1: SOCl2, pyridine / CH2Cl2 / Heating 2: 81 percent / pyridine / tetrahydrofuran / 4 °C View Scheme

1: 1.) 2-chlorotrityl chloride resin, (i-Pr)2EtN, 2-4.) a)piperidine, b) DCC, HOBt, 5.) AcOH, TFE / solid phase peptide synthesis 2: TFA, anisole / CH2Cl2 View Scheme

1: N-methylmorpholine / 1,2-dimethoxy-ethane / 0.02 h / -15 °C 2: NaBH4 / H2O; 1,2-dimethoxy-ethane / 0.01 h / -15 °C View Scheme

1: N-(9-fluorenylmethoxycarbonyl)glycine With ethyl (hydroxylimino)cyanoacetate; diisopropyl-carbodiimide in N,N-dimethyl-formamide T=20°C; 1 h; 2: With piperidine in N,N-dimethyl-formamide 3: N-Fmoc-L-leucine; C27H27NO7S2; Fmoc–Pro–OH; fmoc-L-Ile-OH; fmoc-O-tert-butyl-L-tyrosine; fmoc-Asn(trt)-OH; fmoc-Gln(Trt)-OH Further stages;

1: (S)-9-(allyloxy)-8-[bis((tert-butoxy)carbonyl)amino]-9-oxonon-4-enoic acid With benzotriazol-1-ol; O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate; N-ethyl-N,N-diisopropylamine in dichloromethane; N,N-dimethyl-formamide 24.5 h; Inert atmospheresolid phase reaction; 2: With trifluoroacetic acid in dichloromethane 1.08333 h; solid phase reaction; 3: N-Boc-N,O-dimethyl-3-bromotyrosine; N2-[(1,1-Dimethylethoxy)carbonyl]-L-glutamine; N-(fluoren-9-ylmethoxycarbonyl)-L-Val; fmoc-L-Ile-OH; N-Fmoc-L-threonine-OH; Fmoc-citrulline; butyric acid Further stages;

thionyl chloride in dichloromethane 24 h; Ambient temperature;

1: N-Fmoc-L-leucine With benzotriazol-1-ol; O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate; N-ethyl-N,N-diisopropylamine Automated synthesizersolid phase reaction; 2: Automated synthesizersolid phase reaction; 3: N-(9-fluorenylmethoxycarbonyl)glycine; N-(fluoren-9-ylmethoxycarbonyl)-L-Val; N-Fmoc-L-leucine; N-(9H-fluoren-9-ylmethyloxycarbonylamino)-L-alanine; Fmoc-L-phenylalanine; fmoc-L-Ile-OH; N-(fluoren-9-ylmethoxycarbonyl)-L-Lys(Nε-Boc); N-(9-fluorenyl)methoxycarbonyl-Trp(Boc)-OH Further stages;

1: pyridine; di-tert-butyl dicarbonate; ammonium hydrogen carbonate / 20 °C 2: alkylamine / N,N-dimethyl-formamide / 1 h / 20 °C View Scheme

1: NEt3 / tetrahydrofuran / 0.25 h / -15 °C 2: tetrahydrofuran; diethyl ether / 3 h / Ambient temperature 3: silver benzoate, H2O / dioxane / Ambient temperature View Scheme

Yield given. Multistep reaction;