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

Participants

Reaction Steps

A stirred solution of 4′-fluoro-2′-hydroxyacetophenone (15.97 g), 1-methyl-4-piperidone (12.74 cm3) and pyrrolidine (4.325 cm3) in methyl alcohol (250 cm3) was heated to reflux under nitrogen. After 0.5 h, further pyrrolidine (4.33 cm3) was added and, after another 0.5 h, the solution was allowed to cool. The reaction mixture was then evaporated under reduced pressure to give an oil, which was dissolved in dichloromethane (400 cm3). This solution was washed with water (3×400 cm3), dried (Na2SO4) and evaporated to give an oil (25.7 g). Flash chromatography on silica (eluting with dichloromethane-methyl alcohol-33% aqueous ammonia=380:20:1) gave the purified product as an oil (14.41 g).

Provenance & Evidence