- Attenuation of London Dispersion in Dichloromethane Solutions
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London dispersion constitutes one of the fundamental interaction forces between atoms and between molecules. While modern computational methods have been developed to describe the strength of dispersive interactions in the gas phase properly, the importance of inter-and intramolecular dispersion in solution remains yet to be fully understood because experimental data are still sparse in that regard. We herein report a detailed experimental and computational study of the contribution of London dispersion to the bond dissociation of proton-bound dimers, both in the gas phase and in dichloromethane solution, showing that attenuation of inter-and intramolecular dispersive interaction by solvent is large (about 70% in dichloromethane), but not complete, and that current state-of-The-Art implicit solvent models employed in quantum-mechanical computational studies treat London dispersion poorly, at least for this model system.
- Pollice, Robert,Bot, Marek,Kobylianskii, Ilia J.,Shenderovich, Ilya,Chen, Peter
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supporting information
p. 13126 - 13140
(2017/09/26)
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- Pd-Catalyzed, Ligand-Enabled Stereoselective 1,2-Iodine(III) Shift/1,1-Carboxyalkynylation of Alkynylbenziodoxoles
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A PdII-catalyzed 2:1 coupling reaction of alkynylbenziodoxole with carboxylic acid to afford (alk-1-en-3-ynyl)benziodoxole, which is efficiently promoted by an octahydrophenazine ligand, is reported. The reaction involves a Pd-assisted 1,2-iodine(III) shift of the alkynylbenziodoxole followed by stereoselective introduction of carboxy and alkynyl groups (the latter originating from another molecule of the alkynylbenziodoxole) into the 1-position of the transient Pd-vinylidene species. The product of this 1,1-carboxyalkynylation reaction serves as a new functionalized enyne-type building block for further synthetic transformations.
- Wu, Junliang,Xu, Kai,Hirao, Hajime,Yoshikai, Naohiko
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supporting information
p. 1521 - 1525
(2017/02/10)
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- Polymerization initiator, modified-conjugated diene polymer and tire prepared therefrom
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The present disclosure relates to a polymerization initiator and a modified conjugated diene polymer prepared using the same, and more particularly to a polymerization initiator which is a compound represented by the following formula 1, and a modified conjugated diene polymer prepared using the same: wherein R1 to R5 are each independently hydrogen or a C1-10 alkyl group or its carbanion; n? represents the number of negative charges of the carbanion and is 1? to 5?; M is a metal; and n is equal to the number of carbanions in R1 to R5.
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- POLYMERIZATION INITIATOR, MODIFIED-CONJUGATED DIENE POLYMER AND TIRE PRODUCED THEREFROM
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The present disclosure relates to a polymerization initiator and a modified conjugated diene polymer prepared using the same, and more particularly to a polymerization initiator which is a compound represented by the following formula 1, and a modified conjugated diene polymer prepared using the same: wherein R1 to R5 are each independently hydrogen or a C1-10 alkylgroup or its carbanion; n? represents the number of negative charges of the carbanion and is 1? to 5?; M is a metal; and n is equal to the number of carbanions in R1 to R5.
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Page/Page column
(2014/06/24)
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- Synthetic route optimization of PF-00868554, an HCV polymerase inhibitor in clinical evaluation
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This paper describes the optimization efforts to establish an enabling synthesis to provide multigram quantity of PF-00868554, an HCV polymerase inhibitor currently in phase II clinical evaluations.
- Johnson, Sarah,Drowns, Matt,Tatlock, John,Linton, Angelica,Gonzalez, Javier,Hoffman, Robert,Jewell, Tanya,Patel, Leena,Blazel, Julie,Tang, Mingnam,Li, Hui
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scheme or table
p. 796 - 800
(2010/06/13)
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- INHIBITORS OF HEPATITIS C VIRUS RNA-DEPENDENT RNA POLYMERASE, AND COMPOSITIONS AND TREATMENTS USING THE SAME
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The present invention provides compounds of formula (4), and their pharmaceutically acceptable salts and solvates, which are useful as inhibitors of the Hepatitis C virus (HCV) polymerase enzyme and are also useful for the treatment of HCV infections in HCV-infected mammals. The present invention also provides pharmaceutical compositions comprising compounds of formula (4), their pharmaceutically acceptable salts and solvates. Furthermore, the present invention provides intermediate compounds and methods useful in the preparation of compounds of formula (4).
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Page/Page column 119
(2008/06/13)
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- GLYT1 TRANSPORTER INHIBITORS
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The invention provides a compound of formula (I): or a salt, solvate or a physiologically functional derivative thereof, wherein R1 to R10 are as defined in the specification and uses of such compounds. The compounds inhibit GlyT1 transporters and are useful in the treatment of certain neurological and neuropsychiatric disorders, including schizophrenia.
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Page/Page column 58
(2010/02/12)
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- Synthesis of Some 2,6-Di- and 1,2,6-Trisubstituted -1,4-Dihydropyridines as Antimicrobial Agents
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Reduction of 2,6-diacylpyridine (1) with amalgamated zinc in hydrochloric acid (Clemmensen reduction) and with zinc in formic or acetic acid gave rise to the formation of diethanol- (2) and/diethyl- (3) pyridines. Reduction of (1), (2) and (3) with sodium borohydride afforded the corresponding 1,4 dihydro-pyridines (4),(5) and (6), respectively. Acetylation of (4) and (5) gave triketone- (7) and ketodicarbinol- (8) derivatives, respectively, which were further reduced to the tricarbinol derivative (9). Antimicrobial evaluation of compounds (1-9) showed remarkable results when compared with four known antibiotics.
- Attia, A.,El-Salam, O. I. Abd,Amr, A.
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p. 297 - 308
(2007/10/03)
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- Extension of the Criegee Rearrangement: Synthesis of Enol Ethers from Secondary Allylic Hydroperoxides
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The Criegee rearrangement has been extended to secondary allylic hydroperoxides, allowing for the selective synthesis of cyclic and acyclic enol ethers; the effect of base and electrophilic agent was studied.
- Goodman, Richard M.,Kishi, Yoshito
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p. 5125 - 5127
(2007/10/02)
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- Entropy barriers to proton transfer
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Proton transfer between sterically hindered pyridines and amines proceeds through locked-rotor, low-entropy intermediates. The reactions exhibit slow kinetics (efficiencies of 0.1-0.0001) and large negative temperature coefficients (up to k = CT-8.7). The rates become slower and the temperature dependencies steeper with increasing steric hindrance. The observations are reproduced by a multiple complex-switching RRKM model that allows several alternative complexes to be rate controlling: a series of loose complexes, a locked-rotor tight complex that occurs before the formation of a hydrogen-bonded complex, and a complex located at the central barrier. The rate-limiting transition state shifts from the loose to the tight and central-barrier complexes with increasing temperature. The model suggests that at elevated temperatures, above 1000 K, ion-molecule reactions will become slow even for unhindered, small reactants. Ion kinetics may then become similar to neutral radical kinetics.
- Meot-Ner, Michael,Smith, Sean C.
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p. 862 - 869
(2007/10/02)
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- Synthese und Photoisomerisierung von sterisch gehinderten 2,6-Dialkylpyridin-N-oxiden
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Synthesis of the new sterically hindered pyridine-1-oxides 2c and 6a-c is described.Copper(II)-catalyzed photolysis of 2 and 6a in aqueous medium provides only small amounts of 2-acylpyrroles 8 and 10a together with by-products.Exclusive formation and better yields of 10 can be received upon irradiation of 6 in none protic solvents at low temperature.Introduction of bulky substituents as in 6 failed to stabilize any of the postulated intermediates in order to be identified during photoreaction.It is assumed that the high rate of polymerization is caused by unstable 1,3-oxazepines like 13.
- Weber, Horst,Rohn, Thomas
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p. 701 - 706
(2007/10/02)
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- Tri- et tetraacylation des derives du propene : application a la synthese d'acyl-3 et de diacyl-3,5 pyridines
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The acylation (acetylation, propionylation, isobutyrylation) of isopropyl chloride has been performed under Friedel-Crafts conditions (AlCl3).For the first time, products resulting from triacylation and tetraacylation have been obtained.Treatment with liquid ammonia affords the title compounds.Thus, sophisticated products are obtained readily from very cheap starting materials.
- Erre, Claude H.,Fouillade, Brigitte,Roussel, Christian
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p. 271 - 274
(2007/10/02)
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- Arenes Disubstituted with Primary Alkyl Groups from Xylylene Dianions
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Xylenes were converted into dianions 1.Reaction of dianions 1 with dialkyl sulfates gave symmetrical dialkylbenzenes 2 (R = R'), while methyl iodide caused oxidative coupling followed by alkylation to give 8.Unsymmetrical dialkylbenzenes 2 (R =/= R') were made by an indirect route involving monoanions 9 and 11.Reactions of dianions 1 with dihalides gave cyclophanes o-3 (n = 5,6,9), m-3 (n = 8-10), and p-3 (n = 9-11) and cyclophanes o-4 (n = 2,5,7,9) and m-4 (n = 2,6,7).Dianion 5 from 2,6-lutidine was used to prepare nitrogen analogues of 2 (R = R') and m-3 (n = 8-10).
- Bates, Robert B.,Ogle, Craig A.
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p. 3949 - 3952
(2007/10/02)
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