Acetic Acid → Propyl 2-[(2-methyl-4-oxo-4H-chromen-8-yl)methylene]-3-oxobutanoate

Participants

Reaction Steps

2-Methyl-4-oxo-4H-chromene-8-carbaldehyde (2 g, 10.62 mmol) and propyl acetoacetate (1.53 g, 10.62 mmol) are dissolved in 500 ml of dichloromethane and, after addition of glacial acetic acid (0.76 ml, 13.28 mmol) and piperidine (0.1 ml, 1.06 mmol), heated under reflux with a water trap for 18 h. After cooling, the reaction mixture is diluted with 50 ml of dichloromethane and washed with 20 ml of sodium chloride solution, the organic phase is dried over sodium sulfate, and the solvent is removed in vacuo. 3.3 g (99% of theory) of the title compound are obtained as an E/Z isomer mixture.

Provenance & Evidence