Carbon Dioxide → 5-Methyl-2,3-dihydro-1,4-benzodioxine-6-carboxylic acid

HRID 260718Notes

Reaction equation

HRID 260718 reaction equation
Br[C:2]1[CH:11]=[CH:10][C:5]2[O:6][CH2:7][CH2:8][O:9][C:4]=2[C:3]=1[CH3:12].C([Li])CCC.CCCCCC.[C:24](=[O:26])=[O:25]>O1CCCC1.O>[CH3:12][C:3]1[C:4]2[O:9][CH2:8][CH2:7][O:6][C:5]=2[CH:10]=[CH:11][C:2]=1[C:24]([OH:26])=[O:25]

Participants

7

Reactant 4

HCID 280Carbon Dioxide2×HCID 8058HexaneHCID 124645276-Bromo-5-methyl-2,3-dihydro-1,4-benzodioxineHCID 178418339Butyllithium

Product 1

HCID 107029595-Methyl-2,3-dihydro-1,4-benzodioxine-6-carboxylic acidYield 77%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

In 300 ml of dry tetrahydrofuran, was dissolved 32.0 g of 6-bromo-5-methyl-1,4-benzodioxane and after cooling the solution to -78° C., 96.7 ml of n-butyl lithium (n-hexane solution)was added dropwise over 20 minutes or more. After stirring at the same temperature for 1.5 hours, the reaction mixture was poured onto crushed dry ice and dry ice was sublimated while stirring. Water was added to the -mixture and the tetrahydrofuran was removed under reduced pressure. The resulting alkaline aqueous solution was washed with methylene chloride and adjusted to pH 3 with a 5% hydrochloric acid, and the precipitated crystals were collected by filtration and dried to obtain 20.9 g of 5-methyl-1,4-benzodioxan-6-carboxylic acid (yield: 77%).

Workup

  1. additionthe reaction mixture was poured
  2. stirringwhile stirring
  3. customthe tetrahydrofuran was removed under reduced pressure
  4. washThe resulting alkaline aqueous solution was washed with methylene chloride
  5. filtrationthe precipitated crystals were collected by filtration
  6. customdried

Sources & evidence

ORD record
ord-266f65c38c6d41cfbdb52275a0f7a04a
Source dataset
uspto-grants-1996_06
Patent number
US05530021

Reaction notes

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