Ethyl 3-(4-pyridyl)-3-oxopropionate → (+/-) 2-(4-Oxo-2-pyridin-4-yl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)-1H-isoindole-1,3(2H)-dione

Participants

Reaction Steps

To a suspension of 9.166 g (32.77 mmol) of (+/−) 2-(2-Amino-3,4,5,6-tetrahydropyridin-3-yl)-1H-isoindole-1,3(2H)-dione hydrochloride (1:1) in 50 mL of toluene was added sodium methanolate (freshly prepared from 0.754 g (32.77 mmol) of sodium in 10 mL of methanol and the reaction mixture was stirred at room temperature for 1 h. The mixture was evaporated to dryness, dissolved in 50 mL of toluene and 4.87 g (25.21 mmol) of ethyl 3-(pyridin-4-yl)-3-oxopropionate was added. The resulting solution was stirred under reflux for 12 h. The cooled solution was evaporated to remove solvent. The mixture was dissolved in dichloromethane, washed with a saturated aqueous solution of ammonium chloride, saturated aqueous sodium chloride, dried over sodium sulfate and evaporated to dryness. The residue was chromatographed on silica gel eluting with a mixture of dichloromethane/methanol/aqueous ammonia solution (29%) in the proportions 97/310.3 led to afford 3.2 g (34%) of the desired compound as a white powder.

Provenance & Evidence