Divalent and Multivalent Activation in Phosphate Triesters: A Versatile Method for the Synthesis of Advanced Polyol Synthons

This is the peer reviewed version of the following article: Thomas, C. D., McParland, J. P. and Hanson, P. R. (2009), Divalent and Multivalent Activation in Phosphate Triesters: A Versatile Method for the Synthesis of Advanced Polyol Synthons. Eur. J. Org. Chem., 2009: 5487–5500. doi:10.1002/ejoc.200900560, which has been published in final form at http://doi.org/10.1002/ejoc.200900560. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.The construction of mono- and bicyclic phosphate trimesters possessing divalent and multivalent activation and their subsequent use in the production of advanced polyol synthons is presented. The method highlights efforts to employ phosphate tethers as removable, functionally active tethers capable of multipositional activation and their subsequent role as leaving groups in selective cleavage reactions. The development of phosphate tethers represents an integrated platform for a new and versatile tether for natural product synthesis and sheds light on new approaches to the facile construction of small molecules

Natural Products from the Lithistida: A Review of the Literature since 2000

Lithistid sponges are known to produce a diverse array of compounds ranging from polyketides, cyclic and linear peptides, alkaloids, pigments, lipids, and sterols. A majority of these structurally complex compounds have very potent and interesting biological activities. It has been a decade since a thorough review has been published that summarizes the literature on the natural products reported from this amazing sponge order. This review provides an update on the current taxonomic classification of the Lithistida, describes structures and biological activities of 131 new natural products, and discusses highlights from the total syntheses of 16 compounds from marine sponges of the Order Lithistida providing a compilation of the literature since the last review published in 2002

Purification and structuaral studies of histone and histone associated proteins

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Franklinolidesa A - C from an Australian marine sponge complex: Phosphodiesters strongly enhance polyketide cytotoxicity

Rare discovery: Three novel polyketide phosphodiesters, franklinolidesa A-C, were identified as the cytotoxic components from an Australian marine sponge complex. Preliminary structure-activity relationship studies, using in vitro cytotoxicity and cell proliferation assays, demonstrated that the introduction of the phosphodiester moiety significantly improved the cytotoxicity by 30 to >300 fold

Water Based Synthesis of ZIF-8 Assisted by Hydrogen Bond Acceptors and Enhancement of CO2 Uptake by Solvent Assisted Ligand Exchange

The aim of this work was to synthesize zeolitic imidazolate framework-8 (ZIF-8) by an alternative method and then modify the surface properties for enhancing the CO2 adsorption performance. The ZIF-8 was synthesized by a water based synthesis method using 2-methyl imidazole (2-MeIM) as a hydrogen bond donor and quaternary ammonium salts (QAS) as a hydrogen bond acceptor. The optimal synthesis conditions were investigated by varying (i) the order of precursor mixing during the synthesis process (ii) different QAS (tetrabutyl ammonium bromide (TBAB), tetraethyl ammonium bromide (TEAB) and trimethyl phenyl ammonium bromide (TMPAB)) and (iii) the ratio between 2-MeIM and QAS. The results show that the optimal synthesis condition was using TMPAB as the hydrogen bond acceptor with the ratio between 2-MeIM and TMPAB of 8:2 and in the order of first mixing both hydrogen bond donor and acceptor before adding Zn(NO3)2⋅6H2O solution. TMPAB can provide uniform size distribution with the smallest particle sizes of ZIF-8. This can be explained by the higher hydrogen bond strength between hydrogen bond donor (2-MeIM) and hydrogen bond acceptor (TMPAB) when compared with that of the rest of two QAS. The synthesized ZIF-8 was modified by solvent-assisted ligand exchange methods. The organic linker of ZIF-8 (2-MeIM) was exchanged by 2-aminobenzimidazole (2-NH2bZIM) and 2-phenylimidazole (2-PhIM). The CO2 uptake of modified ZIF-8 was enhanced upon exchanging with 2-NH2bZIM. The increase in CO2 uptake was due to an additional interaction between CO2 and exchanged imidazole linker and an increase in surface properties (higher surface area, pore size and pore volume)

Antimalarial and cytotoxic constituents of <i>Xylaria</i> cf. <i>cubensis</i> PK108

<p><i>Xylaria</i> cf. <i>cubensis</i> PK108 was identified by its distinctive morphological characteristics and its internal transcribed spacers sequence analysis. The chromatographic separation and structural elucidation based on spectroscopic analysis of fungal crude extracts led to 10 compounds; tryptoquivaline L (<b>1</b>), fiscalin C (<b>2</b>), <i>epi</i>-fiscalin C (<b>3</b>), cytochalasin D (<b>4</b>), ergosterol (<b>5</b>), ergosterol peroxide (<b>6</b>), chevalone C (<b>7</b>), xylaranol B (<b>8</b>), helvolic acid (<b>9</b>) and cyclo-(l-Pro-l-Leu) (<b>10</b>). The bioassay screening showed that <b>4</b> displayed cytotoxicity against KB and NCI-H187 cancer cell lines with IC₅₀ values of 3.25 and 5.95 μg mL^− 1. <b>6</b> exhibited cytotoxicity against NCI-H187 with an IC₅₀ value of 5.81 μg mL^− 1. <b>7</b> and <b>9</b> showed antimalarial activity with IC₅₀ values of 25.00 and 6.25 μg mL^− 1, respectively. This result establishes <i>Xylaria</i> as broad spectrum bioactive compound producers.</p