Cyclisation of histidine containing peptides in the solid-phase by anchoring the imidazole ring to trityl resins

Head-to-tail histidine containing cyclopeptides can be efficiently synthesised by a three-dimensional orthogonal solid-phase strategy (Fmoc/tBu/allyl) via anchoring the imidazole ring to trityl-resins. Furthermore, Fmoc-His(Trt-®-OA1 can be a useful starting support for the preparation of diketopiperazine combinatorial libraries.