Yield:-

Reaction Conditions:

Stage #1:o-chloroaniline with hydrogenchloride in water at 0;
Stage #2: with sodium nitrite in water at 0; for 0.5 h;
Stage #3: with hydrogenchloride;tin(II) chloride hydrate in water at 0; for 4 h;

Steps:

4.1.2 General procedure for synthesis of substituted phenylhydrazine hydrochloride (15)
General procedure: Concentrated hydrochloric acid (30mmol, 2.5mL, 12M) was added to phenylaniline (10mmol) and the resulting white suspension was cooled to 0°C, then appropriate amount of water was added to dissolve the white solid. Sodium nitrite (11mmol) in 10mL of water, precooled to 0°C, was slowly added to the solution of phenylaniline hydrochloride. The temperature of the reaction was maintained at 0°C for 0.5h. The diazonium salt solution was treated with a solution of stannous chloride hydrate (40mmol) in 15mL of concentrate hydrochloric acid (12M), then stirred for another 4hat 0°C. A light brown solid which formed was collected by filtration, washed with little precooled ethyl alcohol and dichloromethane, the crude product was used without further purification.

References:

Zhai, Min'an;Wang, Long;Liu, Shiyuan;Wang, Lijing;Yan, Peng;Wang, Junfang;Zhang, Jingbo;Guo, Haifei;Guan, Qi;Bao, Kai;Wu, Yingliang;Zhang, Weige [European Journal of Medicinal Chemistry,2018,vol. 156,p. 137 - 147]

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