1-Trityl-1H-1,2,4-triazole

Synthesis

Triethylamine (5.49 g, 54.30 mmol) was added to a solution of 1,2,4-triazole (3.0 g, 43.44 mmol) in N,N-dimethylformamide (DMF, 50 mL) at room temperature. After stirring for 5 min, triphenylchloromethane (12.11 g, 43.44 mmol) was added and the reaction mixture was stirred overnight at room temperature. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The crude product was partitioned between dichloromethane (50 mL) and water (50 mL) to separate the organic layer. The aqueous layer was extracted with dichloromethane (3 x 50 mL) and the organic layers were combined. The organic layer was washed with water (3 x 40 mL) and then dried over anhydrous sodium sulfate (Na2SO4). The organic layer was concentrated under reduced pressure to afford 1-trityl-1H-1,2,4-triazole (12.6 g, 93% yield). N-butyllithium (n-BuLi, 4.5 mL, 11.24 mmol; 2.5 M hexane solution) was added to a solution of tetrahydrofuran (THF, 120 mL) of 1-trityl-1H-1,2,4-triazole (3.5 g, 11.24 mmol) and stirred for 45 min at -78 °C. Bromine (1.76 g, 11.02 mmol) was added dropwise over 5 min and stirring was continued for 2 h at -78 °C. The reaction mixture was then allowed to slowly warm to -20°C and the reaction was quenched by addition of saturated ammonium chloride (NH4Cl) solution (30 mL). The reaction mixture was diluted with water (60 mL) and dichloromethane (40 mL) and the organic layer was separated. The aqueous layer was extracted with dichloromethane (4 x 50 mL) and the organic layers were combined. The organic layer was dried with anhydrous sodium sulfate (Na2SO4) and the solvent was evaporated under reduced pressure to give the crude product (4.2 g, 95% yield), which was used directly in the next step. Nuclear magnetic resonance hydrogen spectroscopy (1H NMR) data: δ 7.09-7.16 (m, 6H), 7.27-7.40 (m, 9H), 7.86 (s, 1H).

References

[1] Patent: WO2014/159248, 2014, A1. Location in patent: Paragraph 0185
[2] European Journal of Medicinal Chemistry, 2009, vol. 44, # 7, p. 3064 - 3067
[3] Tetrahedron, 1997, vol. 53, # 30, p. 10289 - 10312
[4] MedChemComm, 2014, vol. 5, # 1, p. 72 - 81
[5] Patent: US6620841, 2003, B1