METHOD FOR THE PREPARATION OF (4S)-4-(4-CYANO-2-METHOXYPHENYL)-5-ETHOXY-2,8-DIMETHYL-1,4-DIHYDRO-1-6-NAPHTHYRIDINE-3-CARBOX-AMIDE AND THE PURIFICATION THEREOF FOR USE AS AN ACTIVE PHARMACEUTICAL INGREDIENT

摘要

The invention relates to a new and improved method for preparing (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1,6-naphthyridine-3-carbox-amide of formula (I) and to the production and use of the crystalline modification I of (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1,6-naphthyridine-3-carbox-amide of formula (I).