Hydrochloric Acid → 4-(4-Cyano-2-methoxyphenyl)-5-ethoxy-1,4-dihydro-2,8-dimethyl-1,6-naphthyridine-3-carboxylic acid

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Reaction Steps

1.75 g (4.05 mmol) of the compound from Example 29A are dissolved in 60 ml of 1,2-dimethoxyethane/water (2:1 v/v), 8.09 ml (8.09 mmol) of 1 N sodium hydroxide solution are added, and the mixture is stirred at room temperature for one hour. 30 ml of diethyl ether are then added to the mixture, and the aqueous phase is acidified with 6 N hydrochloric acid. The resulting precipitate is filtered off and washed with water and a little diethyl ether. Drying in a vacuum drying oven at 40° C. results in 1.47 g (96% of theory) of the title compound.

Provenance & Evidence