1.1: dicyclohexylcarbodiimide; 1-hydroxybenzotriazole / tetrahydrofuran / 0.5 h / 20 °C 1.2: diisopropylethylamine / tetrahydrofuran / 4 h / 20 °C 2.1: 76 percent / aq. NaOH / methanol / 1.75 h / 20 °C 3.1: 35 percent / glacial acetic acid; dimethylaminoborane / 0.33 h / 60 °C 4.1: 80 percent / aq. NaOH / 6 h / 20 °C View Scheme

1: 58.1 percent / deuterium oxide; Pd/C / 2 h / 200 °C 2: 2 h / 20 °C View Scheme

T=20°C; 2 h;

1: trifluoroacetyl-[2H4]4-aminobenzoic acid With benzotriazol-1-ol; dicyclohexyl-carbodiimide in tetrahydrofuran T=20°C; 0.5 h; 2: L-(+)-glutamic acid dimethyl ester With N-ethyl-N,N-diisopropylamine in tetrahydrofuran T=20°C; 4 h;