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Proton magnetic resonance studies of compounds with bridgehead nitrogen: XXVIII —Stereochemical studies with perhydropyrido[1,2‐ c ] [1,6,3]dioxazocines and 2‐alkylperhydropyrido[1,2‐ c ] [1,3,6]oxdiazocines
Author(s) -
Crabb Trevor A.,
Jackson Graham C.
Publication year - 1975
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270071007
Subject(s) - piperidine , ring (chemistry) , cyclohexane conformation , steric effects , chemistry , stereochemistry , substituent , proton magnetic resonance , lone pair , crystallography , nitrogen , nuclear magnetic resonance , molecule , hydrogen bond , organic chemistry , physics
A series of perhydropyrido[1,2‐ c ][1,6,3]dioxazocines and 2‐alkylperhydropyrido[1,2‐ c ][1,3,6]oxdiazocines have been prepared. 6‐ p ‐Nitrophenyl‐3,4‐dimethylperhydropyrido[1,2‐ c ][1,6,3]‐dioxazodioxazocine is shown to adopt the cis fused ring conformation in solution with the nitrogen lone pair axial with respect to the piperidine ring. The 2‐alkylperhydropyrido[1,2‐ c ][1,3,6]oxdiazocines adopt a similar cis fused ring conformation and with increasing steric requirement of the 2‐alkyl substituent the 8‐membered ring increasingly favours the chair‐chair conformation, rather than the chair–boat conformation favoured by the 2‐methyl substituted compound.