6-[2-(5-Isopropyl-6-thioxo-[1,3,5]thiadiazinan-3-yl)-2-phenyl-ethanoylamino]-3,3-dimethyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid AIDS-016755 AIDS016755 NSC649775