- Preparation method of telmisartan
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The invention relates to a preparation method of telmisartan. According to the preparation method, 3-methyl-4-n-butylamide benzoic acid is used as a raw material, an intermediate (1) is prepared through cyaniding, nitration, reduction, ring closing and other reactions, the intermediate (1) and 4 '-bromomethyl biphenyl-2-methyl formate are subjected to condensation to generate an intermediate (2), the intermediate (2) and N-methyl o-phenylenediamine are subjected to condensation to prepare an intermediate (3), and finally the telmisartan is prepared through hydrolysis. The invention develops a new preparation method of telmisartan. The raw material 3-methyl-4-n-butyrylamide benzoic acid adopted by the method is easy to obtain and low in price; the method is mild in reaction condition, easy to operate and high in yield, the cyanation reaction avoids the use of toxic cyanide, the environmental pollution is small, and the method is suitable for industrial production.
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- PROCESS FOR THE PREPARATION OF BENZIMIDAZOLES
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Substituted benzimidazoles of formula (I), wherein R1 and R2 independently are hydrogen, C1-6 alkyl or C3-6 cycloalkyl and R3 is cyano or carboxy, are prepared in a multistep synthesis starting from Ν-acyl-4-halo- anilines of formula (II), wherein R1 and R2 are as defined above and X is chlorine or bromine.
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Page/Page column 10-11
(2011/01/12)
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