2-Imido-4, 5-dihydrothiazoles I (X= H, CHs, etc.) and 2-mercaptopyrimidines I1 (R= CHI, CzH6, etc., X= H, CH,, C2Hs) are characterized by their chemical behavior when subjected to the action of chlorine and bromine in aqueous solution. The thiazoles2 I undergo complete degradation by the action of either of these halogens with formation of an amine, carbon dioxide, and a taurine derivative 111. A mercaptopyrimidine I1 interacts with ...