Bromine → 4-Bromo-2-methyl-2,3,6,7-tetrahydro-s-indacen-1(5H)-one

HRID 271791Notes

Reaction equation

[CH3:1][CH:2]1[CH2:13][C:12]2[C:4](=[CH:5][C:6]3[CH2:7][CH2:8][CH2:9][C:10]=3[CH:11]=2)[C:3]1=[O:14].[Cl-].[Cl-].[Cl-].[Al+3].[Br:19]Br>C(Cl)(Cl)Cl>[Br:19][C:11]1[C:10]2[CH2:9][CH2:8][CH2:7][C:6]=2[CH:5]=[C:4]2[C:12]=1[CH2:13][CH:2]([CH3:1])[C:3]2=[O:14]

Participants

Conditions

Temperature: 0 °C

Procedure

31 g (162 mmol) of 2-methyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one (1a) were added to a suspension of 50 g (0.37 mol) of anhydrous aluminum trichloride in 200 ml of chloroform while stirring vigorously at 0° C. After stirring for one hour, a solution of 8 ml (160 mmol) of bromine in 20 ml of chloroform was added dropwise to the mixture at 0° C. and the mixture was subsequently stirred overnight. The reaction mixture was poured into 500 g of an ice/water mixture. The organic phase was separated off, washed with 5% strength sodium hydrogencarbonate solution and water and subsequently dried over magnesium sulfate. Filtration and removal of the solvent under reduced pressure gave 51 g of a red oil. GC-MS analysis indicated that the oil contained 84% of the desired compound (1b) and 14% of a dibromide by-product. The mixture was separated by column chromatography on silica gel using methylene chloride as eluant. This gave 18.7 g (44% yield) of the compound (1b).

Workup

stirringAfter stirring for one hour
customThe organic phase was separated off
washwashed with 5% strength sodium hydrogencarbonate solution and water
dry with materialsubsequently dried over magnesium sulfate
filtrationFiltration and removal of the solvent under reduced pressure

Sources & evidence

ORD record: ord-e250f9f056fb46ef934cbc0708b560c0
Source dataset: uspto-grants-2008_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07452949B2

Reaction notes

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