[Br:1][C:2]1[CH:11]=[C:10]2[C:5]([C:6]([CH3:14])([CH3:13])[CH2:7][CH2:8][C:9]2=O)=[CH:4][C:3]=1[O:15][CH2:16][CH3:17].N1C=CC=N[C:19]1=O.C[Mg]Br.C(OCC)C>C1COCC1>[Br:1][C:2]1[CH:11]=[C:10]2[C:5](=[CH:4][C:3]=1[O:15][CH2:16][CH3:17])[C:6]([CH3:14])([CH3:13])[CH2:7][CH:8]=[C:9]2[CH3:19]To 7-bromo-6-ethoxy-4,4-dimethyl-3,4-dihydro-2H-naphthalen-1-one (Compound A-4, 1.05 g, 3.53 mmol) in THF (12 mL) and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1])-pyrimidinone (2 mL) at 0° C. was added a solution of methylmagnesium bromide (3M in diethylether (3.53 mL, 10.59 mmol). The reaction was allowed to warm up to room temperature and was stirred at 50° C. overnight. The reaction was quenched with ice water and extracted with diethylether. The organic layer was washed successively with water, brine, dried over Na2SO4, and concentrated in vacuo. The crude material was then dissolved in benzene (20 mL). After catalytic amount of p-toluenesulfonic acid was added, the reaction was stirred at reflux for 2 h. The solvent was removed in vacuo. The residue was purified by column chromatography (silica gel, 1% ethyl acetate in hexane) to afford the title compound as a pale yellow oil.
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