Synthesis of Chlorophenyl Benzimidazole Derivatives

Under the catalysis of a mixture of polyphosphoric acid and phosphoric acid,2 (2,4 dichlorophenoxymethyl)benzimidazole and 2 ( o chlorophenyl)benzimidazole were synthesized by condensation of o phenylenediamine with 2,4 dichlorophenoxyacetic acid and o chlorobenzoic acid respectively.Mole ratio n (organic acid)∶ n ( o - phenylenediamine) was 1∶1,reaction time was 6 h,and the yields were 73 7% and 62 0% respectively.The optimum reaction conditions were volume ratio of polyphosphoric acid to phosphoric acid 1∶4 and reaction temperature 190-200 ℃.