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NMR study of conformation and configuration in C‐20‐substituted 5β,14β‐pregnanes, 5β‐pregn‐14‐enes and 21‐nor‐5β,14β‐pregnanes
Author(s) -
Marat Kirk,
Templeton J. F.,
Ling Yangzhi
Publication year - 1993
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260310106
Subject(s) - chemistry , side chain , stereochemistry , pregnane , two dimensional nuclear magnetic resonance spectroscopy , organic chemistry , polymer
Coupling constants and nuclear Overhauser effect measurements were used to establish the C‐20 configuration and the conformation about the C‐17C‐20 bond in a series of sixteen C‐20‐substituted 5β,14β‐pregn‐14‐enes. In the 14β‐pregnane series the conformation of the C‐17 side‐chain is variable, whereas in the pregnenes the side‐chain adopts a conformation in which H‐17 is anti to H‐20. The C‐17 side‐chain conformation of two 21‐nor‐5β,14β‐pregnanes was also determined. In the 21‐nor compounds a C‐20 hydroxyl adopts a conformation anti to H‐17, while a C‐20 nitro group is anti to C‐13.