AIDS-188371 AIDS188371 Spiro[cyclobutane-1,3'(2'H)-pyrrolo[3,2-b]pyrrol]-2'-one, 1'-(cyclopropylcarbonyl)hexahydro-4'-[(2S)-3-methyl-2-[[[(1-methylethyl)amino]carbonyl]amino]-1-oxobutyl]-, (3a'R,6a'S)-