2,3-Dibromopropene → Diethyl (2-Bromoallyl)acetamidomalonate

Participants

Reaction Steps

To a stirred mixture of diethyl acetamidomalonate (217 g, 1.0 mol) and 2,3-dibromopropene (240 g, 1.2 mol) in anhydrous tetrahydrofuran (2.50 L), under nitrogen, was added sodium hydride (26.4 g, 1.1 mol) in several portions. The reaction mixture was stirred at ambient temperature for 30 minutes, then heated to reflux. After heating for 18 hours, the resultant slurry was cooled to ambient temperature and suction filtered through a short pad of silica gel. The solid residue was washed with tetrahydrofuran (2×50 mL), and the filtrates were combined and concentrated. The residue obtained was dissolved in ethyl acetate (2.0 L), washed with water and brine, and then was dried over magnesium sulfate. Filtration and concentration gave a yellow oil which solidified upon drying. The resultant solid was recrystallized from a mixture of hot ethyl acetate/hexane to give 301 g (89%) of the desired product: m.p. 85°-87° C. 1H NMR (300 MHz, CDCl3) δ1.28 (t, J=7.4 Hz, 6H), 2.04 (s, 3H), 3.57 (s, 2H), 4.27 (m, 4H), 5.55 (bs, 1H), 5.61 (bs, 1H), 6.82 (broad, 1H); IR (KBr) 1745, 1635 cm-1Anal calcd for C12H18BrNO5 : C, 42.87; H, 5.40; Br, 23.77; N, 4.12. Found: C, 43.25; H, 5.56; Br, 22.97; N, 4.12.

Provenance & Evidence