Paeonol → 7-Methoxy-n-methylspiro[2h-1-benzopyran-2,4'-piperidine]-4(3h)-one

Participants

Reaction Steps

To a stirred solution of 2-hydroxy-4-methoxyacetophenone (4.08 g, 24.58 mmol) in anhydrous methyl alcohol (60 cm3) under an atmosphere of dry nitrogen was added 1-methyl-4-piperidinone (3 cm3, 24.58 mmol) followed by pyrrolidine (4 cm3, 47.92 mmol) and the solution was heated to reflux. After 7 h, a further portion of 1-methyl-4-piperidinone (0.6 cm3, 4.76 mmol) was added and the mixture was heated to reflux for a further 4.5 h. It was then allowed to cool to room temperature before the volatile fractions were removed under reduced pressure. The resulting oil was treated with dichloromethane (100 cm3), washed with water (5×100 cm3), dried over anhydrous sodium sulfate to afford a dark viscous oil (6.33 g, 24.25 mmol) which partially crystallised on standing over a long period of time.

Provenance & Evidence