Ethyl isocyanate → 3-Ethyl-1-(3-nitrophenyl)pyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione

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Reaction Steps

To a solution of 5.7 g of 2-(m-nitroanilino)nicotinic acid ethyl ester and 50 ml of dry tetrahydrofuran was added 1.1 g of sodium amide and the solution was stirred for one hour. To this was added dropwise under cooling 2.9 g of ethyl isocyanate and this mixture was reacted at 60°C for 10 hours. After the reaction was complete, the solvent was distilled off from the mixture, and to the residue obtained was added water to precipitate a crude product. This product was collected by filtration and recrystallized from methanol to give 3.4 g of 1-(m-nitrophenyl)-3-ethylpyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione as colorless needles, melting at 210°-211°C.

Provenance & Evidence