反应详情

Prepared according to WO 2010/031816. In a 250 mL RBF, sodium diformylamide (Fluka; 2.66 g, 28.0 mmol) and NaI (3.49 g, 23.31 mmol) were treated with ACN (60 mL) and (E)-ethyl 4-bromobut-2-enoate (Aldrich; 4.28 mL, 23.31 mmol) and the flask was fitted with a reflux condenser and heated at reflux overnight (16 h). The mixture was concentrated in vacuo and the crude residue was treated with water and extracted with EtOAc (100 mL). The organic extract was washed with brine, then dried over MgSO4, filtered, and concentrated. The resulting light-brown solid was suspended in Et2O (ca. 10 mL), filtered, and washed with Et2O (5 mL), then dried by drawing air through the filtercake for 2 min to afford (E)-ethyl 4-(N-formylformamido)but-2-enoate (3.66 g, 19.76 mmol, 85% yield) as a brown amorphous solid: 1H NMR (400 MHz, CDCl3) δ ppm 8.91 (2H, br. s.), 6.74-6.84 (1H, m), 5.90 (1H, dt, J=15.8, 1.6 Hz), 4.40 (2H, d, J=4.5 Hz), 4.13-4.24 (2H, m), 1.20-1.33 (3H, m). m/z (ESI, +ve ion) 186.1 (M+H)+. The crude material was used in the subsequent step without further purification.

1. customPrepared
2. customthe flask was fitted with a reflux condenser
3. temperatureheated
4. temperatureat reflux overnight (16 h)
5. concentrationThe mixture was concentrated in vacuo
6. additionthe crude residue was treated with water
7. extractionextracted with EtOAc (100 mL)
8. extractionThe organic extract
9. washwas washed with brine
10. dry with materialdried over MgSO4
11. filtrationfiltered
12. concentrationconcentrated
13. filtrationfiltered
14. washwashed with Et2O (5 mL)
15. customdried
16. customfor 2 min