得到3α,7α-二羟基-5β-胆甾烷-26-
油酸的25R-或25S-非对映异构体作为主要产物。通过柱色谱法纯化得到纯的非对映异构体,总产