Synthesis
The general procedure for the synthesis of 4-nitrophenylhydrazine hydrochloride from 4-nitroaniline was as follows: 4-nitroaniline (1.47 g, 10.6 mmol) was dissolved in concentrated hydrochloric acid (2 mL) and the solution was cooled to 0°C. A solution of sodium nitrite (717 mg, 10.4 mmol) dissolved in water (4 mL) was added dropwise to the above reaction mixture under ice bath conditions with continuous stirring for 1 hour. Subsequently, a pre-cooled solution of concentrated hydrochloric acid (2 mL) of stannous chloride (4.7 g, 20.8 mmol) was slowly added to the diazo reaction mixture. The reaction mixture was continued to be stirred at 0°C for 2 hours. Upon completion of the reaction, the resulting yellow-orange precipitate was collected and washed thoroughly with ice-cold water until the filtrate was neutral (pH ≈ 7). Finally, the precipitate was dried under vacuum conditions overnight to afford the target product 4-nitrophenylhydrazine hydrochloride (640 mg, 4.18 mmol, 39% yield). The structure of the product was confirmed by 1H NMR (DMSO-d6): δ 4.49 (s, 2H), 6.78 (d, J=8.78 Hz, 2H), 7.98 (d, J=9.29 Hz, 2H), 8.41 (s, 1H).
References
[1] Bioorganic and Medicinal Chemistry, 2014, vol. 22, # 9, p. 2739 - 2752
[2] Russian Chemical Bulletin, 2005, vol. 54, # 10, p. 2417 - 2424
[3] European Journal of Medicinal Chemistry, 2010, vol. 45, # 10, p. 4692 - 4696
[4] Journal of Agricultural and Food Chemistry, 2014, vol. 62, # 2, p. 381 - 390
[5] Oriental Journal of Chemistry, 2017, vol. 33, # 2, p. 1041 - 1044
