17660-28-5 18530-66-0 22728-83-2 23-Hydroxy-22beta(Z)-((2-methyl-1-oxo-2-butenyl)oxy)-3-oxo-4beta-olean-12-en-28-oic acid 561-47-7 Crotonic acid, 2-methyl-, 22-ester with 22beta,24-dihydroxy-3-oxoolean-12-en-28-oic acid, (Z)- Icterogenin Olean-12-en-28-oic acid, 22beta,24-dihydroxy-3-oxo-, 22-(2-methylcrotonate), (Z)- Olean-12-en-28-oic acid, 23-hydroxy-22-(((2Z)-2-methyl-1-oxo-2-butenyl)oxy)-3-oxo-, (4beta,22beta)-