13C,1H NMR spectra and the structure of steroids containing a perhydropyran or perhydrofuran E ring and modification in the A and B rings

Autor: Bogdanov, V. S., Cherepanova, E. G., Reshetova, I. G., Levi, V. G., Kamernitskii, A. V.
Zdroj: Russian Chemical Bulletin; March 1983, Vol. 32 Issue: 3 p492-501, 10p
Abstrakt: 1.We deciphered the3C spectra of 19 steroids with additional tetrahydropyran and tetrahydrofuran rings and modified in the A and B rings.2.The chemical shifts and spin-spin coupling constants for13C-1H are characteristic for the two conformations of the tetrahydropyran E ring, “chair” and “boat.”3.We determined the orientation of the substituents at C20 and confirmed the orientation for substituents at C3, C5, and C6.4.We carried out an analysis of thea-,ß-,?-, andd-effects for substituents in the tetrahydropyran ring and the A and B rings. We have shown that acetylation of the 20-OH group enhances thea-effect; theß-effects decrease in the order O > OH > OAc.5.The dependence of the spin-spin coupling constants for13C-1H on the nature of the substituent may be used to identify signals of the ring carbon atoms, along with their chemical shifts.
Databáze: Supplemental Index
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