Hydrochloric Acid → 5-Methyl-4-oxo-2-(thiophen-3-ylmethyl)-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxylic acid

Beteiligte Stoffe

Reaktionsschritte

A mixture of 379 mg of ethyl 5-methyl-4-oxo-2-(thiophen-3-ylmethyl)-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxylate as synthesized in Production Example 1, 3.4 mL of 1N aqueous sodium hydroxide solution and 2.2 mL of ethanol was heated under reflux for 2 hours. After cooling off, the reaction liquid was poured on ice, rendered acidic with diluted hydrochloric acid, and the precipitated crystals were recovered by filtration. After washing with water, the crystals were dried by heating under reduced pressure, to provide 320 mg of 5-methyl-4-oxo-2-(thiophen-3-ylmethyl)-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxylic acid.

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