- Further evidence for the effect of ultrasonic waves on electron transfer processes - The case of the Kornblum-Russell reaction
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The Kornblum-Russell action is directly influenced by sonication. Under optimal conditions of irradiation, the ratio of C/O alkylation is practically reversed with respect to that of the silent reaction, indicating a direct intervention of sonic waves in the electron transfer process.
- Dickens,Luch
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Read Online
- QUATERNARY AMMONIUM SALT COMPOUNDS
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[Problem] The object of the present invention is to provide a novel compound having 132 adrenergic receptor agonist activity and muscarinic receptor antagonist activity. [Means for Solving the Problem] The present invention is a quaternary ammonium salt compounds represented by formula (I), or a pharmaceutically acceptable salt thereof, with superior β32 adrenergic receptor agonist activity and muscarinic receptor antagonist activity.
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Page/Page column 41
(2012/03/10)
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- CCR10 ANTAGONISTS
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The invention relates to a compound of formula (I) or a tautomer thereof or a pharmaceutically acceptable salt thereof, wherein R1 to R11, W, X, Y, Z, and n are as defined herein. The invention also relates to methods of using the compounds of formula (I) and compositions thereof to treat various diseases and disorders in a patient. The invention also relates to processes for preparing the compounds of formula (I) and intermediates useful in these processes.
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Page/Page column 78-79
(2009/05/28)
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- Synthesis of N-protected indolaldehydes using modified Hass procedure
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A detailed study on oxidation of N-protected bromomethylindoles into the respective aldehydes was carried out. Using a modified Hass procedure, synthesis of aryl-/hetero-aryl aldehydes in particular indolaldehydes is achieved in reasonable yields.
- Balamurugan, Ramalingam,Mohanakrishnan, Arasambattu K.
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p. 11078 - 11085
(2008/02/12)
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- Tandem Hass-Bender/Henry reaction for the synthesis of dimethylnitro alcohols from benzylic halides
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Dimethylnitro alcohols are constructed in a one-pot process from benzylic halides and 2-nitropropane. The use of tetrabutylammonium fluoride (TBAF) as the promoter is essential for this tandem Hass-Bender/Henry reaction to proceed.
- Klein, Thomas A.,Schkeryantz, Jeffrey M.
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p. 4535 - 4538
(2007/10/03)
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- Investigation of dissociative electron transfer mechanisms and reactivity patterns through kinetic amplification by a chain process
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The kinetic amplification offered by the S(RN)1 chain process allows the investigation of initiation electron-transfer/bond-breaking steps under very unfavorable thermodynamic conditions, which escape standard kinetic methods. Combining these observations with those derived under conventional thermodynamic conditions allows a considerable extension of the driving force window and thus opens the possibility of uncovering new mechanistic and reactivity patterns. The 'thermal' S(RN)1 reaction of 4-nitrobenzyl chloride with 2-nitropropanate ions is an illustrating example where two-problems of current interest could be investigated. One of these concerns the actively investigated and debated question of the dichotomy and connections between S(N)2 reactions and single electron transfer, particularly the question of catalysis of dissociative electron transfer that may result from mechanism bifurcation along an S(N)2 pathway. The other deals with the existence and magnitude of attractive interactions between fragments within the solvent and the influence of these interactions on the dynamics of dissociative electron transfer. Testing systematically the various mechanistic possibilities through simulation of product distribution and half-reaction time led to the conclusion that a small but sizable interaction between fragments within the solvent cage does exist and influences the dynamics of the dissociative electron-transfer reaction quite significantly. While similar effects have been uncovered or suspected in the electrochemical reductions of CCl4, of other benzyl halides and of phenacyl halides, the reduction of 4-nitrobenzyl chloride by the 2-nitropropanate ion provides a first example of the influence of an interaction between caged fragments on the dynamics of an homogeneous dissociative electron-transfer reaction. The simulations required a precise determination of the various rate constants involved in the chain process. Most of them were derived from cyclic voltammetry and redox catalysis. Particular care was exerted to estimate the ranges of uncertainty on these determinations and hence evaluate the reliability of the mechanistic conclusions.
- Costentin, Cyrille,Hapiot, Philippe,Medebielle, Maurice,Saveant, Jean-Michel
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p. 5623 - 5635
(2007/10/03)
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- A novel borane effect on the C/O alkylation ratio in competing SRN1-SN2 reactions
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The presence of Et3B in the reaction of 2-nitropropane anion (1) with p-nitrobenzyl bromide (5b) in tert-butyl alcohol results in an approximately three-fold increase in C-alkylation [yielding 1-(2-methyl-2-nitropropyl)-4-nitrobenzene (9) by an SRN1 mechanism] versus O-alkylation (by an SN2 mechanism, and leading thereafter to p-nitrobenzaldehyde). Dioxygen completely inhibits C-alkylation in the absence of Et3B, but is ineffective in its presence. p-Dinitrobenzene does not significantly affect the thermal reaction (30°C) of 1 with 5b, but partially inhibits C-alkylation in reaction under photostimulation. However, p-dinitrobenzene catalyzes C-alkylation in the thermal reaction in the presence of Et3B. Rationalizations of these novel results are presented. Qualitatively similar results were obtained for the reaction of phenylnitromethane anion (16) with 5b. Copyright
- Shifman, Ana,Sprecher, Milon,Hoz, Shmaryahu
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p. 105 - 111
(2007/10/03)
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- Nitronate anion recognition and modulation of ambident reactivity by hydrogen-bonding receptors
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Nitronate anions were shown to form complexes in DMSO with hydrogen-bonding receptors such as 1,3-dimethylthiourea 1 (Ka = 120M-1) and bicyclic guanidinium2 (Ka = 3200M-1). A ditopic bis-thiourea exhibited increased association with substrates, that contained either two nitronates (Ka = 7000M-1) or a combination of nitronate and carboxylate (Ka = 1200M-1). Complexation of nitronate resulted in a change in the ambident reactivity during alkylation with p-nitrobenzyl bromide. The predominant reaction pathway was shifted from oxygen alkylation to carbon alkylation as receptor binding strength increased. Kinetic analysis indicated an overall inhibition of nitronate reactivity, and this suggests that greater suppression of the oxygen pathway allows carbon alkylation to predominate.
- Linton, Brian R.,Goodman, M. Scott,Hamilton, Andrew D.
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p. 2449 - 2455
(2007/10/03)
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- Fast electron transfer C-alkylation of 2-nitropropane anion under microwave irradiation
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Microwave irradiation is shown to be an attractive methodology for fast electron transfer C-alkylation reactions of 2-nitropropane anion by different reductive alkylating agent. This method is simple, rapid and affords excellent C-alkylation yields.
- Vanelle, Patrice,Gellis, Armand,Kaafarani, Mustapha,Maldonado, Jose,Crozet, Michel P.
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p. 4343 - 4346
(2007/10/03)
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- Organic Sonochemistry - some illustrative examples of a new fundamental approach
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The sonochemical behaviour of several organic reactions, selected according to their mechanisms, has been examined. Their experimental evolution follows the prediction developed previously, that sonication promotes reactions proceeding through radical pathways.
- Einhorn,Einhorn,Dickens,Luche
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p. 4129 - 4130
(2007/10/02)
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- SELECTIVE REDUCTION OF AROMATIC / ALIPHATIC NITRO GROUPS BY SODIUM SULFIDE.
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Sodium sulfide can be used to reduce selectively aromatic / aliphatic nitro groups.In the absence of water, the aromatic nitro group can be reduced selectively in the presence of a secondary aliphatic one.However, in the presence of a tertiary aliphatic n
- Huber, Didier,Andermann, Guy,Lecrerc, Gerard
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p. 635 - 638
(2007/10/02)
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- Derivatives related to betaxolol with α- and β-adrenergic activities
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The paper describes the synthesis and the pharmacological evaluation of some derivatives of betaxolol, all with an N-aralkylamine instead of the tertiobutylamine. These compounds have been tested for β1-adrenergic receptor antagonism on guinea pig atria, β2-adrenergic receptor antagonism on guinea pig trachea and α-adrenergic blocking activity on rat aorta. Compound U12 with a marked α-blocking activity and compound R8 with a β1/α ratio = 1 were selected for a haemodynamic study in the dog. The decrease in cardiac work and the diminution of total peripheral resistance exhibited by U12 are consistent with a dual α/β-blocking agent. Finally, structure-activity relationships are discussed.
- Leclerc,Decker,Schwartz
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p. 1357 - 1367
(2007/10/02)
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- Kinetics and Mechanism of the C-Alkylation of Nitroalkane Anions by 1-Alkyl-2,4,6-triphenylpyridiniums: A Nonchain Reaction with Radicaloid Characteristics
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The C-alkylation of 2-nitropropanide by N-substituted pyridiniums is first order in each reactant in Me2SO.The effect on the rate of temperature , N substituent, leaving group, and nucleophile was studied quantitatively.Overall, the evidence excludes an SN2 displacement and suggests that the reactions proceed by a free radical nonchain mechanism.
- Katritzky, Alan R.,Kashmiri, M. Akram,Ville, George Z. de,Patel, Ranjan C.
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