Structure-Activity Relationship Studies of Substituted 2-(Isoxazol-3-yl)-2-oxo-N '-phenyl-acetohydrazonoyl Cyanide Analogues: Identification of Potent Exchange Proteins Directly Activated by cAMP (EPAC) Antagonists

摘要

Exchange proteins directly activated by cAMP (EPAC) as guanine nucleotide exchange factors mediate the effects of the pivotal second messenger cAMP, thereby regulating a wide variety of intracellular physiological and pathophysiological processes. A series of novel 2-(isoxazol-3yl)-2-oxo-N'-phenyl-acetohydrazonoyl cyanide EPAC antagonists was synthesized and evaluated in an effort to optimize properties of the previously identified high-throughput (HTS) hit 1 (ESI-09). Structure activity relationship (SAR) analysis led to the discovery of several more active EPAC antagonists (e.g., 22 (HJC0726), 35 (NY0123), and 47 (NY0173)) with low micromolar inhibitory activity. These inhibitors may serve as valuable pharmacological probes to facilitate our efforts in elucidating the biological functions of EPAC and developing potential novel therapeutics against human diseases. Our SAR ring as well as the 5-position of the results have also revealed that further modification at the 3-, 4-, and 5-positions of the phenyl isoxazole moiety may allow for the development of more potent EPAC antagonists.