反应详情

Step 4 can also be carried out starting with a compound that is a mixture of E/Z isomer. For example, Step 4 is the reaction of E/Z-3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid methyl ester (4A) with NaOH to form E/Z-3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid (5A). In one embodiment, prior to step 4, the residue from step 3 is heated about 45° C. to about 60° C. to remove residual amounts of solvent. In one embodiment, the temperature is about 49° C. to about 55° C. In one embodiment, the ester hydrolysis reaction involving reacting E/Z-3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid methyl ester (4A) with NaOH is carried out at about 20° C. to about 25° C. in methanol, water, and a NaOH solution. In one embodiment, the NaOH solution is a 50% wt. aqueous solution.

1. additiona mixture of E/Z isomer