Potassium Iodide → 7-hydroxy-6-(1-methylethoxy)-2H-1-benzopyran-2-one

HRID 22362Notes

Reaction equation

HRID 22362 reaction equation
[OH:1][C:2]1[C:3]([O:13]CC2C=CC=CC=2)=[CH:4][C:5]2[O:10][C:9](=[O:11])[CH:8]=[CH:7][C:6]=2[CH:12]=1.[CH:21](Br)([CH3:23])[CH3:22].C(=O)([O-])[O-].[K+].[K+].[I-].[K+]>CN(C=O)C>[OH:13][C:3]1[C:2]([O:1][CH:21]([CH3:23])[CH3:22])=[CH:12][C:6]2[CH:7]=[CH:8][C:9](=[O:11])[O:10][C:5]=2[CH:4]=1

Participants

6

Reactant 4

HCID 4875Potassium IodideHCID 63582-BromopropaneHCID 11430Potassium CarbonateHCID 12045357-(benzyloxy)-6-hydroxy-2H-chromen-2-one

Product 1

HCID 199276407-hydroxy-6-(1-methylethoxy)-2H-1-benzopyran-2-one

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

50.0 g (186 mmol) 6-hydroxy-7-phenylmethoxy-2H-1-benzopyran-2-one, 36.3 ml (387 mmol) isopropylbromide, 51.5 g (373 mmol) potassium carbonate and 5.0 g potassium iodide are agitated in 500 ml DMF for 14 h at 80° C. After filtration the filtrate is evaporated and the product recrystallized from isopropanol, yield: 57.7 g (100%) 6-(1-methyl-ethoxy)-7-(phenylmethoxy)-2H-1-benzopyran-2-one. Of this 50.0 g (161 mmol) are agitated in 100 ml of glacial acetic acid and 90 ml concentrated hydrochloric acid for 2.5 h at 70° C. This is followed by evaporation and purification using column chromatography on silica gel (eluent: chloroform and methanol 98/2 H 95/5): 24.65 g (69%), fusion point 121°-122° C. (from isopropanol).

Workup

  1. filtrationAfter filtration the filtrate
  2. customis evaporated
  3. customthe product recrystallized from isopropanol, yield: 57.7 g (100%) 6-(1-methyl-ethoxy)-7-(phenylmethoxy)-2H-1-benzopyran-2-one
  4. customThis is followed by evaporation and purification
  5. custom24.65 g (69%), fusion point 121°-122° C. (from isopropanol)

Sources & evidence

ORD record
ord-747befdf939047769ae78720d23bd309
Source dataset
uspto-grants-1995_06
Patent number
US05428038

Reaction notes

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