Hydrochloric Acid → m-Bromocinnamic acid

Participants

Reaction Steps

A magnetically stirred solution of 3-bromobenzaldehyde (86.5 g, 0.468 mol) and malonic acid (107 g, 1.03 mol) in pyridine (200 ml) was treated with peiperidine (4.0 ml, 40.45 mmol) and heated at ~90° C. for 90 min then under reflux for 30 min. The cooled mixture was poured onto ice (200 g) and water (300 ml) then acidified to ph=1 with conc. hydrochloric acid. Filtration afforded a white solid which was washed with water (4×200 ml), dried by suction and placed in an oven at 70° C. for 48 h until constant weight was obtained (96.02 g, 90%); Vmax (nujol)/cm-1 3400-2000 (br. OH), 1684.5, 1631.5, 1587.0; δH (270 MHz) 6.45 (1H, d, 2-H, 3J2,3 =16,2 Hz); 7.28 (1H, t, 5'-H, Jo =7.8 Hz); 7.48 (1-H, dt, 4'-H, Jo =7.9, Jm =1.3 Hz); 7.54 (1-H, dt, 6'-H, Jo =7.9, Jm =1.0 Hz); 7.70 (1-H, t, 2'H, Jm =1.8 Hz); 7.71 (1H, d, 3-H, 3J3,2 =15.8 Hz).

Provenance & Evidence