Synthesis
General procedure for the synthesis of alpha-(2,4-dichlorophenyl)-1H-imidazole-1-ethanol from 2'-(1H-imidazol-1-yl)-2,4-dichloroacetophenone: In a 1000 mL three-necked flask equipped with a stirrer, a thermometer, and a dropping funnel, add 102 g of 2'-(1H-imidazol-1-yl)-2,4-dichloroacetophenone (0.4 mol) and 300 mL of methanol. Potassium borohydride was added in batches and slowly heated to reflux. After completion of the reaction, stirring was continued for 1 h and the progress of the reaction was monitored by thin layer chromatography (TLC) (unfolding agent was ethyl acetate: methanol = 10:1, v/v). At the end of the reaction, methanol was recovered by distillation under reduced pressure. The concentrate was adjusted to pH 4-5 with 5% hydrochloric acid solution and subsequently diafiltrated. The filtrate was adjusted pH to 7-8 with 5% sodium bicarbonate solution, when a white solid precipitated. The solid was collected by filtration, washed with water, dried and recrystallized to give 93.1 g of 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanol in 90.5% yield with a melting point of 134-135 °C.
References
[1] Patent: CN102180835, 2016, B. Location in patent: Paragraph 0015; 0016
[2] Bioorganic and Medicinal Chemistry, 2018, vol. 26, # 8, p. 1665 - 1674
[3] Polyhedron, 2013, vol. 52, p. 106 - 114
[4] Organic and Biomolecular Chemistry, 2018, vol. 16, # 23, p. 4288 - 4294
[5] Medicinal Chemistry Research, 1999, vol. 9, # 3, p. 162 - 175
