Hydrochloric Acid → HCID 12850756, compound

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Reaction Steps

A suspension of ethyl 5,8-dihydro-2-(4-acetyl-1-piperazinyl)-5-oxopyrido[2,3-d]pyrimidine-6-carboxylate (1000 g) and concentrated hydrochloric acid (800 ml) in a mixture of water (1200 ml) and ethanol (1000 ml) was refluxed for 8 hours and allowed to stand overnight. The crystals precipitated were collected, washed with ethanol, and dissolved by heating in an aqueous solution (10 liters) of sodium hydroxide (250 g). The solution was filtered, adjusted to pH 7-8 with acetic acid, and allowed to stand overnight while ice-cooling. The crystalline precipitate was collected, washed with water, and dried at 110° C. to give 5,8-dihydro-2-(1-piperazinyl)-5-oxopyrido[2,3-d] pyrimidine-6-carboxylic acid (625 g). m.p. 299-305° C. (decomp.).

Provenance & Evidence