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

HRID 981785Notes

Reaction equation

HRID 981785 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][C:5]([OH:8])=[CH:4][CH:3]=1.[C:9](O)(=[O:12])[CH:10]=[CH2:11]>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][CH2:11][CH2:10][C:9]2=[O:12]

Participants

4

Reactant 2

HCID 6581Acrylic AcidHCID 97324-Fluorophenol

Product 1

HCID 27332626-fluoro-2,3-dihydro-4H-1-benzopyran-4-oneYield 147.3%

Reagents, catalysts & solvents 1

HCID 7108PhenothiazineCatalyst

Conditions

Temperature
40 °C

Procedure

A 400 ml stainless steel Parr reactor was charged with para-fluorophenol (28.4 grams), acrylic acid (28.8 grams), and an inhibitor phenothiazine (0.02 grams). The system was sealed, evacuated and cooled in dry ice/acetone before the anhydrous hydrogen fluoride (117 grams) was condensed into the system. The mixture was then warmed to 40° C. for one hour thirty minutes with stirring before being heated to 100° C. for four hours thirty minutes. The excess HF was them removed and the system cooled to 0° C. and opened to give 62 grams of brown oil which was washed with D.I. water to give 50 grams of material to be extracted. The 6-Fluoro-4-Chromanone was collected and recrystallized from methanol/water. The HPLC yield was 75%, isolated 52%.

Workup

  1. customThe system was sealed
  2. customevacuated
  3. temperaturecooled in dry ice/acetone before the anhydrous hydrogen fluoride (117 grams)
  4. customcondensed into the system
  5. temperaturebefore being heated to 100° C. for four hours thirty minutes
  6. customremoved
  7. temperaturethe system cooled to 0° C.

Sources & evidence

ORD record
ord-b40cca0945b64bd592c45a3bd25bfa39
Source dataset
uspto-grants-1991_02
Patent number
US04992564

Reaction notes

Loading…