3α,7α,12α-Trihydroxy- and 3α,7α-dihydroxy-24-oxo-5β-cholestan-26-oyl CoAs were chemically synthesized by the conventional method for the study of side chain cleavage in bile acid biosynthesis. 3α,7α,12α-Triformyloxy- and 3α,7α-diformyloxy-5β-cholan-24-als were initially subjected to the Reformatsky reaction with methyl α-bromopropionate, and the products were then converted into methyl 3α,7α,12α-triformyloxy- and 3α,7α-diformyloxy-24-oxo-5β-cholestan-26-oates. Protection by acetalization of the 24-oxo-group of these methyl esters with ethylene glycol, followed by alkaline hydrolysis, gave 3α,7α,12α-trihydroxy- and 3α,7α-dihydroxy-24,24-ethylenedioxy-5β-cholestan-26-oic acids. These acids were condensed with coenzyme A by a mixed anhydride method, and the resulting CoA esters were treated with 4M-hydrocholic acid to remove the protecting group to give 24-oxo-5β-cholestanoic acid CoA esters. The chromatographic behaviors of these CoA esters were also investigated.