METHOD OF SYNTHESIS OF BENZIMIDAZOLE COMPOUND Russian patent published in 2008 - IPC C07D401/12 

FIELD: chemistry.

SUBSTANCE: method of production of 5-methoxy-2[[(4-methoxy-3.5-dimethyl-2-pyridinyle)-methyl]-thio]-1H-benzimidazole, formula I , from (4-methoxy-3.5-dimethyl-2-pyridinyl)-methanol which includes the following reactions performed in sequence in one main solvent system without isolation of intermediate substances formed in the process: stage 1: interaction of (4-methoxy-3.5-dimethyl-2-pyridinyl)-methanol (pyrmethanolic alcohol), formula 1a, with chloro-dehydroxylating agent to obtain (4-methoxy-3.5-dimethyl-2-pyridinyl)-methylchloride (pyrmethylchloride), formula Ib ; stage 2: interaction of (4-methoxy-3.5-dimethyl-2-pyridinyl)-methylchloride, formula 1b, obtained at the stage 1 described above with 2-mercapto-5-methoxybenzimidazole (metmercazole), formula Ic , in the presence of alkali to obtain 5-methoxy-2[[(4-methoxy-3.5-dimethyl-2-pyridinyl)-methyl]-thio]-1H-benzimidazole (pyrmethazole), formula I, and the solvent system which is common for the whole sequence of reactions and contains organic non-miscible with water solvent with definite quantity of water present at stage 1, and this quantity is higher that the saturation concentration of used organic non-miscible with water solvent .

EFFECT: method proposed allows to obtain desired substance with high yield and high purity.

16 cl, 5 ex