ethylenediaminetetraacetic acid; sodium hydrogencarbonate in acetone T=20°C;

N-ethyl-N,N-diisopropylamine in 1,4-dioxane; chloroform T=20°C; 6 h;

1.1: CuCO3*Cu(OH)2 / H2O / Heating 1.2: N-ethyldiisopropylamine / formamide / 20 °C 2.1: 84 percent / aq. NaHCO3; ethylenediaminetetraacetic acid / acetone / 20 °C View Scheme

1.1: CuCO3*Cu(OH)2 / H2O / Heating 1.2: N-ethyldiisopropylamine / formamide / 20 °C 2.1: 84 percent / aq. NaHCO3; ethylenediaminetetraacetic acid / acetone / 20 °C View Scheme

1: 58 percent / NaOH 2: 88 percent 3: 1.) methyl(trimethylsilyl)trifluoroacetamide, 2.) Et3M / 1.) CH2Cl2, reflux, 2.) CH2Cl2, room temperature, 4 h View Scheme

1: 88 percent 2: 1.) methyl(trimethylsilyl)trifluoroacetamide, 2.) Et3M / 1.) CH2Cl2, reflux, 2.) CH2Cl2, room temperature, 4 h View Scheme

methyl(trimethylsilyl)trifluoroacetamide 1.) CH2Cl2, reflux, 2.) CH2Cl2, room temperature, 4 h; Yield given. Multistep reaction;

1: fmoc-O-tert-butyl-L-tyrosine With benzotriazol-1-ol; N-ethyl-N,N-diisopropylamine; diisopropyl-carbodiimide in N,N-dimethyl-formamide 1 h; solid phase reaction; 2: With piperidine in N,N-dimethyl-formamide 0.5 h; solid phase reaction; 3: N-(fluoren-9-ylmethoxycarbonyl)-L-Val; N-(9-fluorenylmethoxycarbonyl)-L-aspartic acid-β-(tert-butyl)ester; N-(fluoren-9-ylmethoxycarbonyl)-L-Lys(Nε-Boc); N-α-Fmoc-N-ω,N-ω'-bis-tert-butoxycarbonyl-L-arginine Further stages;

1: fmoc-O-tert-butyl-L-tyrosine With benzotriazol-1-ol; N-ethyl-N,N-diisopropylamine; diisopropyl-carbodiimide in N,N-dimethyl-formamide 1 h; 2: With piperidine in N,N-dimethyl-formamide 0.5 h; 3: N-(fluoren-9-ylmethoxycarbonyl)-L-Val; N-(9-fluorenylmethoxycarbonyl)-L-aspartic acid-β-(tert-butyl)ester; N-(fluoren-9-ylmethoxycarbonyl)-L-Lys(Nε-Boc); N-α-Fmoc-N-ω,N-ω'-bis-tert-butoxycarbonyl-L-arginine Further stages;