Reaction #332985

Reaction equation

6-bromo-1H-indazole

sodium hydride

SEM-Cl

→

6-bromo-1-(2-trimethylsilanyl-ethoxymethyl)-1H-indazole

Yield 69.0%

Solvents

DMF

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was warmed to room temperature
2. 2
   Temperaturethen cooled back to 0° C.
3. 3
   workup.ADDITIONAfter the addition
4. 4
   Otherthe ice bath was removed
5. 5
   Temperaturethe reaction mixture was warmed to room temperature
6. 6
   OtherAfter 1.5 h the reaction was quenched with water
7. 7
   Extractionextracted with diethyl ether (2×)
8. 8
   WashThe combined organic layers were washed twice with water and once with brine
9. 9
   Dryingthen dried over sodium sulfate
10. 10
    Filtrationfiltered
11. 11
    Concentrationconcentrated
12. 12
    OtherThe residue was chromatographed over silica gel with EtOAc/Hexanes (gradient 0-10% EtOAc)

Procedure

In a round-bottomed flask 6-bromo-1H-indazole (0.70 g, 3.55 mmol) was dissolved in DMF (7.5 ml). The reaction mixture was cooled to 0° C. and sodium hydride (60% dispersion in mineral oil, 172 mg, 4.3 mmol) was added). The reaction mixture was warmed to room temperature and stirred for 30 min then cooled back to 0° C. and SEM-Cl (0.76 ml, 4.28 mmol) was slowly added. After the addition was complete, the ice bath was removed and the reaction mixture was warmed to room temperature. After 1.5 h the reaction was quenched with water and extracted with diethyl ether (2×). The combined organic layers were washed twice with water and once with brine then dried over sodium sulfate, filtered and concentrated. The residue was chromatographed over silica gel with EtOAc/Hexanes (gradient 0-10% EtOAc) to give 802 mg (69%) of 6-bromo-1-(2-trimethylsilanyl-ethoxymethyl)-1H-indazole as a light yellow oil.

Source