Abstract

SYNTHESIS AND ANTIMICROBIAL ACTIVITIES OF NOVEL 2-METHOXY-6-[(3-ALKYL-4,5-D?HYDRO-1H-1,2,4-TR?AZOL-5-ONE-4-YL)-AZOMETH?N]-PHENYL BENZOATES W?TH THE?R NON-AQUEOUS MEDIUM TITRATIONS

Abdurrahman Gürbüz, Muzaffer Alkan, Sevda Manap, Gül Özdemir and Haydar Yüksek*

ABSTRACT

A series of novel 2-methoxy-6-[(3-alkyl-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl)-azomethin]-phenyl benzoates (4) were synthesized from the reactions of 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) with 2-benzoxy-3-methoxybenzaldehyde (3). The acetylation reactions of compounds 4 were investigated and compounds 5 were thus obtained. The structures of fourteen new compounds were characterized from IR, 1H NMR, 13C NMR and UV spectral data. In addition, 4 and 5 type compounds were examined for their in vitro potential antibacterial activities. Antimicrobial activity was determined on five bacteria using the agar well diffusion method. Furthermore, the newly synthesized 4 type compounds were titrated potentiometrically with tetrabutylammonium hydroxide (TBAH) in four non-aqueous solvents, including isopropyl alcohol, tert-butyl alcohol, N,N-dimethylformamide (DMF) and acetone. The half-neutralization potential (HNP) values and the corresponding pKa values were determined for all cases. Thus, the effects of solvents and molecular structure upon acidity were investigated.

Keywords: 1,2,4-Triazol-5-one, Schiff base, acetylation, antimicrobial activity, pKa.