The 5-benzoyl-4,6-diphenyl-1,2,3,4-tetrahydro-2-thioxopyrimidin (1) have been prepared via Biginelli cyclocondensation reaction in acetic acid under reflux condition in good yield (93%). Reactions of 1 and iodomethane to afford thiopyrimidine compounds 3 and 5. Also, the acetylation of compounds 1 and 3 gave 3-acetyl thioxopyrimidine 2 and methylthiopyrimidine 4, respectively. Thioxopyrimidine derivative 6 was synthesized from 1 and POCl3/DMF Furthermore, the starting compound 1 were cyclized with various bromo compounds to the thiazolopyrimidine 7, 8, 9 and pyrimido[2,3-b]thiazine10 derivatives, in approximately 55-78% yields. The purpose of synthesizing the thioxopyrimidine derivatives is because of the high biological activities. All of these derivatives have been characterized by analytical and spectroscopic studies and the reaction mechanism is discussed.