Boron tribromide → HCID 10248135, compound

Participants

Reaction Steps

Boron tribromide (2.2 mL, 23.3 mmol) was added dropwise to a stirring suspension of 9-(4-tert-Butylbenzyl)-6-methoxy-1,9-dihydropyrano[3,4-b]indole-3,4-dione(4.92 g, 13.0 mmol) in methylene chloride (25 mL) at −78° C. under a nitrogen atmosphere over a period of 20 minutes. The mixture was then warmed up to room temperature. After stirring at room temperature for 6.5 hours, the reaction mixture was carefully quenched with a small amount of water and the evaporated to dryness. The residue was stirred in ether and filtered to afford a brown solid. Crystallization from aqueous methanol afforded the title compound as a brown solid (1.72 g). Mass spectrum (ESI, [M−H]−) m/z 362. 1HNMR (400 MHz, DMSO-d6): δ 9.39 (s, 1H), 7.44 (d, 1H, J=8.85 Hz), 7.40 (d, 1H, J=2.29 Hz), 7.34 (d, 2H, J=8.25 Hz), 6.80 (dd, 1H, J=8.86 and 2.29 Hz), 5.84 (s, 2H), 5.37 (s, 2H), 1.22 ppm (s, 9H).

Provenance & Evidence