Diethyl (ethoxymethylene)malonate → Ethyl 1,6-dihydro-1-(2-methoxyethyl)-6-oxo-2-(3-thienyl)-5-pyrimidinecarboxylate

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Reaction Steps

2-Methoxy-1-ethylamine (0.86 g, 11.4 mmol) was added to a solution of 3-thiophenecarboximidic acid ethyl ester hydrochloride (2.0 g, 10.4 mmol) in methanol (10 mL), which was then stirred at ambient temperature for 1.5 h. The reaction mixture was then concentrated under reduced pressure and redissolved in ethanol (10 mL). Sodium ethoxide solution (21% w/w in ethanol, 3.4 g, 10 mmol) and diethyl ethoxymethylenemalonate (2.2 g, 10 mmol) were added and the mixture was heated to reflux for 2 h before being concentrated under reduced pressure and purified by medium pressure liquid chromatography on silica gel eluting with 0 to 100% ethyl acetate in hexanes to provide 1.82 g of the title compound as an oil.

Provenance & Evidence