Towards new neuroprotective agents: design and synthesis of 4H-thieno[2,3-c] isoquinolin-5-one derivatives as potent PARP-1 inhibitors.

An excessive activation of poly(ADP-ribose) polymerase-1 (PARP-1), a nuclear enzyme able to catalyze the transfer of ADP-ribose from NAD to acceptor proteins, is involved in the progression of neuronal damage after brain insult. Potent and selective PARP-1 inhibitors have neuroprotective properties in experimental models of brain ischemia. As a follow up of our previous structure-activity relationship study and in search for novel potent PARP-1 inhibitors, a series of 4H-thieno[2,3-c]-isoquinolin-5-one derivatives was designed and synthesized. Tested for their ability to inhibit PARP-1, these novel derivatives showed high inhibitory potency. The unsubstituted derivative TIQ was selected for further characterization and found to be endowed with strong neuroprotective properties in models of cerebral ischemia.