p-Fluorophenethylamine → (2E)-N-[2-(4-Fluorophenyl)ethyl]-2-butenamide

Participants

Reaction Steps

A solution of 2-(4-fluorophenyl)ethylamine (13.25 mL, 100 mmol) and triethylamine (14.6 mL, 105 mmol) in dichloromethane (375 mL) was stirred on an ice bath. A solution of crotonyl chloride (10.65 mL, 100 mmol) in dichloromethane (25 mL) was added dropwise over 15 minutes. The cooling bath was removed and the solution was stirred at room temperature for 2 hours. It was then washed twice with 1.0 N aqueous hydrochloric acid, then twice with saturated aqueous sodium hydrogen carbonate. The organic phase was dried over sodium sulfate and concentrated under vacuum to provide a yellowish solid (20.78 g, quantitative). Recrystallization from toluene provided white needles (15.5 g, 75%), mp 121-123° C. 1H NMR (300 MHz, CDCl3) δ7.16 (m, 2H), 7.01 (t, J=9 Hz, 2H), 6.85 (dq, J=15, 7 Hz, 1H), 5.74 (dd, J=15, 1 Hz, 1H), 5.49 (bs, 1H), 3.56 (m, 2H), 2.83 (t, J=7 Hz, 2H), 1.85 (dd, J=7, 2 Hz, 3H). Mass spec (ES+) m/z 249.0 (M+H+acetonitrile+, 100%).

Provenance & Evidence