Antimycin A5

8-ethyl-3-(3-formamidosalicylamido)-2,6-dimethyl-4,9-dioxo-1,5-dioxonan-7-yl isovalerate

3-Methylbutyric acid 8-ethyl-3-[(3-formylamino-2-hydroxybenzoyl)amino]-2,6-dimethyl-4,9-dioxo-1,5-dioxonan-7-yl ester