Sodium Bicarbonate → 6-bromo-2H-chromene

HRID 1516321Notes

Reaction equation

HRID 1516321 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][CH2:7][CH2:6][CH:5]2O.O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C(=O)(O)[O-].[Na+]>C1(C)C=CC=CC=1>[Br:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][CH2:7][CH:6]=[CH:5]2

Participants

5

Reactant 3

HCID 516892Sodium BicarbonateHCID 521998p-Toluenesulfonic acid monohydrateHCID 432344236-Bromo-3,4-dihydro-2H-1-benzopyran-4-ol

Product 1

HCID 102422416-bromo-2H-chromeneYield 133.4%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
50 °C

Procedure

To a solution of 6-bromochroman-4-ol (3.98 kg, 17.4 mol) in toluene (18 L) add p-toluenesulfonic acid monohydrate (95 g, 499.42 mmol) at room temperature. Attach a Dean-Stark trap and reflux for 3 hr. and 50 min. Allow the mixture to cool to 50° C. in air and pour into saturated aqueous sodium bicarbonate (10 L) and ice (about 3 kg) with stirring. Separate the two layers. Back extract the aqueous layer with methyl tert-butyl ether (4 L). Wash the organic layer with saturated sodium bicarbonate (10 L) and brine (1×10 L), and evaporate the solvent under reduced pressure to obtain the title compound as a brown oil (4.90 kg, >100%, contains toluene). LCMS m/z (79Br) 209 [M+H]+.

Workup

  1. temperaturereflux for 3 hr
  2. custom50 min
  3. customSeparate the two layers
  4. extractionBack extract the aqueous layer with methyl tert-butyl ether (4 L)
  5. washWash the organic layer with saturated sodium bicarbonate (10 L) and brine (1×10 L)
  6. customevaporate the solvent under reduced pressure

Sources & evidence

ORD record
ord-c1c6d9c79fa94860ada1ab817936653a
Source dataset
uspto-grants-2012_07
Patent number
US08227468B2

Reaction notes

Loading…