7-[2-(4-Hydroxy-phenyl)-2-(5-isopropyl-6-thioxo-[1,3,5]thiadiazinan-3-yl)-ethanoylamino]-3-methyl-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid AIDS-016751 AIDS016751 NSC649771