Synthesis and biological evaluation of pyrrolopyridazine derivatives as novel HER-2 tyrosine kinase inhibitors.

Abstract A series of novel pyrrolopyridazine derivatives have been discovered to be HER-2 inhibitors. These compounds selectively inhibited HER-2 kinase activity at low nanomolar concentrations. Compound 7d was identified as a potent HER-2 inhibitor with an IC 50 of 4 nM.