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Definition of the predominant tautomeric form of 3‐methyl‐1‐phenylpyrazoline‐5‐thione in solution by 1 H and 1 3 C NMR spectroscopy
Author(s) -
Bergman Joseph John,
Lynch Brian Maurice
Publication year - 1974
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570110205
Subject(s) - tautomer , chemistry , thiol , nuclear magnetic resonance spectroscopy , chemical shift , allylic rearrangement , stereochemistry , computational chemistry , medicinal chemistry , organic chemistry , catalysis
Conjoint use of pmr allylic coupling constants and of 1 3 C nmr chemical shift patterns defines the predominant tautomeric form of 3‐methyl‐1‐phenylpyrazoline‐5‐thione in solution in aprotic dipolar and in non‐polar solvents as the thiol species, 3‐methyl‐1‐phenylpyrazole‐5‐thiol. The tautomeric preference thus differs from that of the oxygen analog, and is opposite to that noted for thiol‐thione tautomerism in six‐membered heteroaromatic species.