Hydrochloric Acid → Ethyl 7-amino-4-oxo-4H-chromene-2-carboxylate

HRID 49458Notes

Reaction equation

HRID 49458 reaction equation
[C:1]([C:4]1[CH:9]=[CH:8][C:7]([NH:10]C(=O)C)=[CH:6][C:5]=1[OH:14])(=[O:3])[CH3:2].[C:15](OCC)(=O)[C:16]([O:18][CH2:19][CH3:20])=[O:17].[O-]CC.[Na+].Cl>C(O)C.O>[NH2:10][C:7]1[CH:6]=[C:5]2[C:4]([C:1](=[O:3])[CH:2]=[C:15]([C:16]([O:18][CH2:19][CH3:20])=[O:17])[O:14]2)=[CH:9][CH:8]=1

Participants

7

Reactant 4

HCID 313Hydrochloric Acid2×HCID 7268Diethyl OxalateHCID 2723922Sodium ethoxideHCID 2775185N-(4-acetyl-3-hydroxyphenyl)acetamide

Product 1

HCID 10728325Ethyl 7-amino-4-oxo-4H-chromene-2-carboxylateYield 61%

Reagents, catalysts & solvents 2

HCID 702EthanolSolvent3×HCID 962WaterSolvent

Procedure

A solution of N-(4-acetyl-3-hydroxyphenyl)acetamide (4.00 g., 21 mmol) and diethyl oxalate (7.3 mL, 54 mmol) in absolute ethanol is added dropwise to a solution of sodium ethoxide (0.1 mol) in absolute ethanol. The mixture is heated at reflux temperature for 1.5 h, cooled to ambient temperature, poured into water, acidified to pH 3 with 6N HCl and extracted with ethyl acetate. The extracts are combined and concentrated in vacuo to afford an oily residue. The residue is dissolved in ethanol, treated with concentrated HCl heated at reflux temperature overnight, cooled to 0° C. for several hours and filtered. The filtercake is dried to afford the title compound as an orange solid, 2.95 g (61% yield), mp 195°-198° C., identified by NMR and mass spectral analyses.

Workup

  1. temperatureThe mixture is heated
  2. temperatureat reflux temperature for 1.5 h
  3. extractionextracted with ethyl acetate
  4. concentrationconcentrated in vacuo
  5. customto afford an oily residue
  6. temperatureheated
  7. temperatureat reflux temperature overnight
  8. temperaturecooled to 0° C. for several hours
  9. filtrationfiltered
  10. customThe filtercake is dried

Sources & evidence

ORD record
ord-dc86013d85064869934468b248415d6a
Source dataset
uspto-grants-2004_03
Patent number
US06706757B2

Reaction notes

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