tert-butyl 2-[(Z)-[2-[[(2R,3S)-2-[(2-hydroxyethylamino)methyl]-4-oxoazetidin-3-yl]amino]-1-[2-[(2-methylpropan-2-yl)oxycarbonylamino]-1,3-thiazol-4-yl]-2-oxoethylidene]amino]oxy-2-methylpropanoate