反应详情

Step 5 can also be carried out starting with a compound that is a mixture of E/Z isomer. For example, Step 5 is the reaction of E/Z-3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid (5A) with Pd/C and hydrogen gas and heat to form 3α-hydroxy-6α-ethyl-7-keto-5β-cholan-24-oic acid (6). Step 5 can be carried out in one phase (hydrogenation and isomerization together) or in two phases (hydrogenation, followed by isomerization). In one aspect, step 5 is carried out at a temperature at about 90° C. to about 110° C. and at a pressure at about 4 to about 5 bars. In one embodiment, during workup, the organic phase of the reaction mixture is treated with activated carbon. In one embodiment, the pressure is about 4.5 to about 5.5 bars. In another embodiment, the pressure is about 5 bars. In one embodiment, the hydrogenation reaction mixture is allowed to stir for about 1 hour. In one embodiment, reacting E/Z-3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid (5A) with Pd/C and hydrogen gas is heated to about 100° C. and stirred for about 2 hour to about 5 hours. In one embodiment, reacting E/Z-3α-hydroxy-6-ethylidene-7-keto-5β-cholan-24-oic acid (5A) with Pd/C and hydrogen gas is heated to about 100° C. and stirred for about 3 hours.

1. additiona mixture of E/Z isomer
2. temperatureheat