New 9,10‐Secosteroids from Biotransformations of Bile Acids with Rhodococcus ruber.

Ofrom C(11) C(12) of secosteroids 4a and 4b affords the compounds 5a (5%) and 5b (20%), respectively.Onthe otherhand,in thebiotransformation of hyocholicacid with R.ruber the9,10-secosteroid4c is notdetected,but,rearrangingtoanintramolecularhemiacetalform,itevolvestothefinalfuranderivative6c(35%) by easy elimination of two molecules of H