Hydrochloric Acid → 4-Oxo-4H, 5H-[1]benzopyrano [4,3-b]pyran-2-carboxylic Acid Methyl Ester

HRID 2419472Notes

Reaction equation

HRID 2419472 reaction equation
[CH2:1]([O:3][C:4](=[O:21])[C:5](=[O:20])[CH2:6][C:7]([CH:9]1[C:18](=O)[C:17]2[C:12](=[CH:13][CH:14]=[CH:15][CH:16]=2)[O:11][CH2:10]1)=[O:8])C.Cl>CO>[CH3:1][O:3][C:4]([C:5]1[O:20][C:18]2[C:17]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=3[O:11][CH2:10][C:9]=2[C:7](=[O:8])[CH:6]=1)=[O:21]

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 12677755HCID 12677755, compound

Product 1

HCID 126777564-Oxo-4H, 5H-[1]benzopyrano [4,3-b]pyran-2-carboxylic Acid Methyl Ester

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A solution of 4-(4-chromanone-3-yl)-2,4-dioxobutyric acid ethyl ester [0.70 g, 2.4 mmoles, described above in (a)] in methanol is saturated with hydrogen chloride gas. The solution is heated at reflux temperature overnight and evaporated to dryness. The residue is chromatographed on silica gel using benzene-ethyl acetate (4:1). The eluate is evaporated and the residue is crystallized from chlorofrom-ether to give the title compound, m.p. 173°-174° C.

Workup

  1. temperatureThe solution is heated
  2. temperatureat reflux temperature overnight
  3. customevaporated to dryness
  4. customThe residue is chromatographed on silica gel
  5. customThe eluate is evaporated
  6. customthe residue is crystallized from chlorofrom-ether

Sources & evidence

ORD record
ord-56312ef5ca604696871f0b297b8f6762
Source dataset
uspto-grants-1978_08
Patent number
US04105778

Reaction notes

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