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Showing 1 to 20 of 21 for “"Wittig reaction"”.
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Alkaloid syntheis via novel azabicycles.
… synthesis by intramolecular Wittig reaction has been reviewed and we describe the utility of this strategy in the formation of nitrogen-bridgehead bicycles which can then be used in alkaloid synthesis. Our initial studies on the viability of this strategy in the synthesis of …
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A study of cashew nut shell liquid purification and the synthesis of nonionic surfactants from the component phenols
… by means of a Horner-Emmons modification to the Wittig reaction, is also reported. Some studies with cavitands are also reported, including the synthesis of some novel macrocycles and some sugar transport studies.
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Stereo-directing effect of molecularly imprinted polymers on cinnamic acids
… of molecularly imprinted polymers (MIPs) in reactions involving cinnamic acid derivatives, specifically focusing on (2E)-3-(4-methoxyphenyl) prop-2-enoic acid (trans-4-methoxy cinnamic acid (t-4MCA)). To the best of our knowledge, no prior studies have reported the synthesis of MIPs using …
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Bromonium-Initiated Epoxide-Opening Cascades : total Synthesis of ent-Dioxepandehydrothyrsiferol and Synthetic Studies toward (+)-Scholarisine A
… of exogenous trapping nucleophiles into the reaction. [chemical formulae] CHAPTER 11. Synthetic Studies toward (+)-Scholarisine A. A concise and scalable route toward the monoterpene indole alkaloid (+)- scholarisine A has been developed. Synthetic highlights of the route include: 1) …
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An investigation of the chemistry of lithiotriphenylphosphineacetylmethylene
… in reasonable yields, uncontaminated by normal Wittig products. Reaction of the ylide anion with o-phthalaldehyde resulted in terminal aldol condensation accompanied by an intramolecular Wittig reaction to give 4,5-benzotropone. The condensation of lithiotriphenylphosphineacetylmethylene with …
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Synthesis of D-alanyl-D-alanine dipeptide isosteres and cephalosporin prodrugs
… published syntheses were employed as well as a Wittig reaction using a chiral Wittig reagent, a reaction not used in the synthesis of isosteres before. If the isosteres are directly incorporated, cell wall synthesis will be inhibited. Additionally, it is believed that the isosteres will act as …
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Analysis, Experimental Optimization and Chemical Synthesis of Cyclic Monomers Occurring in Edible Fats and Oils
… decanoate were prepared by a Wittig reaction between 2-alkylcyclopentanones and $\omega$-carbomethoxyalkyl triphenylphosphonium bromides. The GC-retention features, the mass fragmentation pattern and the spectroscopic characteristics of the final synthetic products and …
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Progress Toward The Total Synthesis Of The Natural Product Herbicide Ascaulitoxin Aglycone
… blocks. Strategy 1 invokes the use of the Henry reaction as a key step for the construction of the central C4-C5 cis-aminohydroxy group, which was moderately successful, but abandoned in favor of olefination protocols. Strategy 2 invoked the Wittig reaction as a key reaction for the formation of …
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Development and mechanistic understanding of ball milling as a sustainable alternative to traditional synthesis
… methods, uses mechanical energy to drive organic reactions and transformations towards completion. Not only are we interested in finding reaction pathways that produce desired organic products in high yields, but also we are interested in understanding the mechanisms and theory of these processes …
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The synthesis, structural characterization and biological evaluation of potential chemotherapeutic agents
… The compounds were synthesised via the Wittig reaction and the decarbonylative Heck reaction. In conjunction with fluorine, nitrogen was also used as a replacement for the oxygen atoms of the resveratrol structure. Full structural characterisation of these compounds was carried out …
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Synthetic Study Of Karlotoxins And Investigation Of Alpha-Diaminoboryl Carbanion Chemistry
… the KmTx5, a congener of KmTx2, in a twelve-step reaction sequence starting from a reported tetrahydropyranyl intermediate which can be readily prepared from D-mannose in four steps following the literature precedent. α-Boryl carbanion species are known to exhibit excellent olefinating abilities …
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Suzuki-Miyaura mediated biphenyl synthesis: a spotlight on the boronate coupling partner
… acid or ester is a key partner in this coupling reaction. This work presents the synthesis of a library of new molecules containing the biphenyl scaffold; o-, m- and p-(bromomethyl)phenylboronic acid pinacol esters, 2a-c, were selected as coupling partners. Nucleophilic substitution of the …
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Rhizophoraceae alkaloids : an approach to the synthesis of cassipourine
… 2'-yl]-3-benzyloxy-prop-l-ene, prepared by a Wittig reaction was too low for practical purposes. A novel reaction, the fissioning of the sulphonamide bond by the ylid to give 2- benzyloxyethyl-p-tolylsulphone was noted in this preparation. Attempts to prepare …
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Higher kekulenes and Polymeric Helicenes
… in polymeric form. Ring closing metathesis (RCM) reaction was used to furnish the helicenes from a suitably designed polymer precursor, poly{4,6-di[(1E)-(2-2H)-propenyl]}-,<italic>m</italic)-phenylene. End group analysis revealed that the polymerization reaction resulted in the formation of both …
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Synthesis of o-isotoluenes, o-quinodimethanes, and benzoenynyl carbodiimides and their cyclizations to polycyclic and heterocyclic compounds
… o-isotoluenes in a single operation. The reaction proceeded through an initial formation of (Z)-diene-allenes, which underwent facile eletrocyclizations to produce o-isotoluenes.;Treatment of allenyldicyclohexylborane with 1-lithio-5,5-pentamethylene-3,4-pentadien-1-yne produced the …
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Synthesis and evaluation of tetramethoxy stilbenes related to combretastatin A-4 as potential anticancer agents
… to synthesize a range of combretastatins, via Wittig reactions, with a tetramethoxy unit instead of a trimethoxy unit as the A ring, and to test these for activity against cancer cell lines. The activity of these compounds was found and compared to that of the anti-cancer drug Cisplatin, that …
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Novel oligomeric and polymeric materials based upon the dibenzotetraaza[14]annulenes.
… generally by a one step process involving the reaction of ortho-phenylenediamine and various 2-substituted malondialdehydes in the presence of a suitable acid catalyst and solvent. [chemical formula]. 3. The preparation of 1-D and 2-D unsymmetrical macrocyclic complexes. The introduction of …
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Studies in synthesis using CO2 and H2 gases
… out in this project on the development of a Wittig CO2 utilisation methodology for the synthesis of α,β unsaturated carboxylic acids. Chapter 3 involves discussion on the development of protocols for purification of the α,β-unsaturated carboxylic acids synthesised. The Conclusions and Future …
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