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

HRID 1071194Notes

Reaction equation

HRID 1071194 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].[O-]CC.[Na+].S(=O)(=O)(O)O>C1(C)C=CC=CC=1.C(O)C.O>[O:4]1[C:5]2[C:15](=[CH:16][CH:17]=[CH:18][CH:6]=2)[C:13](=[O:14])[CH:12]=[C:2]1[C:1]([O:8][CH2:9][CH3:10])=[O:7]

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

Into a solution of 12.0 g of diethyl oxalate in 180 g of toluene is added 30 g of 2-hydroxyacetophenone, then dropwise added 65.0 g of 20% sodium ethoxide in ethanol. After the reaction is complete, 13 g of 98% sulfuric acid is added, and the mixture stirred at 60° C. for about 30 min. After adding 140 g of water, the organic fraction is separated. The organic fraction is concentrated and 55.0 g of hexane is added. Filtering below 10° C. affords about 34.0 g of ethyl chromone-2-carboxylate (about 95% yield).

Workup

  1. customthe organic fraction is separated
  2. concentrationThe organic fraction is concentrated
  3. addition55.0 g of hexane is added
  4. filtrationFiltering below 10° C.

Sources & evidence

ORD record
ord-32a29a9a03ea46e8acef25273299df99
Source dataset
uspto-grants-2005_06
Patent number
US06903227B2

Reaction notes

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