p-Toluenesulfonic acid → 7-(2-bromoethyl)-2-methyl-1H-indene

HRID 557492Notes

Reaction equation

HRID 557492 reaction equation
[Br:1][CH2:2][CH2:3][C:4]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:5]=1[CH2:6][CH:7]([CH3:15])[CH:8]2OC.CC1C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1>[Br:1][CH2:2][CH2:3][C:4]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:5]=1[CH2:6][C:7]([CH3:15])=[CH:8]2

Participants

4

Reactant 2

HCID 6101p-Toluenesulfonic acidHCID 584187554-(2-Bromoethyl)-1-methoxy-2-methylindane

Product 1

HCID 584187157-(2-bromoethyl)-2-methyl-1H-indene

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

To a hot (110° C.) solution of 12.0 g (44.6 mmol) of 4-(2-bromoethyl)-1-methoxy-2-methylindane in 200 ml of toluene 1.0 g of TsOH was added. This mixture was refluxed with Dean-Stark trap for 10 minutes and then passed through 5 cm layer of silica gel 60 (40-63 μm). The silica gel layer was additionally washed by 500 ml of toluene. The combined organic extract was evaporated to dryness. The product was isolated by flash chromatography on silica gel 60 (40-63 μm, eluent: hexanes). Yield 10.2 g (97%) of a ca. 1 to 1.5 mixture of 4- and 7-(2-bromoethyl)-2-methyl-1H-indenes. Anal. calc. for C12H13Br: C, 60.78; H, 5.53. Found: C, 60.66; H, 5.46. 1H NMR (CDCl3): δ 6.92-7.31 (m, 6H, 5,6,7-H and 4,5,6-H of minor and major isomers, respectively), 6.60 (m, 1H, 3-H in indenyl of minor isomer), 6.51 (m, 1H, 3-H in indenyl of major isomer), 3.62 (m, 2H, CH2Br of major isomer), 3.57 (m, 2H, CH2Br of minor isomer), 3.32 (br.s, 2H, 1,1′-H in indenyl of minor isomer), 3.28 (br.s, 2H, 1,1′-H in indenyl of major isomer), 3.27 (m, 2H, CH2CH2Br of minor isomer), 3.23 (m, 2H, CH2CH2Br of major isomer), 2.19 (m, 3H, 2-Me in indenyl of minor isomer), 2.18 (m, 3H, 2-Me in indenyl of major isomer).

Workup

  1. temperatureThis mixture was refluxed with Dean-Stark trap for 10 minutes
  2. washThe silica gel layer was additionally washed by 500 ml of toluene
  3. extractionThe combined organic extract
  4. customwas evaporated to dryness
  5. customThe product was isolated by flash chromatography on silica gel 60 (40-63 μm, eluent: hexanes)

Sources & evidence

ORD record
ord-e8668e8243ea433f8ab8492d0a9641ba
Source dataset
uspto-grants-2011_11
Patent number
US08058461B2

Reaction notes

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