Multicomponent synthesis of benzothiazole sulfonyl containing heterocyclic scaffolds

The synthesis of heterocyclic compounds plays a crucial role in pharmaceutical chemistry due to their diverse bioactivities. The ongoing quest for novel properties in an eco-friendly, efficient, and rapid manner is paramount. In this thesis, we achieved three- and four-component reactions using benzothiazole sulfonyl acetonitrile, aromatic aldehydes, and heterocyclic ketene aminals (HKA). Specifically, 2-nitro-methylenethiazoline was employed for the three-component reactions, while propane-1,3-diamine and 1,1-bis(methylthio)-2-nitroethylene were utilized for the four-component reactions. These methodologies yielded benzo[d]thiazol-2-ylsulfonyl thiazolo[3,2-a]pyridin-5-amines 51a-i and benzothiazole sulfonyl pyrido[1,2-a]pyrimidines 54a-c, respectively. Eleven novel fused heterocyclic compounds were synthesized, purified by simple method, and characterized using spectroscopic methods FT-IR, 1H NMR, 13C NMR, HRMS, LCMS and physical properties melting point, and Rf values. The synthesized compounds demonstrated promising antibacterial, antimycobacterial, and antifungal activities, against Gram-positive and Gram-negative bacteria, the compounds exhibited MIC values ranging from 62.5 to 500 μg/mL, with 4 compounds showing notable activity at 62.5 μg/mL. For Mycobacterium tuberculosis H37Rv, the compounds displayed moderate activity (31.5 to 62.5 μg/mL), with 5 compounds being the most effective. Antifungal tests against Candida species revealed MIC values of 62.5 to 125 μg/mL, with 5 compounds showing significant activity. The observed activities of the synthesized compounds put them as promising subjects for continued biological investigation and potential development.