Synthesis and efficiency of new pyridine, chromene and thiazole containing compounds as antimicrobial and antioxidant agents

Abstract

ABSTRACT. The versatile scaffold, N'-(2-cyanoacetyl)-2-hydroxybenzohydrazide (3) was utilized in the production of new pyridine, chromene and thiazole derivatives as antimicrobial and antioxidant agents. The synthetic strategy involves the treatment of precursor 3 with various arylidene-malononitrile and 3-aryl-2-cyanoacrylate compounds to furnish substituted pyridines 5 and 7. The interaction of 3 with salicylaldehyde and/or phenyl isothiocyanate followed by cyclization with chloroacetone produced the corresponding 2-imino-2H-chromene-3-carbohydrazide and (thiazol-2-ylidene-acetyl)-salicylic acid hydrazide compounds 8 and 9, respectively. The structural features of the synthesized compounds were confirmed by using spectroscopic methods such as (IR, 1H NMR, 13C NMR and MS). The new pyridine, chromene and thiazole products showed potent antioxidants and antimicrobial activities. The thiazole derivative 9 exhibited the highest anti-bacterial and antifungal activities against S. aureus (75.0%) and B. subtilis (73.9%) and C. albicans (66.6%). The combination between salicylic acid hydrazide and thiazole moieties in the hybrid 9 indicated the best antioxidant activity (87.9%).                 KEY WORDS: Salicylic hydrazide, Arylidene-malononitrile, Pyridine, Thiazole, Antioxidant   Bull. Chem. Soc. Ethiop. 2022, 36(1), 137-148.                                                            DOI: https://dx.doi.org/10.4314/bcse.v36i1.12