triethylamine in dichloromethane 2 h; Ambient temperature;

in N,N-dimethyl-formamide T=0°C; 1 h;

1: maleic anhydride; 6-amino-hexanoic acid in N,N-dimethyl-formamide T=20°C; 3 h; Inert atmosphere; 2: 1-hydroxy-pyrrolidine-2,5-dione With 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride in N,N-dimethyl-formamide T=20°C; Inert atmosphereCooling with ice;

dicyclohexyl-carbodiimide in tetrahydrofuran; N,N-dimethyl-formamide 1.) -15 deg C, 2 h; 2.) r. t., 3 h;

dicyclohexyl-carbodiimide in N,N-dimethyl-formamide T=0 - 20°C;

1: 1-hydroxy-pyrrolidine-2,5-dione With trifluoroacetic anhydride in N,N-dimethyl-formamide T=0°C; Inert atmosphere; 2: With 2,4,6-trimethyl-pyridine in N,N-dimethyl-formamide T=0°C; Inert atmosphere; 3: 6-(3-carboxyacryloylamino)caproic acid in N,N-dimethyl-formamide T=0 - 20°C; Inert atmosphere;

1.1: N,N-dimethyl-formamide / 20 °C / Inert atmosphere 2.1: trifluoroacetic anhydride / N,N-dimethyl-formamide / 0 °C / Inert atmosphere 2.2: 0 °C / Inert atmosphere 2.3: 0 - 20 °C / Inert atmosphere View Scheme

1.1: N,N-dimethyl-formamide / 20 °C / Inert atmosphere 2.1: trifluoroacetic anhydride / N,N-dimethyl-formamide / 0 °C / Inert atmosphere 2.2: 0 °C / Inert atmosphere 2.3: 0 - 20 °C / Inert atmosphere View Scheme

in N,N-dimethyl-formamide 2 h;