998-97-0Relevant articles and documents
Preparation method of telmisartan intermediate
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Paragraph 0008; 0029; 0032; 0035; 0038, (2019/02/21)
The invention relates to a preparation method of a telmisartan intermediate, namely 2-n-propyl-4-methyl-6-Benzimidazolecarboxylic acid. The preparation method of the 2-n-propyl-4-methyl-6-Benzimidazolecarboxylic acid comprises the following steps: firstly, ethanol hydrochloride acts with butyronitrile and anhydrous hydrogen chloride within the range of 0-35 DEG C; the mixture obtained in the firststep reacts with 3-methyl-4-aminobenzoic acid and ice vinegar within the range of pH 5.0-11.0 at the controlled temperature of 10-40 DEG C, and an intermediate shown in the formula II is obtained; and then the intermediate shown in the formula II reacts with a sodium hypochlorite solution, and the 2-n-propyl-4-methyl-6-Benzimidazolecarboxylic acid is obtained. The intermediate preparation processis suitable for industrial production, and meanwhile the product quality is improved.