Triphenylphosphine → 2-(2-Bromoethyl)-2,5,7,8-tetramethylchroman-6-ol

HRID 375130Notes

Reaction equation

HRID 375130 reaction equation
C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[Br:20]Br.[OH:22][C:23]1[C:24]([CH3:39])=[C:25]([CH3:38])[C:26]2[O:31][C:30]([CH3:35])([CH2:32][CH2:33]O)[CH2:29][CH2:28][C:27]=2[C:36]=1[CH3:37]>ClCCl>[Br:20][CH2:33][CH2:32][C:30]1([CH3:35])[CH2:29][CH2:28][C:27]2[C:36]([CH3:37])=[C:23]([OH:22])[C:24]([CH3:39])=[C:25]([CH3:38])[C:26]=2[O:31]1

Participants

5

Reactant 3

HCID 11776TriphenylphosphineHCID 24408BromineHCID 118070842,5,7,8-Tetramethyl-6-hydroxy-2-(hydroxyethyl)chroman

Product 1

HCID 133751842-(2-Bromoethyl)-2,5,7,8-tetramethylchroman-6-olYield 73.6%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To 11.0 g (0.042 mol) of triphenylphosphine in 200 ml of dichloromethane is added dropwise a solution of 6.71 g (0.042 mol) of bromine in 50 ml of dichloromethane. The solution is stirred for 30 min at room temperature, then 10.0 g (0.04 mol) of 3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-ethanol (CAS 79907-48-5) is added. The resulting solution is refluxed for 4 hours, allowed to cool overnight, washed with a solution of 15 g of sodium carbonate in 200 ml of water, dried over anhydrous sodium sulfate, filtered and evaporated. The resulting oil is crystallized from methanol to give 9.22 g of 3,4-dihydro-2-(2-bromoethyl)-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol.

Workup

  1. temperatureThe resulting solution is refluxed for 4 hours
  2. temperatureto cool overnight
  3. washwashed with a solution of 15 g of sodium carbonate in 200 ml of water
  4. dry with materialdried over anhydrous sodium sulfate
  5. filtrationfiltered
  6. customevaporated
  7. customThe resulting oil is crystallized from methanol

Sources & evidence

ORD record
ord-3cdcf68822c7491cba4f44d6f1696767
Source dataset
uspto-grants-1996_01
Patent number
US05484810

Reaction notes

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