反应详情

Step 4 is the reaction of 3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid methyl ester (4) with NaOH to form E-3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid (5). In one embodiment, prior to step 4, the residue from step 3 is heated to 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 reacting 3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid methyl ester (4) with NaOH is carried out at about 20° C. to about 25° C. in methanol, water, and a NaOH solution.