- Preparation method of ortho-alkoxy substituted pyridine compound
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The invention provides a preparation method of an ortho-alkoxy substituted pyridine compound, the preparation method comprises the following step: reacting an ortho-amino substituted pyridine compound with an ortho-formate compound in the presence of a nitrite compound to generate the ortho-alkoxy substituted pyridine compound. The method has the advantages of high efficiency, low cost, environmental protection and the like.
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Paragraph 0061-0062
(2021/09/08)
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- Novel synthesis method for ortho-alkane superseded pyridine
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The invention relates to a novel synthesis method for ortho-alkane superseded pyridine. According to the method, ortho halogenated pyridine serves as raw materials, the ortho halogenated pyridine and corresponding alcohol react to obtain the ortho-alkane superseded pyridine under the action of sodium hydroxide. The reaction has universality for the ortho halogenated pyridine, and the method is simple and practical. Influence of consumption of the sodium hydroxide on mono-substitution and di-substitution in the reaction is inspected, alkoxy mono-substitution products and alkoxy di-substitution production are acquired, and a novel simply-operated, economical and favorable process for synthesis ortho-alkane superseded pyridine is provided.
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Paragraph 0018; 0019; 0020; 0021
(2017/07/19)
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- A Novel Convenient Synthesis of Pyridinyl and Quinolinyl Triflates and Tosylates via One-Pot Diazotization of Aminopyridines and Aminoquinolines in Solution
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The first effective and simple method for the direct one-pot transformation of 2-, 3-, and 4-aminopyridines, 2,6-diaminopyridines, and 2-aminoquinoline into the corresponding pyridinyl and quinolinyl trifluoromethanesulfonates and tosylates in solvents was developed. The procedure involves diazotization of the heterocyclic amines with sodium nitrite in mixed hexane-DMSO or hexane-DMF solutions in the presence of trifluoromethanesulfonic acid or p-toluenesulfonic acid.
- Kassanova, Assiya Zh.,Krasnokutskaya, Elena A.,Beisembai, Perizat S.,Filimonov, Victor D.
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p. 256 - 262
(2016/01/15)
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- NaBH4-TMEDA and a palladium catalyst as efficient regio- and chemoselective system for the hydrodehalogenation of halogenated heterocycles
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The pair NaBH4-TMEDA as hydride source and a palladium catalyst in THF prove to be an efficient system for the hydrodehalogenation of halogenated heterocycles with one or more heteroatoms. In general, Pd(OAc) 2-PPh3 rapidly hydrodehalogenates reactive halo-heterocycles such as bromo-pyridines, -quinolines, -thiophenes, -indoles, -imidazoles, etc., at room temperature in very good yields, whereas in most cases PdCl2(dppf) reduces less reactive halides such as chloro-pyridines, -quinolines, -pyrimidines and bromo-indoles, -benzofurans, etc. Moreover, PdCl2(tbpf) shows to be even more active removing the 2- and 5-chlorine from both thiophene and thiazole rings. The reaction conditions tolerate various functional groups, allowing highly chemoselective reactions in the presence of halide, ester, alkyne, alkene and nitrile substituents. Moreover, with a proper selection of the catalyst it is also possible to obtain a good control in the regioselective hydrodehalogenation of a variety of polyhalogenated substrates.
- Chelucci, Giorgio,Figus, Susanna
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p. 191 - 209
(2014/07/21)
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- Hydrodehalogenation of halogenated pyridines and quinolines by sodium borohydride/N,N,N′,N′-tetramethylethylenediamine under palladium catalysis
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A protocol for the hydrodehalogenation of halogenated pyridines and quinolines by the sodium borohydride/N,N,N′,N′-tetramethylethylenediamine (NaBH4-TMEDA) system under palladium catalysts is reported. Catalytic amounts of [1,1′-bis(diphenylphosphino)ferrocene] dichloropalladium(II) in combination with NaBH4-TMEDA rapidly hydrodehalogenate chloro(bromo)-pyridines and -quinolines at room temperature in quantitative yields. Chemoselective reduction of 4,7-dichloroquinoline affords 7-chloroquinoline as the sole product in almost quantitative yield. Moreover, palladium(II) acetate-triphenylphosphine and NaBH4-TMEDA are able to reduce efficiently reactive bromo-pyridines and -quinolines.
- Chelucci, Giorgio
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experimental part
p. 1562 - 1565
(2010/06/14)
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- Microwave-assisted silver(I)-mediated selective O-alkylation of aromatic imidate systems
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A novel microwave-assisted protocol has been developed for the selective O-alkylation of aromatic imidate systems with various halides under microwave irradiation using silver carbonate as the base. Products were obtained in short reaction time and in excellent yields. Georg Thieme Verlag Stuttgart.
- Singh, Brajendra K.,Cavalluzzo, Claudia,De Maeyer, Marc,Debyser, Zeger,Parmar, Virinder S.,Van Der Eycken, Erik
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experimental part
p. 2725 - 2728
(2010/01/21)
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- On the thermally induced rearrangement of 2-alkoxypyridines to N-alkylpyridones
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Analogues of 2-methoxypyridine undergo rearrangement to N-methylpyridones under flash vacuum pyrolysis (FVP) conditions. Ethoxy derivatives undergo competitive ethyl migration and elimination of ethylene. Analogues of 4-methoxypyridine do not undergo rearrangement under FVP conditions, but demethylation on silica may occur. The ease of rearrangement follows the basicity of the alkoxyhetarene to some extent. The vapour-phase rearrangements have been contrasted to condensed-phase pyrolyses. and a four-centre transition state for the former is supported by computation. The rearrangement allows structural assignment to the two products from the reaction of 2,4-dichloroquinoline with pyrrolidine.
- Lister, Troy,Prager, Rolf H.,Tsaconas, Michael,Wilkinson, Kerry L.
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p. 913 - 916
(2007/10/03)
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- Elemental fluorine. Part 10.1 Selective fluorination of pyridine, quinoline and quinoxaline derivatives with fluorine-iodine mixtures
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Selective fluorination of a range of pyridine and quinoline substrates to give corresponding 2-fluoro-derivatives can be readily achieved in high yield at room temperature using elemental fluorine-iodine mixtures. Reaction of fluorine with iodine forms, in situ, systems that function like sources of both iodonium and fluoride ions and fluorination of heterocyclic derivatives is suggested to proceed by fluoride ion attack on intermediate W-iodo-heterocyclic species. Quinoxaline derivatives react under similar conditions to give either the 2-fluoro- or 2,3-difluoro-quinoxaline derivatives depending on the ratio of fluorine passed through the solution. In related processes, pyridine can be alkoxylated upon reaction of an appropriate alcohol and fluorine.
- Chambers, Richard D.,Parsons, Mandy,Sandford, Graham,Skinner, Christopher J.,Atherton, Malcolm J.,Moilliet, John S.
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p. 803 - 810
(2007/10/03)
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- Selective alkylation of 2-pyridone in solvent-free conditions
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Alkylation of 2-pyridone has been performed in solvent-free conditions. The effect of base, phase transfer agent, and alkylation agent has been discussed.
- Almena,Diez-Barra,de la Hoz
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p. 1057 - 1063
(2007/10/02)
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- Copper(I) Halide Catalysed Synthesis of Alkyl Aryl and Alkyl Heteroaryl Ethers
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A number of alkyl aryl and alkyl heteroaryl ethers have been prepared from (hetero) aryl halides (mainly bromides) and sodium alkoxides, using copper(I)bromide as a catalyst.The influence of the main solvent, the halogen atom, reaction temperature and the presence of oxygen upon the rate and selectivity has been studied.Furthermore the decomposition of the catalyst and the reduction of the aryl halide are studied.
- Keegstra, Menno A.,Peters, Theo H. A.,Brandsma, Lambert
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p. 3633 - 3652
(2007/10/02)
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- Utilizing Acetyl Hypofluorite for Chlorination, Bromination, and Etherification of the Pyridine System
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Acetyl hypofluorite, which is easily made from F2, possesses a strong electrophilic fluorine.This electrophile is able to attach itself to the nitrogen atom of pyridine and activate the ring toward nucleophilic attacks.The ultimate elimination of HF results in an overall easy nucleophilic displacement of the hydrogen of the important 2-position .The nucleophiles used: Clδ-, Brδ-, ROδ-, originate from solvents such as CH2Cl2, CH2Br2, and various primary alcohols.Thus, 2-halo- or 2-alkoxypyridines were formed.The reaction conditions (room temperature, very short reaction times, and good yields) transform the task of direct substitution of the pyridine ring from an extremely difficult to a very easy procedure.
- Hebel, David,Rozen, Shlomo
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p. 6298 - 6301
(2007/10/02)
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- HETARYLATION OF C-NUCLEOPHILES: A NEW COURSE FOR THE REACTION OF N-FLUOROPYRIDINIUM SALTS WITH CARBANIONS.
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The N-fluoropyridinium tetrafluoroborate reactions with carbanions were found either to follow the cine -(tele)-AEa-substitution or go through possible formation of a carbenic (cationic) intermediate; as a result 2- or 4-pyridyl derivatives are formed.
- Gakh, Andrei A.,Kiselyov, Alexander S.,Semenov, Victor V.
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p. 7379 - 7382
(2007/10/02)
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- Chlorination, Bromination, and Oxygenation of the Pyridine Ring Using AcOF Made from F2
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Acetyl hypofluorite reacts with pyridines in halogenated solvents or alcohols to give the corresponding 2-halo- or 2-alkoxypyridines.
- Hebel, David,Rozen, Shlomo
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p. 1123 - 1125
(2007/10/02)
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- A CONVENIENT PREPARATION OF SULFINIC ACIDS BY THE REACTION OF 2-SULFONYLPYRIDINES AND THEIR N-OXIDES WITH NUCLEOPHILES
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Ipso-substitution reaction of 2-sulfonylpyridines and their N-oxides with alkoxide or thiolate anion afforded the sodium salts of sulfinic acids together with the corresponding substitution product in high yields.This procedure becomes a convenient and versatile method for preparation of various sulfinic acids.
- Furukawa, Naomichi,Tsuruoka, Masayuki,Fujihara, Hisashi
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p. 3019 - 3022
(2007/10/02)
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- ipso-Substitution of a Sulphinyl or Sulphonyl Group Attached to Pyridine Rings and its Application for the Synthesis of Macrocycles
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A sulphinyl or sulphonyl group directly bound to the 2- or 4-position of a pyridine ring was readily displaced by several nucleophiles such as RO-, RS-, and CN- to afford the corresponding ipso-substitution products.Similarly, 2-halogeno-6-methylsulphinyl- or -methylsulphonyl-pyridines also react with nuclephiles to afford 2-halogeno-6-substituted pyridine derivatives.Thus, the leaving abilities of the leaving groups fall in the order RSO2 > RSO > Br ca.Cl >> RS (R = alkyl or benzyl).The ipso-substitution can be applied to the synthesis of 2,6-disubstituted pyridino macrocycles containing both carbon-oxygen and carbon-sulphur bridges, resulting in several new macrocycles in moderate yields.
- Furukawa, Naomichi,Ogawa, Satoshi,Kawai, Tsutomu,Oae, Shigeru
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p. 1839 - 1845
(2007/10/02)
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- SELECTIVE IPSO-SUBSTITUTION IN PYRIDINE RING AND ITS APPLICATION FOR THE SYNTHESIS OF MACROCYCLES CONTAINING BOTH OXA- AND THIA-BRIDGES
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Both the sulfinyl and sulfonyl groups directly bound to 2 or 4 position in pyridine were readily displaced by several nucleophiles such as RO(1-) and RS(1-) .The facility of the leaving groups is RSO2 = RSO > Br = Cl >> RS (R:alkyl or benzyl).The ipso-substitution could be applied for the synthesis of new type of 2,6-disubstituted macrocycles containing both carbon-oxygen and carbon-sulfur bridges in moderate yields.
- Furukawa, Naomichi,Ogawa, Satoshi,Kawai, Tsutomu,Oae, Shigeru
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p. 3243 - 3246
(2007/10/02)
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