2254-25-3 4835-69-2 9,20-Didehydro-17-hydroxy-22-norajmalan-16-carboxylic acid methyl ester Ajmalan-16-carboxylic acid, 19,20-didehydro-1-demethyl-17-hydroxy-, methyl ester, (2alpha,17S,19E)- Quebrachidine