本發明提供了一種如化學式(I)所示之化合物:其中R1 、R2 、R3 、R4 、R5 、以及X係於此定義。此外,本發明更揭露了該些化合物之醫藥組成物以及使用其之方法。Compounds of formula (I): wherein R1 , R2 , R3 , R4 , R5 , and X are defined herein. Also disclosed are pharmaceutical compositions and methods related to use of these compounds.