Intermediates for the synthesis of benzimidazole compounds and process for the preparation thereof

摘要

This invention provides a process for the preparation of a benzimidazole derivative (9) or a pharmaceutically acceptable salt thereof, by condensation of a compound of formula (6) with a compound of formula (7) in the presence of a condensing agent to afford a compound of formula (8), followed by, if necessary removal of the amino protecting group of compound (8), and then cyclization of compound (8) in the presence of an acid, wherein R<1e>, R<2e>, R<3e> and R<4e> are each independently hydrogen, hydroxyl, alkyl, alkoxy, benzyloxy, acetoxy, trifluoromethyl or halogen, R<7e> is alkyl and R<8e> is hydrogen or an amino protecting group, wherein R<1e>, R<2e>, R<3e>, R<4e>, R<7e> and R<8e> are as defined above, wherein R<1e>, R<2e>, R<3e>, R<4e>, and R<7e> are as defined above.