The present invention encompasses compounds of general formula (I) wherein the groups R1 to R3, X3 to X6 have the meanings given in the claims and in the specification. The compounds of the invention are suitable for the treatment of diseases characterized by excessive or abnormal cell proliferation pharmaceutical preparations containing such compounds and their uses as a medicament.本發明包括通式(I)之化合物其中基團R1至R3、X3至X6具有申請專利範圍及說明書中指定之含義。本發明之化合物適用於治療特徵在於過度或異常細胞增殖之疾病,含有此類化合物之醫藥製劑及其作為藥劑之用途。
