(1′R,2S,4′S,5S,6R,8′R,10′E,12′S,13′S,14′E,16′E,20′R,21′R,24′S)-12′,24′-Dihydroxy-6-isopropyl-21′-methoxy-5,11′,13′,22′-tetramethyl-5,6-dihydro-2′H-spiro[pyran-2,6′-[3,7,19]trioxatetracyclo[15.6.1.1~4, 8~.0~20,24~]pentacosa[10,14,16,22]tetraen]-2′-one

(1′R,2S,4′S,5S,6R,8′R,10′E,12′S,13′S,14′E,16′E,20′R,21′R,24′S)-12′,24′-Dihydroxy-6-isopropyl-21′-methoxy-5,11′,13′,22′-tetramethyl-5,6-dihydro-2′H-spiro[pyran-2,6′-[3,7,19]trioxatetracyclo[15.6.1.1~4, 8~.0~20,24~]pentacosa[10,14,16,22]tetraen]-2′-one

Avermectin A1b aglycone