Abstract

Microwave assisted synthesis of some new thiazolopyrimidine derivatives with potential biological activity

Author(s): Mohamed Mohamed Youssef, Mahmoud Ahmed Amin

Biginelli reaction of ethyl acetoacetate, thiourea and the proper aromatic aldehydes was used to produce ethyl 4-aryl-6-methyl-2-thioxo-1,2,3,4- tetrahydropyrimidine-5-carboxylates (1a-d). The latter compounds reacted with bromomalononitrile (2) to give ethyl 3-amino-5-aryl-2-cyano-7-methyl- 5H-thiazolo[3,2-a]pyrimidine-6-carboxylate (3a-d) rather than the isomeric structures (4a-d). Thiazolopyrimidine derivatives (3a-d) reactedwith carbon disulphide to yield ethyl 9-aryl-7-methyl-2,4-dithioxo-2,3,4,9-tetrahydro- 1H-thiazolo[3,2-a:4,5-dÂÂ’]dipyri-midine-8-carboxy-lates (5a-d). The aforementioned reactions were carried out using both traditional chemical methods and with the assistance of the modern microwave technique. Comparison between both methods showed that microwave assisted method is preferred because of time and energy reduction as well as being environmentally friendly. Structures of the newly synthesized compounds were proved by using spectroscopic methods such as IR, 1H-NMR, 13CNMR andMS. The newcompoundswere tested for their biological activity as antioxidants, antibacterial or antifungal agents. Some of the new compounds were found to have moderate to good antioxidant and antimicrobial activities.