3,3-Dimethyl-7-oxo-6-[2-phenyl-2-(5-propyl-6-thioxo-[1,3,5]thiadiazinan-3-yl)-ethanoylamino]-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid AIDS-016754 AIDS016754 NSC649774