Ethyl chloroformate → HCID 68109201, compound

Participants

Reaction Steps

A mixture of the product of step B (90 mg, 0.19 mmol), sodium hydroxide (31 mg, 0.76 mmol) tetrabutylammonium hydrogen sulfate (13 mg, 0.04 mmol) and water (2 drops) in dichloromethane (10 mL) was stirred at ambient temperature for 5 min under an argon atmosphere before addition of ethyl chloroformate (24 μL, 0.25 mmol). The reaction mixture was stirred for 2 h before quenching with aqueous ammonium chloride (15 mL) and extracted with dichloromethane. The organic extract was washed with brine, dried over sodium sulfate and concentrated in vacuo. The residue was purified by flash column chromatography (SiO2, 30:70 hexane/ethyl acetate) to give tert-butyl 8-((1-(ethoxycarbonyl)-1H-indol-5-yl)sulfonyl)-6-hydroxy-3,4-dihydrobenzofuro[3,2-c]pyridine-2(1H)-carboxylate (30 mg, 29%) as a yellow solid: 1H NMR (CDCl3, 400 MHz) δ 8.25 (d, J=8.8 Hz, 1H), 8.20 (s, 1H), 7.85 (d, J=8.4 Hz, 1H), 7.78-7.52 (m, 2H), 7.43 (d, J=1.6 Hz, 1H), 6.70-6.63 (m, 1H), 4.54 (s, 2H), 4.50 (q, J=7.2 Hz, 2H), 3.89-3.72 (m, 2H), 2.91-2.77 (m, 2H), 1.51 (s, 9H), 1.46 (t, J=7.2 Hz, 3H).

Provenance & Evidence