3-Methyl-2-butenoic acid → 6-Bromo-7-hydroxy-2,2-dimethyl-chroman-4-one

HRID 2180453Notes

Reaction equation

HRID 2180453 reaction equation
[Br:1][C:2]1[CH:8]=[CH:7][C:5]([OH:6])=[CH:4][C:3]=1[OH:9].[CH3:10][C:11]([CH3:16])=[CH:12][C:13](O)=[O:14]>>[Br:1][C:2]1[CH:8]=[C:7]2[C:5](=[CH:4][C:3]=1[OH:9])[O:6][C:11]([CH3:16])([CH3:10])[CH2:12][C:13]2=[O:14]

Participants

3

Reactant 2

HCID 109313-Methyl-2-butenoic acidHCID 811054-Bromoresorcinol

Product 1

HCID 224908286-Bromo-7-hydroxy-2,2-dimethyl-chroman-4-one

Conditions

Temperature
90 °C

Procedure

A mixture of 4-bromoresorcinol (5.00 g, 26.5 mmol) and 3,3-dimethylacrylic acid (2.64 g, 26.5 mmol) were ground in a mortar. The mixture was then added portion-wise into polyphosphoric acid (8 g) at 90° C. After stirred at 90° C. for 15 min, the reaction mixture was cooled to room temperature and quenched with water. The mixture was then extracted with diethyl ether. The organic layer was separated, washed with water, brine, dried (MgSO4) and concentrated at reduced pressure to give a yellow residue. Purification by recrystallization (methanol and water) afforded the title compound as a yellow solid.

Workup

  1. temperaturethe reaction mixture was cooled to room temperature
  2. customquenched with water
  3. extractionThe mixture was then extracted with diethyl ether
  4. customThe organic layer was separated
  5. washwashed with water, brine
  6. dry with materialdried (MgSO4)
  7. concentrationconcentrated at reduced pressure
  8. customto give a yellow residue
  9. customPurification
  10. customby recrystallization (methanol and water)

Sources & evidence

ORD record
ord-3e0a6371764f4e1ca38ec3a47942bcf0
Source dataset
uspto-grants-2005_05
Patent number
US06887896B1

Reaction notes

Loading…