Parallel synthesis of 19-membered ring macro-heterocycles via intramolecular thioether formation

Starting from resin-bound orthogonally protected lysine, the generation of 19-membered ring macro-heterocycles via intramolecular thioether formation is described. The on resin cyclization occurred by the coupling of p-fluoro-m-nitro benzoic acid or bromo acetic acid followed by intramolecular substitution SNAr or SN2 displacement of the fluoro and bromo groups, respectively. The described approaches present versatile synthetic routes toward the synthesis of libraries of macro-heterocycles in an attempt to establish lead drug candidates. The desired cyclic products were obtained in good yields and good purities.