反应详情

Add at room temperature under nitrogen, trimethyloxonium tetrafluoroborate (229.34; g, 1.52; mol) portion wise to a mixture of 5-bromo-1H-indazole (199.6; g, 1.01 mol) in ethyl acetate (3.04; L, 31.06; mol), stir 2.5; h and filter to give a white solid. Wash the recovered solid twice with ethyl acetate (500; mL) and then add it portion wise to a cooled aqueous solution of 2; M sodium hydroxide (3.80; L, 7.60; mol) in an ice bath. Stir the mixture for 1; h, sonicate for 15; min., filter and wash the recovered solid twice with water (200; mL). Dry the solid overnight under vacuum, slurry in dichloromethane (1; L) and filter. Concentrate the filtrate and purify by silica gel chromatography eluting with dichloromethane to give the title compound as a yellow solid (149.77; g, 70%). MS (m/z): 211, 213; (M+1).

1. additionAdd at room temperature under nitrogen
2. filtrationh and filter
3. customto give a white solid
4. washWash the recovered solid twice with ethyl acetate (500; mL)
5. additionadd it portion wise to a cooled aqueous solution of 2
6. stirringStir the mixture for 1
7. customh, sonicate for 15
8. filtration, filter
9. washwash the recovered solid twice with water (200; mL)
10. dry with materialDry the solid overnight under vacuum, slurry in dichloromethane (1; L)
11. filtrationfilter
12. concentrationConcentrate the filtrate
13. custompurify by silica gel chromatography
14. washeluting with dichloromethane