Sulfuric Acid → 6-Chloro-7-hydroxy-2,3-dihydro-4H-1-benzopyran-4-one

HRID 1626405Notes

Reaction equation

HRID 1626405 reaction equation
Cl[CH2:2][CH2:3][C:4]([C:6]1[CH:11]=[C:10]([Cl:12])[C:9]([OH:13])=[CH:8][C:7]=1[OH:14])=[O:5].OS(O)(=O)=O>[OH-].[Na+]>[Cl:12][C:10]1[CH:11]=[C:6]2[C:7](=[CH:8][C:9]=1[OH:13])[O:14][CH2:2][CH2:3][C:4]2=[O:5]

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 67166662HCID 67166662, compound

Product 1

HCID 203471666-Chloro-7-hydroxy-2,3-dihydro-4H-1-benzopyran-4-oneYield 73%

Reagents, catalysts & solvents 1

HCID 14798Sodium HydroxideSolvent

Procedure

3-Chloro-1-(5-chloro-2,4-dihydroxyphenyl)propan-1-one (140 g, 596 mmol) was dissolved in a 2M aqueous NaOH solution (2085 mL) at 0° C., and then the reaction was warmed to ambient temperature over 2 hours. The reaction was acidified by the addition of 6M H2SO4 to a pH of ˜2. The resulting solids were removed by filtration and dried under high vacuum. The resulting solid was dissolved in THF (600 mL) and washed with water. The organic layer and was dried over magnesium sulfate, filtered, and concentrated. The resulting solid was treated with a minimal amount of diethyl ether and sonicated until a homogeneous suspension resulted. The resulting solid was collected by filtration to provide the desired product (85.7 g, 73%).

Workup

  1. customThe resulting solids were removed by filtration
  2. customdried under high vacuum
  3. dissolutionThe resulting solid was dissolved in THF (600 mL)
  4. washwashed with water
  5. dry with materialThe organic layer and was dried over magnesium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated
  8. additionThe resulting solid was treated with a minimal amount of diethyl ether
  9. customsonicated until a homogeneous suspension
  10. customresulted
  11. filtrationThe resulting solid was collected by filtration

Sources & evidence

ORD record
ord-80eb979244e3483dade620ff93d6f92b
Source dataset
uspto-grants-2014_07
Patent number
US08785445B2

Reaction notes

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