Synthesis of Some New 3-Oxo-2-[(Z)-1-phenylmethylidene]-5H-[1,3]thiazolo[3,2-a]-and N-Acetylated Pyrimidines

3-Oxo-2-[(Z)-1-phenylmethylidene]-5H-[1,3]thiazolo[3,2-a] pyrimidine derivatives 2a–f were synthesized by the reaction of an appropriate 3,4-dihydro-2(H)-pyrimidone 1 , chloroacetic acid, sodium acetate and benzaldehyde. Reaction of 1 with acetic anhydride under heating afforded only 3-N-acetylated 3,4-dihydro-2(H)-pyrimidines 3a–f . The yields of the products after recrystallization from ethanol were of the order of 60–92 %. IR, ¹ H NMR spectroscopy, and elemental analysis were used for the identification of these compounds.