The invention relates to compounds of formula (A):or a salt thereof, wherein R1, R2, R5a, R5b, R6a, R6b, R7a, R7b, R8a, R8b, R9a, R9b, R10a, R10b, R11a, R11b, R21, n, and G are as described herein. Compounds of formula (I) and pharmaceutical compositions thereof are αVβ6integrin inhibitors that are useful for treating fibrosis such as idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP).本發明係關於式(A)化合物，或其鹽，其中R1、R2、R5a、R5b、R6a、R6b、R7a、R7b、R8a、R8b、R9a、R9b、R10a、R10b、R11a、R11b、R21、n及G係如本文所闡述。式(I)化合物及其醫藥組合物係αVβ6整聯蛋白抑制劑，其可用於治療纖維化，例如特發性肺纖維化(IPF)及非特異性間質性肺炎(NSIP)。
