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Ring a conformation in steroids. 3 —Cyclosteroids and cyclopropanosteroids
Author(s) -
Marat Kirk,
Templeton J. F.,
Ling Yangzhi,
Lin Weiyang,
Gupta R. K.
Publication year - 1995
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.1260330707
Subject(s) - geminal , chemistry , vicinal , cyclopropane , ring (chemistry) , proton , chemical shift , coupling constant , methylene , computational chemistry , proton nmr , stereochemistry , spin (aerodynamics) , crystallography , medicinal chemistry , organic chemistry , thermodynamics , physics , particle physics , quantum mechanics
Proton and carbon NMR data are provided for 21 ring A and ring B cyclosteroids and cyclopropano (or methylene) steroids. Shift assignments were made using standard 2D NMR techniques, while ring A proton subspectra were extracted with a 1D TOCSY experiment. Coupling constants were obtained from iterative spin system simulation of these sub‐spectra. Ring A conformations were determined from the two‐ and three‐bond proton‐proton couplings and NOE measurements. The utility and limitations of extended Karplus‐type equations, the effect of cyclopropyl groups on vicinal and geminal couplings and cyclopropane‐induced chemical shifts are discussed.