5-Bromo-2,4-bis(1,1-dimethylethoxy)pyrimidine → 5-(2,8-Dimethyl-5h-dibenzo[a,d]cyclohepten-5-yl)-2,4(1h,3h)-pyrimidinedione

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

n-Butyllithium (5.6 ml of a 2.5M solution in hexanes) was added dropwise to a solution of 5-bromo-2,4-bis(1,1,-dimethylethoxy)pyrimidine (example 1 step (i)) (3.85 g) in tetrahydrofuran (30 ml) at -78° C. The solution was stirred for 30 minutes and a solution of 10,11-dihydro-2,8-dimethyl-5H-dibenzo[a,d]cyclohepten-5-one (European Patent, 1993, 0 589 322 A1) (3.0 g) in tetrahydrofuran (20 ml) was added. The mixture was stirred at -78° C. for 45 minutes and room temperature for 15 minutes and then partitioned between brine and ethyl acetate. The organic phase was dried (MgSO4) and evaporated. The residue was dissolved in glacial acetic acid (100 ml) and heated at 120° C. for 30 minutes. The solvent was evaporated and the residue azeotroped with toluene and triturated with diethyl ether to give a solid. Yield 4.03 g.

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