Bromic acid → 6-Bromo-1-tetralone

HRID 1501081Notes

Reaction equation

HRID 1501081 reaction equation
N[C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[C:8](=[O:12])[CH2:7][CH2:6][CH2:5]2.N([O-])=O.[Na+].[Br:17](O)(=O)=O>O.[Cu]Br>[Br:17][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[C:8](=[O:12])[CH2:7][CH2:6][CH2:5]2

Participants

6

Reactant 3

HCID 24445Bromic acid2×HCID 3395376-Amino-1,2,3,4-tetrahydronaphthalen-1-oneHCID 23668193Sodium Nitrite

Product 1

HCID 101050696-Bromo-1-tetraloneYield 45%

Reagents, catalysts & solvents 2

HCID 24593copper(I) bromideCatalystHCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

To a solution of 6-amino-3,4-dihydronaphthalen-1(2H)-one (2.0 g, 12 mmol) in bromic acid (aqueous, 10 mL, 25%) was added sodium nitrite (0.92 g, 13.3 mmol) at 0° C. The mixture was stirred at 0° C. for 15 minutes, and then copper (I) bromide (2.0 g, 13.8 mmol) and bromic acid (aqueous, 20 mL, 25%) was added at 0° C. After addition completed, the reaction mixture was stirred at room temperature for 1 hour. After the reaction, it was diluted with water (200 mL) and the product was extracted with ethyl acetate (200 mL), dried over anhydrous sodium sulfate, concentrated and purified by column chromatography (silica gel, ethyl acetate/petroleum ether=1:20) to give the pure product 6-bromo-3,4-dihydronaphthalen-1(2H)-one (1.2 g, 45%). 1H NMR (300 MHz, CDCl3): δ 7.87 (d, J=8.7 Hz, 1H), 7.44-7.42 (m, 2H), 2.93 (t, J=6.0 Hz, 2H), 2.64 (t, J=6.0 Hz, 2H), 2.15-2.11 (m, 2H).

Workup

  1. additionAfter addition
  2. stirringthe reaction mixture was stirred at room temperature for 1 hour
  3. customAfter the reaction, it
  4. extractionthe product was extracted with ethyl acetate (200 mL)
  5. dry with materialdried over anhydrous sodium sulfate
  6. concentrationconcentrated
  7. custompurified by column chromatography (silica gel, ethyl acetate/petroleum ether=1:20)

Sources & evidence

ORD record
ord-20d8b70792f7443aa3c1de9776d78c18
Source dataset
uspto-grants-2015_12
Patent number
US09206128B2

Reaction notes

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