Synthesis
Step 1. Synthesis of 1-benzyl-4-iodo-1H-pyrazole; 4-iodo-1H-pyrazole (17 g, 87.63 mmol, 1.00 eq.) was dissolved in N,N-dimethylformamide (150 mL) in a 250 mL round bottom flask. Sodium hydride (3.6 g, 105.00 mmol, 1.20 eq., 70% dispersed in mineral oil) was added in batches at 0 °C. Subsequently, benzyl bromide (16.5 g, 96.49 mmol, 1.10 eq.) was added dropwise at the same temperature. The reaction mixture was slowly warmed to room temperature and stirring was continued for 2 hours. Upon completion of the reaction, the reaction was quenched with an ice-water mixture (200 mL). The reaction mixture was extracted with ethyl acetate (3 x 200 mL). The organic layers were combined, dried over anhydrous sodium sulfate, filtered and concentrated on a rotary evaporator to give 1-benzyl-4-iodo-1H-pyrazole as a yellow solid (22 g, 80% yield).
References
[1] Organic Letters, 2017, vol. 19, # 19, p. 5114 - 5117
[2] Patent: WO2006/84338, 2006, A1. Location in patent: Page/Page column 63
[3] Patent: US8080566, 2011, B1. Location in patent: Page/Page column 56-57
[4] Patent: WO2016/615, 2016, A1. Location in patent: Paragraph 00555
[5] Patent: WO2014/128465, 2014, A1. Location in patent: Page/Page column 160; 161
