Cephamycin A

O-Sulfocephamycin B

(6R,7S)-7α-[[(R)-5-Amino-5-carboxy-1-oxopentyl]amino]-7-methoxy-3-[[[2-methoxy-1-oxo-3-[4-(sulfooxy)phenyl]-2-propenyl]oxy]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid