Water → 4-Bromoindole

Participants

Reaction Conditions

Reaction Steps

2-Bromo-6-nitrotoluene (3.2 g, 15 mmol), N,N-dimethylformamide dimethyl acetal (5.4 g, 45 mmol) and pyrrolidine (1.1 g, 15 mmol) were combined in 30 mL of DMF and heated at 110° C. The reaction mixture was stirred at 110° C. for 2.5 hours and then water was added. The aqueous layer was extracted with Et2O and the combined organic layers were washed with water and brine, dried over MgSO4 and concentrated. The brown syrup was dissolved in 80% aqueous AcOH (80 mL) and heated to 75° C. Zn powder (8.5 g), 130 mmol) was then added portionwise over 1 hour and the temperature was raised to 85° C. for 2 hours. The reaction mixture was filtered and water was added. The aqueous layer was extracted with Et2O and the combined organic layers were washed with saturated aqueous sodium bicarbonate and water, dried over Na2SO4 and concentrated. The residue was purified by silica gel chromatography eluted with 20% EtOAc in Hexanes to provide 2 g of the title compound as a greenish oil used as such.

Provenance & Evidence