Water → 7-hydroxy-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

HRID 1701558Notes

Reaction equation

HRID 1701558 reaction equation
[C:1]1([CH:8]=[CH:7][CH:6]=[C:4]([OH:5])[CH:3]=1)[OH:2].[CH3:9][C:10]([CH3:15])=[CH:11][C:12](O)=[O:13].O>C(Cl)Cl>[CH3:9][C:10]1([CH3:15])[CH2:11][C:12](=[O:13])[C:8]2[C:1](=[CH:3][C:4]([OH:5])=[CH:6][CH:7]=2)[O:2]1

Participants

5

Reactant 3

HCID 962WaterHCID 5054ResorcinolHCID 109313-Methyl-2-butenoic acid

Product 1

HCID 6009027-hydroxy-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-oneYield 68%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
110 °C

Procedure

In a flask were placed 55.1 grams (0.5 mole) of resorcinol and 55.1 grams (0.5 mole) 3,3-dimethylacrylic acid. Then, 150 grams of polyphosphoric acid was added, and a steam bath applied to the flask. A red liquid began to form; the temperature of the reaction mixture quickly rose to 120° C. The flask was stirred for 45 minutes at 110° C., then allowed to cool. The contents were poured into a mixture of 500 milliliters water and 400 milliliters methylene chloride then stirred and filtered. The precipitate was washed several times with portions of methylene chloride, water and toluene. There was obtained 65.8 grams, (68% of theoretical yield) 2,2-dimethyl-7-hydroxy-4-chromanone, m.p. 170°-174° C.

Workup

  1. customIn a flask were placed
  2. customa steam bath applied to the flask
  3. customto form
  4. customquickly rose to 120° C
  5. temperatureto cool
  6. stirringthen stirred
  7. filtrationfiltered
  8. washThe precipitate was washed several times with portions of methylene chloride, water and toluene

Sources & evidence

ORD record
ord-732c75d89ee34c8f9944c6f302bd6efc
Source dataset
uspto-grants-1980_03
Patent number
US04194029

Reaction notes

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