反应详情

6-Nitro-1H-pyrazolo[4,3-b]pyridine. A solution of sodium nitrite (2.163 g, 31.3 mmol) in water (20 mL) was added to a stirred solution of 2-methyl-5-nitropyridin-3-amine (4 g, 26.1 mmol) in acetic acid (70 mL). The resulting orange solution was stirred at room temperature for 16 h. The reaction was cooled to 0° C. and the reaction mixture was brought to pH=7 via addition of aqueous sodium hydroxide (6 M). Water and ethyl acetate were added. The resulting mixture was shaken in a reparatory funnel and the layers were separated. The organics were washed with water and brine, dried over magnesium sulfate, filtered, and concentrated on a rotary evaporator. The residue was triturated with diethyl ether. Solids were collected by vacuum filtration, washed with diethyl ether, and dried under high vacuum to give the desired product, as a dark orange solid (2.3 g, 14.01 mmol, 53.7% yield). 1H NMR (400 MHz, DMSO-d6) δ (ppm) 9.29 (d, J=2.34 Hz, 1H), 8.91 (br s, 1H), 8.59 (br s, 1H). MS (ESI) m/z 165.2 [M+1]+.

1. temperatureThe reaction was cooled to 0° C.
2. stirringThe resulting mixture was shaken in a reparatory funnel
3. customthe layers were separated
4. washThe organics were washed with water and brine
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated on a rotary evaporator
8. customThe residue was triturated with diethyl ether
9. filtrationSolids were collected by vacuum filtration
10. washwashed with diethyl ether
11. customdried under high vacuum