Compounds of formula I active on protein kinases are described, as well as methods of using such compounds to treat diseases and conditions associated with aberrant activity of protein kinases. Formula (I) wherein Ar is optionally substituted heteroaryl； R2 is hydrogen, lower alkyl or halogen； U is selected from the group consisting of &mdash；S(O)2&mdash；, &mdash；C(X)&mdash；, &mdash；C(X)&mdash；N(R10)&mdash；, and &mdash；S(O)2&mdash；N(R10)&mdash；； R3 is optionally substituted lower alkyl, optionally substituted C3.6 cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl or optionally substituted heteroaryl； and wherein R1, R3, R4, m, L1, X R10 are as described herein.
