Bromine → 7-Bromo-3,4-dihydro-5,8-dimethyl-1(2H)-naphthalenone

HRID 1418808Notes

Reaction equation

[CH3:1][C:2]1[CH:11]=[CH:10][C:9]([CH3:12])=[C:8]2[C:3]=1[CH2:4][CH2:5][CH2:6][C:7]2=[O:13].[Cl-].[Al+3].[Cl-].[Cl-].[Br:18]Br>C(Cl)Cl>[Br:18][C:10]1[C:9]([CH3:12])=[C:8]2[C:3]([CH2:4][CH2:5][CH2:6][C:7]2=[O:13])=[C:2]([CH3:1])[CH:11]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 15.0 g of 5,8-dimethyltetralone (purchased from Wiley Organics) in 250 mL of methylene chloride was added 28.7 g of aluminum chloride (purchased from Aldrich Chemical Co.). The mixture was cooled to 0° C. and then a solution of 15.2 g bromine in 90 mL of methylene chloride was added dropwise. After the mixture was stirred at room temperature for 2 h, it was cooled to 0° C. and then approximately 200 g of ice was added. The resulting mixture was filtered. The organic layer was separated and was washed with 1N aqueous sodium hydroxide, dried over MgSO4, filtered, and concentrated under reduced pressure. The resulting solid was crystallized from 1-chlorobutane to give 21.8 g of the title compound of Step A as a solid melting at 64°-68° C. 1H NMR (CDCl3): δ 2.11 (m, 2H), 2.25 (s, 3H), 2.64 (t, 2H), 2.66 (s, 3H), 2.77 (t, 2H), 7.53 (s, 1H).

Workup

temperatureit was cooled to 0° C.
filtrationThe resulting mixture was filtered
customThe organic layer was separated
washwas washed with 1N aqueous sodium hydroxide
dry with materialdried over MgSO4
filtrationfiltered
concentrationconcentrated under reduced pressure
customThe resulting solid was crystallized from 1-chlorobutane

Sources & evidence

ORD record: ord-777d173851df4b528eeb888b17c361f4
Source dataset: uspto-grants-1999_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05885936

Reaction notes

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