Synthesis
Cyanogen bromide (22.5 g, 212 mmol) was slowly added to a solution of 1H-imidazole (42 g, 617 mmol) in dichloromethane (1 L) and the reaction mixture was heated to reflux for 30 min. After completion of the reaction, it was cooled to room temperature and white solid was observed to precipitate. The solid was separated by filtration. The filtrate was concentrated under reduced pressure to about 100 mL and subsequently allowed to stand in a refrigerator for 3 days to promote crystallization. The precipitated solid was collected by filtration to give the final bis(1H-imidazol-1-yl)methanimine (8 g, 49.6 mmol, 8% yield).
References
[1] Patent: US2012/149718, 2012, A1. Location in patent: Page/Page column 35
[2] Journal of Organic Chemistry, 2002, vol. 67, # 21, p. 7553 - 7556
[3] Journal of Heterocyclic Chemistry, 2003, vol. 40, # 1, p. 191 - 193
[4] Chemical Communications, 2014, vol. 50, # 91, p. 14257 - 14260
[5] Patent: WO2012/85586, 2012, A1. Location in patent: Page/Page column 66; 68
