7-(2-(2-amino-4-thiazolyl)-4-carboxy-2-butenoylamino)-3-cephem-4-carboxylic acid
(+)-(6R,7R)-7-((Z)-2-(2-amino-4-thiazolyl)-4-carboxycrotonamido)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid