反应详情

温度

105 °C

To a 75 mL pressure vessel was added 1-(1-methylethyl)-6-oxo-6,7-dihydro-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (4.12 g, 18.62 mmol), followed by phosphorous oxychloride (26.0 ml, 279 mmol). The flask was sealed and the stirring mixture heated at ca. 105° C. for ca. 18 h. After cooling to room temperature, the contents were concentrated in vacuo to remove most of volatiles. The residual contents were poured into a mixture of ice and 3M NaOH (60 mL), followed by additional 3M NaOH to ensure the pH stayed basic. The mixture was stirred for 30 min., and then cooled in an ice bath. The heterogenous mixture was slowly acidified to pH=3-4 with 6M HCl. The resulting suspension was extracted with EtOAc (3×). The combined organic layers were dried over MgSO4, filtered, and concentrated in vacuo to afford a yellow solid which was dried in a hi-vac oven overnight. The title compound was collected as 4.11 g (90%), and used without further purification. LCMS E-S (M+H)=240.2/242.2. 1H NMR (400 MHz, DMSO-d6) δ ppm 1.51 (d, J=6.57 Hz, 6 H) 5.17 (quin, J=6.63 Hz, 1 H) 7.65 (s, 1 H) 8.41 (s, 1 H) 14.25 (br. s., 1 H).

1. customThe flask was sealed
2. temperatureAfter cooling to room temperature
3. concentrationthe contents were concentrated in vacuo
4. customto remove most of volatiles
5. additionThe residual contents were poured into a mixture of ice and 3M NaOH (60 mL)
6. temperaturecooled in an ice bath
7. extractionThe resulting suspension was extracted with EtOAc (3×)
8. dry with materialThe combined organic layers were dried over MgSO4
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. customto afford a yellow solid which
12. customwas dried in a hi-vac oven overnight
13. customThe title compound was collected as 4.11 g (90%)
14. customused without further purification