Carbazole derivatives: Synthesis, spectroscopic characterization, antioxidant activity, molecular docking study, and the quantum chemical calculations

Abstract

A various carbazole derivatives were synthesized for the synthesis 2,3-Dihydro-1H-carbazol-4(9H)-one O-acetyl oxime (3), ethyl 2-(2,3,4,9-tetrahydrospiro[carbazole-1,2′-[1,3]dithiolane]-2-yl)acetate (5), 2- hydroxyethyl {2,3,4,9-tetrahydrospiro[1H-carbazole-1,2′[1,3]dithiolane-4-one]-2-yl}-acetamide (7). These products (3, 5, and 7) were characterized by the spectroscopic techniques (IR, 1H NMR, 13C NMR and elemental analysis). Then, the observed FT-IR and NMR peaks of the studied compounds were compared with the calculated values. The FMO analyses disclosed that the (5) would prefer intermolecular interactions more than intramolecular interactions because of its higher energy gap. NBO analyses displayed that the n → П* and П → П* interactions were responsible for the lowering of the stabilization energy. The molecular docking studies showed that (5) exhibited highest binding affinity with the human glutathione reductase at binding site (−7.21 kcal/mol). Also, the antioxidant activities were investigated using the CUPRAC method, and TEAC coefficient implied that compound (3) have an antioxidant property. In addition, docking calculations of the compound (3), (5), and (7) were performed on bacterial tyrosinase enzyme and human glutathione reductase protein.