Microwave assisted synthesis of some new thiazolopyrimidine and pyrimidothiazolopyrimidopyrimidine derivatives with potential antimicrobial activity

Background and objective: A series of thiazolopyrimidine derivatives have been synthesized via multicomponent reaction and tested for biological activities. This research aims to develop a new synthetic method of poly fused pyrimidines under microwave irradiation. 6-Amino-4-aryl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitriles reacted with bromomalono-nitrile to give 3,7-diamino-5-aryl-5H-thiazolo[3,2-a] pyrimidine-2,6-dicarbonitrile more willingly than the isomeric 7H-thiazolo[3,2-a] pyrimidines. Thiazolopyrimidine derivatives reacted with carbon disulphide to produce 11-aryl-11H-1,2,3,4,7,8,9,10-octahydropyrimido[4 '', 5 '': 4', 5'] thiazolo[3', 2'-a] pyrimido[4,5-d] pyrimidine-2,4,8,10tetrathione. The above mentioned reactions were established by using both conventional methods and microwaveassisted irradiation. Conclusion: This work provides a new method for preparing poly fused pyrimidines. The microwave-assisted technique is preferable due to the yield enhancements attained, time saving, and environmental safety reactions. The newly prepared compounds were verified for their antimicrobial activities. Also, the absorption and emission of some of the prepared compounds were studied.