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Substituent‐dependent conformational changes in 6β‐substituted codeine derivatives
Author(s) -
Szilágyi László,
Makleit Sándor,
Hosztafi Sándor,
Simon Csaba
Publication year - 1992
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.1260300617
Subject(s) - chemistry , steric effects , substituent , ring (chemistry) , stereochemistry , cyclohexane conformation , molecule , hydrogen bond , organic chemistry
Complete 1 H and 13 C NMR data are reported for eleven isocodeine and seven dihydroisocodeine derivatives bearing various substituents at position 6. In isocodeines having bulky succinimido or phthalimodo groups at C‐6 ring C adopts a half‐boat conformation, characterized by the quasi‐equatorial orientation of the C‐6N bond. The distortion from the usual boat form is due to steric interactions between C‐14 and β‐substituents at C‐6, and it is greater in 14‐hydroxy derivatives than in isocodeines unsubstituted at this position. In dihydroisocodeines the conformation of ring C is close to a chair, irrespective of the steric demand of the substituent at C‐6.