Hydrogen Bromide → 2-(4-Hydroxyphenyl)-4H-pyrano[3,2-b]pyridin-4-one

HRID 884697Notes

Reaction equation

HRID 884697 reaction equation
C[O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9](=[O:21])[CH2:10][C:11]([C:13]2[C:18](OC)=[CH:17][CH:16]=[CH:15][N:14]=2)=[O:12])=[CH:5][CH:4]=1.Br.C([O-])(O)=O.[Na+]>CCOC(C)=O>[OH:2][C:3]1[CH:4]=[CH:5][C:6]([C:9]2[O:21][C:18]3[C:13](=[N:14][CH:15]=[CH:16][CH:17]=3)[C:11](=[O:12])[CH:10]=2)=[CH:7][CH:8]=1

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 516892Sodium BicarbonateHCID 57555827HCID 57555827, compound

Product 1

HCID 116372872-(4-Hydroxyphenyl)-4H-pyrano[3,2-b]pyridin-4-oneYield 3.3%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

In 50 mL round-bottom flask fitted with magnetic stirrer were placed 1-(4-methoxyphenyl)-3-(3-methoxypyridin-2-yl) propane-1,3-dione (4.68 g, 16 mmol) and 45% aqueous solution of HBr (25 mL). The reaction mixture was refluxed for 3 h, then cooled down to rt. Solid NaHCO3 was used to adjust pH to 7, followed by EtOAc (30 mL). The organic layer was separated and aqueous layer was extracted with EtOAc (2×30 mL). The combined organic extracts were dried over Na2SO4, concentrated to give the crude product, which was purified by column chromatography using 30% MeOH in EtOAc to give 125 mg of 2-(4-hydroxy-phenyl)-pyrano[3,2-b]pyridin-4-one (3.2%). MS (ES) m/z: 240.09 (M+1), and 149.06.

Workup

  1. customIn 50 mL round-bottom flask fitted with magnetic stirrer
  2. temperatureThe reaction mixture was refluxed for 3 h
  3. customThe organic layer was separated
  4. extractionaqueous layer was extracted with EtOAc (2×30 mL)
  5. dry with materialThe combined organic extracts were dried over Na2SO4
  6. concentrationconcentrated
  7. customto give the crude product, which
  8. customwas purified by column chromatography

Sources & evidence

ORD record
ord-b2badddda967447087f34bf3b908d1a2
Source dataset
uspto-grants-2012_08
Patent number
US08242130B2

Reaction notes

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