7-[2-(5-Isopropyl-6-thioxo-[1,3,5]thiadiazinan-3-yl)-2-phenyl-ethanoylamino]-3-methyl-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid AIDS-016753 AIDS016753 NSC649773