Revisiting the sponge sources, stereostructure, and biological activity of cyclocinamide a

Naturally Occurring Organohalogen Compounds-A Comprehensive Review

The present volume is the third in a trilogy that documents naturally occurring organohalogen compounds, bringing the total number-from fewer than 25 in 1968-to approximately 8000 compounds to date. Nearly all of these natural products contain chlorine or bromine, with a few containing iodine and, fewer still, fluorine. Produced by ubiquitous marine (algae, sponges, corals, bryozoa, nudibranchs, fungi, bacteria) and terrestrial organisms (plants, fungi, bacteria, insects, higher animals) and universal abiotic processes (volcanos, forest fires, geothermal events), organohalogens pervade the global ecosystem. Newly identified extraterrestrial sources are also documented. In addition to chemical structures, biological activity, biohalogenation, biodegradation, natural function, and future outlook are presented.

Application of the DP4 Probability Method to Flexible Cyclic Peptides with Multiple Independent Stereocenters: The True Structure of Cyclocinamide A

A DP4 protocol has been successfully utilized to establish the true structure of the natural product cyclocinamide A, a flexible cyclic peptide with four isolated stereocenters. Benchmarking the necessary level of theory required to successfully predict the NMR spectra of three previously synthesized isomers of cyclocinamide A led to the prediction of the natural stereochemistry as 4 S, 7 R, 11 R, 14 S, which has been confirmed by total synthesis.

Marine natural products

Covering: 2015. Previous review: Nat. Prod. Rep., 2016, 33, 382-431This review covers the literature published in 2015 for marine natural products (MNPs), with 1220 citations (792 for the period January to December 2015) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1340 in 429 papers for 2015), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Synthesis of indoles and tryptophan derivatives via photoinduced nitrene C–H insertion

Functionalized indoles and tryptophans can be obtained from stannylated alkenes and o-iodoanilines via Stille coupling.

Total Synthesis of Nominal Cyclocinamide B and Investigation into the Identity of the Cyclocinamides

The total synthesis of nominal cyclocinamide B, a cyclic peptide marine natural product, is reported together with an isomer of nominal cyclocinamide A. Initial attempts at the synthesis of the title compounds by inclusion of a turn inducer failed. However, direct synthesis succeeded in formation of the 14-membered cyclic peptide structure. Comparison of the data from all synthetic cyclocinamide A and B compounds with those of the natural products leads to the conclusion that the two natural products possess the same relative stereochemistry and that the true structures have not been defined.

Marine natural products

This review covers the literature published in 2012 for marine natural products, with 1035 citations (673 for the period January to December 2012) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1241 for 2012), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Total synthesis of nominal (11S)- and (11R)-cyclocinamide A

The cyclocinamides possess a unique β(2)αβ(2)α 14-membered tetrapeptide core. The initially reported biological data and intriguing structure, which was without full stereochemical identification, necessitated synthesis of both nominal (all-S) cyclocinamide A and the 11R isomer. The completed synthesis is highlighted by the use of a (cyclo)asparagine-containing dipeptide as a turn inducing fragment. Due to inconsistencies in analytical data between natural and synthetic samples, a re-evaluation of the natural product stereochemistry appears necessary.

A selective account of effective paradigms and significant outcomes in the discovery of inspirational marine natural products

Marine natural products continue to be a source of significant molecular structures that serve as a stimulus to seed further significant research. This account reviews some of the major advances in the study of marine biomolecules made at UC Santa Cruz over more than three decades. The continuing challenge of discovery and characterization of what we term "inspirational molecular structures" will be presented in a comprehensive fashion. Examples of privileged molecular structures and their impact on biomedicinal research will be an important theme. The three major groups of organisms explored include seaweeds, sponges, and marine-derived fungi, and the study of their active principles has greatly benefited from synergistic collaborations with both academic and biopharmaceutical groups. The concluding sections of this chronicle will touch on prospects for future outcomes involving new sources and strategies.