N-bromobutanimide → 2,8-dimethyl-5H-dibenzo[a,d][7]annulen-5-one

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

10,11-Dihydro-2,8-dimethyl-5H-dibenzo[a,d]cyclohepten-5-one (European Patent, 1993, 0 25 589 322 A1) (6 g) and N-bromosuccinimide (5 g) in ethyl acetate (100 ml) was irradiated with a 500 W halogen lamp. After 5 hours the reaction mixture was cooled and quenched with brine. The organic layer was collected, dried (MgSO4) and evaporated under reduced pressure. The residue was dissolved in dry dimethylformamide, treated with 1,5-diazabicyclo[4.3.0]non-5-ene (3.5 ml) and heated at 80° C. for 0.25 hours. The cooled reaction mixture was washed with 2M HCl, brine, dried (MgSO4) and evaporated under reduced pressure. Purification was by chromatography eluting with toluene. Yield 4.5 g.

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