Provided herein are small molecule inhibitors of maternal embryonic leucine zipper kinase (MELK) having the structure of formula (I), wherein X and R1-R3 are defined in the specification. The compounds are useful for treating cancer and other conditions or diseases associated with aberrant MELK expression. Also provided herein are pharmaceutical compositions comprising a compound of formula (I) and a pharmaceutically acceptable carrier. The invention also provides methods of treating cancers associated with over-expression of MELK.
