1,3-Dibromopropane → HCID 11738953, compound

HRID 2304030Notes

Reaction equation

HRID 2304030 reaction equation
[Li][CH2:2][CH2:3][CH2:4][CH3:5].[CH3:6][CH2:7][CH2:8][CH2:9][CH2:10][CH3:11].[CH3:12][C:13]1[CH:21]=[CH:20][C:19]([CH3:22])=[C:18]2[C:14]=1[CH:15]=[CH:16][CH2:17]2.BrCCCBr.[CH2:28]1[CH2:32]O[CH2:30][CH2:29]1>>[CH3:5][C:4]1[CH:32]=[CH:28][C:29]([CH3:30])=[C:2]2[C:3]=1[CH:6]=[CH:7][CH:8]2[CH2:9][CH2:10][CH2:11][CH:17]1[C:18]2[C:14](=[C:13]([CH3:12])[CH:21]=[CH:20][C:19]=2[CH3:22])[CH:15]=[CH:16]1

Participants

6

Reactant 5

HCID 80011,3-DibromopropaneHCID 8028Tetrahydrofuran2×HCID 8058HexaneHCID 814584,7-dimethyl-1H-indeneHCID 178418339Butyllithium

Product 1

HCID 11738953HCID 11738953, compoundYield 71%

Procedure

31 mL of BuLi 2.5 M in hexane (76 mmol) were added dropwise to a solution of 4,7-dimethylindene (10.00 g, 69 mmol) in THF (30 mL) at −78° C. and stirred for 1 hour at the same temperature and another hour at ambient temperature. This mixture was added to a solution of 1,3-dibromopropane (3.92 mL, 38.6 mmol) in THF at −78° C. through an addition funnel over a period of 1.5 hours. The orange mixture was stirred at −78° C. for 2 hours, allowed to slowly warm to room temperature and kept at ambient temperature overnight (16 h). The reddish-brown mixture was quenched with water (50 mL). The aqueous layer was extracted with Et2O (5×100 mL). All organic layers were combined, washed with water (50 mL) and then brine (50 mL), and then dried over anhydrous MgSO4. Concentration of the organic layer by rotary evaporator yielded 13.07 g of crude product, with a GC purity of 80% (theoretical yield based on 4,7-dimethylindene: 11.33 g; GC yield 92%). Kugelrohr distillation (130-170° C./0.2 mmHg) yielded 8.04 g (71%) of 1,3-bis(4,7-dimethyl-1-indenyl)propane. Spectroscopically pure compound was obtained through re-crystallisation from MeOH. NMR (CDCl3, δ, ppm): 1.20-1.50 (m, 4H), 2.04-2.2 (m, 2H), 2.34 (s, 6H) (s, 6H), 3.50 (br d, J=9.01 Hz, 2H), 6.49 (br d, J=5.64 Hz, 2H), 6.85-6.87 (m, 4H), 6.95 (br d, J=7.63 Hz, 2H).

Workup

  1. stirringThe orange mixture was stirred at −78° C. for 2 hours
  2. temperatureto slowly warm to room temperature
  3. waitkept at ambient temperature overnight
  4. custom(16 h)
  5. customThe reddish-brown mixture was quenched with water (50 mL)
  6. extractionThe aqueous layer was extracted with Et2O (5×100 mL)
  7. washwashed with water (50 mL)
  8. dry with materialbrine (50 mL), and then dried over anhydrous MgSO4
  9. customConcentration of the organic layer by rotary evaporator
  10. customyielded 13.07 g of crude product
  11. customwith a GC purity of 80% (theoretical yield based on 4,7-dimethylindene: 11.33 g; GC yield 92%)
  12. distillationKugelrohr distillation (130-170° C./0.2 mmHg)

Sources & evidence

ORD record
ord-fd40bc3d12ca4d9ca5bd79315371a36e
Source dataset
uspto-grants-2002_08
Patent number
US06433203B1

Reaction notes

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