反应详情

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.

1. temperaturethe mixture was refluxed for 2 hours
2. temperatureAfter cooling
3. customthe volatiles were removed in vacuo
4. customAfter evaporation of the solvent in vacuo dichloromethane and 1N HCl
5. additionwere added
6. customThe phases were separated
7. washthe organic layer was washed with brine
8. dry with materialdried over MgSO4
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. customPurification of the crude material on silica gel