Electric Literature of 3994-50-1,Some common heterocyclic compound, 3994-50-1, name is 1-Methyl-4-nitro-1H-pyrazole, molecular formula is C4H5N3O2, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
Example 317 3-amino-6-bromo-N-(1-methyl-1H-pyrazol-4-yl)picolinamide 317 1-Methyl-4-nitro-1H-pyrazole (1.62 g, 12.7 mmol) was dissolved in methanol (250 mL) and hydrogenated on H-Cube at 60 bar hydrogen pressure and 70 C. to give 1-methyl-1H-pyrazol-4-amine (1.23 g, 99%). To a 100 mL round bottom flask containing 1-methyl-1H-pyrazol-4-amine (700 mg, 7.0 mmol), 3-amino-6-bromopicolinic acid (1.86 g, 8.5 mmol) and PyBop (4.12 g, 8.0 mmol) was added methylene chloride (30 mL) and diisopropylethylamine (3.8 mL, 21.6 mmol). The reaction mixture was stirred for 24 hr at room temperature and the reaction was monitored by LCMS. Upon completion of the reaction, the solvent was distilled off and the crude material was purified via flash chromatography, heptane/ethyl acetate 0% to 100% to afford a yellow solid. A fraction of it was purified via reverse phase HPLC to afford 317. 1H NMR (400 MHz, DMSO) delta 10.25 (s, 1H), 8.03 (s, 1H), 7.70 (s, 1H), 7.43 (d, J=8.7 Hz, 1H), 7.19 (d, J=8.7 Hz, 1H), 7.02 (br, 2H), 3.81 (s, 3H). MS (ESI) m/z: 296.0/298.0 [M+H+].
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 1-Methyl-4-nitro-1H-pyrazole, its application will become more common.