The invention provides novel compounds having the general formula (I) wherein R1, R2, R3, R4, W, A and B are as described herein, compositions including the compounds and methods of using the compounds.本發明提供新穎的具有通式(I)之化合物其中R1、R2、R3、R4、W、A及B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。