Phosphoric Acid → 5,7-Dimethyl-8-methoxy-1,2,3,4,4a,9a-hexahydro-9-fluorenone

Participants

Reaction Steps

197.0 Grams of 1-cyclohexenyl 3,5-dimethyl-2-methoxyphenyl ketone was gradually added to polyphosphoric acid prepared from 900 g of phosphorus pentoxide and 900 g of phosphoric acid at 100° C. with stirring and the mixture was stirred at 100° C. for 3 hours. The reaction mixture was poured into 3 liters of ice water and extraction was carried out with 3 liters of methylene chloride. The extract was washed with water and then saturated aqueous sodium chloride solution and then dried with anhydrous magnesium sulfate. Methylene chloride was distilled off under reduced pressure. The residue was purified by a silica gel column chromatography (eluent: ethyl acetate:n-hexane =99:1) and then recrystallized from n-hexane to obtain 46.0 g of 5,7-dimethyl-8-methoxy-1,2,3,4,4a,9a-hexahydro-9-fluorenone.

Provenance & Evidence