PROCESSES FOR THE PREPARATION OF ROFLUMILAST AND INTERMEDIATES THEREOF

摘要

Provided are processes for the preparation of 3-(cyclopropylmethoxy)-N-(3,5-dichloropyridine-4-yl)-4-(difluoromethoxy)benzamide (namely roflumilast), its N-oxide and pharmaceutically acceptable acid addition salts, and intermediate compounds 3,4-dihydroxy-N-(3,5-dichloropyridine-4-yl)benzamide, 3-hydroxy-N-(3,5-dichloropyridine-4-yl)-4-(difluoromethoxy)benzamide and 3-(cyclopropylmethoxy)-N-(3,5-dihydroxypyridine-4-yl)-4-(difluoromethoxy)benzamide in the processes.