89532-38-7

A methanol (5 mL) solution of cyclopropanecarboxaldehyde (500 mg, 7.13 mmol) and acetaldehyde (455 mg, 7.84 mmol) was added to a 25 mL round bottom flask. The reaction mixture was cooled to 0 °C, followed by dropwise addition of 25% aqueous ammonium hydroxide solution (1 mL). The resulting mixture was stirred at 0 °C for 3 h, followed by continued stirring at room temperature overnight. Upon completion of the reaction, the mixture was concentrated under reduced pressure and the residue was dissolved in saturated saline (50 mL). The aqueous phase was extracted with ethyl acetate (3 x 10 mL), the organic layers were combined and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure to afford the title compound 2-cyclopropyl-1H-imidazole (600 mg, 78% yield) as a light brown solid.

[1] Patent: WO2014/8197, 2014, A1. Location in patent: Page/Page column 115
[2] Patent: WO2015/95767, 2015, A1. Location in patent: Page/Page column 130
[3] Patent: US2011/52578, 2011, A1
[4] European Journal of Medicinal Chemistry, 2016, vol. 108, p. 605 - 615