Synthesis and Pharmacological Evaluation of Tricyclic Carbazole Annulated with Substituted Benzothiazole-2-Amine Under Microwave Irradiation

Abstract

Tricyclic carbazole nucleus is an integral part of naturally occurring alkaloids and synthetic derivatives, possessing various potential biological activities such as anticancer, antimicrobial and antiviral. Binding mechanism of carbazole with target receptor as molecule or fused molecule exhibit potential lethal effect. In the present work, development of microwave assisted organic synthesis (MAOS) methods for synthesis of a novel series of N-Mannich bases of carbazole annulled with substituted benzothiazole-2-amine with carbazole (secondary aromatic amine) and aldehyde derivatives has been presented. All the synthesized compounds were characterized by physicochemical and spectral methods viz. ultra-violet, FT-IR, 1H-NMR, Mass and elemental analysis. The newly developed MAOS method evident the improvement in percentage yield (% yield) and reaction time compared to conventional method. The synthesized compounds were screened for antibacterial (B. subtilis, S. aureus, E. coli and P. aeruginosa) and antifungal activities (A. niger and C. albicans) using impregnated paper-disc diffusion method. Compounds posses electronegative functional group at C5 and C6 position showed significant potential for antibacterial (compd. 2c and 3c) and antifungal (compd. 1b, 2b and 7b). Furthermore, in silico (PASS prediction) analysis predicts the possible mechanism of synthesized compounds could be a glycosylphosphatidylinositol phospholipase D inhibitor (antifungal action) and potassium channel blocker (antibacterial action).