Ammonia → 2-Naphthylamine

Participants

Reaction Conditions

Reaction Steps

To a 300 mL autoclave was added 36.5 g of 2-naphthol (2, 0.253 mol), 34.0 g of (NH4)2SO3.H2O (0.254 mol) and 85 mL of concentrated aqueous ammonia, the mixture was heated to 150° C. with an oil-bath for 10 h. The pressure was built to about 10 atm at 150° C. and then cooled to room temperature while stirring. The solid was filtered, washed with water, and dissolved in a mixture of 70 mL of concentrated hydrochloric acid, 300 mL of ethanol and 200 mL of water at 70° C. The solution was treated with 5 g of activated charcoal for 0.5 h at 70° C. and filtered. The impurity in the filtrate was extracted with 200 mL of toluene and discarded. The aqueous phase was cooled to room temperature and neutralized with 90 mL of concentrated aqueous ammonia. The mixture was extracted with toluene (2×400 mL) at 70° C. The toluene layer was washed with water (2×100 mL), and degassed under N2 for 5 min. The small amount of water in toluene was removed by refluxing with a Dean-Stark trap, and concentrated to obtain the crude product. The crude product was recrystallized from 200 mL of degassed toluene to afford 26.9 g of 3, the second crop from the mother liquid was 2.4 g. Yield: 29.3 g (80% ): mp 106-108° C., 1H NMR (CDCl3) —4.07 (s, 2H ), 7.19-7.24 (m, 2H), 7.47-7.52 (m, 1H), 7.61-7.66 (m, 1H), 7.85-7.97 (m, 3H), 13C NMR (CDCl3) —108.5, 118.2, 122.4, 125.8, 126.3, 127.7, 127.9, 129.2, 134.9, 144.0.

Provenance & Evidence