Synthesis and characterization of 5-(4-hydroxy-3-methoxy-phenyl)-3,7-dimethyl-5H-thiazolo[3,2-a]pyrimidine-2,6-dicarboxylic acid 2-ethyl ester 6-methyl ester and its 6-ethyl ester 5-naphthalene derivative

The compounds 5-(4-hydroxy-3-methoxy-phenyl)-3,7-dimethyl-5H-thiazolo[3,2-a]pyrimidine-2,6-dicarboxylic acid 2-ethyl ester 6-methyl ester (2a) and 3,7-dimethyl-5-naphthalen-1-yl-5H-thiazolo[3,2-a]pyrimidine-2,6-dicarboxylic acid diethyl ester (2b) were synthesized by the base catalyzed cyclocondensation of 3,4-dihydropyrimidine-2-thione with ethylacetoacetate. IR, 1H NMR, 13C NMR spectra and elemental analysis were used to characterize these compounds. The structures were determined by single crystal X-ray diffraction. The crystal structure is stabilized by intermolecular O–H…N, C–H…O, C–H…π and π…π weak interactions.