Sodium hydride → (E)-3-[1-Butyl-5-(4-fluorophenyl)-7-isopropyl-2,4-dioxo-1,2,3,4-tetrahydro-pyrido(2,3-d)pyrimidin-6-yl]prop-2-enal

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Reaction Conditions

Reaction Steps

A solution of 1.15 g (4.4 mol) of diethyl 2-(cyclohexylamino)-vinyl-phosphonate in 15 ml of tetrahydrofuran is added dropwise in the course of 10 min at 0°-5° C. under argon to a suspension of 0.25 g (8.4 mmol) of 80% strength sodium hydride in 15 ml of anhydrous tetrahydrofuran. The mixture is stirred at 0° C. for 15 min, a solution of 1.5 g (4 mmol) of the compound from Example 5 in 15 ml of tetrahydrofuran is added dropwise at 0° C. in the course of 20 min, and the mixture is stirred at room temperature for 1 h and under reflux for 20 min. The mixture is cooled, 50 ml of water are added cautiously, the mixture is extracted twice with ethyl acetate, and the combined organic phases are washed with sodium chloride solution and concentrated in vacuo. The residue is heated under reflux with a mixture of 25 ml of toluene, 35 ml of water and 2.6 g (36 mmol) of oxalic acid dihydrate for 1 h. The phases are separated, the aqueous phase is extracted with ethyl acetate, and the combined organic phases are washed with sodium chloride solution, dried over magnesium sulphate and concentrated in vacuo. The residue is crystallized from ether/petroleum ether.

Provenance & Evidence