Bioactive diterpenoids

Barriault developed a new pericyclic domino process for the synthesis of the bioactive diterpenoid vinigrol (4-262), which was isolated from Vtrgaria nigra [92]. The natural product possesses antihypertensive and anti-platelet-aggregating properties. 4-262 contains a unique tricyclo [4.4.4.04a8a]tetradecane framework, which could be obtained by a combination of an oxy-Cope, a Claisen and an ene reaction... 

Phenylbutenoid dimers from the rhizomes of Zingiber cassumunar. Phytochemistry 1993 32(2) 357-363. ZO082 Ayafor, J. F., M. H. K. Tchuendem, B. Nyasse, F. Tillequin, and H. Anke. Aframodial and other bioactive diterpenoids from Aframomum species. Pure Appl Chem 1994 66(10/11) 2327-2330. 

Paul, V. J. and Fenical, W., Bioactive diterpenoids from tropical marine algae of the genus Halimeda (Chlorophyta), Tetrahedron, 40, 3053, 1984. 

NOVEL DOMINO REACTIONS FOR SYNTHESIS OF BIOACTIVE DITERPENOIDS AND ALKALOIDS... 

Scoparia dulcis was found to be one of attractive natural resources producing unique bioactive diterpenoids. 

Similarly, the bicyclo[2.2.2]octene double bond in 28 was readily opened in a domino ROM/double RCM process, leading to tricyclic bisenone 29 with catalyst 2 under ethylene atmosphere in good overall yield from dialdehyde 27 (Scheme 2.11) [7]. Compound 29 was successfully utihzed as the key intermediate in a total synthesis of the bioactive diterpenoid (-l-)-cyanthiwigin U. 

Bouaicha, N. et al. (1993) Bioactive diterpenoids isolated from Dilophus ligulatus. Planta Med. 59, 256-258... 

Grafting an electron-withdrawing group onto a dienic structure has important consequences on its reactivity therefore many methods have been proposed to access dienic esters, amides, nitriles, etc. The electron-deficiency induced on a diene not only reverses its behavior in cycloaddition reaction but also makes it a possible substrate for Michael additions. This well-known phenomenon has, for instance, been put into evidence in the recently isolated bioactive diterpenoid briareolate esters L-N where an ( ,Z)-dienone motive acts as a reversible spring-loaded acceptor [52]. 

Miyamoto, T., Yamada, K, Ikeda, N., Komori, T, and Higudii, R. (1994) Bioactive terpenoids from Octocorallia. I. Bioactive diterpenoids litophynols A and B from the mucus of the soft coral Litophyton sp. J. Nat. Prod., 57,1212-1219. 

Yamada, K. and Higuchi, R. (2001) Bioactive diterpenoids from Japanese soft corals, in Bioactive Compounds from Natural Sources (ed. C. Tringali), Taylor Francis, pp. 639-673. 

Andrographolide, a labdane-diterpenoid lactone, is the principal bioactive chemical constituent of Andrographis paniculata (Brum. F.) Nees (family Acanthaceae) this prime constituent is mainly concentrated in leaves and can easily be isolated from the crude plant extracts as crystalline... 

Guella, G., Dini, F., and Pietra, F., Epoxyfocardin and its putative biogenic precursor, focardin, bioactive, new-skeleton diterpenoids of the marine ciliate Euplotes focardii from Antarctica, Helv. Chim. Acta, 79, 439, 1996. 

In the area of natural product characterization, Wall and colleagues utilized 3 mm NMR probe capabilities in the characterization of novel bioactive clerodane diterpenoids from the leaves and twigs of Casearia sylvestris.149 The general structure of the three new clerodanes is shown by 72, the molecules differing in the length and branching of the alkyl side-chain substituent. 

Tanshinone diterpenoids, including tanshinone I (Gl) and tanshinone IIA (G2), are bioactive compounds from S. miltiorrhiza (71). Sodium tanshinone sulfate (G3) is a water-soluble derivative of G2, is used clinically to treat angina pectoris and myocardial infarction, and exhibits strong membrane-stabilizing effects on red blood corpuscles. In addition, novel seco-... 

Bioactivity of the diterpenoid alkaloids from A. naviculare has been assessed in a few instances. 

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