Synthesis and Biological Activities of (4Z)-2-(1H-benzimidazol-2-ylmethyl)-4-arylidene-5-methyl-2,4-dihydro-3H-pyrazol-3-one Compounds

Abstract

Pyrazoles are reported to be well known pharmacophores. This has motivated the synthesize some of the pyrazole derivatives by using hydrazine hydrate as well as adding benzimidazole in pyrazoles. A series of (4Z)-2-(1H-benzimidazol-2-ylmethyl)-4-arylidene-5-methyl-2,4-dihydro-3H-pyrazol-3-ones (IIIa3 to IIIe3) was synthesized by conventional method by refluxing compounds (IIIa2-IIIe2) with  O-Phenylene diamine in absolute ethanol.  A series of compounds (IIIa2-IIIe2) was prepared by reacting compounds (IIIa1-IIIe1) with chloroacetic acid. A series of (4E)-4-arylidene-5-methyl-2,4–dihydro-3H-pyrazol-3-ones (IIIa1-IIIe1) was prepared by the reaction between 5-methyl-2,4-dihydro- 3H-pyrazol-3-one (II) and  different aldehydes in presence of Sodium acetate. All of the compounds were synthesised with high yields (58-80%) and identified using IR, 1H NMR spectrum data, as well as C, H, and N elemental analyses. At varying MIC values, all of the produced compounds showed antibacterial and antifungal activity, as well as analgesic and anti-inflammatory properties. Anticonvulsant, CNS depressive, ulcerogenic, and anthelmintic properties are thought to be exhibited by the produced compounds.