Reference of 26621-44-3, Each compound has different characteristics, and only by selecting the characteristics of the compound suitable for a specific situation can the compound be applied on a large scale. 26621-44-3, name is 3-Nitro-1H-pyrazole, This compound has unique chemical properties. The synthetic route is as follows.
To a 0 C. solution of 3-nitro-1H-pyrazole (250.0 g, 2.17 mol, 1.0 eq) in anhydrous DMF (2.5 L; 10.2 vol eq) under nitrogen was added NaH (95.42 g of 60% w/w, 2.39 mol, 1.1 eq) in batches over 30 min while maintaining temperature below 8 C. The mixture was stirred for 1 h then 2,4-difluoropyridine (300 mL, 3.29 mol, 1.5 eq) was added, and the reaction was warmed to room temperature and stirred for approximately 16 hours (h). The reaction mixture was diluted with water (12.5 L) and stirred vigorously for 1 h. The off-white solid was collected by vacuum filtration. The solid was re-suspended in water (2 L) and filtered, and this step was repeated once further. The product was dried under vacuum, then suspended in heptane (4 L), stirred 3 h at room temperature, and filtered. The solid was washed with two further portions of heptane (2 L each) and dried under vacuum to provide 2-fluoro-4-(3-nitro-1H-pyrazol-1-yl)pyridine (426.3 g of 92% purity, 87% yield). 1H NMR (400 MHz, DMSO-d6) delta 9.01 (d, J=2.8 Hz, 1H), 8.45 (d, J=5.7 Hz, 1H), 7.95 (ddd, J=5.7, 1.9, 1.2 Hz, 1H), 7.81 (t, J=1.4 Hz, 1H), 7.46 (d, J=2.8 Hz, 1H) ppm. ESI-MS m/z calc. 208.04, found 209.01 (M+1).
The chemical industry reduces the impact on the environment during synthesis 3-Nitro-1H-pyrazole. I believe this compound will play a more active role in future production and life.
Reference:
Patent; VERTEX PHARMACEUTICALS INCORPORATED; Bligh, Cavan McKeon; Court, John J.; Liang, Jianglin; O’Dowd, Hardwin; Roeper, Stefanie; Ryan, Michael P.; US2019/177295; (2019); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics