5637-42-3

Off-White Solid

An intermediate in the preparation of Etravirine

The general procedure for the synthesis of N-(4-cyanophenyl)guanidine from cyanamide and p-aminobenzonitrile is as follows: P-aminobenzonitrile (100 g), ethanol (500 ml), concentrated nitric acid (36 ml), and a 50% aqueous ammoniacal nitrile solution (54 ml) were mixed and heated to reflux. The reflux reaction was maintained for 16 hours. Upon completion of the reaction, the reaction mixture was cooled to 0 °C, followed by the slow addition of methyl tert-butyl ether (500 mL) at 0 to 5 °C. The mixture was continued to be stirred at 0 to 5 °C for 5 h. The precipitated solid was separated by filtration to give 59 g of guanidine nitrate. Guanidine nitrate (59 g) was dissolved in water (590 mL) and 1M sodium hydroxide solution (325 mL) was added. The precipitated solid was separated by filtration again and dried to give 33 g of 1-(4-cyanophenyl)guanidine.

[1] European Journal of Medicinal Chemistry, 2010, vol. 45, # 1, p. 244 - 255
[2] Patent: WO2012/1695, 2012, A1. Location in patent: Page/Page column 10
[3] Patent: US2013/96148, 2013, A1. Location in patent: Paragraph 0085; 0086
[4] Patent: US2015/336900, 2015, A1. Location in patent: Paragraph 0027; 0028