AIDS-170439 AIDS170439 N-{(1S)-2-[(5S,1R)-6-(2-Methylpropanoyl)-7-oxo-2,6-diazaspiro[bicyclo[3.3.0]octane-8,1'-cyclobutane]-2-yl]-1-(methylethyl)-2-oxoethyl}(tert-butoxy)carboxamide