反应详情

A mixture of propionic acid (3.8 ml, 50.64 mmol), diphenylphosphoryl azide (10.9 ml, 50.64 mmol), and triethylamine (7.1 ml, 50.64 mmol) in toluene (30 ml) was refluxed for 1 hour. After cooling to room temperature, ethyl 2-amino-4-methylthiophene-3-carboxylate (3.13 g, 16.88 mmol) was added, and the mixture was refluxed for 18 hours. The product was partitioned between ethyl acetate and water, the organic layer washed with brine, dried over sodium sulfate, and solvent removed under reduced pressure. The residue was chromatographed on silica gel, eluting with ethyl acetate/hexane 1:1, to provide ethyl 4-methyl-2-[(methylamino)carbonylamino]-thiophene-3-carboxylate as pink crystals.

1. temperaturewas refluxed for 1 hour
2. temperaturethe mixture was refluxed for 18 hours
3. customThe product was partitioned between ethyl acetate and water
4. washthe organic layer washed with brine
5. dry with materialdried over sodium sulfate, and solvent
6. customremoved under reduced pressure
7. customThe residue was chromatographed on silica gel
8. washeluting with ethyl acetate/hexane 1:1