The molecule is the monocarboxylic acid anion formed by deprotonating carumonam at the carboxyl proton. It is a conjugate base of a carumonam.
2-[(Z)-[1-(2-amino-1,3-thiazol-4-yl)-2-[[(2S,3S)-2-(carbamoyloxymethyl)-4-oxo-1-sulfoazetidin-3-yl]amino]-2-oxoethylidene]amino]oxyacetate