Mass Spectral Fragmentation of Bile Acid Ester Derivatives

Article abstract of DOI:10.1021/jo01290a027

The current mechanistic understanding and evidence for the decreasing preferential order (12α > 7α > 3α) of consecutive loss of three carboxylic acid or three water molecules from the molecular ion of 3α,7α,12α-tricarboxy-5β-cholanoates or 3α,7α,12α-trihydroxy-5β-cholanoates, respectively, are summarized.Additional mechanistic details for water loss have been determined with the aid of deuterium labeling.The fragmentation pathways of 3α,7α,12α-triacetoxy-5β-pregnan-20-one, a bile acid derivative, have been defined by comparison with four deuterated analogues.Evidence for the nominal loss of acetic anhydride or its equivalent from triacetate esters of cholic acid is presented.