PROCEDURE FOR THE PREPARATION OF (4S)-4-(4-CYANO-2-METHOXYPHENYL)-5-ETHOXY-2,8-DIMETHYL-1,4-DIHYDRO-1,6-NAPHTHYRIDINI-3-CARBOXAMIDE

Abstract

Process for the preparation of (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1,6-naphthyridin-3-carboxamide of formula (1) as well as the preparation and use of the crystalline modification I of (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1,6-naphthyridin-3-carboxamide of formula (1).

Claims

1. A process for preparing an intermediate compound of formula (VI), (FORMULA 1) useful in obtaining (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1,6-naphthiridin-3-carboxamide, characterized by comprising the reaction of a compound of formula (XIV) or formula (XIVa), (FORMULAS 2 and 3) with dimethyl sulfate to give a compound of formula (XV) or (Xva), (FORMULAS 4 and 5) reducing the unisolated methyl esters of formula (XV) or (XVa) with 1.21 equivalents of REDAL (sodium bis(2-methoxyethoxy)aluminum dihydride) and 1.28 equivalents of N-methylpiperazine to give an aldehyde of formula (XVI) or (XVIa) (FORMULAS 6 and 7) and reacting the aldehyde of formula (XVI) or (XVIa) without isolating it to obtain the compound of formula (VI) (FORMULA 8). Sole Claim