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Showing 1 to 20 of 24 for “"Regiochemistry"”.
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Studies on the stereo- and regiochemistry of [4+2] cycloaddition of nitroso compounds to chiral halobenzenediols. Total synthesis of lycoricidine
All four monosubstituted halobenzenes Sa-d have been converted to the corresponding cis-arenediols by a microbial oxidation with the bacterium Pseudomonas putida strain 39- D. Enantiomerically pure cis-diols were obtained from chloro- and bromobenzene. The acetonides of these two diols have been …
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Synthesis of Insecticidal Mono- and Diacylhydrazines for Disruption of K+ Voltage-Gated Channels, and Elucidation of Regiochemistry and Conformational Isomerism by NMR Spectroscopy and Computation
… electron transfer mechanism that predicts the regiochemistry of arylhydrazines toward acylating agents better than the nucleophilicity model based on pKa values. While synthesizing the acylhydrazine library for assay against An. gambiae, NMR spectroscopy revealed rotational isomerisms of two …
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Direction and Stabilization of Alpha' and Beta Metalations by Tertiary Carboxamides
… investigated. Control and understanding of the regiochemistry of these novel metalations is discussed.
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Synthesis and Characterization of Well-Defined Poly(1,3-Cyclohexadiene) Homopolymers and Copolymers
… and the polymerization temperature. The regiochemistry of the polymers were shown to be dependent on the tertiary amine used in the polymerization, which provided a route for the synthesis of polymers with a microstructure rich in either high 1,2-addition (70%) or high 1,4-addition (90%). …
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Spectroscopic and electrochemical investigation of phenyl, phenoxy, and hydroxyphenyl-terminated alkanethiol monolayers
… a dependence of peak intensity on substitution regiochemistry of the aromatic ring. This result suggests that the orientation of the aromatic ring changes with substitution. Peak intensity, and peak widths of alkyl C-H vibrational features in the RAIRS spectra also reveal a dependence of the …
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Chemistry of oxa- and aza-bicyclic(4.1.0)heptenes, total synthesis of (+)-pancratistatin
… in order to determine the stereo- and regiochemistry of ring opening with carbon nucleophiles. The results indicate that 6 and 7 could serve as useful new synthons for C-disaccharides and Amaryllidaceae alkaloid syntheses. The utility of synthon 7b has been demonstrated by a concise …
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Structure-Property Relationships of Polyester Regioisomers and Pendant Functionalized Polyetherimides
… of composition on performance. Altering regiochemistry is a subtle way to maintain the same polymer composition but tune desired properties. Similarly, introducing functional pendant groups expands the property profile of common industrial polymers and installs a handle for secondary …
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Synthesis and Biosynthesis of Polyketide Natural Products
… pertained to the uncertainty surrounding the regiochemistry of dehydration and cyclization in the biosynthetic pathway of the marine polyketide spiculoic acid A. The molecule's key intramolecular cyclization was proposed to occur through a linear chain containing an abnormally dehydrated …
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Evaluation of 1,1-Dimethyl-5,7-Di-T-Butylspiro[2.5]Octa-4,7-Dien-6-One as a Mechanistic Probe for Single Electron Transfer
… of the mechanism at work on the basis of the regiochemistry of spirocyclic ring opening. This "regiodifferentiation" based probe was studied with a variety of nucleophiles (particularly Grignard reagents) and has been found to be effective in differentiating SET from polar processes, although …
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Investigating the evolution of cytochromes P450 involved in GA biosynthesis
… which further leads to altered hydroxylation regiochemistry. Our results demonstrate greater promiscuity of AtKO, which evolved in the absence of other potential labdane-related diterpene substrates, relative to OsKO2 from rice, which contains many such alternative substrates. Thus, our data …
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ΜΕΛΕΤΗ ΑΝΤΙΔΡΑΣΕΩΝ 1,3-ΔΙΠΟΛΙΚΗΣ ΚΥΚΛΟΠΡΟΣΘΗΚΗΣ ΣΕ ΕΤΕΡΟΚΥΚΛΙΚΑ ΣΥΣΤΗΜΑΤΑ
… DATA AND BY CHEMICAL METHODS.THE OBSERVED REGIOCHEMISTRY IS ALSO RATIONALIZED BY FRONTIER MOLECULAR ORBITALCONSIDERATIONS OF THE REACTING SYSTEMS, USING EHMO-CALCULATIONS FOR THE MAGNITUDES OF OXAZOLONE ATOMIC ORBITAL COEFFICIENTS. ATTEMPTS TO CARRY OUT CYCLOADDITIONS REACTIONS OF THESE …
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Self-Assembly of Functional Helical Metallopolymers
… and develop techniques to control the length, regiochemistry and stereochemistry of the two helical strands and determine the effect that these three structural parameters have on the electronic properties of the metallopolymers. By controlling these structural properties, the polymerisation …
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Some uses of tin compounds in organic synthesis.
… used. Unfortunately, the factors governing the regiochemistry of the reaction with allene are not yet fully understood, and mixtu r es of products often result. Finally, I describe efforts to perform a kinetic resolution of a racemic Grignard reagent in which the chiral centre is the meta 1-bear …
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The elucidation of single electron transfer (SET) mechanisms in the reactions of nucleophiles with carbonyl compounds
… establishment of aromaticity. On this basis, the regiochemistry of the ring opening of the radical anion derived from <b>20</b> suggests that polar and SET pathways can be differentiated based upon the regiospecificity of cyclopropyl ring opening. In reactions between <b>20</b> and nucleophiles …
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Novel Monomer Design for Next-Generation Step-Growth Polymers
… analysis of the effect of molecular weight and regiochemistry on the thermomechanical and rheological properties of PEIs. The design of linear, high performance PEIs comprising 3,3'- and 4,4'-bisphenol-A dianhydride (bis-DA) and m-phenylene diamine (mPD) provided an opportunity to elucidate the …
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Base modified peptidic nucleic acids: synthesis and crystallographic analysis of intermediates
… analysis was undertaken to probe the regiochemistry of isomers, and to reveal interesting structural features of the new series of similarly-substituted purine bases. The attainment of the versatile synthetic intermediate 2,6-dichloro~9- (carboxymethyl)purine ethyl ester, and its …
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The Use of Natural Product Substrates for the Synthesis of Libraries of Biologically Active, New Chemical Entities
… the vital importance of stereochemistry and regiochemistry. To establish the importance of the nonactic acid moiety itself in the triazoloester compounds, analogues of these compounds were made by replacing the nonactic acid moiety with a cyclohexane moiety, specifically starting with both …
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The Use of Natural Product Substrates for the Synthesis of Libraries of Biologically Active, New Chemical Entities
… the vital importance of stereochemistry and regiochemistry. To establish the importance of the nonactic acid moiety itself in the triazoloester compounds, analogues of these compounds were made by replacing the nonactic acid moiety with a cyclohexane moiety, specifically starting with both …
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Design and synthesis of mechanoresponsive materials and multivalent polymer-peptide conjugates
… In chapter two of this thesis, the effect of regiochemistry on the mechanochemical reactivity of a naphthopyran mechanophore is examined. A series of constitutional isomers was evaluated computationally, then synthesized and incorporated into a crosslinked polymer matrix. Experiments revealed …
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Studies of multicomponent assemblies
… were differentiated based primarily on the regiochemistry of the anionic groups. In the second chapter, further studies with AT-PAMAM dendrimers were carried out to provide some understanding of the thermodynamic origins of binding. Utilizing isothermal titration calorimetry, the binding of …
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