Hydrochloric Acid → 3-[1-(2-Hydroxyethyl)-6-methoxy-1H-indol-3-yl]-4-(1-methyl-1H-indol-7-yl)-pyrrole-2,5-dione

Participants

Reaction Steps

To a solution of methyl {1-[2-(tert-butyldimethylsilyloxy)ethyl]-6-methoxy-1H-indol-3-yl}oxoacetate (10.4 g, 26.5 mmol) and 2-(1-methyl-1H-indol-7-yl)acetamide (5.0 g, 26.5 mmol) in DMF (250 mL) was added a 1.0 M solution of potassium tert-butoxide (79.5 mL, 79.5 mmol) at room temperature and under nitrogen. The reaction was stirred overnight. A solution of concentrated HCl (10 mL) was added and the mixture was stirred at room temperature for 1 h, then quenched with water (200 mL) and diluted with EtOAc (300 mL). The two layers were separated and the aqueous phase was extracted with EtOAc (3×200 mL). The organic phases were combined and washed with water (3×300 mL), brine (500 mL), dried (MgSO4), filtered and concentrated. Flash chromatography (SiO2, 30% hexanes/EtOAc) gave the title compound (9.5 g, 86%) as a red solid. 1H NMR (300 MHz, DMSO-d6) 11.10 (s, 1H), 8.08 (s, 1H), 7.65 (d, J=6.1 Hz, 1H), 7.22 (d, J=2.8 Hz, 1H), 7.00–6.83 (m, 3H), 6.49 (d, J=2.8 Hz, 1H), 6.03 (d, J=5.8 Hz, 1H), 5.94 (d, J=6.3 Hz, 1H), 4.88 (t, J=5.3 Hz, 1H), 4.22 (t, J=5.5 Hz, 2H), 3.70–3.55 (m, 8H).

Provenance & Evidence