- Selective formation of a single atropisomer of meso-meso-linked Zn II diporphyrin through supramolecular self-assembly
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One-way atropisomerism: ineso-(4-Butoxypyrid-3-yl)-substituted Zn II porphyrins self-assemble to form zigzagshaped cyclic hexamers, whereas the meso-meso-linked ZnII diporphyrins 1 undergo self-sorting self-assembly to form different assemblies. Upon heating, entropically driven one-way atropisomerism to 1in-in has been achieved through fragmentary reconstitution of supramolecular aggregates.
- Maeda, Chihiro,Kamada, Taisuke,Aratani, Naoki,Sasamori, Takahiro,Tokitoh, Norihiro,Osuka, Atsuhiro
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Read Online
- Deaminative chlorination of aminoheterocycles
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Selective modification of heteroatom-containing aromatic structures is in high demand as it permits rapid evaluation of molecular complexity in advanced intermediates. Inspired by the selectivity of deaminases in nature, herein we present a simple methodology that enables the NH2 groups in aminoheterocycles to be conceived as masked modification handles. With the aid of a simple pyrylium reagent and a cheap chloride source, C(sp2)?NH2 can be converted into C(sp2)?Cl bonds. The method is characterized by its wide functional group tolerance and substrate scope, allowing the modification of >20 different classes of heteroaromatic motifs (five- and six-membered heterocycles), bearing numerous sensitive motifs. The facile conversion of NH2 into Cl in a late-stage fashion enables practitioners to apply Sandmeyer- and Vilsmeier-type transforms without the burden of explosive and unsafe diazonium salts, stoichiometric transition metals or highly oxidizing and unselective chlorinating agents. [Figure not available: see fulltext.]
- Cornella, Josep,Faber, Teresa,Gómez-Palomino, Alejandro,Ghiazza, Clément
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- Photocatalytic deoxygenation of N-O bonds with rhenium complexes: From the reduction of nitrous oxide to pyridineN-oxides
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The accumulation of nitrogen oxides in the environment calls for new pathways to interconvert the various oxidation states of nitrogen, and especially their reduction. However, the large spectrum of reduction potentials covered by nitrogen oxides makes it difficult to find general systems capable of efficiently reducing variousN-oxides. Here, photocatalysis unlocks high energy species able both to circumvent the inherent low reactivity of the greenhouse gas and oxidant N2O (E0(N2O/N2) = +1.77 Vvs.SHE), and to reduce pyridineN-oxides (E1/2(pyridineN-oxide/pyridine) = ?1.04 Vvs.SHE). The rhenium complex [Re(4,4′-tBu-bpy)(CO)3Cl] proved to be efficient in performing both reactions under ambient conditions, enabling the deoxygenation of N2O as well as synthetically relevant and functionalized pyridineN-oxides.
- Anthore-Dalion, Lucile,Cantat, Thibault,Kjellberg, Marianne,Nicolas, Emmanuel,Ohleier, Alexia,Thuéry, Pierre
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p. 10266 - 10272
(2021/08/12)
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- Catalyst-Free N-Deoxygenation by Photoexcitation of Hantzsch Ester
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A mild and operationally simple protocol for the deoxygenation of a variety of heteroaryl N-oxides and nitroarenes has been developed. A mixture of substrate and Hantzsch ester is proposed to result in an electron donor-acceptor complex, which upon blue-light irradiation undergoes photoinduced electron transfer between the two reactants to afford the products. N-oxide deoxygenation is demonstrated with 22 examples of functionally diverse substrates, and the chemoselective reduction of nitroarenes to the corresponding hydroxylamines is also shown.
- Cardinale, Luana,Jacobi Von Wangelin, Axel,Konev, Mikhail O.
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supporting information
(2020/02/15)
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- A 3 - aldehyde -4 - chloro pyridine green preparation method
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The invention discloses a 3 - aldehyde - 4 - chloro pyridine green preparation method, which belongs to the technical field of organic synthesis. Technical proposal of the invention points are: to pyridine as raw materials, the selective chlorination, after the adoption of the salt in the solvent impurities and product of different solubility, can be recrystallized separation, to obtain 4 - chloro pyridine pure product, finally is then subjected to an N, N - dimethyl formamide substitution reaction to obtain the 3 - aldehyde - 4 - chloro pyridine. The invention compared with the prior art has the following advantages: the invention synthetic method is simple, cheap price of raw materials, and is favorable for industrial production.
- -
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Paragraph 0010-0026
(2019/03/25)
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- A 3 - aldehyde -4 - chloro pyridine preparation method
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The invention discloses a 3 - aldehyde - 4 - chloro pyridine of the preparation method, which belongs to the technical field of organic synthesis. Technical proposal of the invention points are: to pyridine as raw materials, the selective chlorination of at first, through the molecular distillation treatment to obtain a pure 4 - chloro pyridine, then in N, N - dimethyl formamide substitution reaction to obtain the 3 - aldehyde - 4 - chloro pyridine. The invention compared with the prior art has the following advantages: the invention synthetic method is simple, cheap price of raw materials, and is favorable for industrial production.
- -
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Paragraph 0010; 0011; 0012; 0013-0018
(2019/03/25)
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- Efficient Chemoselective Reduction of N-Oxides and Sulfoxides Using a Carbon-Supported Molybdenum-Dioxo Catalyst and Alcohol
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The chemoselective reduction of a wide range of N-oxides and sulfoxides with alcohols is achieved using a carbon-supported dioxo-molybdenum (Mo@C) catalyst. Of the 10 alcohols screened, benzyl alcohol exhibits the highest reduction efficiency. A variety of N-oxide and both aromatic and aliphatic sulfoxide substrates bearing halogens as well as additional reducible functionalities are efficiently and chemoselectively reduced with benzyl alcohol. Chemoselective N-oxide reduction is effected even in the presence of potentially competing sulfoxide moieties. In addition, the Mo@C catalyst is air- and moisture-stable, and is easily separated from the reaction mixture and then re-subjected to reaction conditions over multiple cycles without significant reactivity or selectivity degradation. The high stability and recyclability of the catalyst, paired with its low toxicity and use of earth-abundant elements makes it an environmentally friendly catalytic system.
- Li, Jiaqi,Liu, Shengsi,Lohr, Tracy L.,Marks, Tobin J.
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p. 4139 - 4146
(2019/05/27)
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- C6-Selective Direct Arylation of 2-Phenylpyridine via an Activated N-methylpyridinium Salt: A Combined Experimental and Theoretical Study
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An elegant pre-activation strategy, based on the formation of N-methylpyridinium iodide salts for C6-selective direct arylation of 2-phenylpyridines using Pd/Cu cooperative catalysis, has been developed. By this methodology, a wide range of unsymmetrical 2, 6-diarylpyridines were synthesized with high reactivity and regioselectivity as well as good functional group tolerance. In particular, challenging substrates bearing electron donating groups (EDGs), such as OMe, NMe2, were also successfully employed in this reaction. Deuterium incorporation studies revealed that the C?H bond acidity is improved significantly in N-methylpyridinium salts compared with their N-Oxide and N-iminopyridinium ylide counterparts, thus solving the long-standing problem associated with previous strategies for the synthesis of diaryl pyridines. Finally, the control experiments and DFT calculations supported a Pd-catalyzed and Cu-mediated mechanism in which a carbenoid copper species that is formed in-situ from N-methylpyridinium salts, participates in a Pd-catalyzed arylation followed by an iodide-promoted N-demethylation process. (Figure presented.).
- Yin, Changzhen,Zhong, Kangbao,Li, Wenjing,Yang, Xiao,Sun, Rui,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Lan, Yu,Fu, Haiyan,Chen, Hua
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supporting information
p. 3990 - 3998
(2018/09/12)
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- Palladium-Catalysed Cross-Coupling Reactions Controlled by Noncovalent Zn???N Interactions
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Non-covalent interactions between halopyridine substrates and catalytically inert building blocks, namely zinc(II)–porphyrins and zinc(II)–salphens, influence the catalytic outcome of Suzuki–Miyaura and Mizoroki–Heck palladium-catalysed cross-coupling reactions. The weak Zn???N interactions between halopyridine substrates and zinc(II)-containing porphyrins and salphens, respectively, were studied by a combination of 1H NMR spectroscopy, UV/Vis studies, Job-Plot analysis and, in some cases, X-ray diffraction studies. Additionally, the former studies revealed unique supramolecular polymeric and dimeric rearrangements in the solid state featuring weak Br???N (halogen bonding), C?H???π, Br???π and π???π interactions. The reactivity of halopyridine substrates in homogeneous palladium-catalysed cross-coupling reactions was found to correlate with the binding strength between the zinc(II)-containing scaffolds and the corresponding halopyridine. Such observation is explained by the unfavourable formation of inactive over-coordinated halopyridine???palladium species. The presented approach is particularly appealing for those cases in which substrates and/or products deactivate (or partially poison) a transition-metal catalyst.
- Kadri, Mohamed,Hou, Jingran,Dorcet, Vincent,Roisnel, Thierry,Bechki, Lazhar,Miloudi, Abdellah,Bruneau, Christian,Gramage-Doria, Rafael
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supporting information
p. 5033 - 5043
(2017/04/18)
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- Visible-light-responsive catalysis of a zinc-introduced lacunary disilicoicosatungstate for the deoxygenation of pyridine N-oxides
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We herein report the synthesis and photoredox catalysis of a mononuclear zinc-introduced lacunary disilicoicosatungstate TBA7[{Zn(CH3CN)}(γ-SiW10O34){γ-SiW10O32(CH3CONH)}(μ-O)2] (II, TBA = tetra-n-butylammonium). POM II showed efficient photocatalytic activity in the selective deoxygenation of pyridine N-oxides under visible light irradiation (λ > 400 nm).
- Jeong, Jinu,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information
p. 13226 - 13229
(2017/11/27)
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- Efficient transposition of the sandmeyer reaction from batch to continuous process
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The transposition of Sandmeyer chlorination from a batch to a safe continuous-flow process was investigated. Our initial approach was to develop a cascade method using flow chemistry which involved the generation of a diazonium salt and its quenching with copper chloride. To achieve this safe continuous process diazotation, a chemometric approach (Simplex method) was used and extrapolated to establish a fully continuous-flow method. The reaction scope was also examined via the synthesis of several (het)aryl chlorides. Validation and scale-up of the process were also performed. A higher productivity was obtained with increased safety.
- D'Attoma, Joseph,Camara, Titi,Brun, Pierre Louis,Robin, Yves,Bostyn, Stéphane,Buron, Frédéric,Routier, Sylvain
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- Cl3CCN/PPh3 and CBr4/PPh3: Two efficient reagent systems for the preparation of N-heteroaromatic halides
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Cl3CCN/PPh3 and CBr4/PPh3 are two highly reactive reagent systems for the conversion of N-heteroaromatic hydroxy compounds into N-heteroaromatic chlorides or bromides in moderate to excellent yields under mild and acid-free conditions.
- Kijrungphaiboon, Woranun,Chantarasriwong, Oraphin,Chavasiri, Wainthorn
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scheme or table
p. 674 - 677
(2012/02/15)
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- CHEMICAL MOLECULES THAT INHIBIT THE SLICING MECHANISM FOR TREATING DISEASES RESULTING FROM SPLICING ANOMALIES
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The present invention relates to a compound of one of the formulas I to XXI; a pharmaceutical composition comprising at least one such compound; and the use of at least one such compound in preparing a drug to treat, in a subject, a genetic disease resulting from at least one splicing anomaly.
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Page/Page column 60
(2011/04/14)
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- TBAF-Catalysed silver oxide-mediated cross-coupling of functional trimethysilylpyridines: Access to arylpyridines and bihetaryl compounds
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The concomitant use of silver oxide and catalytic amount of TBAF allowed the efficient and chemoselective coupling of readily available 4-chloro- and 4-methyl-2-trimethyl-silyl-pyridines with heteroaromatic and aromatic halides. Based on control experiments, a mechanism involving the formation of a pyridylsilver intermediate and TBAF recycling is postulated.
- Louerat, Frederic,Tye, Heather,Napier, Spencer,Garrigou, Michael,Whittaker, Mark,Gros, Philippe C.
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scheme or table
p. 1768 - 1773
(2011/04/26)
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- HETEROARYLS AND THEIR USE AS PI3K INHIBITORS
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This invention provides compounds of formula (IA) or (IB): wherein R1, R2, G1 and HY are as described in the specification. The compounds are inhibitors of PI3K and/or mTor and are thus useful for treating proliferative, inflammatory, or cardiovascular disorders.
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Page/Page column 301
(2010/08/18)
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- Structure-activity relationship of antiparasitic and cytotoxic indoloquinoline alkaloids, and their tricyclic and bicyclic analogues
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Based on the indoloquinoline alkaloids cryptolepine (1), neocryptolepine (2), isocryptolepine (3) and isoneocryptolepine (4), used as lead compounds for new antimalarial agents, a series of tricyclic and bicyclic analogues, including carbolines, azaindoles, pyrroloquinolines and pyrroloisoquinolines was synthesized and biologically evaluated. None of the bicyclic compounds was significantly active against the chloroquine-resistant strain Plasmodium falciparum K1, in contrast to the tricyclic derivatives. The tricyclic compound 2-methyl-2H-pyrido[3,4-b]indole (9), or 2-methyl-β-carboline, showed the best in vitro activity, with an IC50 value of 0.45 μM against P. falciparum K1, without apparent cytotoxicity against L6 cells (SI > 1000). However, this compound was not active in the Plasmodium berghei mouse model. Structure-activity relationships are discussed and compared with related naturally occurring compounds.
- Van Baelen, Gitte,Hostyn, Steven,Dhooghe, Liene,Tapolcsanyi, Pal,Matyus, Peter,Lemiere, Guy,Dommisse, Roger,Kaiser, Marcel,Brun, Reto,Cos, Paul,Maes, Louis,Hajos, Gyoergy,Riedl, Zsuzsanna,Nagy, Ildiko,Maes, Bert U.W.,Pieters, Luc
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experimental part
p. 7209 - 7217
(2010/03/30)
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- Expedient synthesis of 3-alkoxymethyl- And 3-aminomethyl-pyrazolo[3,4-b] pyridines
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An effective strategy has been developed for the preparation of 3-alkoxymethyl-pyrazolo[3,4-b]pyridines, compounds that are currently not readily accessible by existing synthetic methods. Further manipulation of these compounds allows for access to 3-alkoxymethyl-pyrazolo[3,4-b]pyridines with a variety of substitution patterns as well as 3-aminomethyl-pyrazolo[3,4-b] pyridines.
- Beutner, Gregory L.,Kuethe, Jeffrey T.,Kim, Mary M.,Yasuda, Nobuyoshi
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supporting information; body text
p. 789 - 794
(2009/06/20)
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- CHEMICAL MOLECULES THAT INHIBIT THE SLICING MECHANISM FOR TREATING DISEASES RESULTING FROM SPLICING ANOMALIES
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The present invention relates to a compound of one of the formulas I to XXI; a pharmaceutical composition comprising at least one such compound; and the use of at least one such compound in preparing a drug to treat, in a subject, a genetic disease resulting from at least one splicing anomaly.
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Page/Page column 97
(2009/09/04)
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- Chemoselective hydrogenation of nitroarenes and deoxygenation of pyridine N-oxides with H2 catalyzed by MoO2Cl2
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A chemoselective and highly efficient hydrogenation of nitroarenes and deoxygenation of pyridine N-oxides using a cheap and environmentally friendly H2/MoO2Cl2 system has been developed.
- Reis, Patrícia M.,Royo, Beatriz
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scheme or table
p. 949 - 952
(2009/05/27)
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- Displacement of neutral nitrogen donors by chloride in AuCl3(am) (am = pyridines and amines): Kinetics and DFT calculations show the effects of basicity and π-acceptor ability
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The kinetics of the process AuCl3(am) + Cl- → AuCl4- + am (am = sp2 N-donor isosteric pyridines with different π systems and sp3 amines; they cover a wide range of basicity) have been studied in methanol at 25°C. The reactions obey the usual two-term rate law observed in substitutions on square-planar complexes. The second-order rate constants, k2, are very sensitive to the nature of the leaving group, and plots of log k2 against the pKa of the conjugate acids are linear, with the same slope, -0.68, for both normal pyridines and pyridines with a more extended π system, such as 4-cyanopyridine, isonicotinic acid, methyl isonicotinate and 4-acetylpyridine. The reactivity of the considered N-donors is different and follows the order sp3 N-donors > normal pyridines > π-extended pyridines. This result, with the support of ground-state DFT calculations on the AuCl3(am) derivatives, is explained on the basis of an Au-N bond enforcement due to an increased π-back-donation contribution. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Pitteri, Bruno,Bortoluzzi, Marco
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p. 4456 - 4461
(2008/03/12)
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- Indazoles, benzothiazoles, benzoisothiazoles, benzisoxazoles, pyrazolopyridines, isothiazolopyridines, and preparation and uses thereof
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The present invention relates generally to the field of ligands for nicotinic acetylcholine receptors (nACh receptors), activation of nACh receptors, and the treatment of disease conditions associated with defective or malfunctioning nicotinic acetylcholine receptors, especially of the brain. Further, this invention relates to novel compounds (e.g., indazoles and benzothiazoles), which act as ligands for the α7 nACh receptor subtype, methods of preparing such compounds, compositions containing such compounds, and methods of use thereof.
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Page/Page column 69
(2010/11/26)
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- 1 H-INDAZOLES, BENZOTHIAZOLES, 1,2-BENZOISOXAZOLES, 1,2-BENZOISOTHIAZOLES, AND CHROMONES AND PREPARATION AND USES THEREOF
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The present invention relates generally to the field of ligands for nicotinic acetylcholine receptors (nAChR), activation of nAChRs, and the treatment of -disease conditions associated with defective or malfunctioning nicotinic acetylcholine receptors, especially of the brain. Further, this invention relates to novel compounds (indazoles and benzothiazoles), which act as ligands for the α7 nAChR subtype, methods of preparing such compounds, compositions containing such compounds, and methods of use thereof.
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Page/Page column 75
(2010/11/27)
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- Nucleophilicities and carbon basicities of pyridines
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Rate and equilibrium constants for the reactions of pyridines with donor-substituted benzhydrylium ions have been determined spectrophotometrically. The correlation equation log k(20°C) = s(N+E). in which s and N are nucleophile-specific parameters and E is an electrophile-specific parameter, has been used to determine the nucleophilicity parameters of various pyridines in CH2Cl2 and aqueous solution and to compare them with N of other nucleophiles. It is found that the nucleophilic organocatalyst 4-(dimethylamino)pyridine (DMAP) and tertiary phosphanes have comparable nucleophilicities and carbon basicities despite widely differing Bronsted basicities. For that reason, these reactivity parameters are suggested as guidelines for the development of novel organocatalysts. The Marcus equation is employed for the determination of the intrinsic barriers of these reactions.
- Brotzel, Frank,Kempf, Bernhard,Singer, Thomas,Zipse, Hendrik,Mayr, Herbert
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p. 336 - 345
(2007/10/03)
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- Deoxygenation of N-oxides with triphenylphosphine, catalyzed by dichlorodioxomolybdenum(VI)
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Chemoselective deoxygenation of N-oxides was carried out under mild conditions with common phosphines in the presence of dichlorodioxomolybdenum(VI) . Georg Thieme Verlag Stuttgart.
- Sanz, Roberto,Escribano, Jaime,Fernández, Yolanda,Aguado, Rafael,Pedrosa, María R.,Arnáiz, Francisco J.
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p. 1389 - 1392
(2007/10/03)
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- SUBSTITUTED 4-AMINO-1-(PYRIDYLMETHYL)PIPERIDINE AND RELATED COMPOUNDS
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This invention provides 4-amino-1-(pyridylmethyl)piperidine and related compounds and pharmaceutically acceptable salts thereof which are useful as muscarinic receptor antagonists. This invention also provides pharmaceutical compositions containing such compounds; processes and intermediates useful for preparing such compounds; and methods for treating disease conditions mediated by muscarinic receptors, such as overactive bladder, irritable bowel syndrome and chronic obstructive pulmonary disease, using such compounds.
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- Large-scale Negishi coupling as applied to the synthesis of PDE472, an inhibitor of phosphodiesterase type 4D
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5-[2-Methoxy-5-(4-pyridinyl)phenyl]-2,1,3-benzoxadiazole (PDE472) is a selective inhibitor of the phosphodiesterase PDE4D isoenzyme, which is a recognised drug target for the treatment of asthma. Different synthetic routes to PDE472 were investigated, and the research synthesis was optimised to prepare a phase I batch on pilot-plant scale with the focus on the elimination or minimization of inherent process risks. An important refinement of the key Negishi aryl-aryl coupling involved preforming the arylpalladium complex, which was then added to the arylzinc intermediate. Residual palladium was removed from PDE472 via crystallization of the hemi-maleate salt, which afforded drug-substance containing 2 ppm Pd.
- Manley, Paul W.,Acemoglu, Murat,Marterer, Wolfgang,Pachinger, Werner
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p. 436 - 445
(2013/09/06)
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- An Efficient Deoxgenation of Heteroaromatic N-Oxides Using Zinc Dust/Ammonium Formate Reagent System
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Heteroaromatic N-oxides were readily and selectively deoxygenated to the corresponding bases with zinc/ammonium formate reagent system.
- Balicki, Roman,Cybulski, Marcin,Maciejewski, Grzegorz
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p. 4137 - 4141
(2007/10/03)
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- A mild and selective deoxygenation of N-oxides with ammonium formate as a catalytic hydrogen transfer agent
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Ammonium formate catalytic transfer hydrogenation in the presence of raney nickel has shown utility for mild and selective deoxygenation of heteroaromatic N-oxides in neutral medium.
- Balicki, Roman,Maciejewski, Grzegorz
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p. 1681 - 1683
(2007/10/03)
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- Process for preparation of 2-chloropyridine
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Described are processes for producing 2-chloropyridine by reacting pyridine with molecular chlorine in the vapor phase in the presence of a catalyst which includes an organic compound which generates free radicals under the conditions of the reaction.
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Page column 4-5
(2010/01/31)
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- Anti-viral method
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PCT No. PCT/US97/07431 Sec. 371 Date Jan. 6, 1999 Sec. 102(e) Date Jan. 6, 1999 PCT Filed May 2, 1997 PCT Pub. No. WO97/41846 PCT Pub. Date Nov. 13, 1997The present invention provides compounds which inhibit an envelope virus by inhibiting the fusion of the virus with the host cell. The virus may be inhibited in an infected cell, a cell susceptible of infection or a mammal in need thereof.
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- An efficient and chemoselective deoxygenation of hetero cyclic N-oxides using LiCl/NaBH4
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A practical and novel reagent system LiCl/NaBH4 is used for the deoxygenation of N-Oxides to amines is described.
- Raja Ram,Purushothama Chary,Iyengar
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p. 3511 - 3515
(2007/10/03)
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- Efficient catalytic conversion of pyridine N-oxides to pyridine with an oxorhenium(V) catalyst
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(Equation Presented) The compound CH3Re(O)(SR)2PPh3, where (SR)2 represents the dianion of 2-(mercaptomethyl)thiophenol, catalyzes the rapid and efficient transfer of an oxygen atom from a wide range of ring-substituted pyridine N-oxides to triphenylphosphine, yielding the pyridines in high yield.
- Wang, Ying,Espenson, James H.
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p. 3525 - 3526
(2007/10/03)
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- A mild deoxygenation of heteroaromatic N-oxides by formamidinesulfinic acid
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Various heteroaromatic N-oxides were efficiently deoxygenated to the corresponding bases under mild conditions using formamidinesulfinic acid (thiourea S,S-dioxide).
- Balicki, Roman,Chmielowiec, Urszula
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p. 1105 - 1107
(2007/10/03)
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- Indium-mediated deoxygenation of nitrones, N-oxides and deoxygenative reductive coupling of nitrones to vicinal diamines
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We reported transformation of nitrones selectively either to aldamines or vicinal diamines and deoxygenation of N-oxides using Indium at ambient temperature in good yields.
- Jeevanandam, Arumugasamy,Cartwright, Charles,Ling, Yong-Chien
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p. 3153 - 3160
(2007/10/03)
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- A Novel and Efficient Deoxygenation of Hetero Cyclic N-Oxides Using ZrCl4/NaBH4
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A practical and novel reagent system ZrCl4/NaBH4 is used for the deoxygenation of N-Oxides to amines is described.
- Chary, K. Purushothama,Mohan, G. Hari,Iyengar, D. S.
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p. 1339 - 1340
(2007/10/03)
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- Urea, thiourea and guanidine compounds and their use as anti-viral agents
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The present invention provides compounds which inhibit an envelope virus by inhibiting the fusion of the virus with the host cell. The virus may be inhibited in an infected cell, a cell susceptible of infection or a mammal in need thereof.
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- A new redox system: Trichloromethylarene - Pyridine base. On the mechanism of the synthesis of N-(4-pyridyl)pyridinium dichloride
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A redox reaction of trichloromethylarenes with pyridines results in respective N-(α-chloroarylmethyl)-substituted pyridinium chlorides which give on hydrolysis aromatic aldehydes and 4-chloropyridines or 1,4'- bipyridinium salts.
- Belen'kii, Leonid I.,Poddubnyi, Igor S.,Krayushkin, Mikhail M.
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p. 5075 - 5078
(2007/10/02)
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- Reactivity of Heterocyclic Nitrogen Donors in Systems containing the Tetrachloroaurate(III) Anion
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A series of gold(III) complexes of the type has been prepared and characterized (L = oxazole, benzoxazole, thiazole, their benzo and methyl-substituted derivatives, or 2-methylbenzoselenazole).The five-membered N.O-, N,S- and N,Se-heterocyclic bases are all bound to Au(III) through nitrogen.The kinetics of the displacement of L by chloride to give (1-) has been studied in methanol-water (95:5. v/v) at 25.0 deg C and I = 0.20 mol dm-3 (LiClO4).The equilibrium constants for the reversible processes have also been determined.The reactions of the corresponding pyridine, 4-chloro-, 4-cyano- and 2,6-bis(chloromethyl)-pyridine complexes have also been reexamined under the same conditions.The equlibrium constants, K2, depend upon the basicity of the nitrogen in the ligands and points for all ligands, irrespective of ring size and composition, lie roughly on the same log K2 versus pKa curve.There is no significant systematic steric effect on the equilibrium constants of the sort found for the more basic methyl pyridines.The complexes of the five-membered heterocyclic ligands are approximately ten times less reactive than those of the six-membered N-heterocycles of comparable basicity and exhibit steric retardation from ortho-methyl substituents.The nucleophilicities of these ligands have been calculated and five-membered N,O- and N,S-heterocycles are considerably less reactive than six-membered N-heterocycles of similar basicity.
- Canovese, Luciano,Cattalini, Lucio,Tomaselli, Michele,Tobe, Martin L.
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p. 307 - 314
(2007/10/02)
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- Cephem derivatives
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Cephalosporins having a 3-position substituent of the formula: STR1 are described, wherein R5 is hydrogen, alkenyl, alkyl or substituted alkyl, Q is a mono- or bicyclic heterocyclic ring, variously substituted, Y is variously substituted alkylene, Y' represents various linking groups, m and n are independently zero or one, and P is a benzene ring with two ortho groups, one of which is hydroxy or an in-vivo hydrolysable ester thereof and the other is hydroxy, an in vivo hydrolysable ester thereof, carboxy, sulpho, hydroxymethyl, --NHSO2 CH3 or --NHCONH2 ; or P is a particularly substituted pyridone or pyranone. The use of such compounds as antibacterial agents is described, as are processes for their preparation.
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- The displacement of the heterocyclic base R-py from [pd(dien)(R-py)]2+ (dien = 1,5-diamino-3-azapentane, R-py = 4-chloropyridine or 4-aminopyridine) by water in acid and basic solution and by chloride. The involvement of a stable five-co-ordinate species
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The kinetics of displacement of R-py from the [Pd(dien)(R-py)]2+ cation in acid and basic solution in the absence and presence of chloride ions are reported. In acid solution the rate of displacement of 4-chloropyridine is independent of [H+] but that for 4-aminopyridine is acid catalysed, the pyridylammonium ligand being a much better leaving group. In basic solution, the rate of displacement of 4-chloropyridine obeys the rate equation l03kobs. = 8.7 + 11.5[OH-] + 122[OH-]2 s-1, while that for the 4-aminopyridine complex is independent of [OH-]. The reaction between [Pd(dien)(4Cl-py)]2+ and Cl- leads to the rapid formation of a stable intermediate species which is in equilibrium with [Pd(dien)Cl]+ and 4Cl-py. No such intermediate is observed in the reaction of the 4-aminopyridine complex which loses the ligand by the normal path for substitution in square-planar complexes. In the presence of acid the entry of Cl- is irreversible and both substrates revert to the classical mechanism for ligand substitution.
- Canovese, Luciano,Cattalini, Lucio,Uguagliati, Paolo,Tobe, Martin L.
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p. 3271 - 3276
(2007/10/02)
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- TiCl4/NaI - A Novel, Efficient Reagent for Mild Reduction of the N-O Bond in Amine N-Oxides and Nitrones
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Heteroaromatic N-oxides and nitrones were readily and selectively deoxygenated to the corresponding bases or imines in excellent yields with the TiCl4/NaI reagent system.
- Balicki, Roman
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p. 647 - 649
(2007/10/02)
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- SELECTIVE REDUCTION OF THE N-O BOND IN HETEROAROMATIC N-OXIDES BY TiCl4/SnCl2.
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Heteroaromatic N-oxides bearing various functionalities are readily and selectively converted under mild conditions into the corresponding bases using TiCl4/SnCl2.
- Balicki, Roman,Kaczmarek, Lukasz,Malinowski, Marek
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p. 897 - 900
(2007/10/02)
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- THE PYRIDYL CATION AS A REACTIVE INTERMEDIATE IN THE PHOTOREACTION OF IODOPYRIDINES WITH BENZENES
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The electrophilic behavior of the reactive entity in the photosubstitution of benzenes with 2-iodopyridine was found to be ascribable to the intermediary 2-pyridyl cation, rather than the electrophilic 2-pyridyl radical.
- Ohkura, Kazue,Seki, Koh-ichi,Terashima, Masanao,Kanaoka, Yuichi
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p. 3433 - 3436
(2007/10/02)
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- PHOTODECARBOXYLATIVE CHLORINATION OF CARBOXYLIC ACIDS VIA THEIR BENZOPHENONE OXIME ESTERS
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Decarboxylative chlorination of various aromatic and aliphatic carboxylic acids is performed successfully by the photolysis of their benzophenone oxime esters in carbon tetrachloride and corresponding chloro compounds are prepared in good yields.High selective generation of the certain radical and efficiency of the stable radical precursor, benzophenone oxime ester, afford much advantage for radical chemistry.
- Hasebe, Masato,Tsuchiya, Takashi
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p. 6287 - 6290
(2007/10/02)
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- Site-Selectivity in the Reaction of 3-Substituted Pyridine 1-Oxides with Phosphoryl Chloride
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Site-selectivity in the reaction of 3-substituted pyridine 1-oxide with phosphoryl chloride was investigated.When a strongly electron-withdrawing group (e.g.CN, CONRR', COOR, or NO2) was substituted at the 3-position, the reaction of 3-substituted pyridine 1-oxides with phosphoryl chloride yielded 3-substituted 2-chloropyridines as the main products.Keywords- site-selectivity; 3-substituted pyridine 1-oxide; phosphoryl chloride; 3-substituted 2-chloropyridine; chlorination
- Yamanaka, Hiroshi,Araki, Tomio,Sakamoto, Takao
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p. 2244 - 2247
(2007/10/02)
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- Herbicidal (2 or 6)-fluoroalkyl-4-amino pyridine derivatives
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Disclosed herein are 3,5-pyridinedicarboxylic acid derivatives having heteroatom substitution at the 4 position which are useful as herbicides and herbicide precursors.
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- Titanium(0) Reagents; 2. A Selective and Efficient Deoxygenation of Halogen Containing Heteroaromatic N-Oxides
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Following successful reductions of unfunctionalized heteroaromatic N-oxides by titanium(0), we applied this method to halogenated aromatic N-oxides to give the deoxygenated halogeno derivatives in 90-95percent yield.
- Malinowski, Marek,Kaczmarek, Lukasz
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p. 1013 - 1015
(2007/10/02)
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- Mild Selective Deoxygenation of Amine Oxides by Tin-Tin Bonded Derivatives
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A new method of deoxygenation of amine oxides with tin reagent is proposed.It utilizes the reductive properties of the tin-tin bond in hexabutyldistannane or 1,2-dichlorotetrabutyldistannane.Oxides of tertiary amines are reduced into amines by hexabutyldistannane in high yields, whereas pyridine N-oxides react cleanly with 1,2-dichlorotetrabutyldistannane to give the corresponding pyridines.These reactions occur under mild conditions and are very selective.
- Jousseaume, Bernard,Chanson, Evelyne
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- 2-Nitroxymethyl and 2,6-bis-nitroxymethyl-pyridine compounds having vasodilating activity
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This invention relates to pyridylalkyl nitrate compound and a salt thereof. More particularly, it relates to a new pyridylalkyl nitrate compound and a pharmaceutically acceptable salt thereof which have vasodilating activities, to process for the preparation thereof, and to a pharmaceutical composition comprising the same for therapeutical treatment of cardiovascular disorder in human being.
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