The present invention provides for compounds of formula (I) wherein R1, R2, R6, Y1, Y2, Y3, A1, A2, A3, and A4 have any of the values defined in the specification, and pharmaceutically acceptable salts thereof, that are useful as agents in the treatment of diseases and conditions, including inflammatory diseases, cancer, and AIDS. Also provided are pharmaceutical compositions comprising one or more compounds of formula (I).本發明提供式(I)化合物其中R1、R2、R6、Y1、Y2、Y3、A1、A2、A3及A4具有本說明書中所定義之任何值,及其醫藥學上可接受之鹽,其等適用作治療疾病及病狀之藥劑,該等疾病及病狀包括發炎性疾病、癌症及AIDS。本發明亦提供包含一或多種式(I)化合物之醫藥組合物。