(18β and 18a)-2a-Cyano-3,11-dioxo-olean-12-en-29-oic acids and lower-alkyl esters thereof, useful as ulcer preventing and ulcer healing agents, are prepared from 18β- or 18a-glycyrrhetinic acid, the final step being alkaline cleavage of 18β- or 18α-11-oxo-olean-2,12-dieno[2,3-djisox-azol-29- oic acid followed by optional acidification of the basic salt obtained and optional esterification of the free acid thus obtained.
(18β和18a)-2a-
氰基-3,11-二氧代-油环-12-烯-29-酸及其低级烷基酯,可作为溃疡预防剂和溃疡愈合剂,由18β-或18a-
甘草次酸制备、最后一步是碱性裂解 18β- 或 18α-11- 氧代-2,12-二烯并[2,3-二
异噁唑-29-酸,然后任选酸化得到的碱性盐,并任选酯化由此得到的
游离酸。