A standard structure for bile acids and derivatives

Abstract

The crystal structures of two ester compounds (a monomer in its methyl ester form,with anamino isophthalic group, and a dimer in which the two steroid units are linked by a urea bridgerecrystallized from ethyl acetate/methanol) derived from cholic acid are described. Average bondlengths and bond angles from the crystal structures of 26 monomers and four dimers (some of themin several solvents) of bile acids and esters (and derivatives) are used for proposing a standardsteroid nucleus. The hydrogen bond network and conformation of the lateral chain are also discussed.This standardstructure was used to compare with the structures of both progesterone and cholesterol