The invention provides novel compounds having the general formula: wherein R1, R2, R3 and R4 are as defined in the description and in the claims, as well as or pharmaceutically acceptable salts, or tautomerism isomers, or enantiomers, or diastereomers thereof. The invention also contains compositions including the compounds and methods of using the compounds.本發明提供具有以下通式之新穎化合物，□其中R1、R2、R3及R4係如說明書及申請專利範圍中所定義；以及或其醫藥上可接受之鹽、或互變異構性異構物、或對映異構物或非對映異構物。本發明亦含有包括該等化合物之組合物及使用該等化合物之方法。
