Ampicillin(Piperacillin EP Impurity A, Sultamicillin EP Impurity C) CAS No:69-53-4 ||Chemical Formula:C16H19N3O4S ||Molecular Weight:349.40500 ||Exact Mass:349.10963 ||(2S,5R,6R)-6-((R)-2-amino-2-phenylacetamido)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid