Marine-derived diterpenoid

Diisocyanoadociane, a novel marine-derived diterpenoid, was analyzed retrosynthetically using the intramolecular Diels-Alder transform as T-goal concurrently with topological and stereochemical guidance. The enantioselective synthesis outlined below allowed assignment of absolute configuration. 

The total synthesis of the marine-derived diterpenoid sarcodictyin A was accomplished in the laboratory of K.C. Nicolaou. The most challenging part of the synthesis was the construction of the tricyclic core, which contains a 10-membered ring. This macrocycle was obtained by the intramolecular 1,2-addition of an acetylide anion to an a, 3-unsaturated aldehyde. This unsaturated aldehyde moiety was installed by utilizing the Knoevenagel condensation catalyzed by (3-alanine. The Knoevenagel product was exclusively the ( )-cyanoester. 

Sarcodictyins A 204 and B 205 are marine-derived diterpenoids with potential anti-cancer properties originally isolated by Pietra et al. from the Mediterranean stoloniferan coral Sarcodictyon roseum These compounds have similarities to Taxol on two fronts First, they are believed to exert their cytotoxic properties through microtubule stabilization, and second, they proved attractive to groups active in the art and science of total synthesis. To date, the groups... 

Frankincense, also called olibanum, is a natural oleo gum resin that exudes from incisions in the bark of Boswellia trees [46, 47]. Diterpenes like incensole or isoincensole and their oxide or acetate derivatives (see Figure 10.3) are characteristic biomarkers of olibanum [48]. Although diterpenoid hydrocarbons possessing the cembrane skeleton have been isolated from a variety of terrestrial and marine organisms, their occurrence and particularly that of cembrenes A and C (see Figure 10.3) is supplementary proof of the presence of olibanum in a sample. Optimisation of the SPME conditions was done with the aim of trapping these low volatile diterpenes. 

A large number of cembrane diterpenoids have been obtained from marine organisms, particularly soft corals. 2-Hydroxynephthenol (116) was isolated from Litophyton viridis. A dehydro-derivative (117) of epoxynephthenol was... 

Two diterpenoids, focardin (Structure 7.171) and an epoxide derivative (Structure 7.172), are produced by the marine ciliate Euplotes focardii, collected from Ross Sea coastal waters.195 Focardin is autotoxic and inhibits other ciliates, including one sympatric species, suggesting they are present... 

The diterpenoids constitute a large group of compounds derived from geranylgeranyl diphosphate. They are found in higher plants, fungi, insects and marine organisms. 

The red algae (Rhodophyta) are the most prolific sources of halogenated organics in the marine environment, and this topic was recently reviewed (Fenical, 1975). At least six orders, representing some ten families of red algae are now known to produce a wide variety of structure types from halo-methanes (C,) to halogenated products derived from squalene (C30). Within this group are aromatic and acyclic compounds produced from acetate (poly-ketide) biosynthesis and monoterpenes (Cio), sesqui- (Cu) and diterpenoids (C2o)- The structures of well over 200 compounds have now been firmly established. 

Gonzalez P, Marin C, Rodriguez-Gonzalez I et al (2005) In vitro activity of C20-diterpenoid alkaloid derivatives in promastigotes and intracellular amastigotes of Leishmania infantum. Int J Antimicrob Agents 25 136-141... 

A chiral homoallyl carbocation/cyclopropyl carbinyl carbocation system has been used to prepare ehiral derivatives of the marine natural product, spiniferin-1. Chiral acetals have been used to prepare optically active diterpenoids in biomimetic cationic cyclizations. ... 

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