1: N-tert-butoxycarbonyl-L-phenylalanine With 4-methyl-morpholine; isobutyl chloroformate in tetrahydrofuran 2: cyclohexylamine in tetrahydrofuran; N,N-dimethyl-formamide T=0 - 4°C;

1: 1-(4-carboxyphenyl)-3-(4-nitrophenyl)-2-pyrazolin-5-one; amino polystyrene With dacarbazine; 4-(N,N-dimethlyamino)pyridine in N,N-dimethyl-formamide 24 h; 2: N-tert-butoxycarbonyl-L-phenylalanine With dacarbazine; 4-(N,N-dimethlyamino)pyridine in N,N-dimethyl-formamide 24 h; 3: cyclohexylamine in tetrahydrofuran; dichloromethane T=20°C; 1 h;

in dichloromethane T=0°C; 1 h;

pyridine; di-tert-butyl dicarbonate; sodium hydrogencarbonate in acetonitrile

1: N-methylmorpholine / ethyl acetate / 0.33 h / -15 °C 2: ethyl acetate / 3 h / -15 - 20 °C View Scheme

in ethyl acetate T=-15 - 20°C; 3 h; Yield given;

1.1: sodium hydroxide / 1,4-dioxane; water / 6.33 h / 0 - 20 °C 1.2: pH 2 - 3 2.1: (benzotriazo-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate; triethylamine / tetrahydrofuran / 0 - 20 °C View Scheme

1.1: sodium hydroxide / 1,4-dioxane; water / 6.33 h / 0 - 20 °C 1.2: pH 2 - 3 2.1: (benzotriazo-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate; triethylamine / tetrahydrofuran / 0 - 20 °C View Scheme

trifluoroacetic acid in dichloromethane T=0°C; 2 h;