Ammonia → 4-(4-Cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1,6-naphthyridine-3-carboxamide

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Reaction Steps

1.46 g (3.84 mmol) of the compound from Example 30A are introduced into 50 ml of ethyl acetate and, after addition of 777 mg (4.79 mmol) of 1,1′-carbonyldiimidazole, stirred at room temperature overnight. A TLC check (silica gel; mobile phase: ethyl acetate) shows complete conversion. The volatile components are removed in a rotary evaporator, and the residue is taken up in 20 ml of DMF. Then 10.74 ml of ammonia (28% by weight solution in water, 76.8 mmol) are added, and the reaction mixture is heated at 100° C. for 30 min. The solvent is distilled out under reduced pressure, and the residue is purified by preparative HPLC (eluent: acetonitrile/water with 0.1% formic acid, gradient 20:80→95:5). The residue after concentration of the product fractions is dissolved in 40 ml of dichloromethane/methanol (1:1 v/v) and mixed with 100 ml of ethyl acetate. The solvent is concentrated to a volume of about 20 ml, whereupon the product crystallizes. The precipitate is filtered off and washed with a little diethyl ether. Drying at 40° C. in a vacuum drying oven results in 1.40 g (96% of theory) of the title compound.

Provenance & Evidence