Acrylic Acid → 6-fluoro-2,3-dihydro-4H-1-benzopyran-4-one

HRID 981788Notes

Reaction equation

HRID 981788 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][C:5]([O:8][CH3:9])=[CH:4][CH:3]=1.[C:10](O)(=[O:13])[CH:11]=C.C1C2NC3C(=CC=CC=3)SC=2C=CC=1>>[F:1][C:2]1[CH:7]=[C:6]2[C:5](=[CH:4][CH:3]=1)[O:8][CH2:9][CH2:11][C:10]2=[O:13]

Participants

4

Reactant 3

HCID 6581Acrylic AcidHCID 7108PhenothiazineHCID 99874-Fluoroanisole

Product 1

HCID 27332626-fluoro-2,3-dihydro-4H-1-benzopyran-4-one

Conditions

Temperature
-78 °C

Procedure

Using the procedure established in Example 1, the reactor was charged with p-fluoroanisole (31.5 grams), acrylic acid (27 grams) and phenothiazine (0.02 grams) before being sealed, evacuated, and cooled to -78° C. The anhydrous hydrogen fluoride (110 grams) was vacuum transferred into the reactor and the mixture warmed to 40° C. for one hour then 100° C. for 4.5 hours. The excess hydrogen fluoride was then vented and the reactor cooled to 5° C. before being opened and the contents washed with D.I. water. Analysis by HPLC indicated the presence of para-fluoroanisole and 6-Fluoro-4-Chromanone. The para-fluoroanisole was removed by distillation and the desired 6-Fluoro-4-Chromanone isolated by extraction and characterized.

Workup

  1. custombefore being sealed
  2. customevacuated
  3. temperaturethe mixture warmed to 40° C. for one hour
  4. temperaturethe reactor cooled to 5° C.
  5. washthe contents washed with D.I
  6. customThe para-fluoroanisole was removed by distillation

Sources & evidence

ORD record
ord-1037a67615104038acf45cadf7a2fd39
Source dataset
uspto-grants-1991_02
Patent number
US04992564

Reaction notes

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