Ammonia → 2-Naphthylamine

Temperature

150 °C

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.

1. customwas built to about 10 atm at 150° C.
2. temperaturecooled to room temperature
3. filtrationThe solid was filtered
4. washwashed with water
5. dissolutiondissolved in a mixture of 70 mL of concentrated hydrochloric acid, 300 mL of ethanol and 200 mL of water at 70° C
6. additionThe solution was treated with 5 g of activated charcoal for 0.5 h at 70° C.
7. filtrationfiltered
8. extractionThe impurity in the filtrate was extracted with 200 mL of toluene
9. temperatureThe aqueous phase was cooled to room temperature and neutralized with 90 mL of concentrated aqueous ammonia
10. extractionThe mixture was extracted with toluene (2×400 mL) at 70° C
11. washThe toluene layer was washed with water (2×100 mL)
12. customdegassed under N2 for 5 min
13. customThe small amount of water in toluene was removed
14. temperatureby refluxing with a Dean-Stark trap
15. concentrationconcentrated
16. customto obtain the crude product
17. customThe crude product was recrystallized from 200 mL of degassed toluene

ORD record

ord-1023cee5a26e45f3bee6edf3d7989289

Source dataset

uspto-grants-2002_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06380392B1