Sulfuric Acid → 7-Hydroxy-4-benzopyrone

HRID 741723

Reaction equation

HRID 741723 reaction equation
[OH-].[Na+].[OH:3][C:4]1[CH:9]=[C:8]([OH:10])[CH:7]=[CH:6][C:5]=1[C:11](=[O:15])[CH2:12][CH2:13]Cl.S(=O)(=O)(O)O>>[OH:10][C:8]1[CH:7]=[CH:6][C:5]2[C:11](=[O:15])[CH:12]=[CH:13][O:3][C:4]=2[CH:9]=1

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 14798Sodium HydroxideHCID 118057423-chloro-1-(2,4-dihydroxyphenyl)propan-1-one

Product 1

HCID 54092797-Hydroxy-4-benzopyroneYield 88%

Procedure

To a cooled (5° C.) solution of 2N sodium hydroxide (10.0 L) was added the compound of step A (244.1 g) in one portion. The solution was warmed to room temperature over 2 hours using a warm water bath then recooled to 5° C. and the pH adjusted to 2 with 6M sulfuric acid (1.2 L). The mixture was extracted with 3×3.0 L of ethyl acetate, washed with brine (1×2.0 L) dried over sodium sulfate and filtered. Concentration in vacuo gave a tan solid. Trituration with hexanes, and filtration afforded 173.7 g (58% yield) of the title compound. M.P. 136° C.-137° C.

Workup

  1. customthen recooled to 5° C.
  2. extractionThe mixture was extracted with 3×3.0 L of ethyl acetate
  3. washwashed with brine (1×2.0 L)
  4. dry with materialdried over sodium sulfate
  5. filtrationfiltered
  6. concentrationConcentration in vacuo
  7. customgave a tan solid
  8. filtrationTrituration with hexanes, and filtration

Sources & evidence

ORD record
ord-850973f56ac44474b4b10b2933702cb0
Source dataset
uspto-grants-1996_09
Patent number
US05552435

Linked notes

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