Trifluoroacetic acid → 5-(3-dimethylaminopropylidene)-3-methylsulfonyl-5H-dibenzo[a,d]cycloheptene

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Reaction Conditions

Reaction Steps

5-(3-Dimethylaminopropyl)-5-hydroxy-3-methylsulfonyl-5H-dibenzo[a,d]cycloheptene (13.62 g., 0.037 mole) is dissolved in 136 ml. of trifluoroacetic acid. Trifluoroacetic anhydride, 68 ml., is added and the solution heated under reflux for 1 hour in a water-bath at 70°C. The dark green solution is cooled and poured into 250 ml. of ice-water. The mixture is rendered alkaline with 10 N. sodium hydroxide solution while stirring and cooling and extracted with benzene. The benzene extract is washed with water, dried over sodium sulfate and the benzene distilled under reduced pressure. The mixed geometric isomers of 5-(3-dimethylaminopropylidene)-3-methylsulfonyl-5H-dibenzo[a,d]cycloheptene is obtained as a brown oily residue in a yield of 13.19 g. (theory, 13.08 g.).

Provenance & Evidence