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Showing 1 to 20 of 35 for “"para-substituted"”.
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Study of the kinetics of the [1,5]-sigmatropic phenyl rearrangement in 3,4-bis(para-substituted phenyl)-1,2,5-triphenyl-2,4-cyclopentadien-1-ols
… phenyl rearrangements of 3,4-bis- (para-substituted)-1,2,5-triphenyl-2,4- cyclopentadien-1-ols to 3,4-bis-(para-substituted)-2, 2,5-triphenyl-3-cyclopenten-1-ones, where the substituent were, t-butyl, methyl, hydrogen, chloro and bromo, has been performed at 180, 190, 200 and 210 ± …
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A kinetic study of the hydrolysis of some derivatives of brilliant green
… absorption for the x-band of the nieta- and para- substituted derivatives and the respective Haurnett substituent constant has been established. The effect on the x-band of ortho- substition is consistent with the relief of steric hindrance by rotation of the phenyl ring. The perchlorates of …
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Dielectric and Kerr Effect Studies of Electro-Active Polymer Complexes
… proportion of this material is comprised of para-substituted oligophenylenes. The reduction coupling of benzene has been found to yield a great variety of polyaryl compounds in addition to para-substituted polyphenylenes. The polymerization of biphenyl in solution in cyclohexane using …
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Pd-Ag Catalyzed Aza-Piancatelli Reaction: From Synthesis to Mechanistic Investigations
… at room temperature for synthesizing trans-substituted cyclopentenones derivatives utilizing the Piancatelli reaction. The methodology resulted in a broad substrate scope across ortho-substituted anilines but shows limited reactivity with para-substituted anilines at room temperature. Oxygen …
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Progressive design and self-assembly of supramolecular architectures : based on metallamacrocyclic nickel(II) complexes with bipodal tetra-alkylaroylbis (thioureas)
… 2:2 or 3:3 can be achieved by using meta- or para- substituted ligands. The metallamacrocyclic complexes are subsequently converted into octahedral adducts via the addition of monodentate nitrogen donor ligands. Metallamacrocycles are further employed as secondary building units in the …
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The production and synthetic utility of the dioxygenase-derived metabolites of substituted aromatics
… with series of ortho-halobenzoates and para-substituted arenes. Palladium-catalyzed carbonylation methodology was developed to convert halogenated cis-dihydrodiol metabolites to the corresponding carboxylates and a comparison of the overall efficiency between the enzymatic and chemical …
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Study of Substituted Benzenesulfonate-Containing Layered Double Hydroxides and Investigation of the Hexamethylenetetramine Route of LDH Synthesis
Benzenesulfonates, para-substituted with amine, chloride and methyl groups were successfully incorporated into layered double hydroxides of two different compositions, 2:1 Mg-Al LDH and 2:1 Zn-Al LDH. These parent materials were also doped with small amounts of nickel and the differences in the two …
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Construction and Application of Reference Scales for the Characterization of Cationic Electrophiles and Neutral Nucleophiles
… useful for the determination of nucleophilicity parameters (N) and electrophilicity parameters (E) of new compounds by kinetic measurements. This was shown by adding various new classes of nucleophiles like enamines, phosphanes and phosphites, and pyridines as well as by adding new electrophiles. …
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ELECTROCHEMICAL REDUCTION OF CYCLIC AND ACYCLIC BENZYL DISULFIDES
… and coulometry. The cyclic disulfides were substituted 2,3- benzodithiin molecules and the acyclic series were bibenzyl disulfides, having the général formula of (X-C6H4-CH2-S-)2. The acyclic series were synthesized as a more suitable model for the cyclic compounds, than those of the …
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The sodium borohydride reduction of organic halides and related derivatives in aprotic solvents
… on carbon. The reduction of a series of para-substituted benzyl chlorides revealed that the electronic effects of groups ranging from p-methoxy to p-nitro had a rather small effect on the rate of reduction. Aryl halides arc reduced by sodium borohydride in yields dependent upon the …
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Alkyl, alkenyl and cycloalkyl substituted triphenylmethane dyes
… absorption for the x-band of the meta- and para- substituted derivatives of Malachite Green and the respective Hammett substituent constants has been confirmed. The cyclopropyl group is found to produce the largest hypsochromic shift of the x-band for the 4-substituted compounds and this is …
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The acetanilide crystal structures: packing and conformational similarities
… on molecular changes has been studied for mono-substituted acylanilides. A library of 255 crystal structures has been investigated. 217 structures were determined during this project and 38 originated from the CSD. A subset of 64 mono-substituted acetanilides was studied in detail for crystal …
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A dimensional analysis of the benzylic hydroxylase active site in mortierella isabellina
… benzylic hydroxylase were tested using suitably substituted ethyl benzenes. Both the depth (para substituted substrates) and width (ortho and meta substituted substrates) of this region were investigated, with results demonstrating absolute spatial limits in both directions in the plane of the …
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Preparation of Novel Carbenes and their Catalytic Application to the Cross-Benzoin, Aza-Benzoin and Stetter Reactions
… reaction was also effective with ortho, meta or para substituted aromatic aldehydes (possessing either electron donating or withdrawing substituents) and was tolerant to α and β branched aliphatic aldehydes as well. A library of bis(amino)cyclopropenium salts were prepared, and the corresponding …
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Study of Receptor Binding and Growth Effect of Gastrin Gene Products
… gastrin analogs were tested, which include: (i) para-substituted analogs, [Leu15,p-X-Phe17]G(ll-17), where X=C1, CH3, and NH2, (ii) analogs in which Phe" was substituted with hydrophobic amino acids of increasing size, Ala, Abu, Val, Leu and Cha and (iii) analogs in which Phe" was replaced by …
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Flavin Amine Oxidases from the Monoamine Oxidase Structural Family Utilize a Hydride Transfer Mechanism
… Steady-state and transient kinetic studies of para-substituted N,N'-dibenzyl-1,4- diaminobutanes as substrates for PAO show that the kred values for each correlate with the van der Waals volume (VW) and the value. The coefficient for VW is the same at pH 8.6 and 6.6, whereas the p value …
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Synthesis and analysis of polyphenyl compounds and their derivatives
… terphenyls. The focus is the synthesis of para substituted three-ring structures, from fully aromatic p-terphenyl to fully saturated p-tercyclohexyl and the intermediary partially reduced compounds. These compounds are successfully synthesised. The methods used are extended to some …
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Heterocyclic Calix[4]arene Derivatives for Fluorescence Investigations
… were prepared using three 1,3 bis-bromo-alkyl-disubstituted calix[4]arenes (ethyl, propyl and butyl), and ortho, meta and para substituted di-imine bridged diphenol units. All these reactions yielded the desired product with the exception of the bis-bromoethyl variants which did not result in …
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Studies in asymmetric synthesis: I. the asymmetric α-alkylation of N,N-dimethylhydrazones II. the asymmetric aldol-Tishchenko reaction of (S)-tert-butanesulfinyl imines for the introduction of 2, 3, 4 and 5 new chiral centres in one pot
… This included examining a number of reaction parameters such as changing the chiral diamine, investigating different organolithium/(+)-sparteine and (+)-sparteine surrogate complexes and exploring different solvent combinations. The final section of this chapter examines the use of …
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Boron in the primary and secondary coordination spheres of iron and nickel
… are described. The catalytic hydrosilylation of para-substituted benzaldehydes was studied and a mechanism for the transformation proposed. An intermediate nickel borohydridosiloxyalkyl species was identified and characterized by NMR spectroscopy. A series of nickel borohydridothiolate complexes …
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