The absorption spectra of some thiazines and thiazoles

Abstract

The infrared and ultraviolet spectra of some tetrahydro-2-thio-thiazines and -thiazoles are compared with those of 4-hydroxyl substituted compounds. The position of the O–H stretching, O–H deformation, and C–O stretching bands of the latter are discussed. The ultraviolet spectra of these compounds and derived dihydro-2-thio-thiazines and -thiazoles were compared with those of certain 2- and 3-substituted derivatives. It is concluded that the compounds capable of thione–thiol tautomerism exist as the thione form in aqueous solution.