A two-directional approach to pyrrolizidines: total syntheses and biological evaluation of alkaloid cis-223B and (+/-)-xenovenine

Total syntheses of alkaloid cis-223B and xenovenine are reported in 3 and 4 steps respectively using a two-directional synthesis/triple reductive amination strategy, and their neurotoxic properties assessed

Cytotoxic Cembranes from Indonesian Specimens of the Soft Coral Nephthea sp

Methanol extracts of two specimens of the soft coral Nephthea sp. collected from the Seribu Islands, Indonesia, were active in an anticancer bioassay. One new (1) and four known diterpenes (2–5) based on the cembrane carbon skeleton were isolated from these extracts, as was arachidonic acid (8). The structures of all compounds were elucidated using NMR, including 1,1-ADEQUATE and 1D gradient selective NOESY where applicable to determine the relative stereochemistry. Spectroscopic data, including 1H and 13C NMR, UV, IR and optical rotations are reported when enough material was available and where this has not been done previously. Inhibition assays employing three cancer cell lines; SF-268 (CNS), MCF-7 (breast), and H460 (lung) were used to guide the isolation of all compounds

Soft Coral Sarcophyton (Cnidaria: Anthozoa: Octocorallia) Species Diversity and Chemotypes

Research on the soft coral genus Sarcophyton extends over a wide range of fields, including marine natural products and the isolation of a number of cembranoid diterpenes. However, it is still unknown how soft corals produce this diverse array of metabolites, and the relationship between soft coral diversity and cembranoid diterpene production is not clear. In order to understand this relationship, we examined Sarcophyton specimens from Okinawa, Japan, by utilizing three methods: morphological examination of sclerites, chemotype identification, and phylogenetic examination of both Sarcophyton (utilizing mitochondrial protein-coding genes MutS homolog: msh1) and their endosymbiotic Symbiodinium spp. (utilizing nuclear internal transcribed spacer of ribosomal DNA: ITS- rDNA). Chemotypes, molecular phylogenetic clades, and sclerites of Sarcophyton trocheliophorum specimens formed a clear and distinct group, but the relationships between chemotypes, molecular phylogenetic clade types and sclerites of the most common species, Sarcophyton glaucum, was not clear. S. glaucum was divided into four clades. A characteristic chemotype was observed within one phylogenetic clade of S. glaucum. Identities of symbiotic algae Symbiodinium spp. had no apparent relation to chemotypes of Sarcophyton spp. This study demonstrates that the complex results observed for S. glaucum are due to the incomplete and complex taxonomy of this species group. Our novel method of identification should help contribute to classification and taxonomic reassessment of this diverse soft coral genus

The soft coral community on a sheltered reef quadrat at Laing Island (Papua New Guinea)

Thirty-one species of soft corals have been found on a 30×20 m quadrat on the sheltered shore of Laing Island, on the north coast of Papua New Guinea. Their contribution to the living coverage has been quantified, with special attention to zonation. The observed distribution patterns are discussed and the importance of vegetative propagation for some of the species is stressed. © 1982 Springer-Verlag.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Chemical studies of marine invertebrates-XX. The structures of the genuine aglycones of thelothurins A and B, defensive saponins of the indo-pacific sea cucumber Thelonota ananas Jaeger (Echinodermata)

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Combining two-directional synthesis and tandem reactions, part 11: second generation syntheses of (±)-hippodamine and (±)-epi-hippodamine

Background<p>Hippodamine is a volatile defence alkaloid isolated from ladybird beetles which holds potential as an agrochemical agent and was the subject of a synthesis by our group in 2005.</p><p>Results</p><p>Two enhancements to our previous syntheses of (±)-hippodamine and (±)-epi-hippodamine are presented which are able to shorten the syntheses by up to two steps.</p><p>Conclusions</p><p>Key advances include a two-directional homologation by cross metathesis and a new tandem reductive amination / double intramolecular Michael addition which generates 6 new bonds, 2 stereogenic centres and two rings, giving a single diastereomer in 74% yield.</p

Chemical studies of marine invertebrates. VIII africanol, an unusual sesquiterpene from Lemnalia africana (Coelenterata, Octocorallia, Alcyonacea).

SCOPUS: ar.jinfo:eu-repo/semantics/publishe