Hydrochloric Acid → 1-(3-Ethoxy-benzoyl)-6,7-dimethoxy-isoquinoline-4-carboxylic acid

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Reaction Conditions

Reaction Steps

To the suspension of 1-(3-Ethoxy-benzoyl)-6,7-dimethoxy-isoquinoline-4-carbonitrile (from example 82) (2.0 g, 5.52 mmol) in methanol (120 mL) was added 25% of aqueous sodium hydroxide solution (30 mL, 190 mmol). The mixture was stirred at 100° C. for 12 h more. After cooling to room temperature, the reaction was adjusted to pH=2 with 2 N HCl solution. The product was extracted with chloroform (2×200 mL). The combined organic layers were washed with water (3×50 mL), dried over sodium sulfate, filtered, and concentrated in vacuo to give solid. Recrystallization from ethanol and ether to afford 1-(3-Ethoxy-benzoyl)-6,7-dimethoxy-isoquinoline-4-carboxylic acid yellow solid. LC/MS m/e calcd for C21H19NO6 (MH+) 382,

Provenance & Evidence