Oxonium, trimethyl-, tetrafluoroborate(1-) (1:1) → 5-iodo-2-methyl-2H-indazole

To a solution of 5-iodo-1H-indazole (500 g, 2.05 mol) in EtOAc (4 L) is added trimethyloxonium tetrafluoroborate (450 g, 3.04 mol). After the resulting white suspension is stirred at room temperature for 2 h, it is concentrated under vacuum. Ice water (1 L) is added to the residue, and it is basified to pH 12 with 10% aqueous NaOH solution. The solids are collected by filtration, and redissolved in DCM (5 L). The insolubles are filtered off and the filtrate is washed with 10% aqueous NaOH solution (2×100 mL). The organic layer is dried over anhydrous Na2SO4, filtered through a short silica gel column, and concentrated. Methyl tert-butyl ether is added to the residue to give a slurry and the product is collected by filtration to give the title compound (360 g, 68.0%). MS (m/z): 259.0 (M+H).

1. concentrationit is concentrated under vacuum
2. additionIce water (1 L) is added to the residue, and it
3. filtrationThe solids are collected by filtration
4. dissolutionredissolved in DCM (5 L)
5. filtrationThe insolubles are filtered off
6. washthe filtrate is washed with 10% aqueous NaOH solution (2×100 mL)
7. dry with materialThe organic layer is dried over anhydrous Na2SO4
8. filtrationfiltered through a short silica gel column
9. concentrationconcentrated
10. additionMethyl tert-butyl ether is added to the residue
11. customto give a slurry
12. filtrationthe product is collected by filtration

ORD record

ord-7594323884ef44ddb1545629df0fe6e4

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08268836B2