Discovery of tetrahydro-beta-carbolines as inhibitors of the mitotic kinesin KSP.

Inhibitors of kinesin spindle protein (KSP) are a promising class of anticancer agents that cause mitotic arrest in cells from a failure to form functional bipolar mitotic spindles. Here, we report the synthesis and biological evaluation of a novel series of tetrahydro-beta-carboline analogs based on the structure of the known KSP inhibitor HR22C16. Preferred compounds 11b, 12a and 19b were identified as potent inhibitors in a KSP ATPase assay with good anti-proliferative activity in A549 cells.