Water → 4-(4-Cyano-2-methoxyphenyl)-5-ethoxy-2,7-dimethyl-1,4-dihydro-1,6-naphthyridine-3-carboxylic acid

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Reaction Steps

642 mg (2.52 mmol) of the compound from Example 26A are dissolved in 40 ml of 1,2-dimethoxyethane/water (3:1 v/v), mixed with 5.04 ml (5.04 mmol) of 1 N sodium hydroxide solution and stirred at room temperature overnight. The mixture is then mixed with 30 ml of diethyl ether and 30 ml of water, the organic phase is separated off, and the aqueous phase is adjusted to pH 4-5 with 1 N hydrochloric acid. The resulting suspension is stirred for 1 h, and the precipitated solid is then removed by filtration. The precipitate is washed with water and a little diethyl ether. Drying at 40° C. in vacuo results in 642 mg (67% of theory) of the title compound.

Provenance & Evidence