反应详情

Methyl 6-chloro-1H-indazole-4-carboxylate (0.410 g, 1.947 mmol) was dissolved in DMF (10 mL) and placed into an ice bath and stirred for 15 min. Sodium hydride (0.101 g, 2.53 mmol) was added, the contents stirred for 15 min., and then 2-iodopropane (0.389 mL, 3.89 mmol) was added. The contents were stirred with warming to RT. After stirring at RT for 2 h, a scoop of sodium carbonate and then 0.4 mL of methyl iodide were added. After stirring at RT for an additional 1 h, the reaction mixture was diluted with saturated NH4Cl and then extracted with EtOAc (2×). The combined organic layers were washed with brine, dried over MgSO4, filtered, and concentrated in vacuo. The crude residue was dissolved in a minimal amount of DCM and purified by silica gel chromatography (eluent: 3-20% ethyl acetate in hexanes). The title compound was the less polar of the two products separated from chromatography, and was collected as 0.22 g (45% yield). 1H NMR (400 MHz, DMSO-d6) ppm 1.45-1.52 (m, 6H), 3.93-3.99 (m, 3H), 5.11 (quin, J=6.57 Hz, 1H), 7.73 (d, J=1.77 Hz, 1H), 8.30 (s, 1H), 8.42 (s, 1H).

1. customplaced into an ice bath
2. stirringthe contents stirred for 15 min.
3. stirringThe contents were stirred
4. stirringAfter stirring at RT for 2 h
5. stirringAfter stirring at RT for an additional 1 h
6. extractionextracted with EtOAc (2×)
7. washThe combined organic layers were washed with brine
8. dry with materialdried over MgSO4
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. dissolutionThe crude residue was dissolved in a minimal amount of DCM
12. custompurified by silica gel chromatography (eluent: 3-20% ethyl acetate in hexanes)
13. customseparated from chromatography
14. customwas collected as 0.22 g (45% yield)