trans-Ceftibuten

7β-[[(E)-2-(2-Amino-4-thiazolyl)-4-carboxy-1-oxo-2-butenyl]amino]cepham-3-ene-4-carboxylic acid

(6R,7R)-7α-[[(E)-2-(2-Amino-4-thiazolyl)-4-carboxy-1-oxo-2-butenyl]amino]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid