Abstract
Ethyl 2-thio-1, 2, 3, 4-tetrahydropyrimidine-5-carboxylate (VIII) and 2-thio-1, 2, 3, 4-tetrahydropyrimidine-5-carbonitrile (XXIII) were used for various kinds of condensation reactions. From the reaction with ethylene dibromide, VIII gave biscompound IX, and with phenacyl-bromide and p-chlorophenacylbromide thiazolo [3, 2-a] pyrimidine derivatives were obtained. In this reaction, 5H-thiazolo [3, 2-a] pyrimidine derivative (XIII, XVII, XXV) and the 7H-isomer (XIV, XVIII, XXVI) were obtained separately. The structures of these isomers were assigned from NMR and UV spectra. In this thiazolo [3, 2-a] pyrimidine syntheses, 3-hydroxy compounds (XII, XVI, XXIV) were considered to be the key intermediates.
