Structure-based design and synthesis of non-nucleoside, potent, and orally bioavailable adenosine deaminase inhibitors

We disclose optimization efforts based on the novel non-nucleoside adenosine deaminase (ADA) inhibitor, 4 (K-i = 680 nM). Structure-based drug design utilizing the crystal structure of the 4/ADA complex led to discovery of 5 (Ki = 11 nM, BA = 30% in rats). Furthermore, from metabolic considerations, we discovered two inhibitors with improved oral bioavailability [6 (K-i = 13 nM, BA = 44%) and 7 (K-i = 9.8 nM, BA = 42%)]. 6 demonstrated in vivo efficacy in models of inflammation and lymphoma.