The molecule is one of three naturally occurring cephamycin antibiotics, differing from the A and B forms in its carbamoyloxymethyl substituent at C-3.
(6R,7S)-7-[[(5R)-5-amino-5-carboxypentanoyl]amino]-3-(carbamoyloxymethyl)-7-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid