The invention provides novel compounds having the general formula (I) wherein R1, R2, R3, R4, R5, R6 and R7 are as described herein, compositions including the compounds and methods of using the compounds.本發明提供新穎化合物,其具有通式(I)其中R1、R2、R3、R4、R5、R6及R7係如本文中說明,包含該等化合物之組合物及使用該等化合物之方法。