Condensation of cyclohexylamine and acetophenoneCondensation of cyclohexylamine and acetophenone
SyntheticPage 752
Published Aug 11, 2014
To a 100 mL one-neck round bottom flask equipped with stirbar, was added benzene (50 mL), cyclohexylamine (5.21g, 0.0525 mol, 1.05 equiv), acetophenone (6.01 g, 0.050 mol, 1 equiv, 1 M) and p-toluenesulfonic acid monohydrate (0.0951 g 0.00050 mol, 0.01 equiv). The flask was equipped with a graduated Dean-Stark trap along with a reflux condenser.1 The reaction mixture was heated to reflux in a 120 oC oil bath and stirred via a magnetic stir plate. The reaction mixture was allowed to reflux until 1 equivalent of water was observed in the trap (≈ 0.9 mL). Upon completion the reaction mixture was cooled to room temperature and the benzene was removed in vacuo by rotary evaporation. p-Toluenesulfonic acid was precipitated out by diluting the mixture with pentane. The fine precipitate was filtered, followed by removal of the solvent in vacuo by rotary evaporation. The crude imine was then purified via vacuum distillation2,3 (b.p. 96-99 oC @ 0.1 mmHg) giving the pure N-(1-phenylethylidene)cyclohexanamine as a clear, colorless oil.4.