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NMR studies of sulphur heterocycles: III— 13 C spectra of benzo[ b ]thiophene and the methylbenzo[ b ]thiophenes
Author(s) -
Clark P. D.,
Ewing D. F.,
Scrowston R. M.
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.1270080507
Subject(s) - steric effects , thiophene , chemistry , furan , substituent , naphthalene , sulfur , stereochemistry , medicinal chemistry , nmr spectra database , chemical shift , spectral line , organic chemistry , physics , astronomy
All carbon resonances in the title compounds have been unequivocably assigned. Steric effects in the peri substituted compounds have been compared with analogous effects in naphthalene and benzo[ b ]furan. The observed effects are not explained by current theory. Unusual deshielding steric shifts are observed at some carbons. Methyl substituent effects are not additive at any position in the sterically crowded 2,3‐disubstituted compounds.