Chromocarb → 3,4-dihydro-2H-1-benzopyran-2-carboxylic acid

HRID 1803756Notes

Reaction equation

HRID 1803756 reaction equation
O=[C:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[O:5][C:4]([C:12]([OH:14])=[O:13])=[CH:3]1>[Pd].C(O)(=O)C>[O:5]1[C:6]2[C:11](=[CH:10][CH:9]=[CH:8][CH:7]=2)[CH2:2][CH2:3][CH:4]1[C:12]([OH:14])=[O:13]

Participants

4

Reactant 1

HCID 2741Chromocarb

Product 1

HCID 27236653,4-dihydro-2H-1-benzopyran-2-carboxylic acid

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 176Acetic AcidSolvent

Conditions

Temperature
70 °C

Procedure

4-Oxo-4H-chromene-2-carboxylic acid (Aldrich, 3.0 g, 15.8 mmol) was added to a mixture of acetic acid (30 mL) and 10% palladium on carbon (0.3 g) in a Parr shaker. The glass reactor was sealed and flushed with nitrogen, and it was pressurized with hydrogen (60 psi). The mixture was shaken at 70° C. for 2.5 hours. The mixture was filtered and the solids were rinsed with methanol. The filtrate was concentrated under reduced pressure and chromatographed on silica gel eluting with 0-to-10% methanol in ethyl acetate to afford the title compound. 1H NMR (300 MHz, DMSO-d6) δ ppm 2.04 (m, 1H), 2.14 (m, 1H), 2.63 (dt, 1H), 2.78 (dt, 1H), 4.76 (dd, 1H), 6.80 (m, 2H), 7.05 (m, 2H). MS (ESI) m/z 177.09 (M−H)−.

Workup

  1. customThe glass reactor was sealed
  2. customflushed with nitrogen, and it
  3. filtrationThe mixture was filtered
  4. washthe solids were rinsed with methanol
  5. concentrationThe filtrate was concentrated under reduced pressure
  6. customchromatographed on silica gel eluting with 0-to-10% methanol in ethyl acetate

Sources & evidence

ORD record
ord-2652dfbc49d149869829057f98f9541b
Source dataset
uspto-grants-2013_01
Patent number
US08350083B2

Reaction notes

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