Scheme 1. Synthesis of Aniline Amides with Various Linker Lengths 6a–c from Aniline 4.

Reagents and conditions: (i) N,N’-dicyclohexylcarbodiimide (DCC), 4-dimethylaminopyridine (DMAP), CH₂Cl₂, room temperature (rt), overnight; (ii) Et₃N, CH₂Cl₂, rt, overnight; (iii) aniline, tBuONO, TMSN₃, CH₃CN, 2 h, then 6d, Amberlyst-A21 CuI cat., rt, overnight; (iv) xanthate, dilauroyl peroxide (DLP), ClCH₂CH₂Cl, reflux, overnight; (v) H₃PO₂/Et₃N, azobisisobutyronitrile (AIBN), dioxane, reflux, 2 h; (vi) Ac₂O, Et₃N, DMAP, 1 h at 0 °C, 2 h at rt.