(6R-trans)-7-Amino-3-(((5-methyl-1,3,4-thiadiazol-2-yl)thio)methyl)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid 30246-33-4 7-AMINO-3-((5-METHYL-1,3,4-THIAZOL-2-YL)-THIOMETHYL)-CEPH-3-EM-4-CARBOXYLIC ACID EINECS 250-099-1