Acta Pharm. 65 (2015) 117-132
Original research paper
Synthesis
and characterization of some novel 1,2,4-triazoles, 1,3,4-thiadiazoles and
Schiff's bases incorporating imidazole moiety as potential antimicrobial agents
MOHAMED
REDA AOUAD, MOUSLIM MESSALI, NADJET REZKI, ADEEB AL-SHEIKH ALI and ALAIN
LESIMPLE
aouadmohamedreda@yahoo.fr
1 Department of
Chemistry, Faculty of Sciences, Taibah University, Al-Madinah Al-Munawarah,
P.O.Box 30002, Saudi Arabia
2 Department of
Chemistry, Faculty of Sciences, University of Sciences and Technology Mohamed
Boudiaf, Laboratoire de Chimie & Electrochimie des Complexes Métalliques (LCECM) USTO-MB, P.O. Box 1505 Oran, El
M`nouar, Algeria
3 King Abdullah
University of Science and Technology (KAUST), Saudi Arabia
Accepted October 27, 2014
(1,4,5-Triphenylimidazol-2-yl-thio)butyric acid hydrazide (3) was obtained via alkylation of 1,4,5-triphenylimidazol-2-thiol (1) with ethylbromobutyrate, followed by addition of hydrazine hydrate. Treatment of acid hydrazide 3 with carbon disulfide in an ethanolic potassium hydroxide solution gave the intermediate potassium dithiocarbazinate salt, which was cyclized to 4-amino-5-[(1,4,5-triphenylimidazol-2-yl)thiopropyl]-2H-1,2,4-triazole-3-thione (4) in the presence of hydrazine hydrate. Condensation of compound 3 with alkyl/arylisothiocyanate afforded the corresponding 1-[4-(1,4,5-triphenylimidazol-2-ylthio)butanoyl]-4-alkyl/arylthiosemicarbazides (5-7), which upon refluxing with sodium hydroxide, yielded the corresponding 1,2,4-triazole-3-thiols (8-10). Under acidic conditions, compounds 4-6 were converted to aminothiadiazoles 11-13. Moreover, the series of Schiff bases 14-18 were synthesized from the condensation of compound 3 with different aromatic aldehydes. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectral analyses. They were also preliminarily screened for their antimicrobial activity.
Keywords: imidazole, 1,2,4-triazole, 1,3,4-thiadiazole, Schiff bases,
antimicrobial activity