1: With N-(diphenylmethylene)amine in toluene 0.5 h; Inert atmosphere; 2: With palladium diacetate; caesium carbonate; 2,2'-bis-(diphenylphosphino)-1,1'- binaphthyl T=95 - 100°C; 20 h; 3: With citric acid in ethanol; water T=55 - 60°C; 15 h; Large scale reaction;

1.1: N-(diphenylmethylene)amine / toluene / 0.5 h / Inert atmosphere 1.2: 20 h / 95 - 100 °C 1.3: 15 h / 55 - 60 °C / Large scale reaction 2.1: N-ethyl-N,N-diisopropylamine / acetonitrile / 2.5 h / 0 - 20 °C View Scheme

1.1: N-(diphenylmethylene)amine / toluene / 0.5 h / Inert atmosphere 1.2: 20 h / 95 - 100 °C 1.3: 15 h / 55 - 60 °C / Large scale reaction 2.1: N-ethyl-N,N-diisopropylamine / acetonitrile / 2.5 h / 0 - 20 °C 3.1: hydrogenchloride / ethanol / 16 h / 50 - 55 °C View Scheme