Boron tribromide → 6-(1-Benzyl-3-pentyl-1H-indol-2-yl)-2-naphthol

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of the 1-benzyl-2-(6-methoxy-2-naphthyl)-3-pentyl-1H-indole (109.0 g, 251 mmol) in CH2Cl2 (1000 mL) under N2 at −78° C. was added BBr3 (1M in CH2Cl2, 302 mL), dropwise, over 1.5 h. After the addition, the reaction was warmed to 0° C. and stirred for 2.5 h then warmed to rt. After a total of 5 h the reaction mixture was cooled to 0° C. and quenched with water (250 mL). The mixture was stirred overnight then rotovap'd to a residue. The residue was partitioned between EtOAc (1500 mL) and H2O (500 mL). The layers were shaken, separated, and the organic layer was washed with H2O (2×250 mL), brine (2×250 mL), dried over Na2SO4, filtered, rotovap'd and dried in vacuo to give a viscous black goo (114 g). The residue was dissolved in CHCl3 and flashed on silica (2000 g). The column was eluted with hexane and 8% EtOAc/Hexane. The product was collected, filtered, rotovap'd and the residue triturated with hexane then dried to give the product as an off-white solid (89.2 g, 213 mmol, 85%) with mp 96-100° C. 400 mg of the crude solid was recrystallized from hexane to give desired product as an off-white solid (311 mg) with mp 97-100° C.; 1H NMR (DMSO-d6) δ 0.73 (t, J=6.7 Hz, 3H), 1.10-1.20 (m, 4H), 1.51-1.60 (m, 2H), 2.67 (t, J=7.3 Hz, 3H), 5.29 (s, 2H), 6.82 (d, J=7.2 Hz, 2H), 7.04-7.20 (m, 7H), 7.30-7.35 (m, 2H), 7.59 (d, J=7.8 Hz, 1H), 7.73-7.78 (m, 3H); IR (solid) 3380, 2920, 1610, 1200, 740 cm−1; mass spectrum [ES], m/z 420 (M+H)+;

Provenance & Evidence