Synthesis method of 2-ethoxy benzimidazole-7-carboxylic acid methyl ester

The invention discloses a synthesis method of 2-ethoxy benzimidazole-7-carboxylic acid methyl ester. The problem that an existing process is not high in content and is very low in yield is solved. According to the synthesis method, 3-nitryl phthalic acid is used as a raw material, rearrangement is performed in a water solution after methyl esterification, acylation and re-nitridation, then tin powder is adopted to perform reduction and loop closing so as to obtain the 2-ethoxy benzimidazole-7-carboxylic acid methyl ester. By the adoption of the synthesis method, produced impurities are very little, the content is high, and the yield is also high.