12-Amino-15,18,21,24,27-pentakis(4-((2-(((benzyloxy)carbonyl)amino)-4-methylpentanoyl)amino)butyl)-5-isobutyl-3,6,13,16,19,22,25-heptaoxo-1-phenyl-2-oxa-4,7,14,17,20,23,26-heptaazaoctacosan-28-oic aci\td AIDS-144921 AIDS144921 NSC668446