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 dry 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 room temperature for 30 min, then heated to reflux. After heating for 18 h, the resultant slurry was cooled to room 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 was dissolved in ethyl acetate (2.0 L), washed with water and brine, and then was dried over MgSO4. 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-1. Anal. 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