Synthesis of Some Novel 3,5-Diaryl-1,2,4-Triazole Derivatives and Investigation of Their Antimicrobial Activities

Authors: MEVLUT SERDAR, NURHAN GÜMRÜKÇÜOĞLU, ŞENGÜL ALPAY KARAOĞLU, NESLİHAN DEMİRBAŞ

Abstract: A series of acylhydrazones (2a-d) was synthesized from the reactions of iminoester hydrochlorides (1a-e) with acyl hydrazines. 2,5-Dialkyl 1,3,4-oxadiazoles (3a-d) were obtained in the same reaction media. The treatment of acylhydrazones with hydrazine hydrate afforded 4-amino-3,5-dialkyl-1,2,4-triazoles (4a-c). The acetylation of 4-amino-3-(4-hydroxyphenyl)-5-phenyl-4H-1,2,4-triazole (4a) produced 4-amino-5-(4-acetoxyphenyl)-3-phenyl-4H-1,2,4-triazole (9), while the acetylation of 4-amino-3-(4-tolyl)-5-phenyl-4H-1,2,4-triazole (4b) gave 4-acetylamino-3-phenyl-5-(4-tolyl)-4H-1,2,4-triazole (10). The treatment of compound 4b with various aromatic aldehydes or acetophenone and 4-nitroacetophenone resulted in the formation of 4-arylidenamino-3,5-dialkyl-4H-1,2,4-triazoles (5a-e and 7a,b). Sodium borohydride reduction of 4-arylidenamino derivatives of 1,2,4-triazoles afforded 4-alkylamino-3,5-dialkyl-4H-1,2,4-triazoles (6a-e and 8a,b). All newly synthesized compounds were screened for their antimicrobial and antifungal activities using agar-well diffusion. Compounds 5c and 6d showed marginal antimicrobial activities against Staphylococcus aureus, while compound 6b displayed moderate antifungal activity towards Candida tropicalis.

Keywords: Acyl hydrazone, 1,2,4-triazole, 1,3,4-oxadiazole, Schiff base, reduction, acetylation, antimicrobial activity, antifungal activity

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