Trifluoroacetic acid → Ethyl 5-bromoindoline-7-carboxylate

Participants

Reaction Steps

NBS (51.3 g, 0.29 mol) was added in several portions to a solution of 1-(1,1-dimethylethyl) 7-ethyl 2,3-dihydro-1H-indole-1,7-dicarboxylate (140.3 g, 0.48 mol) in CH2Cl2 (1200 mL) and the reaction mixture was stirred at room temperature overnight. The reaction solution was washed with 2 M NaOH (500 mL) and water (500 mL), and was then dried (Na2SO4). The solution was concentrated in vacuo to 500 mL and TFA (130 mL, 1.69 mol) was added. The mixture was stirred at room temperature overnight. A solution of 2 M NaOH was added to bring the reaction mixture to pH>8. The organic layer was separated and the aqueous layer was extracted with CH2Cl2 (3×300 mL). The combined organic layers were dried (Na2SO4) and the solvent was evaporated, giving 129.1 g (99%) of the title compound.

Provenance & Evidence