11 results for Brimble, Margaret, Book item

  • Di-(-)-(1R,2S)-2-phenyl-1-cyclohexyl Diazenedicarboxylate

    Brimble, Margaret (2002)

    Book item
    The University of Auckland Library

    InChI = 1S/C26H30N2O4/c29-25(31-23-17-9-7-15-21(23)19-11-3-1-4-12-19)27-28-26(30)32-24-18-10-8-16-22(24)20-13-5-2-6-14-20/h1-6,11-14,21-24H,7-10,15-18H2/b28-27+/t21-,22-,23+,24+/m0/s1 InChIKey = RHBWBKFUCXVAMA-KQEKZTIUSA-N (reagent used as a chiral azo-enophile in asymmetric azo-ene reactions) Alternate Name: (1R-{1α[E(1R*,2S*)],2β})-Bis(2-phenylcyclohexyl) diazenedicarboxylate. Physical Data: [α]D –56.9 (c 0.65, CHCl3). Solubility: soluble in CH2Cl2, diethyl ether, and most organic solvents. Form Supplied in: yellow oil. Analysis of Reagent Purity: 1H NMR, IR, TLC, elemental analysis. Preparative Methods: The title reagent is prepared1 by reaction of (1R, 2S)-2-phenyl-1-cyclohexanol with excess phosgene in the presence of quinoline to afford a chloroformate which is treated directly with hydrazine monohydrate (0.5 equiv) to afford di-(–)-(1R, 2S)-2-phenyl-1-cyclohexyl diazanedicarboxylate. Oxidation of the diazanedicarboxylate to the diazenedicarboxylate is then readily effected using N-bromosuccinimide and pyridine (eq 1).

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  • 2-Trimethylsilyloxyfuran, CAS No: 61550-02- Update

    Brimble, Margaret; Sperry, Jonathan (2008)

    Book item
    The University of Auckland Library

    InChI = 1S/C7H12O2Si/c1-10(2,3)9-7-5-4-6-8-7/h4-6H,1-3H3 InChIKey = ILBCDLOQMRDXLN-UHFFFAOYSA-N (provides 5-substituted 2(5H)-furanones by alkylation,2 aldolization,3 and conjugate addition;4 transforms quinones into furo[3,2-b]benzofurans;5 useful for the four-carbon elongation of sugars6) Alternate Name: TMSOF. Physical Data: bp 44–46 °C/17 mmHg; d 0.93 g mL–1. Solubility: sol most organic solvents, e.g. CH2Cl2, Et2O, benzene, THF, MeCN. Form Supplied in: colorless liquid; commercially available (98% pure) but expensive. Preparative Method: accessible by silylation of 2(5H)-furanone,1c,5b which is obtained at very low cost by oxidation of furfural (see also ). Handling, Storage, and Precautions: flammable liquid; sensitive to moisture. To avoid hydrolysis, it should be kept under Ar at –18 °C or below. For best results, reactions should be performed under strictly anhydrous conditions in aprotic solvents. Use in a fume hood.

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  • Polyether Antibiotics

    Brimble, Margaret (2006)

    Book item
    The University of Auckland Library

    Several polyether antibiotics have found commercial application as anticoccidials in poultry farming and in improvement of feed efficiency for ruminants. These antibiotics are characterized by multiple tetrahydrofuran and tetrahydropyran rings connected by aliphatic bridges, direct CC linkages, or spiro linkages. Other features include a free carboxyl function, many lower alkyl groups, and a variety of functional oxygen groups. These structural features enable transport of cations across lipid membranes. Some polyethers have found application as components in ion-selective electrodes for use in clinical medicine or in laboratory studies involving transport studies or measurement of transmembrane electrical potential. The polyether class can be subdivided based on the number of carbon atoms in the backbone, ie, the longest chain of contiguous carbons between the carboxyl group and the terminal carbon. The 30 C skeleton group accounts for ~60% of the polyethers for which structures have been determined. Monensin, widely used as an anticoccidial and feed efficiency enhancer, is an example of the 26 C backbone class. Maduramicin, another commercially important polyether, is shown as an example of the 30 C group with a sugar moiety. Many of the production procedures for polyethers utilize the separation of the mycelium followed by extraction using solvents such as methanol or acetone. A number of the polyethers can be readily crystallized. Polyethers such as monensin, lasalocid, salinomycin, and narasin are sold in many countries in crystalline or highly purified forms for incorporation into feeds or sustained-release bolus devices. There are also mycelial or biomass products, especially in the United States, generally prepared by separation of the mycelium and then drying by azeotropic evaporation, fluid-bed driers, or other types of commercial driers. Sophisticated methods have been developed for the chemical analysis of polyether antibiotics in feeds and residues that include the use of liquid chromatography–mass spectrometry (LCMS), bioautography, and enzyme-linked immunosorbent assay (ELISA). The polyether antibiotics exhibit a broad range of biological, antibacterial, antifungal, antiviral, anticoccidial, antiparasitic, and insecticidal activities. They improve feed efficiency and growth performance in ruminant and monogastric animals. Only the anticoccidial activity in poultry and cattle, and the effect on feed efficiency in ruminants such as cattle and sheep, are of commercial interest. It is estimated that the polyether ionophores constitute > 80% of the total worldwide usage of anticoccidials. Bacteria belonging to the order Actinomycetales are the organisms reported to produce all of the polyethers. Most are secondary metabolites of Streptomyces sp. with the species hygroscopicus and albus accounting for about one-third of the antibiotics. An alternative to the Cane-Clemer-Westley unified stereochemical model for the biosynthesis of polyether antibiotics via cyclization of polyepoxides has been proposed. The alternative model invokes construction of polyethers via hydroxyl-directed syn oxidative polycyclization of a hydroxypolyene. Biosynthesis of polyether antibiotics is catalyzed by a large family of polyketide synthases (PKSs) that function in a similar manner to fatty acid synthase using malonyl-CoA, methylmalonyl-CoA, and ethylmalonyl-CoA as extender units for building the polyketide backbone. Many gene clusters encoding the enzymes of polyketide biosynthesis have been cloned and characterized. Combinatorial biosynthesis provides a promising new approach of growing importance for the synthesis of hybrid “unnatural” antibotics by means of genetic engineering of recombinant strains bearing the biosynthetic genes of bacterial polyketide synthases. The polyether antibiotics provide a complex molecular framework for the development of new synthetic strategies for their total synthesis. Over 16 of the polyether antibiotics have succumbed to total synthesis. Monensin and salinomycin represent ~ 65–70% of worldwide usage of polyether antibiotics for controlling coccidiosis. Lasalocid, narasin, and maduramicin make up the remainder. Other compounds for coccidiosis control include nicarbazine, halofunginone, amprolium, and robenidine.

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  • Methyltrichlorosilane, CAS No: 75-79-6 Update

    Brimble, Margaret (2010)

    Book item
    The University of Auckland Library

    InChI = 1S/CH3Cl3Si/c1-5(2,3)4/h1H3 InChIKey = JLUFWMXJHAVVNN-UHFFFAOYSA-N (precursor to organosilicon compounds;1 silylating agent;1 Lewis acid2) Physical Data: bp 66 °C; d 1.273 g cm–3. Solubility: sol methylene chloride. Form Supplied in: liquid; commercially available. Purification: can be purified by distillation. Handling, Storage, and Precautions: is corrosive and moisture sensitive. It should be handled in an anhydrous atmosphere in a fume hood.

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  • Alkylarsenic, -Antimony, and -Bismuth Compounds volume 2 Chapter 2.09

    Brimble, Margaret; Levi, MS (2005)

    Book item
    The University of Auckland Library

    The chemistry of arsenic, antimony and bismuth, a class of elements in group V of the periodic table and known as the pnicogens, has a colorful past from the ancient alchemists to Cadet’s fuming arsenical liquid to green pigments. Today, they are even used in some lasers. This chapter presents an update of the preparations of compounds containing one or more of the pnicogens as well as complexes with other metals.

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  • Chemistry Research: Making Molecules for Medicines

    Brimble, Margaret (2008)

    Book item
    The University of Auckland Library

    Natrual products have long been regarded as 'nature's medicine chest' because they offer a rich source of compounds with complex and novel structures tha inspire the development of new drugs. The synthesis of these challenging, naturally occurring compunds in the laboratory is a scientific endeauvour that forms the backbone of the pharmaceutical industry. ...

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  • Total Synthesis of the Fungal Metabolite Virgatolide B

    Hume, Paul; Furkert, Daniel; Brimble, Margaret (2015)

    Book item
    The University of Auckland Library

    This account describes the total synthesis of the title compound, a polyketide metabolite with in vitro antitumor activity. A first-generation approach involving an sp3???sp2 Suzuki cross-coupling reaction of a chiral trifluoroboratoamide and a rotationally symmetric aryl bromide successfully established the carbon framework required to construct the spiroketal core of the molecule. However, removal of the phenolic protecting groups with concomitant spiroketalization could not be achieved. A revised strategy was therefore devised, employing different protecting groups and incorporating greater functionality on the aryl bromide coupling partner. Suzuki cross-coupling, extension of the carbon backbone using a diastereoselective Mukaiyama aldol reaction and deprotection/cyclization furnished the spiroketal ring system. The final transformation required was carboalkoxylation of the aromatic ring to form the phthalide subunit present in the molecule. This manipulation was difficult to achieve due to competing protodehalogenation. Finally, a reordering of synthetic events provided access to virgatolide B by exploitation of an intramolecular hydrogen-bonding interaction in order to control the regioselectivity of the spiroketalization process.

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  • Synthesis of 5,6- and 6,6-Spirocyclic Compounds

    Brimble, Margaret; Stubbing, Louise (2014-01)

    Book item
    The University of Auckland Library

    The selective and efficient synthesis of spiroacetals has attracted attention from the synthetic community, both because of the synthetic challenge of complex spiroacetal natural product scaffolds, as well as the drive to develop and improve existing methods. A number of recently reported methods for the synthesis of spiroacetals are discussed, including their application in the synthesis of natural products containing the spiroacetal scaffold.

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  • Recent Developments in Neoglycopeptide Synthesis

    Brimble, Margaret; Miller, N; Williams, GM (2011-04)

    Book item
    The University of Auckland Library

    Closing a gap in the literature, this is the only book series in 6 volumes to cover this important topic in organic and biochemistry.

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  • Pyrans and their Benzo Derivatives: Synthesis

    Brimble, Margaret; Sperry, Jonathan; Gibson, JS (2008)

    Book item
    The University of Auckland Library

    The abundance of six-membered oxygen containing heterocycles in bioactive natural products continues to encourage the development of new and improved syntheses. There is a vast amount of new literature dedicated to the synthesis of pyrans and their benzo derivatives; however, many traditional approaches are still of great value and this chapter should be read in conjunction with the corresponding chapters in the first and second editions of Comprehensive Heterocyclic Chemistry ....

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  • Synthesis of mannosylated glycopeptides as components for synthetic vaccines

    Kowalczyk, R; Brimble, Margaret; Dunbar, R (2009)

    Book item
    The University of Auckland Library

    Introduction The immune system often recognizes tumour cells and infectious agents from the unique peptides (epitopes) found on their surfaces [1] therefore, synthetic vaccines that combine many epitopes together with appropriate glycal adjuvants that stimulate Cytotoxic T Lymphocytes (CTLs) would have considerable clinical utility. The cells responsible for initiating an immune response are APCs (antigenpresenting cells) that capture and process antigen-derived peptides for presentation to CTLs. Dendritic cells are a type of APC that express receptors capable of recognizing and internalizing foreign agents. Several of these receptors are C-type lectin receptors that bind carbohydrates [2]. The receptors we are interested in, in particular, are mannose receptors that are known in the uptake and presentation of mannosylated antigens to T cells [3]. In order to target these receptors and test their specificity for binding human skin APCs in vitro we have synthesized twenty mannosylated peptide derivatives, which differ in their chain length and the position of the mannosyl unit on the peptide backbone.

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