1 BTH 4-oxo-3-{6-[4-(quinoxalin-2-ylamino)-benzoylamino]-2-thiophen-2-yl-hexanoylamino}-pentanoic acid 1.000 2 4QB 3-{2-ethyl-6-[4-(quinoxalin-2-ylamino)-benzoylamino]-hexanoylamino}-4-oxo-butyric acid 0.814