1: 6-[5-(2-oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)-pentanoylamino]-hexanoic acid With pyridine; dicyclohexyl-carbodiimide in N,N-dimethyl-formamide T=20°C; 0.0833333 h; 2: 1-hydroxy-pyrrolidine-2,5-dione in N,N-dimethyl-formamide 18 h;

1.1: pyridine; dicyclohexyl-carbodiimide / N,N-dimethyl-formamide / 0.08 h / 20 °C 1.2: 24 h / 20 °C 2.1: N,N-dimethyl-formamide / 4 h / 20 °C / pH 8 / sodium bicarbonate buffer 3.1: pyridine; dicyclohexyl-carbodiimide / N,N-dimethyl-formamide / 0.08 h / 20 °C 3.2: 18 h View Scheme

1.1: N,N-dimethyl-formamide / 4 h / 20 °C / pH 8 / sodium bicarbonate buffer 2.1: pyridine; dicyclohexyl-carbodiimide / N,N-dimethyl-formamide / 0.08 h / 20 °C 2.2: 18 h View Scheme

1.1: N,N-dimethyl-formamide / 4 h / 20 °C / pH 8 / sodium bicarbonate buffer 2.1: pyridine; dicyclohexyl-carbodiimide / N,N-dimethyl-formamide / 0.08 h / 20 °C 2.2: 18 h View Scheme