34279-51-1 5-Thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid, 7-(5-amino-5-carboxyvaleramido)-3-(hydroxymethyl)-7-methoxy-8-oxo-, carbamate (ester), monosodium salt 842-A A-16886-I Antibiotic 842 A Cephamycin C sodium Cephemimycin P-6621 WS-3442-C