AN EFFICIENT SYNTHESIS AND REACTIONS OF 3-(8-HYDROXYQUINOLIN-5-YL)-7- METYHLTHIO-5-OXO-5H-(1, 3) THIAZOLO (3, 2-a) PYRIMIDINE-6-CARBONITRILE AS ANTIMICROBIAL AGENTS

In the present study, a series of 3-(8-hydroxyquinolin-5-yl)-5-oxo-5H-[1,3]thiazolo[3,2-a]pyrimidines (4a,b ), ( 5a-c) and (7a-c) were synthesized by the reaction of 7-metyhlthio-3-(8-hydroxyquinolin-5-yl)-5-oxo-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carbonitrile (3) with different N- and Onucleophiles, such as hetaryl amines, aryl amines, substituted phenols in the presence of anhydrous potassium carbonate (K 2CO 3) and dimethyl formamide (DMF). Also, other fused tetracyclic thiazolo[2′,3′:1,2]pyrimido[5,4-d]thiazolo[3,2-a]pyrimidines (8a,b ) and ( 9) were synthesized on treatment of 3 with substituted aminothiazoles and 2-aminobenzothiazole. The parent compound ( 3) was reacted with hydrazine hydrate to obtain the corresponding aminopyrazole derivative ( 10 ) which was conducted to react with various reagents, such as acetic anhydride, acetyl acetone, ethyl acetoacetate and diethyl malonate to yield thiazolo[2,3′:1,2]pyrimido[4,5-c]pyazolo[2,3-a]pyrimidine derivatives ( 12-14 ). On the other hand, treatment of 10 with appropriate aromatic aldehydes afforded the corresponding arylidene derivatives ( 15a-c) . Finally, reaction of 4chlorobenzylidine derivative ( 15b) with thioglycolic acid and chloroacetyl chloride furnished the thiazolidinone and azetidenone derivatives ( 16) and ( 17) , respectively. All the new title compounds were characterized by elemental and spectral data. The antimicrobial activity of some novel products was evaluated by agar well-diffusion.