8-Amino-2-naphthalenol → 8-Amino-1,2,3,4-tetrahydronaphthalen-2-ol

Participants

Reaction Conditions

Reaction Steps

Ethanol (1 liter) was added to 8-amino-2-naphthol (100 g, 0.61 mol), Raney nickel (40 g water wet), and sodium hydroxide (4.0 g 8 mol % aqueous) in a stirred reactor. The reactor was sealed and sparged with hydrogen. The reaction mixture was stirred for 13 hours at 85° C. and then an additional 8 hours at 100° C. The mixture was then filtered through a pad of Celite. The resulting solution was treated with Darco G-60 (35 grams) and heated to reflux for 1 hour, then cooled to ambient temperature and stirred an additional 3 hours. This mixture was filtered through Celite (350 grams), and the pad washed with ethyl acetate (1.5 liters). The solvent was removed in vacuo and methyl tert-butyl ether (1 liter) was added. This was heated for 15 minutes at 50° C., stirred for one hour at ambient temperature, filtered, and the solvent removed in vacuo. Approximately half of the resulting crude solid was purified by chromatography on silica gel using 2% to 30% methanol/methylene chloride as eluent, which gave 37 g of the title compound as a light brown solid. 1H NMR (300 MHz, CDCl3) δ 6.96 (t, J=7.63 Hz, 1H), 6.55 (dd, J=10.68, 7.63 Hz, 2H), 4.14-4.24 (m, 1H), 2.80-2.95 (m, 3H), 2.38 (dd, J=16.11, 7.63 Hz, 1H), 1.96-2.09 (m, 1H), 1.70-1.85 (m, 1H).

Provenance & Evidence