Abstract

DESIGN, SYNTHESIS, AND EVALUATION OF NOVEL 1,2-SUBSTITUTED BENZIMIDAZOLE DERIVATIVES AS POTENTIAL ANTHELMINTIC AGENTS

Abhiram M.S., Kumara Prasad S.A.* and Raju H.V.

ABSTRACT

The benzimidazole nucleus was synthesized from o-phenylenediamine and chloroacetic acid in the presence of 4N hydrochloric acid. A new series of 1,2-substituted benzimidazole derivatives were then synthesized by treating the parent compound with 2,4-dinitrophenylhydrazine. Mannich bases of the resultant compound were prepared by treating it with different secondary amines. The completion of the reaction was monitored by TLC, and the crude synthesized compounds were purified by recrystallization. The structural confirmation of the synthesized derivatives was carried out using spectroscopic techniques. The IR (KBr) spectrum exhibited characteristic peaks in the range around 3043 cm⁻¹ (CH, str, ar), 2982 cm⁻¹ (CH, str, ali), 3324 cm⁻¹ and 3412 cm⁻¹ (–NH, str), and 1561 cm⁻¹ (C=N, str). The ¹H NMR (DMSO-d₆) spectrum showed signals at δ 7.6 (1s, 2H, Ar–CH), 3.79 (1s, 2H, CH₂–NH), 4.0 (1s, 1H, Ar⋅N–H), 2.1 (1s, 1H, N–H), and 1.1 (1s, 6H, CH₃). The synthesized 1,2-substituted benzimidazole derivatives were screened for anthelmintic activity, showing promising results.

Keywords: Anthelmintic activity, benzimidazole, o-Phenylene diamine, Mannich Bases.