1-[[(6R,7R)-7-[[(2Z)-(2-Amino-4-thiazolyl)[(1-carboxy-1-methylethoxy)imino] acetyl] amino]-2-carboxy-8-oxo-5-thia-1-azabicyclo[4.2.0] oct-2-en-3-yl]methyl]pyridinum hydroxide inner salt
(6R,7R)-3-[(4-Carbamoylpyridin-1-ium-1-yl)methyl]-8-oxo-7-[[(2R)-2-phenyl-2-sulfoacetyl]amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate
