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Compounds with bridgehead nitrogen. 62 —NMR spectra and stereochemistry of perhydropyrido[1,2‐ c ][1,3]thiazepines and related systems
Author(s) -
Crabb Trevor A.,
Fallah Asadollah
Publication year - 1990
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.1260280509
Subject(s) - chemistry , conformational isomerism , stereochemistry , diazepine , nmr spectra database , spectral line , ring (chemistry) , molecule , organic chemistry , physics , astronomy
Perhydropyrido[1,2‐ c ][1,3] thiazepine adopts (CDCl 3 solution, 25°C) an equilibrium containing > 98% trans ‐fused conformer, in contrast to perhydropyrido[1,2‐ c ][1,3]oxazepine, which adopts a ca. 74% trans ‐fused ⇌ 26% O ‐inside‐ cis ‐fused conformational equilibrium. The cis ‐(H‐5a, H‐8)‐8‐ethyl‐substituted derivatives of both systems show increased preference for the S/O inside cis conformations. The related 2‐ tert ‐butylperhydropyrido[1,2‐ c ][1,3]diazepine adopts predominantly the trans ‐fused conformation.