Fluorescent 7-azaindole N-linked 1,2,3-triazole: synthesis and study of antimicrobial, molecular docking, ADME and DFT properties

Abstract

Two libraries of biologically essential and fluorescent 7-azaindole N-linked benzyl 1,2,3-triazole (4a–4i) and 7-azaindole N-linked phenyl 1,2,3-triazole (4j–4q) hybrids have been designed and synthesized from N-propargyl 7-azaindole, i.e., 1-prop-2-ynyl-1H-pyrrolo[2,3-b]pyridine (2) with benzyl azides (3a–3i) and phenyl azides (3j–3q), respectively, via a Cu(I)-catalyzed alkyne azide cycloaddition (CuAAC) click reaction. The structures of the synthesized hybrids were confirmed with the help of the IR, ¹H-NMR, ¹³C-NMR, and HRMS data. However, the structure of one of the solid crystalline compounds, 4f, was finally supported by its single-crystal X-ray data. In vitro, antimicrobial activity results revealed that most compounds exhibited superior efficacy towards Aspergillus compared to fluconazole. Compounds 4e, 4f, and 4g showed high potency against A. niger with MIC values of 0.0193, 0.0170, and 0.0187 μmol mL⁻¹, respectively. Compound 4f also showed increased activity against P. aeruginosa and E. coli (MIC: 0.0170 μmol mL⁻¹). The most promising compounds, 4d, 4f, and 4n, showed excellent binding energies of −8.81, −8.76, and −8.79 kcal mol⁻¹ with a dynamic DNA site 14α-demethylase lanosterol enzyme (PDB ID:1EA1). Chemical properties such as chemical potential (μ), chemical hardness (η), and electrophilicity index (ω) were studied by DFT at the B3LYP level with a 6-311G(d,p) basis set. All compounds excellently follow Lipinski's rule of five.