Iodine → 5,6-Dichloro-3-hydroxy-3-(2-methoxyphenyl)-1,3-dihydro-2H-indol-2-one

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Reaction Steps

7.5 g of 1-bromo-2-methoxybenzene are added dropwise to a suspension of 1.1 g of magnesium in 20 ml of ether containing a few crystals of iodine, the reflux being maintained once it has started. At the end of the addition, the mixture is heated at reflux for 2 hours. A suspension of 4.3 g of 5,6-dichloro-1H-indole-2,3-dione in 20 ml of THF is then added and the resulting mixture is refluxed for 30 minutes. After cooling to RT, the reaction mixture is poured into a water/ice/concentrated HCl mixture and extracted with EtOAc, the organic phase is dried over Na2SO4 and the solvent is evaporated off under vacuum. The residue is triturated in hot iso ether and the precipitate formed is filtered off by suction and washed with ether. 5.2 g of the expected product are obtained, m.p.=245–246° C.

Provenance & Evidence