Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 35 for “"cyclohexadiene"”.
-
Synthesis and Characterization of Well-Defined Poly(1,3-Cyclohexadiene) Homopolymers and Copolymers
Polymers containing poly(1,3-cyclohexadiene) were synthesized using a novel pre-formed initiator comprised of an alkyllithium and a tertiary diamine. The use of a pre-formed intiator at moderate temperatures (25° C) enabled the synthesis of high molecular weight poly(1,3-cyclohexadiene) …
-
The synthesis of amino- and deutero- sugars from halo-cyclohexadiene-cis-diols
… thereof, from the metabolite d₅- bromocyclohexadiene-cis-diol 189 obtained from the microbial oxidation of d₅- bromobenzene 2 (Figure 2). See: Figure 2: Perdeuterated Sugar Synthesis
-
Studies on the Synthesis and Metabolism of Methyl Omega-(two-Alkyl-Cyclohexadiene) Carboxylate Isomers
Made available in DSpace on 2014-12-10T22:38:21Z (GMT). No. of bitstreams: 1 7317569.pdf: 6220687 bytes, checksum: fe610f7afdaf5cc8359c862f84dfad3f (MD5) Previous issue date: 1973
-
Selective criteria in Werner clathrates
… hydrocarbons: cyclohexane, cyclohexene, 1,3-cYclohexadiene, 1,4-cyclohexadiene and benzene. Host to guest ratios were elucidated by density and proton nuclear magnetic resonance spectroscopy. The thermal characteristics of the compounds were analysed by thermogravimetric analysis and …
-
Einfache Decarbonylierungen und stereoselektive Oxidationen von Cyclohexadienen und Cyclohexenen
… Rahmen dieser Arbeit das Synthesepotential von Cyclohexadienen und Cyclohexenen deutlich erweitert werden. Die Darstellung der 1-Alkylcyclohexa-2,5-dien-1-carbonsäuren erfolgte mittels Birch-Reduktion in flüssigem Ammoniak und anschließender Umsetzung der intermediär entstehenden Dianionen mit …
-
Niobium-mediated synthesis of phosphorus-rich molecules
… pyridine-N-oxide in the presence of excess 1,3-cyclohexadiene, generating niobium oxo and R2CP8(C 6H8). Searching for new platforms to investigate niobium-phosphorus chemistry led to the synthesis of [Na(THF) 3][P3Nb(ODipp) 3], an anionic cyclo-P3 complex that is accessible in two steps from …
-
Conformational Analysis of 1-Tertiarybutyl-1, 4-Dihydronaphthalene a Turnover from SRNI to SNI Mechanism
<p>The cyclohexadiene porition of 1-tertiarybutyl-1, 4-dihydronaphthalene exists in a puckered rather than planar conformation at room temperature, with approximately equal populations of the isomer with the t-butyl group “axial” and “equatorial.” Analysis of chemical shifts and coupling constants …
-
The enantioselective synthesis of C₁₈-sphingosines
… of chlorobenzene to the corresponding homochiral cyclohexadiene cis-diol (113) allows, through careful symmetry-based planning, the stereodivergent synthesis of all sphingosine stereoisomers. This was achieved via the selective preparation of the appropriate diastereomer of azido alcohol (118), …
-
Isolation and structure determination of the metabolites from Pseudomonas putida 39D: oxidation of di-substituted aromatics
… 2R, 3S-dihydroxy-5-bromo-4,6-cyclohexadiene 2. The absolute stereochemistry was discovered by comparison of the products from the convergent synthetic pathway of 2 and the known diol metabolite from α,α,α-trifluorotoluene, 4.
-
Approaches towards C-10-hydroxylated analogues of narciclasine
… approach involves the use of homochiral cyclohexadiene diols, products of the biocatalytic transformation of aromatic compounds, as precursors to ring C, and of highly oxygenated aromatic molecules to construct ring A. The document also reports a detailed account of the protocols studied …
-
Part One: Radical Cation and Triplex Diels-Alder Reactions. Part Two: Photochemistry of Tri-1-Naphthylboron
… the Diels-Alder dimerization of 1,3-cyclohexadiene (1) is shown to be the result of the reaction of the radical cation of 1. A chain mechanism and a fast rate constant for addition of the radical cation of 1 to a neutral molecule of 1 are applied to explain a similar reaction using an …
-
Studies of the Synthesis of Polycyclic Homocyclopropylcarbinols
… anti-oxide prepared from 1,4-cyclohexadiene underwent cyclization to endo-tricyclo{3.2.0.0('2,7)}-heptan-4-ol in 69% yield. Lithiation of a stereoisomeric mixture of the bromocyclopropyl epoxides from 1,5-hexadiene afforded the endo and exo isomers of both …
-
The mechanisms of melt stabilisation of polyolefins
… -tetra-tert-butyl-4'-phenoxy-4-methylene-2, 5-cyclohexadiene-1- one (galvinoxyl), iodine, nitroxyl radicals and cupric stearate were found to be very efficient melt stabilisers particularly when processed in a restricted amount of air. The mechanisms of their melt stabilising action have been …
-
I. Direct observation of o-xylylene (o-quinodimethane) in solution, Dimerization kinetics of some o-quinodimethanes; II. Kinetic and product studies on the dimerization of [alpha]-methyl-substituted o-quinodimethanes; III. Direct observation of 1,2-napthoquinodimethane and 9,10-phenanthroquinodimethane, Dimerization kinetics of resonance-stabilized o-quinodimethanes
… kinetics of 5-ethylidene-6-methylene-1,3-cyclohexadiene (9) and 5,6-bis(ethylidene)-1,3-cyclohexadiene (10) were studied by stopped-flow UV-visible spectroscopy. At 25(DEGREES)C in CH(,3)CN k(,9)/k(,1) = 0.59 and k(,10)/k(,1) = 0.016. The dimerization of 9 and 10 led predominantly to one …
-
Field-mediated ring-expansion isomerization of cyclic hydrocarbons in ion-pair complexes: a computational study
… complexes formed by seven- and nine-membered, cyclohexadiene-based, fused bicyclic molecules and their monocyclic tautomers confined in Na-I and Li-I counterion pairs. The stability, structural characteristics, charge distributions, and predicted infrared spectra of the complexes were analyzed. …
-
Exploring Enantioselective and Multicomponent One-Pot Reactions Utilizing Alkynes as Linchpins Toward Biologically Active Molecules
… yield and enantiomeric ratios. The products, 1,4-cyclohexadienes, have two regiochemically different alkenes, which can serve as functional handles that can be further elaborated to furnish molecules of biological interest. While expanding the scope of the enantioselective alkyne DA, alkynyl …
-
Enantiodivergent chemoenzymatic synthesis of codeine
… synthesis of codeine utilizing a cis-cyclohexadiene diol derived from microbial whole cell oxidation of ~-bromoethylbenzene,as starting material is discussed. The total synthesis of (+)-codeine in 14 steps featuring a Mitsunobu inversion and two intramolecular Heck cyclizations is …
-
Singlet Oxygen Generation Via Irradiation of 4-Benzylamino-7-Nitrobenz-2-Oxa-1, 3-Diazole
… method of singlet oxygen detection with 1, 3-cyclohexadiene (CHD) as acceptor. A reaction between BBD and the acceptor rendered this method of singlet oxygen detection useless. In a second approach, the rate of light-induced oxygen consumption for solutions having various components was …
-
A study of methods of preparation of phthalaldehyde
… formed by the present method was dibutyl-2,6-cyclohexadiene-1,2-dicarboxylate.</p><p>The second method was an attempt to use the Stephen method for the reduction of nitriles to prepare phthalaldehyde from phthalonitrile. The method apparently failed completely of aldehyde formation, but the …
-
Novel materials for membrane separation processes
… hydrophilic derivatives of cis-1,2-dihydroxy-3,5-cyclohexadiene (cis-DHCD) and copolymerise them with 2-hydroxyethyl methacrylate (HEMA), to produce a completely new range of hydrogel materials. It is theorised that hydrogels incorporating such derivatives of cis-DHCD will exhibit good strength …
Page 1 of 2