6-BroMoisoquinolin-4-ol synthesis

Yield:1015070-56-0 75%

Reaction Conditions:

Stage #1: 6-Bromo-2-(phenylsulfonyl)-2,3-dihydroisoquinoline-4(1H)-onewith sodium ethanolate in ethanol at 20; for 1 h;
Stage #2: with hydrogenchloride in ethanol;water;

Steps:

15.15a

6-Bromo-2-(phenylsulfonyl)-2,3-dihydroisoquinoline-4(1H)-one (29 g, 79.2 mmol) was produced from 4-bromobenzyl bromide in accordance with the method described in Tetrahedron 61 (2005) 8282 to 8287, and then suspended in ethanol (300 ml). To the resulting mixture, a 21% sodium ethoxide/ethanol solution (88.6 ml, 238 mmol) was added, followed by stirring at room temperature for one hour. To the resulting reaction liquid, 5M hydrochloric acid (approximately 50 ml) was added for neutralization, and then ethanol was distilled off under reduced pressure. A solid precipitate was collected by filtration. The solid was dried and then purified by silica gel column chromatography (dichloromethane : methanol, 100 _: 0 - 50 _: 50, V/V) to give the desired title compound (13.2 g, yield 75%). ¹H-NMR (DMSO-D₆) δ: 7.79 (1H, dd, J = 8.7, 1.8 Hz), 8.03 (1H, d, J = 8.7 Hz), 8.11 (1H, s), 8.25-8.27 (1H, m), 8.82 (1H, s), 10.62 (1H, s).

References:

EP2380878,2011,A1 Location in patent:Page/Page column 30