The invention provides novel compounds having the general formula (I) wherein R1, R2, R3, R4, R5, R6, R7, R8 and R9 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、R8及R9係如本文描述,包括該等化合物之組合物及使用該等化合物之方法。