The tautomerism of N-heterocycles. Pyridazinones and pyridazinethiones

Abstract

Hydroxy- and mercapto-pyridazines have been shown to exist predominantly in the pyridazin-one and -thione forms with the help of the following new compounds: the anhydro-bases of 3-hydroxy-1-methyl- and 3- and 5-mercapto-1-methylpyridazinium hydroxides.

Ionization constants and ultraviolet spectra of the parent compounds and all N-1-, N-2- and O- or S-methyl derivatives are discussed.