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Synthesis of tetra‐ortho‐chloro‐azobenzene amino acid 3 (Tfa‐CEBA‐OH). Reaction conditions: a) Zn powder (2.5 equiv), NH4Cl (1.5 equiv), H2O, 2‐methoxyethanol, 0 °C to rt, 17 h; then FeCl3 (3.0 equiv), EtOH, H2O, 0 °C, 1.5 h. b) 6 (1 equiv), AcOH, rt, 18 h, 54 % (2 steps). c) Pd(OAc)2, NCS (6 equiv), AcOH, 140 °C, 19 h, 85 %. Tfa=trifluoroacetyl; NCS=N‐chlorosuccinimide.
