The invention provides novel compounds having the general formula (I) wherein R1, R2, R3, R4, R5, R6, R7, A1, A2 and A3 are as described herein, compositions including the compounds and methods of using the compounds.本發明提供具有通式(I)之新穎化合物:其中R1、R2、R3、R4、R5、R6、R7、A1、A2及A3係如本文中所述;包括該等化合物之組合物,及使用該等化合物之方法。