Adriadysiolide, the First Monoterpenoid Isolated from a Marine Sponge

Abstract

Spectra and chemical transformations allow to establish the gross structure 6,7‐epoxy‐4,7‐dimethyl‐l‐oxa‐spiro[4.4]non‐3‐en‐2‐one for adriadysiolide (1), the first monoterpenoid isolated from a marine sponge, a Dysidea sp. of the Adriatic Sea. Its configuration 5R*, 6S*, 7S* as given in 1a is derived from diastereoselective total syntheses of both 1a and its diastereoisomer 1b via stereochemically predictable peracid epoxidations of olefinic precursors. Thus, OH assistance in allylic alcohol 8 leads to oxirane 13 which is subjected to methyl cuprate conjugate addition to give epiadriadysiolide (1b), whilst electronic deactivation by a neighboring heterocyclic O‐atom in intermediate 5, derived from 8 mainly leads to adriadysiolide (1a). Comparative 1H‐NMR shift‐reagent effects with 1a and 1b, evaluated with the aid of molecular‐mechanics calculations, support these conclusions.

A New Brominated Diphenyl Ether from a Philippine Dysidea Species

“…The tic of this material showed a single uv-active spot, but the 'Hnmr spectrum indicated the presence of two compounds. A major portion of the material was separated by hplc on Partisil into two fractions that consisted of 2-(2'-bromophenoxy)-3,4,5,6-tetrabromophenol [1] (66 mg., 2% dry wt) and 2-(2' ,4' -dibromophenoxy)-3,4,5,6-tetrabromophenol [2] (10 mg., 0.3% dry wt).…”

“…Sponges of the genus Dysidea are renowned for the variability of their chemical constituents, which include an unusual aziridine (1), monoterpenes (2), sesquiterpenes (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), diterpenes (21)(22)(23), meroterpenoids (24)(25)(26)(27)(28)(29)(30)(31)(32), polyhydroxy lated sterols and secosterols (33)(34)(35)(36)(37)(38), polychlorinated metabolites derived from amino acids (39-46), and polybrominated diphenyl ethers (47)(48)(49)(50)(51). Although terpenoids are found in both temperate and tropical species, the polyhalogenated metabolites appear to be limited to tropical species of Dysidea that coincidentally contain large populations of cyanophytes within their tissues.…”

“…Specimens of an unidentified species of Dysidea were collected by hand using scuba at a depth of 20 m near San Jose, Batangas, Philippines. The nonpolar material from an MeOH extract of the [2] (0.3% dry wt). 2-(2',4'-Dibromophenoxy)-3,4,5,6-tetrabromophenol [2] was identified by comparison of the spectral data with those reported by Utkina et al (51).…”

“…The nonpolar material from an MeOH extract of the [2] (0.3% dry wt). 2-(2',4'-Dibromophenoxy)-3,4,5,6-tetrabromophenol [2] was identified by comparison of the spectral data with those reported by Utkina et al (51). The corresponding methyl ethers 3 and 4, prepared by treating an Et20 solution of the intermediate mixture of phenols with ethereal CH2N2 solution, were easily separated by Si gel chromatography.…”