1,3-Cyclohexadiene → 3a-(3,4-difluorophenyl)-3a,4,7,7a-tetrahydro-2-methyl-4,7-ethano-1H-isoindole-1,3(2H)-dione

Participants

Reaction Steps

A 5.0 g amount of 3-(3,4-difluorophenyl)-1-methyl-1H-pyrrole-2,5-dione was dissolved in 25 ml of chloroform with warming. The solution was cooled to room temperature and 2.0 g of cyclohexadiene was added. After prolonged standing another 11/2 ml of diene was added with a small amount of butylated hydroxytoluene. The solution was heated at reflux for 24 hours. The reaction mixture was subjected to high pressure liquid chromatography using a silica gel column and 20% ethyl acetate in hexane as eluent giving 4.9 g of 3a-(3,4-difluorophenyl)-3a,4,7,7a-tetrahydro-2-methyl-4,7-ethano-1H-isoindole-1,3(2H)-dione as a white solid, mp 125°-127° C.

Provenance & Evidence