Synthesis
GENERAL STEPS: A mixture of 2-bromoethanol (3.75 g, 30.00 mmol), 4-nitropyrazole (3.39 g, 30.00 mmol) and potassium carbonate (K2CO3, 4.97 g, 36.00 mmol) in acetonitrile (30 mL) was heated and refluxed for 16 hours. Upon completion of the reaction, the mixture was filtered and the filtrate was concentrated under reduced pressure to remove the solvent to afford the crude product 1-(2-hydroxyethyl)-4-nitro-1H-pyrazole as a white solid (4.70 g, yield: 100%), which could be used in the next reaction without further purification. The product was analyzed by electrospray ionization mass spectrometry (ESI-MS) and showed a molecular ion peak (M + H)+ m/z of 158.0.
References
[1] Patent: WO2015/89337, 2015, A1. Location in patent: Paragraph 0214
[2] Patent: WO2009/154769, 2009, A1. Location in patent: Page/Page column 41
[3] Patent: WO2016/42341, 2016, A1. Location in patent: Page/Page column 183; 184
[4] Patent: WO2015/48281, 2015, A1. Location in patent: Paragraph 00413; 00414
[5] Patent: US2015/336982, 2015, A1. Location in patent: Paragraph 0342; 0343
