PCILO study of the conformation of 20‐oxopregnane hormones

Abstract

PCILO calculations on conformations of the C-17 side chains of three 20-oxopregnane hormones, progesterone, corticosterone, and cortisol, reveal that the calculated conformations are generally in close agreement with those observed crystallographically. Average deviation of the calculated rotation angle around the C(17)-C(20) bond from the experiment is 9". The PCILO calculations also predict the intramolecular hydrogen bond between the 20-carbonyl group and the 21-hydroxyl for the three hormones. This is in accordance with experiment. It was concluded that the PCILO method is reliable in predicting conformations of the side chains of hormones whereas the extended Huckel theory (EHT) predicted wrong conformations. Based upon the PCILO calculations, biological activities of the hormones are discussed.

Application of photoelectron spectroscopy to biologically active molecules and their constituent parts XI: Steroids

“…Low-resolution He1 photoelectron spectra of (top to bottom) 18-nor-5-androstene-17-one(4).18-nor-4-androstene-3, 17-dione ( 5 ) , and 18-nor-…”