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1 H NMR spectra of the 2‐trifluoroacetyl derivatives of benzo[ b ]furan and benzo[ b ]thiophene
Author(s) -
Benassi Rois,
Folli Ugo,
Iarossi Dario,
Schenetti Luisa,
Taddei Ferdinando
Publication year - 1984
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.1270220315
Subject(s) - chemistry , furan , thiophene , chemical shift , chloroform , nmr spectra database , acetone , solvent , medicinal chemistry , stereochemistry , spectral line , computational chemistry , organic chemistry , physics , astronomy
Abstract The 1 H NMR spectra of the 2‐trifluoroacetyl derivatives of benzo[ b ]furan and benzo[ b ]thiophene were recorded at 200MHz in two solvents, chloroform and acetone. A long‐range coupling constant, 5 J (HF), between the fluorine nuclei of the trifluoroacetyl group and H‐3, of a value higher than 1 Hz, was measured. From the comparison of the 1 H chemical shifts of, and the solvent effects on, the trifluoroacetyl compounds and those of the corresponding 2‐acetyl derivatives, and on the basis of an empirical interpretation of the 5 J (HF) coupling constant, a predominant Z conformation was tentatively assigned to these derivatives.