Hydrogen Bromide → 6-Bromo-1-tetralone

Temperatur

0 °C

To a suspension of 6-amino-3,4-dihydro-2H-naphthalen-1-one (20.5 g, 127 mmol) in 25% HBr (aq) (1017 ml) at 0° C. was added a solution of sodium nitrite (10.53 g, 153 mmol) in water (50 ml) dropwise at a rate as to maintain the temperature below 3°. The cooled reaction mixture was then added to a cooled solution of copper(I) bromide (18.79 g, 131 mmol) in HBr (98 ml, 865 mmol). When the addition was done, the reaction mixture was stirred at 0° C. for 1 h, then warmed to rt. Water (380 mL) was added and the product was extracted with a mixture of Et2O/EtOAc (8:2, 3×). The organic layer was dried over Na2SO4, filtered, and concentrated in vacuo to give a dark brown crude oil. The crude was purified by distillation (3 mm Hg) to give 16.415 g of 6-bromo-3,4-dihydro-2H-naphthalen-1-one.

1. temperatureto maintain the temperature below 3°
2. customThe cooled reaction mixture
3. additionWhen the addition
4. temperaturewarmed to rt
5. extractionthe product was extracted with a mixture of Et2O/EtOAc (8:2, 3×)
6. dry with materialThe organic layer was dried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customto give a dark brown crude oil
10. distillationThe crude was purified by distillation (3 mm Hg)

ORD-Eintrag

ord-8250d8215efc4d1f8c8ced1ec71915f9

Quelldatensatz

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08865701B2