PURPOSE: To obtain easily the titled substance useful as an intermediate for drugs, etc., by using 2,3,4-trichloronitrobenzene requiring no operation such as steam distillation, obtainable easily at relative low price as a raw material, treating it with an aqueous solution of caustic soda.

CONSTITUTION: 2,3,4-Trichloronitrobenzene as a raw material is reacted with an aqueous solution of caustic soda or an aqueous solution of caustic potash preferably in an aprotic polar solvent such as dimethyl sulfoxide preferably in the presence of a phase transfer catalyst such as tetermethylammonium chloride at 100W170°C, preferably at 140W160°C (when the aprotic polar solvent is used, the reaction is smoothly promoted at 40W60°C), to give the desired compound. The starting raw material can be easily synthesized from 1,2,3-trichlorobenzene through nitration process.