Protomeric equilibrium solvent effect

Steric effects of the substituents in positions 4 and 5 cannot shift the protomeric equilibrium sufficiently to permit spectroscopic observation of the thiol form (43b) ultraviolet spectra of 4-terr-butyl-5-methyl-A-4-thia2oline-2-thione (49a) in neutral solvents do not reveal any trace of the thiol protomer (49bi (Scheme 21) (70). [Pg.380]

Uses, aminothiazoles derivatives, 132-172 hydroxythiazole derivatives, 438-442 mercaptothiazole derivatives, 438-442 UV spectra, 21 of alkylaminothiazoles. 38 and amino-imino equilibrium, 19, 20 and charge transfer, 21 of iminothiazolines, 38 and PPP calculations, 21 and potentiometric measurements, 21 representative data, 22 of Schiff bases, 41 and solvent effects, 21 and substituent effects, 22 of sulfathiazoles, 20 -of sulfonamidothiazoles, 116 of A-2-thiazoline-4-one, 422 pKa determination, 423 of A-4-thiazoline-2-one, in relation with protomerism, 387 representative data, 389 of A-4-thiazoline-2-thiones, 380. 381 in relation with protomerism. 378 of thiazolylcarbamates, 97 of thiazolyl-2-oxides, 409 of thiazolyl-4-oxides, 426 of 2-thiazolylthioethers, 404 of thiazolylthioureas, 94, 96 of thiazolylureas, 93... [Pg.302]

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