Triterpenoid analogues

The hydroxylation of triterpenols to the corresponding diols in the flowers of Calendula officinalis apparently occurs exclusively in the chromoplasts, " and the triterpenol ester is substrate. The formation of triterpenoid analogues of carotenoids... 

Many glycosidase inhibitors are structurally related to natural substrates, closely resembling carbohydrates. However, several exceptions to this generalization are known. These include such diverse structures as the diterpene andrographolide and its analogues (38, Scheme 12),134 3,21-di-O-acetylcichoridiol (39, a triterpenoid),135 acridone alkaloids, and oriciacridone (40).136... 

Other common plant-derived triterpenoid acids, such as oleanolic and ursolic acid, exhibit weak antiinflammatory and antitumor activities, and studies have been directed at the synthesis of new analogues having increased potencies. These studies have led to the synthesis of 2-cyano-3,12-dioxoolean-l,9-dien-28-oic acid (CDDO) (54) and its methyl ester (55), which exhibit potent in vitro and in vivo antitumor activity against a wide range of tumors, including breast and pancreatic carcinomas and leukemias. ... 

The successful preparation of angeloyl chloride has been utilized in the partial synthesis of the hepatoxic triterpenoid lantadene A (167) from the diphenyl-methyl ester (168) of 22/3-hydroxyoleanolic acid. " Several analogues of lantadene A have also been made. Reaction of 22/8-hydroxyoleanolic acid with dicyclohexylcarbodi-imide afforded " the j8-lactone (169) [see (146) above]. Forced Wolff-Kishner reduction of the 19-oxo-olean-12-ene derivatives (170) and (171) yielded the corresponding 13aH-olean-18-ene products (172) and... 

Kuo RY, Qian K, Morris-Natschke SL, Lee K-H (2009) Plant-derived triterpenoids and analogues as antitumor and anti-HIV agents. Nat Prod Rep 26 1321-1344... 

Laird, W., F. S. Spring, and R. Stevenson Triterpenoids. Part LVIII. The Synthesis of Isoursenol, the Ursane Analogue of Taraxerol. J. Chem. Soc. 1961, 2638. 

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