Labeled bile acids V: Deuterium and carbon-13 labeled cholic, chenodeoxycholic and ursodeoxycholic acids

This paper describes a general, simple and short procedure for the introduction of stable isotopes (deuterium and carbon-13) to the side chain of bile acids. The bisnorcholyl aldehydes of cholic and chenodeoxycholic acids are key intermediates, while the isotope is introduced by the Wittig condensation of [1,2-13C2]-(carbethoxymethylene)triphenyl-phosphorane.