Kaurenoid Diterpenoids

The synthesis of some 18-norkaurene-15-carboxylic acids from 4[3,18-norkaurene-3-one has been described82 as has the synthesis of 15-carboxykaurene.83 The preparation of a series of fluorinated kaurenoids, including 16,16-difluoro-17-norkauran-19-oic acid from xylopic acid, has been described.84 Ruboside, from 

Murakami, N. Tanaka, H. Iida, and Y. Iitaka, Chem. Pharm. Bull., 1981, 29, 773. 

Although a number of Isodon species have been reclassified as Rabdosia (Labiatae) species, their similarity is revealed by the highly hydroxylated kaurenoids which they contain. Effusin, which was isolated from R. effusus and shown to inhibit insect growth, possesses90 the unusual spiro-secokaurene structure (50). A 

The structures of the leukamenins I—VI (58)—(63), which were isolated from R. umbrosia, were established94 by spectral studies and a series of chemical correlations. The glycosides shikokiasides A (64) and B (65), from R. shikokiana, have a similar oxygenation pattern.95 

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Kaurenoid Diterpenoids.—ent-1 la-Acetoxykaur-16-en-15-one and its dihydroderivative have been obtained from the liverwort Jungermannia infusca. ent-Kaur-16-en-19-oic acid has been detected in a number of Stevia (Compositae) species, and ent-3j8-acetoxy- and ent-lla-acetoxy-kaur-16-en-19-oic acids have been isolated from Helichrysum cooperii (Compositae). ent-16/8-Hydroxy-... 

Kaurenoid Diterpenoids Beyerene Diterpenoids Atiserene Diterpenoids Trachylobane Diterpenoids Gibberellins Grayanotoxins Diterpenoid Alkaloids... 

There are two types of 6,7-seco-ent-kaurenoid diterpenoids. One has a C-7,20-lactone moiety (spiro-lactone type) and the other a C-1, 7-lactone moiety. The discrimination of these two... 

The carbon skeleton of the ent-kaurenoid precursors of the gibberellins is closely related to that of the diterpenoids of the ent-atiserene (10.29), ent-beyerene (10.30) and ent-trachylobane (10.31) series. The dilferences lie in the structure of ring D. The flexibility of the gibberellin biosynthetic pathway in... 

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