With the goal of improving metabolic stability and further enhancing FBPase inhibitory activity, a series of tricyclic 8H-indeno [1, 2-d][1, 3] thiazoles was designed and synthesized with the aid of structure-based drug design. Extensive SAR studies led to the discovery of 19a with an IC50 value of 1nM against human FBPase. X-ray crystallographic studies revealed that high affinity of 19a was due to the hydrophobic interaction arising from better ...