2,2-Dimethylchroman → 2,2-Dimethylchroman-8-carboxylic acid

HRID 1756826Notes

Reaction equation

HRID 1756826 reaction equation
C([Li])CCC.[CH3:6][C:7]1([CH3:17])[CH2:16][CH2:15][C:14]2[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=2)[O:8]1.[C:18](=[O:20])=[O:19].C(OCC)C>CCCCCC.C(OCC)C>[CH3:6][C:7]1([CH3:17])[CH2:16][CH2:15][C:14]2[C:9](=[C:10]([C:18]([OH:20])=[O:19])[CH:11]=[CH:12][CH:13]=2)[O:8]1

Participants

6

Reactant 3

HCID 1369362,2-DimethylchromanHCID 86742199Dry ice diethyl etherHCID 178418339Butyllithium

Product 1

HCID 130516922,2-Dimethylchroman-8-carboxylic acid

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolvent2×HCID 8058HexaneSolvent

Procedure

To a solution of 1.6M n-butyllithium in hexane and 150 ml of diethyl ether were added a solution of 27 g of 2,2-dimethylchroman in diethyl ether over a one hour period at room temperature. The solution was then heated at reflux 160 minutes, cooled, and poured into dry ice/diethyl ether. The mixture was allowed to come to room temperature, poured into ice water, and layers separated. The organic layer was washed with water, dried over sodium sulfate, and concentrated in vacuo to provide 21 g of solid. The aqueous layer was acidified and the resulting precipitate extracted into diethyl ether/ethyl acetate. The organic extract was washed with water, dried over sodium sulfate, and concentrated in vacuo to provide 9 g of solid. The two isolated solids were combined and chromatographed over silica gel eluting with 10% ethyl acetate in toluene. The appropriate fractions were combined and concentrated in vacuo to provide 9.8 g of the desired title intermediate, m.p. 90°-92° C.

Workup

  1. temperatureThe solution was then heated
  2. temperatureat reflux 160 minutes
  3. temperaturecooled
  4. customto come to room temperature
  5. customseparated
  6. washThe organic layer was washed with water
  7. dry with materialdried over sodium sulfate
  8. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-6d3f783b063b42aa872e5b940c48248f
Source dataset
uspto-grants-1995_08
Patent number
US05442078

Reaction notes

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