Figure 2 | Scientific Reports

Figure 2

From: Peptide aromatic interactions modulated by fluorinated residues: Synthesis, structure and biological activity of Somatostatin analogs containing 3-(3′,5′difluorophenyl)-alanine

Figure 2

Schematic representations of the Dfp synthesis and the synthetic protocol used for the preparation of peptides 1–6.

(a) Synthesis of Fmoc-L-Dfp-OH. a) N-Ac-Gly-OH, AcONa, Ac2O, 2 h, 100 °C; b) MeONa, MeOH, 2 h, 70 °C; c) [Rh(S-MaxPHOS)(COD)]BF4 cat 3%, H2 (5 bar), MeOH, r.t.; d) HCl aq, 6 h, reflux; e) FmocOSu, Na2CO3, H2O, acetone, 0 °C to r.t.; (b) General schematic synthesis pathway for peptides. a) 1. Fmoc-L-Cys(trt)-OH (3 eq.), DIPEA (4 eq.), 2. MeOH; b) 1. Piperidine 20% DMF, 2. Fmoc-Aaa-OH (1.5–3 eq.), DIPCDI (3 eq.), HOBt (3 eq.), DMF, c) CH2Cl2/TFE/AcOH, d) 1. I2, 2. TFA/CH2Cl2/anisole/H2O.

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