Effect of Different Substituents on Amine-imine Tautomerism of 2-Amino-4-methylthiazole Derivatives

We have used 1H NMR to study the amine-imine tautomerism of some esters and amides of 2-N-labeled 4-methylthiazole-5-carboxylic acids and 5-carbamic acids. We have shown that the nature of the substituents of the 2-NHR1, 5-COR2, or 5-NHCOR2 groups affects that position of the tautomeric equilibrium.