Réaction #77736

Équation de réaction

HCl

N-(4-acetyl-3-hydroxyphenyl)acetamide

diethyl oxalate

sodium ethoxide

HCl

→

title compound

Rendement 61.0%

Ethyl 7-Amino-4-oxo-4H-chromene-2-carboxylate

Rendement 61.0%

Solvants

ethanol

ethanol

ethanol

water

Conditions de réaction

Traitement

1. 1
   TempératureThe mixture is heated
2. 2
   Températureat reflux temperature for 1.5 h
3. 3
   Extractionextracted with ethyl acetate
4. 4
   Concentrationconcentrated in vacuo
5. 5
   Autreto afford an oily residue
6. 6
   Températureheated
7. 7
   Températureat reflux temperature overnight
8. 8
   Températurecooled to 0° C. for several hours
9. 9
   Filtrationfiltered
10. 10
    AutreThe filtercake is dried

Mode opératoire

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.

Source