Synthesis, Docking Study, and Antimicrobial Activity of Some New Heterocyclic Compounds Bearing Naphthalene Moiety

Abstract

Upon reaction with α,β‐unsaturated nitriles (2 a–d) and/or salicylaldehyde, 3‐(naphthalen‐2‐yl)‐3‐oxopropanenitrile (1) yields pyridine derivatives 3 a–d and/or the imino chromene derivative 4. Compound 1 reacted with phenyl isothiocyanate in a basic medium to give the intermediate potassium salt 6. Upon stirring at room temperature, the intermediate 6 with some α‐halogenated compounds yielded the acyclic compounds 7, 9, 11, 13, and 15. On the other hand, refluxing intermediate 6 with the same α‐halogenated compounds in DMF in the presence of TEA afforded the corresponding thiophene derivatives 8, 10, 12, 14, and 16. The reaction of thiol 17 with hydrazine hydrate derivatives 18 a–d yielded the corresponding pyrazole derivatives 21 a–d. Compound 20 reacted with o‐phenylenediamine or o‐aminothiophenol in the presence of DMF/TEA to give the corresponding benzothiazole or benzoimidazole derivatives 27 a and 27 b, respectively. Thirty new synthesized compounds were examined for their antibacterial activity against Gram‐positive bacteria including S. aureus and B. subtilis, Gram‐negative bacteria such as P. aeruginosa and E. coli, and yeast‐like fungi like C. albicans in vitro. Compounds 15, 16, 21 d, 27 a, 27 b, exhibited the highest antibacterial activity against Gram‐positive bacteria. Molecular docking experiments were conducted to explore the binding affinities and interaction modalities of selected derivatives with the target PDB‐3cmt protein.