Synthesis
To a stirred solution of 4-iodopyrazole (5.0 g, 25.8 mmol) in dichloromethane (10 mL) was sequentially added p-toluenesulfonic acid monohydrate (TsOH-H2O, 0.5 g, 2.9 mmol) and 3,4-dihydro-2H-pyran (4.5 g, 53.5 mmol). The reaction mixture was stirred at room temperature for 2 hours. After completion of the reaction, the mixture was concentrated under reduced pressure to remove the solvent. The crude product was purified by silica gel column chromatography using ethyl acetate/petroleum ether (1:3, v/v) as eluent to afford the target compound, 4-iodo-1-(tetrahydropyran-2-yl)-1H-pyrazole (7 g, 93% yield), as a colorless oil.The LC-MS (ESI) analysis showed [M-84 + H]+ = 195.1 .
References
[1] European Journal of Inorganic Chemistry, 2017, vol. 2017, # 2, p. 446 - 453
[2] Patent: US2018/282328, 2018, A1. Location in patent: Paragraph 1171; 1172
[3] Journal of Organic Chemistry, 2007, vol. 72, # 9, p. 3589 - 3591
[4] European Journal of Medicinal Chemistry, 2014, vol. 73, p. 167 - 176
[5] Zeitschrift fur Naturforschung - Section B Journal of Chemical Sciences, 2014, vol. 69, # 1, p. 83 - 97
