High-purity dabigatran etexilate as well as preparation method and application thereof

The invention discloses high-purity dabigatran etexilate as well as a preparation method and application thereof. According to the high-purity dabigatran etexilate or a pharmaceutically acceptable salt thereof, the purity of the dabigatran etexilate is not less than 99.0%, and the content of an impurity B in the dabigatran etexilate is not more than 0.1%. The preparation method comprises the following steps: (1) 3-[[[2-[[(4-cyanophenyl) amino] methyl]-1-methyl-1H-benzimidazole-5-yl] carbonyl] pyridine-2-ylamino] ethyl propionate (compound 1) is subjected to a pinner reaction and then salified with p-toluenesulfonic acid to prepare 3-[[[2-[[(4-amidino phenyl) amino] methyl]-1-methyl-1H-benzimidazole-5-yl] carbonyl] pyridine-2-ylamino] ethyl propionate p-toluenesulfonate (a compound 2); and (2) enabling the compound 2 to react with hexyl chloroformate to prepare the dabigatran etexilate. According to the preparation method disclosed by the invention, generation of an impurity B is remarkably reduced by controll