The present invention provides for compounds of formula (I) wherein R1, R2, R6, Y1, Y2, 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、A1、A2、A3及A4具有說明書中所定義之值中之任一者,及其醫藥上可接受之鹽,其可用作治療包含發炎疾病、癌症及AIDS之疾病及病狀之藥劑。亦提供包括一或多種式(I)化合物之醫藥組合物。