Compounds in accord with Formula I:wherein R1, R2, R3and R4are as defined in the specification, pharmaceutically acceptable salts, methods of making, pharmaceutical compositions containing and methods for using the same.一種通式I化合物:其中R1、R2、R3及R4係如說明書之定義,及醫藥上可接受之鹽,其製造方法,包含其之醫藥組合物及其使用方法。