6-fluoro-4-oxo-4H-chromene-2-carboxylic acid → 6-Fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid

HRID 1906879Notes

Reaction equation

HRID 1906879 reaction equation
[F:1][C:2]1[CH:3]=[CH:4][C:5]2[O:10][C:9]([C:11]([OH:13])=[O:12])=[CH:8][C:7](=O)[C:6]=2[CH:15]=1.[H][H]>[Pd].C(O)(=O)C>[F:1][C:2]1[CH:3]=[CH:4][C:5]2[O:10][CH:9]([C:11]([OH:13])=[O:12])[CH2:8][CH2:7][C:6]=2[CH:15]=1

Participants

5

Reactant 2

HCID 40960466-fluoro-4-oxo-4H-chromene-2-carboxylic acidHCID 178418361HCID 178418361, compound

Product 1

HCID 153828436-Fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acidYield 83.3%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 176Acetic AcidSolvent

Procedure

A mixture of 63.4 parts of 6-fluoro-4-oxo-4H-1-benzopyran-2-carboxylic acid and 400 parts of acetic acid was hydrogenated at normal pressure and at room temperature with 3 parts of palladium-on-charcoal catalyst 10%. After the calculated amount of hydrogen was taken up, the catalyst was filtered off and the filtrate was evaporated. The residue was stirred in petroleum ether. The product was filtered off and dried in vacuo at about 70° C., yielding 49 parts (83.3%) of 6-fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid (intermediate 5).

Workup

  1. filtrationthe catalyst was filtered off
  2. customthe filtrate was evaporated
  3. filtrationThe product was filtered off
  4. customdried in vacuo at about 70° C.

Sources & evidence

ORD record
ord-c28019c266244d769d37ca5ab6a97960
Source dataset
uspto-grants-1987_03
Patent number
US04654362

Reaction notes

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