2,3-Difluoro-4-(2-phenyldiazenyl)phenol → 4-Amino-2,3-difluorophenol

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Reaction Steps

61 g (0.26 mol) of 2,3-difluoro-4-(phenyldiazenyl)phenol from Example 3 and 1 g of Pd/C (10%) are initially charged in 800 ml of ethanol. The solution was degassed and aerated with hydrogen. The mixture was stirred at room temperature under a 1 bar hydrogen atmosphere for 18 hours. On completion of hydrogen uptake, the catalyst was filtered off and the filtrate was concentrated on a rotary evaporator, in the course of which the product already crystallized out. The resulting solid was filtered off, washed with a little cold ethanol and dried under high vacuum for 4 hours. 28 g (74%) of the desired compound were obtained as a light brown powder.

Provenance & Evidence