9-hydroxy-3ξ-isopropyl-5-methyl-A,23,24,25-tetranor-5ξ,10ξ-urs-12-ene-27,28-dioic acid-27-lactone 在
氢氧化钾 、
potassium permanganate 作用下,
生成 9,13-dihydroxy-3ξ-isopropyl-5-methyl-11,12-dioxo-
A,23,24,25-tetranor-5ξ,10ξ,18ξ-ursane-27,28-dioic acid-27=>9;28=>13-dilactone