1-NITROPYRAZOLE

The acetic anhydride and fuming nitric acid are slowly mixed in an ice water bath at a volume ratio of 5.5:1 to obtain a nitrating agent, and the nitratingagent and the pyrazole acetic acid solution are respectively delivered to the microchannel reactor through a high-pressure constant-flow pump with precise flow control. The twoinlets control the molar ratio of nitric acid to pyrazole to be 1.1:1. At 45-70 °C, the two liquids are instantaneously mixed in the microchannel reactorand reacted. The reaction solution is poured into crushed ice and filtered. It was washed with ice water and dried under vacuum to give N-nitropyrazole; theflow rate of the acetic acid solution of the pyrazole was 0.1 mL/min.The yield and purity of N-nitropyrazole are shown in Table 1 and Figure 2.Fuming nitric acid (3.3 mL) was added dropwise to a stirred solution of pyrazole (4.5 g, 66 mmol) in glacial acetic acid (14.1 mL) that had been cooled to −10 °C using an ice-salt bath. A voluminous precipitate was formed. Acetic anhydride (9.45 mL) was added dropwise and the resultant mixture was stirred at ambient temperature for 1.5 h. The mixture was poured onto ice and was neutralized with potassium carbonate. The precipitate was isolated by filtration. The yield of the obtained white solid of N-nitropyrazole is 78percent.4-Nitro-lJH-pyrazoIe=N; [547] [Ref: Huettel, R. and Buechele, F., Chem. Ber. 1955, 88, 1586-1590] 1-Nitro-l/Z'-pyrazole (2.2g, 0.019 mol) was dissolved in sulfuric acid (lOmL) at-10°C, and theresulting mixture was slowly warmed to rt overnight. The solution was added to ice (lOOg)dropwise, and the resulting white solid was collected by filtration and washed with water.The aqueous phase was extracted with EtOAc (3x30mL), the combined organic phases werewashed with brine (2x30mL), and dried over anhydrous sodium sulfate. Evaporation underreduced pressure provided an off-white solid, which was combined with the first solid anddried in vacua to provide the title compound. LC-MS (ES, Pos.): 1 14 [MH+]. 'H NMR(DMSO-d6, 400 MHz): 8 = 8.27 (s, 1H), 8.90 (s, 1H), 13.96 (br s, 1H).Concentrated sulphuric acid (80 ml) was added dropwise to a stirred sample of Concentrated sulphuric acid (80 ml) was added dropwise to a stirred sample of Concentrated sulphuric acid (80 ml) was added dropwise to a stirred sample of Concentrated sulphuric acid (80 ml) was added dropwise to a stirred sample of Concentrated sulphuric acid (80 ml) was added dropwise to a stirred sample of 1-Nitropyrazole (1 g) was slowly added to a round-bottomed flask containing H2SO4 (98percent, 5 mL) and stirred for 20 h at room temperature. The reaction mixture was slowly transferred to a beaker containing ice with stirring. The solution was extracted with ether. The organic layer was dried with Na2SO4 then evaporated to afford 4-The compound may be explosive and should be handled cautiously.Concentrated sulphuric acid (80 ml) was added dropwise to a stirred sample of Concentrated sulphuric acid (80 ml) was added dropwise to a stirred sample of

Molecular Weight:113.08
XLogP3:0.5
Hydrogen Bond Acceptor Count:3
Exact Mass:113.022526347
Monoisotopic Mass:113.022526347
Topological Polar Surface Area:63.6
Heavy Atom Count:8
Complexity:99.2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes