%0 Journal Article
%T Novel Antimicrobial Agents: Fluorinated 2-(3-(Benzofuran-2-yl) pyrazol-1-yl)thiazoles
%A Hanan A. Mohamed
%A Ehab Abdel-Latif
%A Bakr F. Abdel-Wahab
%A Ghada E. A. Awad
%J International Journal of Medicinal Chemistry
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/986536
%X A new series of 2-pyrazolin-1-ylthiazoles 8a每d and 13每16 was synthesized by cyclization of N-thiocarboxamide-2-pyrazoline with different haloketones and 2,3-dichloroquinoxaline. The structures of the new compounds were confirmed by elemental analyses as well as NMR, IR, and mass spectral data. The newly synthesized compounds were evaluated for their antimicrobial activities, and also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Amongst the tested ones, compound 8c displayed excellent antimicrobial activity. 1. Introduction Pyrazolines are nitrogen-containing heterocyclic compounds, well known for their pronounced biological activity. These biological activities include antibacterial [1], antifungal [2], herbicidal [3], and insecticidal activities [4]. It was demonstrated that the combination of pyrazole with azole ring, linked to each by one sigma bond, led to more biologically active targets; for example, pyrazolylthiazoles showed excellent antimicrobial activities [5]. Continuing our work in this research field [6每9] and in an attempt to identify new and potent antimicrobial agents, we tried here to generate new benzofuryl 2-pyrazolin-1-ylthiazoles as antimicrobial agents using simple methods. 2. Results and Discussion 2.1. Chemistry The starting pyrazoline-1-carbothioamide 5 was prepared by treatment of 2-acetylbenzofuran 1 with equivalent of 4-flurobenzaldehyde 2 in the presence of 10% alcoholic NaOH in 90% ethanol with stirring at room temperature to give chaconne 3. Reaction of chalcone 3 with equivalent amount of thiosemicarbazide was performed in ethanol in the presence of 2.5 equivalent of sodium hydroxide to the target precursor 5. The resulting pyrazoline-1-carbothioamide 5 was cyclized to the corresponding 2-(3-(benzofuran-2-yl)-5-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-methyl-5-(p-subs.phenyldiazenyl)thiazole derivatives 8a每d by reaction with hydrazonoyl halides 6a每d in anhydrous ethanol and in the presence of an equivalent of triethylamine (Scheme 1). Scheme 1 The reaction product structures were elucidated by means of NMR, MS spectroscopy, and elemental analyses (Table 1). Table 1: Characteristic data of the synthesized compounds. For example, 1H NMR spectra of 8a每d contained two doublet-doublet and one triplet signals due to the presence of CH2 adjacent asymmetric carbon. The mass spectra of 8a每d showed the molecular ion peaks at m/z 481, 499, 515 and 561, respectively in agreement with the calculated masses. The reaction between pyrazoline-1-carbothioamide 5 and the equivalent amount
%U http://www.hindawi.com/journals/ijmc/2013/986536/