Pyrrolidine → 6-Bromoindole

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-bromo-2-nitrotoluene (4.3 g., 20 mmol.) in DMF (40 mL.) was added DMF dimethylacetal (7.15 g., 60 mmol.) and pyrrolidine (1.4 g., 20 mmol.). The solution was heated to 110° C. for 4 hr. then cooled to rt. and diluted with ethyl ether. The mixture was washed 3×with water, dried with Na2SO4, filtered and the solvent evaporated. The residue was dissolved in 80% aqueous acetic acid (125 mL.) and heated to 75° C. Zinc dust (9.75 g., 150 mmol.) was added gradually over 20 min. The reaction mixture was heated to 85° C. for 2 hr. then cooled to ~35° C. and filtered to remove unreacted zinc. The filtrate was diluted with ethyl ether, washed 3×with water then with saturated aqueous NaHCO3. The solution was dried with Na2SO4, filtered and concentrated in vacuo to ~30 mL. then diluted with hexanes and filtered. The filtrate was concentrated to an off-white solid which was dissolved in hexane, filtered, and concentrated to give 1.65 g. of the title compound as a light green solid.

Provenance & Evidence