本發明係有關於一種下式之化合物: 其中R、R1 、R2 、R3 、R4 、R5 、R6 、R7 、R8 、及X如內文定義。本發明亦揭露一種以此種化合物有效抑制纖維母細胞活化蛋白或治療癌症或發炎情況之方法。A compound of the following formula: wherein R, R1 , R2 , R3 , R4 , R5 , R6 , R7 , R8 , and X are as defined herein. Also disclosed is a method for inhibiting actively of fibroblast activation protein 或 for treating cancer 或 inflammation conditions with such a compound.