1: N-[(1,1-dimethylethoxy)carbonyl]-L-histidine With benzotriazol-1-ol; dicyclohexyl-carbodiimide in N,N-dimethyl-formamide T=25°C; 2 h; 2: (S)-pyrrolidine-2-carboxamide in N,N-dimethyl-formamide T=25°C; 18 h;

1: 73 percent / NaOH / methanol / 1 h 2: 1.) DCC, Et3N, 2.) Pd-C, H2, Rh-C, Amberlite IR 45 (acetate form) / 1.) DMF, 0 deg C, 4 h, 2.) aq. AcOH, 2 h View Scheme

1: 25 percent / Et3N, Br2 / CHCl3 / 0 deg C to room temperature 2: 73 percent / NaOH / methanol / 1 h 3: 1.) DCC, Et3N, 2.) Pd-C, H2, Rh-C, Amberlite IR 45 (acetate form) / 1.) DMF, 0 deg C, 4 h, 2.) aq. AcOH, 2 h View Scheme

palladium on activated charcoal; Rh on carbon; Amberlite IR 45 (acetate form); hydrogen; triethylamine; dicyclohexyl-carbodiimide 1.) DMF, 0 deg C, 4 h, 2.) aq. AcOH, 2 h; Yield given. Multistep reaction. Yields of byproduct given. Title compound not separated from byproducts;

palladium on activated charcoal; rhodium on CaCO3; hydrogen; triethylamine; dicyclohexyl-carbodiimide 1.) DMF, 0 deg C, 4 h, 2.) DMF, 2 h; Yield given. Multistep reaction. Yields of byproduct given. Title compound not separated from byproducts;

palladium on activated charcoal; hydrogen; triethylamine; dicyclohexyl-carbodiimide 1.) DMF, 0 deg C, 4 h, 2.) aq. AcOH, 72 h; Yield given. Multistep reaction. Yields of byproduct given. Title compound not separated from byproducts;