Synthesis, Characterization, and Biological Activity Study of Some Schiff Base Compounds of Indole‐3‐carbaldehyde

ABSTRACT

This study aimed to design and synthesize a series of Schiff bases derived from indole and evaluate their biological activity as antimicrobial compounds (against bacteria and fungi). Five imine derivatives (R1–R5) were synthesized via a condensation reaction between indole‐3‐carbaldehyde and various primary amines (4‐aminoacetophenone, 2‐aminobenzothiazole, 2‐aminothiazole, 2‐aminopyridine, and 5‐amino‐1,3,4‐thiadiazole‐2‐thiol). The chemical structure of the synthesized compounds was confirmed using FTIR and ¹ H‐NMR spectroscopy, with the results clearly showing the formation of azomethine (C═N) bonds, along with other groups depending on the type of amine used. Biological studies have shown that the compounds possess varying degrees of antimicrobial activity, exhibiting moderate activity against Staphylococcus aureus, while showing weak or no activity against some Gram‐negative bacteria. In contrast, all the compounds demonstrated significant antifungal activity against Candida albicans and Candida tropicalis, with compound R4 showing the highest efficacy. These results suggest that indole derivatives of Schiff bases represent promising structural platforms for developing highly potent antifungal compounds.