5,17-Dibenzyl-11-(4-((tert-butoxycarbonyl)amino)butyl)-14-(1-tert-butoxyethyl)-8-(1H-indol-3-ylmethyl)-3,6,9,12,15-pentaoxo-1-phenyl-2-oxa-4,7,10,13,16-pentaazaoctadecan-18-oic acid AIDS-146273 AIDS146273 NSC672652