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

HRID 981787Notes

Reaction equation

HRID 981787 reaction equation
[Br: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>>[Br: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 3

HCID 6581Acrylic AcidHCID 7108PhenothiazineHCID 78084-Bromophenol

Product 1

HCID 41974516-bromo-3,4-dihydro-2H-1-benzopyran-4-one

Conditions

Temperature
-78 °C

Procedure

Following the procedure of Example 1, para-bromophenol (43.25 grams), acrylic acid (27 grams) and phenothiazine (0.02 grams) were added to the pressure reactor. The system was closed and evacuated before being cooled to -78° C. and the anhydrous hydrogen fluoride (110 grams) was added. After the mixture was heated and stirred for six hours at 100° C., 140 psig, the excess hydrogen fluoride was vented and the reaction mixture cooled to 0°-5° C. After washing the mixture with D.I. water, HPLC analysis indicated one major product which was separated and characterized as 6-Bromo-4-Chromanone.

Workup

  1. additionwere added to the pressure reactor
  2. customThe system was closed
  3. customevacuated
  4. additionthe anhydrous hydrogen fluoride (110 grams) was added
  5. temperatureAfter the mixture was heated
  6. temperaturethe reaction mixture cooled to 0°-5° C
  7. washAfter washing the mixture with D.I
  8. customwas separated

Sources & evidence

ORD record
ord-aa1c073536f84e2298dd7dc28f85cc11
Source dataset
uspto-grants-1991_02
Patent number
US04992564

Reaction notes

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