Reaktion #962368

Reaktionsgleichung

N,O-dimethyl-hydroxylamine hydrochloride

triethylamine

4-methyl-1,3-oxazole-5-carboxylic acid

N,N-dimethylformamide

→

N-methoxy-N,4-dimethyl-1,3-oxazole-5-carboxamide

Ausbeute 48.1%

Lösungsmittel

tetrahydrofuran

thionyl chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture was refluxed for 2 hours
2. 2
   TemperaturAfter cooling
3. 3
   Sonstigethe volatiles were removed in vacuo
4. 4
   SonstigeAfter evaporation of the solvent in vacuo dichloromethane and 1N HCl
5. 5
   workup.ADDITIONwere added
6. 6
   SonstigeThe phases were separated
7. 7
   Waschenthe organic layer was washed with brine
8. 8
   Trocknendried over MgSO4
9. 9
   Filtrationfiltered
10. 10
    Einengenconcentrated in vacuo
11. 11
    SonstigePurification of the crude material on silica gel

Vorschrift

To a stirred solution of 4-methyl-1,3-oxazole-5-carboxylic acid (4.00 g, 31.5 mmol) in thionyl chloride (4 ml) were added 0.4 ml N,N-dimethylformamide and the mixture was refluxed for 2 hours. After cooling, the volatiles were removed in vacuo and the remaining material was suspended in tetrahydrofuran (10 ml). This suspension was added to a stirred suspension of N,O-dimethyl-hydroxylamine hydrochloride (3.38 g, 34.6 mmol) and triethylamine (9.55 g, 94.4 mmol) in tetrahydrofuran (10 ml). The reaction mixture was stirred at room temperature for 20 h. After evaporation of the solvent in vacuo dichloromethane and 1N HCl were added. The phases were separated, the organic layer was washed with brine, dried over MgSO4, filtered and concentrated in vacuo. Purification of the crude material on silica gel afforded N-methoxy-N,4-dimethyl-1,3-oxazole-5-carboxamide (2.58 g, 45%) as an orange solid.

Quelle