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100 MHz n.m.r. spectra and conformational analysis of some methyl and trimethyl derivatives of 1‐tetralone
Author(s) -
Bergesen Knut,
Cook Michael J.,
Hock Teh Kim
Publication year - 1976
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.1270081006
Subject(s) - chemistry , substituent , methyl group , spectral line , stereochemistry , group (periodic table) , medicinal chemistry , crystallography , organic chemistry , physics , astronomy
The 100 MHz spectra of 2‐methyl‐, 4‐methyl‐, 4,5,8‐trimethyl‐ and 4,5,7‐trimethyl‐1‐tetralones have been analysed as 8‐spin systems using iterative computation. The monomethyl derivatives exist in inverting half‐chair conformations, the 2‐methyl group favouring the equatorial site and the 4‐methyl group showing equal preference for both axial and equatorial environments. The 5‐methyl substituent of the trimethyl derivatives constrains the 4‐methyl group to the axial site of rings which adopt non‐half‐chair conformations. The n.m.r. spectrum of 3‐methyl‐1‐tetralone is also discussed.