Catalytic hydrogenation of 19-hydroxy-A'-3-keto steroids affords predominantly A, B-cis dihydro derivatives. Unexpectedly, reduction in a lithium-ammonia system also gave substantial yields of the A, B-cis isomer. Hydrogenation of the esters and ethers of the 19- hydroxy compounds led in general to significant increases in the yields of A, B-trans isomers. The reduction of some 19-chloro-Ab-and-A4-androstenes is also discussed.
