Hydrochloric Acid → 3-Hydroxybenzo[b]naphtho[2,3-d]furan-6,11-dione

Participants

Reaction Steps

Resorcinol (6.6 g, 60 mmol) in ethanol (80 mL) was added dropwise to a stirred ethanolic sodium ethoxide solution (prepared by dissolving 3.8 g of sodium metal in 120 mL of absolute ethanol) containing 2,3-dichloro-1,4-naphthoquinone (6.9 g, 30 mmol) at 0° C. After stirring at room temperature overnight, the black reaction mixture was acidified with 5N HCl at 0° C. The yellow solid that precipitated was collected by filtration, washed successively with water, methanol, diethyl ether and air-dried to give crude 12 as a deep yellow solid (7.1 g, 88%); mp>310° C. (lit.>300° C.);Cheng 1993 JMC TLC (chloroform/acetone, 8:1): Rf 0.47; νmax (KBr) 3400 (OH), 1670 and 1620 (C═O) cm−1; δH (400 MHz, DMSO-d6) 7.05 (1H, d, JC-5-H, C-4-H=8.54 Hz, C-4-H), 7.16 (1H, s, C-2-H), 7.2–7.7 (2H, m, C-8-H and C-9-H), 7.95 (1H, d, JC-4-H, C-5-H=8.5 Hz, C-5-H), 8.2–8.7 (2H, m, C-7-H and C-10-H) and 10.53 (1H, br s, exchanged with D2O, C-3-OH); MS m/z (FAB+) 265.1 [70, (M+H)+], 255.3 (75), 243.2 (30), 173.2 (100); MS m/z (FAB−) 263.1 [100, (M-H)−], 242.1 (20), 210.1 (25), 198.1 (45), 181.1 (35); Acc. MS (FAB+) 265.0502 C16H9O4 requires 265.0501.

Provenance & Evidence