Hydrochloric Acid → 3-Oxo-4-phenyl-3,4-dihydropyrido[2,3-b]pyrazine-2-carboxylic acid

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Reaction Steps

10.74 g (36 mmol) of ethyl 3-oxo-4-phenyl-3,4-dihydropyrido[2,3-b]pyrazine-2-carboxylate was dissolved in acetic acid (270 mL), and 6N hydrochloric acid (80 mL) was added thereto at room temperature. Then, the mixture was stirred overnight at room temperature. After confirming the completion of the reaction, the solvent was distilled off under reduced pressure, and water (100 mL) was added. The solid thus obtained was separated by filtration and dried, to obtain 6.50 g (yield: 67%) of 3-oxo-4-phenyl-3,4-dihydropyrido[2,3-b]pyrazine-2-carboxylic acid as pale brown crystals.

Provenance & Evidence