Reaktion #333208

Reaktionsgleichung

iodomethane

6-tert-butyl-3-iodo-1H-indazole

KOt-Bu

→

6-tert-butyl-3-iodo-1-methyl-1H-indazole

Ausbeute 69.0%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGStirred at 0° C. for 30 min
2. 2
   Temperaturthen warmed to room temperature
3. 3
   workup.STIRRINGstirred for 1.5 h
4. 4
   SonstigeThe reaction was quenched with water
5. 5
   Extraktionextracted with EtOAc (2×)
6. 6
   WaschenThe combined organics were washed with brine
7. 7
   Trocknenthen dried over MgSO4
8. 8
   Einengenconcentrated
9. 9
   SonstigeThe crude residue was purified by silica gel chromatography with 10% to 50% EtOAc/heptane

Vorschrift

To a solution of 6-tert-butyl-3-iodo-1H-indazole (820 mg, 2.73 mmol) in THF (8 ml) at 0° C. was added KOt-Bu (429 mg, 3.82 mmol). The reaction mixture was stirred at 0° C. for 30 min then added iodomethane (0.24 ml, 3.82 mmol). Stirred at 0° C. for 30 min then warmed to room temperature and stirred for 1.5 h. The reaction was quenched with water and extracted with EtOAc (2×). The combined organics were washed with brine then dried over MgSO4 and concentrated. The crude residue was purified by silica gel chromatography with 10% to 50% EtOAc/heptane to afford 592 mg (69%) of 6-tert-butyl-3-iodo-1-methyl-1H-indazole as a white solid. 1H NMR (CDCl3, 300 MHz): δ (ppm) 7.37-7.43 (m, 1H), 7.31 (d, J=9.8 Hz, 2H), 4.10 (s, 3H), 1.41 (s, 9H). The minor 6-tert-butyl-3-iodo-2-methyl-1H-indazole regioisomer was also observed but not isolated.

Quelle