acetic acid under reflux condition in approximately 52-65% yields. The acetylation of compounds 4a-d gave 3-acetyl thioxopyrimidine derivatives 5a-d. Also, pyrimidothiazine compounds 6a-d were prepared by a simpleone-pot condensation reaction of starting pyrimidine derivatives 4a-d and 3-bromopropionic acid. The structures of compounds were characterized on the basis of elemental analyses, IR, 1H and 13C-NMR