Protonation of some cyclic β-Aminovinylthiones and β-aminovinylketones

The NMR method was used to study the protonation of 3-N,N-dimethylammo-5,5-dimethyl-3-cyclohexene-1-thione, 3-N,N-dimethylamino-2-phenylidene-1-thione, and their oxygen analogs. The protonation center for these compounds is different, and is, respectively, N and O, and S and 2-C.