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

HRID 1732112Notes

Reaction equation

HRID 1732112 reaction equation
[F:1][C:2]1[CH:12]=[CH:11][C:5]([O:6][CH2:7][CH2:8][C:9]#N)=[CH:4][CH:3]=1.S(=O)(=O)(O)[OH:14]>>[F:1][C:2]1[CH:12]=[C:11]2[C:5](=[CH:4][CH:3]=1)[O:6][CH2:7][CH2:8][C:9]2=[O:14]

Participants

3

Reactant 2

HCID 1118Sulfuric AcidHCID 30204753-(4-Fluorophenoxy)propanenitrile

Product 1

HCID 27332626-fluoro-2,3-dihydro-4H-1-benzopyran-4-oneYield 43%

Conditions

Temperature
90 °C

Procedure

A mixture of 2.00 g of 3-(4-fluorophenoxy)propionitrile and 40 g of 85% sulfuric acid was stirred for 10 hours at 90° C. After cooling, the reaction mixture was poured into a proper amount of ice-water and extracted with ethyl acetate. After an ethyl acetate layer was neutralized with 20% aqueous solution of sodium hydroxide, the layer was dehydrated with anhydrous magnesium sulfate. Ethyl acetate was distilled away to give 861 mg of a white crystal of 6-fluoro-4-chromanone (yield: 43%).

Workup

  1. temperatureAfter cooling
  2. extractionextracted with ethyl acetate
  3. distillationEthyl acetate was distilled away

Sources & evidence

ORD record
ord-8766cf9635714733bd0ca7d5b067d6b2
Source dataset
uspto-grants-1986_11
Patent number
US04625042

Reaction notes

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