Design and synthesis of cyclic sialyl Lewis X mimetics: a remarkable enhancement of inhibition by pre-organizing all essential functional groups

Two rigid macrocyclic glycopeptides 1 and 2 were designed to mimic the tetrasaccharide SLeX as inhibitors of P-selectin. While compound 1 was found to be 1000-fold more potent than SLeX with IC50=1 μM, compound 2 was not soluble in water for evaluation of its activity.