Sulfuric Acid → Ethyl 4-oxo-4H-1-benzopyran-2-carboxylate

HRID 354103Notes

Reaction equation

HRID 354103 reaction equation
[C:1]([O:8][CH2:9][CH3:10])(=[O:7])[C:2]([O:4][CH2:5][CH3:6])=O.O[CH2:12][C:13]([C:15]1C=C[CH:18]=[CH:17][CH:16]=1)=[O:14].CC[O-].[Na+].S(=O)(=O)(O)O>C(O)C.O.C1(C)C=CC=CC=1>[O:14]=[C:13]1[C:15]2[C:5](=[CH:6][CH:18]=[CH:17][CH:16]=2)[O:4][C:2]([C:1]([O:8][CH2:9][CH3:10])=[O:7])=[CH:12]1

Participants

8

Reactant 4

HCID 1118Sulfuric AcidHCID 7268Diethyl OxalateHCID 68490alpha-HydroxyacetophenoneHCID 2723922Sodium ethoxide

Product 1

HCID 26861Ethyl 4-oxo-4H-1-benzopyran-2-carboxylateYield 189.8%

Reagents, catalysts & solvents 3

HCID 702EthanolSolventHCID 962WaterSolventHCID 1140TolueneSolvent

Conditions

Temperature
60 °C

Procedure

In a mixture containing 180 g of toluene and 12.0 g of diethyl oxalate was dissolved 30 g of 2-hydroxyacetophenone, to which 65.0 g of a 20% solution of sodium ethylate in ethanol was added dropwise. After completion of the reaction 13 g of 98% sulfuric acid was subsequently added, and the mixture was stirred at 60° C. for about 30 minutes. Then 140 g of water was added, and the mixture was subjected to separation of the organic layer. The resultant organic layer was concentrated, after which 55.0 g of hexane was added and the mixture was filtered below 10° C. which yields about 34.0 g of ethyl 4-oxochromene-2-carboxylate. (Approximately 95% yield).

Workup

  1. additionwas subsequently added
  2. customthe mixture was subjected to separation of the organic layer
  3. concentrationThe resultant organic layer was concentrated
  4. additionafter which 55.0 g of hexane was added
  5. filtrationthe mixture was filtered below 10° C. which

Sources & evidence

ORD record
ord-f50ce56a73824c9196e2b915b2900948
Source dataset
uspto-grants-2004_06
Patent number
US06756403B2

Reaction notes

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