The present work involved the synthesis of compound (1) (1-amino-4-methyl-6-phenyl pyrimidine- 2-(1H)-thione). This compound reacts with different aromatic aldehyde using glacial acetic acid as catalytic on absolute ethanol to give a new series of Schiff's bases (2-7). New thiazolidine-4-one were prepared from reactions of Schiff's bases (2,3,4,7) with thioglycolic acid in absolute ethanol giving compounds (8-11). Finally the preparation of new tetrazole derivatives (12-15) by reaction of Schiff's bases (2,3,4,7) with sodium azide in THF. The structure of the synthesized compounds are confirmed by I.R., 1H-NMR and 13C-NMR spectra and some physical  data.