Trimethyl borate → 4-Ethoxy-2,3-difluorophenol

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Reaction Steps

0.02 mol of 2,3-difluoroethoxybenzene are metalated according to 1b. Subsequently, 0.02 mol of trimethyl borate are added dropwise at a temperature of about -55° to -60° C. during the course of 0.5 h. The resulting suspension is subsequently stirred for a further 0.5 h, the temperature climbing to about -20°. 1.5 ml of 98% acetic acid are added. After about 15 min, the mixture is cooled to about -35° and a solution of 30% H2O2 /H2O (5 ml/2 ml) is added dropwise. After stirring for 2 h while slowly warming to room temperature, the organic phase is separated and the aqueous phase is extracted with methyl tert.butyl ether. Finally, the mixture is washed with saturated NaCl solution, dried and evaporated.

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