The compound was synthesized by improving the method reported in the literature [22]. The procedure was as follows: in a 1L round bottom flask, ammonium chloride (10.7 g, 0.200 mol), glyoxal (40% aqueous solution, 15.3 mL, 0.134 mol), formaldehyde (30% aqueous solution, 16.0 mL, 0.134 mol) and deionized water (250 mL) were mixed well. Another flask was taken and cyclohexylamine (11.5 mL, 0.100 mol) was dissolved in deionized water (100 mL) and acidified with phosphoric acid (85%, 15 mL). The acidified cyclohexylamine solution was slowly added to the ammonium chloride mixture. The resulting colorless solution was heated and refluxed for 12 h. When the reaction was complete, it was cooled to room temperature to give a clarified orange solution. This solution was poured into a half-full of 1 L of ice and the pH was adjusted to 10-12 with 40% sodium hydroxide solution.Subsequently, the product was extracted with ethyl acetate and the organic layer was washed with water and dried with anhydrous sodium sulfate. After removing the solvent under reduced pressure, the product was purified by vacuum distillation (105 °C) to give 7.5 g of 1-cyclohexyl-1H-imidazole as a colorless oil in 50% yield. The structure of the product was confirmed by 1H NMR, 13C NMR and HR-EI-MS.1H NMR (400 MHz, CDCl3, 25°C) δ/ppm: 7.53 (s, 1H), 7.04 (s, 1H), 6.95 (s, 1H), 3.90 (tt, J = 11.8, 3.8 Hz, 1H), 2.12-2.09 (m, 2H), 1.92-1.92 (m, 1H), 2.12-2.09 (m, 1H), 2.12-2.09 (m, 1H), 2.12-2.09 (m, 1H), 2.12-2.09 (m, 1H). 2H), 1.92-1.87 (m, 2H), 1.79-1.70 (m, 1H), 1.67-1.57 (m, 2H), 1.45-1.35 (m, 2H), 1.29-1.18 (m, 1H). 13C NMR (101 MHz, CDCl3, 25°C) δ/ppm: 135.43, 129.03, 117.10, 56.90 117.10, 56.90, 34.54, 25.54, 25.34. HR-EI-MS [M]+ m/z: C9H14N2 calculated value 150.1157; measured value 150.1162.
