A solution of 2-methoxyphenylmagnesium bromide is prepared from 1.9 g of magnesium in 4 ml of ether and from a solution of 14.54 g of 1-bromo-2-methoxybenzene in 21 ml of ether. This solution is added drop wise, under an argon atmosphere, to a mixture of 5 g of 5-trifluoromethoxy-1H-indole-2,3-dione in 26 ml of THF, cooled beforehand in an ice bath, and then heated at the reflux point of the ether for 1 hour 30 minutes and allowed to cool to RT. The reaction mixture is poured slowly into saturated NH4Cl solution and extracted with EtOAc, the organic phase is washed with 5% K2CO3 solution, with water and with saturated NaCl solution and dried over Na2SO4, and the solvent is evaporated off under vacuum. 2.8 g of the expected product are obtained.
