Butanoic acid, 2-ethyl-3-oxo-, ethyl ester → 2-(5-chloro-2-thienyl)-5-ethyl-4-methyl-1H-pyrimidin-6-one

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Reaction Steps

A 100-mL round bottomed flask was charged with 5-chlorothiophene-2-carboxamidine HCl salt (394 mg, 2 mmol, 1 eq.), ethyl 2-ethyl-3-oxo-butanoate (950 mg, 6 mmol, 3 eq.), and ethanol (10 ml). To the mixture was added sodium methoxide (25 w % in methanol, 1.73 g, 8 mmol, 3 eq.). The resulting mixture was stirred under reflux for 7 hr. After cooling to room temperature, the mixture was evaporated under reduced pressure to dryness and the residue was treated with 2N HCl (4.5 ml). Solid was collected by filtration and washed with water followed by hexane. The product thus obtained was forwarded to the next step without any further purification (240 mg, 47% yield).

Provenance & Evidence