(3aS,9aS,9bR)-3a-metil-6-[2-(2,5,5-trimetil-1,3-dioksan-2-il)etil]-1,2,4,5,8,9,9a,9b-oktahidro-3aH-ciklopenta[a]naftalen-3,7-dion
(25S)-25-cyklohexyl-25-de(sek-butyl)-5-O-demetyl-22,23-dihydroavermectin A1a