反应详情

A mixture of ethyl-3-(2,6-difluorobenzylamino)crotonate (2.55 g, 10.0 mmol) and 2,2,6-trimethyl-1,3-dioxin-4-one (1.85 g, 13.0 mmol) in toluene (100 mL) was heated at reflux for 3 hours. The reaction progress was monitored by LC/MS. An additional aliquot of 2,2,6-trimethyl-1,3-dioxin-4-one (2.0 mL) was added and the reaction mixture was refluxed for another 2 hours. LC/MS indicated complete conversion to product. The mixture was cooled down and the solvent was removed in vacuo. The solid residue was triturated with diethyl ether to yield the product as a tan solid (1.37 g, 4.3 mmol, 43%). 1H NMR (CDCl3, 300 MHz): 7.40-7.30 (m, 1H), 7.00-6.91 (m, 2H), 6.30 (s, 1H), 5.20 (s, 2H), 4.37 (q, J=6.9 Hz, 2H), 2.37 (s, 3H), 2.31 (s, 3H), 1.35 (t, J=6.9 Hz, 3H); LRMS m/z 322.1 (M++1).

1. temperaturewas heated
2. temperatureat reflux for 3 hours
3. temperaturethe reaction mixture was refluxed for another 2 hours
4. temperatureThe mixture was cooled down
5. customthe solvent was removed in vacuo
6. customThe solid residue was triturated with diethyl ether