Sulfuric Acid → 3-benzyl-6,7-dihydroxy-4-methyl-2H-chromen-2-one

HRID 613211Notes

Reaction equation

HRID 613211 reaction equation
C([O:4][C:5]1[CH:10]=CC(OC(=O)C)=[CH:7][C:6]=1[O:15]C(=O)C)(=O)C.[CH2:19]([CH:26]([C:32]([CH3:34])=O)[C:27]([O:29][CH2:30][CH3:31])=[O:28])[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1.S(=O)(=O)(O)O>>[OH:4][C:5]1[CH:10]=[C:31]2[C:30](=[CH:7][C:6]=1[OH:15])[O:29][C:27](=[O:28])[C:26]([CH2:19][C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1)=[C:32]2[CH3:34]

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 691691,2,4-TriacetoxybenzeneHCID 246929Ethyl alpha-benzylacetoacetate

Product 1

HCID 163946973-benzyl-6,7-dihydroxy-4-methyl-2H-chromen-2-one

Procedure

1,2,4-triacetoxybenzene (6.3 g, 25 mmol) and ethyl 2-benzylacetoacetate (5.5 g, 25 mmol) were heated together as described in Example 1. 75% sulphuric acid (35 ml) was added to the stirred solution and stirring continued for 16 hours. The dark coloured suspension was poured into ice/water (350 ml) with good stirring and the grey suspension filtered and the residue washed with abundant water. The residual solid was air dried and recrystallised from hot ethanol with subsequent addition of a little water to aid crystallisation. The esculetin derivative formed small white needles (5.5 g, 75.3%).

Workup

  1. stirringwith good stirring
  2. filtrationthe grey suspension filtered
  3. washthe residue washed with abundant water
  4. customdried
  5. customrecrystallised from hot ethanol with subsequent addition of a little water
  6. customcrystallisation

Sources & evidence

ORD record
ord-a29ec01c446548ebb542a0f28ee242e2
Source dataset
uspto-grants-1999_12
Patent number
US06008008

Reaction notes

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