The present invention relates to a compound of Formula (I)-(IV) useful as ²-lactamase inhibitor, a pharmaceutically acceptable salt, ester, solvate or stereoisomer thereof, wherein R 1 , R 2 , M and ring A have definitions as those in the specification. The present invention further relates to methods for preparing these compounds, pharmaceutical compositions comprising these compounds, and uses of these compounds. For example, the compounds of the present invention can be used as ²-lactamase inhibitors, for treatment and/or prophylaxis of diseases caused by bacterial infections, solving drug-resistance problems caused by ²-lactamases, especially bacterial drug-resistant diseases caused by type B metallo-²-lactamases.本發明涉及通式(Ⅰ)所示的可用作β-內醯胺酶抑制劑的化合物、其藥學上可接受的鹽、其酯以及其立體異構體，其中R1、R2、M、環A如說明書中所定義。本發明還涉及這些化合物的製備方法，以及這些化合物的用途。例如，本發明的化合物可以用作β-內醯胺酶抑制劑，用於治療和/或預防細菌感染性疾病，解決由β-內醯胺酶引起的細菌耐藥性問題，特別是B類金屬β-內醯胺酶導致的細菌耐藥疾病。
