Compound (1a) (1-amino-4-methyl-6-phenyl pyrimidine- 2-(1H)-thione) was synthesized in the current study. By using a tetrabutylammonium iodide (TBAI) as a catalyst to react with various aromatic aldehydes in distilled water to give a new series of Schiff’s bases (2a-2h ). New tetrazole derivatives (3a-3h) were made by reacting Schiff's bases (2a-2h) with sodium azide in H2O. New thiazolidine-4-one was prepared from reactions of Schiff’s bases (2a-2h) with thioglycolic acid in distilled water-giving compounds (4a-4h). Finally, The structure of the synthesized compounds is confirmed by,1H NMR, IR, and 13C-NMR spectra as well as some physical data.