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Chemical investigation of the nonpolar extract of soft coral Clavularia viridis resulted in isolation of five new prostanoids, designated as claviridic acids A-E (1-5, resp.), in addition to the known clavulones I-III. Their structures were determined on the basis of spectroscopic techniques, especially HR-ESI-MS, CD, and 2D-NMR experiments. The isolated marine prostanoids exhibited potent inhibitory effect on PHA-induced proliferation of peripheral blood mononuclear cells (PBMC), as well as significant cytotoxic activity against human gastric cancer cells (AGS).

We describe an efficient solid-phase synthesis of clavulones via the sequential coupling of the alpha- and omega-chains, involving two separate carbon-carbon bond-forming steps. The tetrahydropyranyl linker survived these reaction conditions and was cleaved without decomposing the unstable cross-conjugated dienones. Our methodology has allowed us to prepare six clavulone derivatives that are varied within the alpha-chain.

Two new marine prostanoids, preclavulone lactones I (1) and II (2) were isolated from the Okinawan soft coral, Clavularia viridis . Their structures were determined based on spectroscopic analysis and chemical synthesis from ( S )-malic acid. Preclavulone lactones with side chains having absolute configurations opposite to those of mammalian prostanoids could be recognized as key intermediates in biosynthesis of clavulones.

The present review is concerned with a group of prostanoids from soft corals, namely, clavulones and their congeners, as well as with related octadecanoids found in plants of the genus Chromolaena (Compositae). Known physiological properties of these prostaglandinlike fatty acids are discussed. Special attention is paid to published hypotheses on the biogenetic origin of clavulones and related fatty acids. According to a newly proposed biosynthetic route, acyclic a-ketols are metabolic precursors of cyclopentenolones.

In this review, questions of the isolation, biosynthesis, and total chemical synthesis of new marine prostanoids — clavulones, halogenovulones, and punaglandins — are considered.

Two new marine prostanoids, preclavulone lactones I (1) and II (2) were isolated from the Okinawan soft coral, Clavularia viridis . Their structures were determined based on spectroscopic analysis and chemical synthesis from ( S )-malic acid. Preclavulone lactones with side chains having absolute configurations opposite to those of mammalian prostanoids could be recognized as key intermediates in biosynthesis of clavulones.

The isolation, structure elucidation, biological activities, total synthesis, and biosynthesis of the marine prostanoids such as clavulones, chlorovulones and punaglandins are described. These marine prostanoids have unique structural features and show strong antileukemic activities. Owing to their biosynthetic route which is different from those of the mammalian prostaglandins, the marine prostanoids are recognized as a new series of arachidonic acid cascade.

A highly enantioselective synthesis of the (8S,12S)-enantiomer of preclavulone A and its methyl ester is described featuring the Julia protocol for installing the (Z)-double bond in the lower chain. This procedure is suitable for the preparation of labeled preclavulone analogues for biosynthetic studies on marine clavulones.

We describe the design and synthesis of alkylating reagents based on the structure of clavulones. They are composed of cross-conjugated dienone system and irreversibly reacted with two nucleophiles under mildly basic conditions via beta-elimination. Hydroxyl derivative 7b showed the highest reactivity toward thiols and showed the strongest cytotoxicity in Hela S3 cells among the three derivatives having a different protecting group at the tert-hydroxyl group.

Three marine prostanoids, 1, 2, and 3, were isolated from the extract of the Okinawan soft coral Clavularia viridis. The structures of these compounds were assigned based on the results of spectroscopic analysis. Compound 1 was shown to be preclavulone-A methyl ester, and this is the first isolation of the ester of preclavulone-A as a natural product. Preclavulone-A is proposed to be the key intermediate in the biosynthesis of marine prostanoids exemplified by clavulones in C. viridis. The new prostanoid 3 was suggested to be a biosynthetic intermediate from preclavulone-A to clavulones, and a possible biogenetic pathway via 3 is proposed.

The enantiomerically pure endo-cycloadduct (2) under bar obtained from the thermal Diels-Alder reaction of SR-(1-menthyloxy)-2(5H)-furanone with cyclopentadiene is converted into (+)-tricyclo[5.2.1.0(2,6)]decadi-4,8-en-3-one ((+)-(1) under bar) in a one-pot procedure via ring-opening with lithium methyl dimethylphosphonate followed by an intramolecular Wittig-Horner-Emmons reaction in THF. The use of LiBr as additive in this step is highly beneficial to the formation of (1) under bar. (C) 1997 Published by Elsevier Science Ltd.

Absolute configurations at the C-4 and -12 positions of a new type of prostanoids clavulone I ( 1 ), II ( 2 ) and III ( 3 ), isolated from Clavularia viridis Quoy and Gaimard, have been elucidated on the basis of chemical and spectral evidence.

An enantioselective and stereoselective synthesis of novel marine prostanoids clavulone II (1) and 12-O-desacetylclavulone II (2) has been accomplished.

A cell-free homogenate of Clavularia viridis converts tritiated arachidonic acid into a new eicosanoid identified as 4 (free acid) by chemical and chromatographic studies in comparison with synthetic substances. The isolation of 4 suggests a novel, non-prostanoid type pathway for the biosynthesis of the clavulones.

New marine eicosanoid clavulones (claviridenones) were synthesized from the Corey lactone and D -glutamic acid.

Three new prostanoids, clavulone I( 1 ), II( 2 ) and III( 3 ), were isolated from the Japanese Stolonifer Claularia viridis Quoy and Gaimard. The structures of these prostanoids were determined on the basis of spectral data and chemical reactions.

Total synthesis of clavulones in naturally occurring form has been accomplished by the aldol coupling of the hydroxy-cyclopentenone 2 efficiently obtainable from 1,2-bis-trimethylsilyloxycyclopentene ( 4 ) by using 1,3-hydroxy transposition via the allylic methanesulfonate 11 and the α,β-unsaturated aldehyde 3 .

On prepare la clavulone I et son isomere 5,6-(E), analogues des prostaglandines, a partir du cyclopentadienure de lithium et du iodo-1 octyne-2

The biosynthesis of the newly discovered clavulones is suggested to proceed from arachidonic acid by a novel pathway, outlined in chart I, involving an unbroken series of 10 free radical intermediates and an uptake of 3 O2 molecules.

On prepare la clavulone I et son isomere 5,6-(E), analogues des prostaglandines, a partir du cyclopentadienure de lithium et du iodo-1 octyne-2