873-74-5

2863-98-1

The general procedure for the synthesis of 4-cyanophenylhydrazine hydrochloride from 4-aminobenzonitrile was as follows: to a stirring suspension of 4-aminobenzonitrile (50 g, 423 mmol) concentrated hydrochloric acid (550 mL) was slowly added dropwise an aqueous sodium nitrite solution (31.5 g, 457 mmol, dissolved in 200 mL of water) at a low temperature of -5 to 0 °C. Keeping the reaction temperature below 0 °C, a solution of tin(II) chloride dihydrate (477 g, 2.1 mol) concentrated hydrochloric acid (370 mL) pre-cooled to 0 °C was added to the above diazotized solution. The reaction mixture was continued to be stirred for 15 minutes. Upon completion of the reaction, the resulting white precipitate was collected by filtration, washed with diethyl ether and recrystallized from aqueous ethanol. The resulting 4-cyanophenylhydrazine hydrochloride had a melting point of 234-236 °C (literature value 235-237 °C) and yielded 60 g in 84% yield.