Bromine → 2,5-Dibromo-3,4-dihydro-1(2H)-naphthalenone

HRID 1760612Notes

Reaction equation

HRID 1760612 reaction equation
[Br:1][C:2]1[CH:11]=[CH:10][CH:9]=[C:8]2[C:3]=1[CH2:4][CH2:5][CH2:6][C:7]2=[O:12].[Br:13]Br>C(Cl)Cl.CCOCC>[Br:13][CH:6]1[CH2:5][CH2:4][C:3]2[C:8](=[CH:9][CH:10]=[CH:11][C:2]=2[Br:1])[C:7]1=[O:12]

Participants

5

Reactant 2

HCID 24408BromineHCID 108895725-Bromo-1,2,3,4-tetrahydronaphthalen-1-one3×

Product 1

HCID 121288082,5-Dibromo-3,4-dihydro-1(2H)-naphthalenoneYield 79.4%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolvent2×HCID 6344DichloromethaneSolvent

Procedure

A clear yellow solution of 5-bromo-3,4-dihydro-1(2H)-naphthalenone(12.09 g, 53.7 mmol) in freshly opened Et2O (220 mL) under an N2 atmosphere was chilled to −5° C. HCl was bubbled in subsurface for 1 min, causing no visible change. The dropwise addition of a solution of Br2 (8.58 g, 53.7 mmol) in CH2Cl2 (20 mL) and Et2O (2 mL) to the vigorously stirring solution of 5-bromo-3,4-dihydro-1(2H)-naphthalenone over 2 h (each drop was allowed to fully decolorize before adding the next) produced a product mixture that assayed by HPLC. Peak area showed 79.4% title compound, 9.5% unreacted 5-bromo-3,4-dihydro-1(2H)-Naphthalenone, 0.6% unidentified, and 9.4% 2,2′,5-tribromo-1-tetralone. The addition of H2O produced a top light brown organic phase, and a clear, colorless bottom aqueous phase which was separated. After drying with MgSO4, the organic layer was concentrated in vacuo at room temperature to give the crude intermediate title compound as a light brown oil (16.08 g, 98.5%).

Workup

  1. customHCl was bubbled in subsurface for 1 min
  2. additionbefore adding the next)
  3. customproduced a product mixture

Sources & evidence

ORD record
ord-823e9707db5c4c608d1f723b600f654d
Source dataset
uspto-grants-2005_01
Patent number
US06844344B2

Reaction notes

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