The invention provides novel compounds having the general formula (I) wherein R1, R2, R3, R4, R5, R6 and n 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n如本文中所描述,包括該等化合物之組合物,及該等化合物之使用方法。