Selective inhibitor of JNK2 and JNK3 (pIC50 values are 6.7, 6.5, <5.0 and <4.8 for JNK3, JNK2, JNK1 and p38α respectively). Displays no significant activity at a range of other protein kinases including EGFR, ErbB2, cdk2, PLK-1 and Src (pIC50 < 5.0). Purity 99%. MW (observed): 332.42