- Method for preparing 2-chloro-5-substituted pyridine
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The invention belongs to the technical field of chemical synthesis of pesticides, and particularly relates to a method for preparing 2-chloro-5-substituted pyridine, in particular to a method for preparing 2-chloro-5-methylpyridine. The method comprises the following steps: reacting amide as shown in a formula C which is used as a raw material in the presence of a chlorinating agent and N, N-dimethylformamide, and distilling after the reaction is finished to obtain the 5-substituted 2-chloropyridine as shown in a formula I which is described in the specification. When the 5-substituted 2-chloropyridine is prepared from the compound with the structure shown in the formula C, the by-product is allyl chloride (or homologues thereof) with small molecular weight, the boiling point of the by-product is obviously different from that of the product, the reaction conversion rate and the yield are higher than those of the prior art, the by-product is easy to separate from the product, and the by-product is more beneficial to recovery; therefore, according to the preparation method, the equipment investment can be greatly saved, the production cost is reduced, and the operation procedure is simplified; and in the route, the amine with lower price is used as a starting raw material, so that the production cost is reduced.
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Paragraph 0061-0064; 0065-0067
(2021/09/21)
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- Site-Selective, Modular Diversification of Polyhalogenated Aryl Fluorosulfates (ArOSO2F) Enabled by an Air-Stable PdI Dimer
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Since 2014, the interest in aryl fluorosulfates (ArOSO2F) as well as their implementation in powerful applications has continuously grown. In this context, the enabling capability of ArOSO2F will strongly depend on the substitution pattern of the arene, which ultimately dictates its overall function as drug candidate, material, or bio-linker. This report showcases the modular, substrate-independent, and fully predictable, selective functionalization of polysubstituted arenes bearing C?OSO2F, C?Br, and C?Cl sites, which makes it possible to diversify the arene in the presence of OSO2F or utilize OSO2F as a triflate surrogate. Sequential and triply selective arylations and alkylations were realized within minutes at room temperature, using a single and air-stable PdI dimer.
- Mendel, Marvin,Kalvet, Indrek,Hupperich, Daniel,Magnin, Guillaume,Schoenebeck, Franziska
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supporting information
p. 2115 - 2119
(2020/01/02)
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- Transition-metal-free decarboxylative halogenation of 2-picolinic acids with dihalomethane under oxygen conditions
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A convenient and efficient method for the synthesis of 2-halogen-substituted pyridines is described. The decarboxylative halogenation of 2-picolinic acids with dihalomethane proceeded smoothly via N-chlorocarbene intermediates to afford 2-halogen-substituted pyridines in satisfactory to excellent yields under transition-metal-free conditions. This new type of decarboxylative halogenation is operationally simple and exhibits high functional-group tolerance.
- Zhang, Xitao,Feng, Xiujuan,Zhang, Haixia,Yamamoto, Yoshinori,Bao, Ming
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supporting information
p. 5565 - 5570
(2019/10/22)
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- Modular Functionalization of Arenes in a Triply Selective Sequence: Rapid C(sp2) and C(sp3) Coupling of C?Br, C?OTf, and C?Cl Bonds Enabled by a Single Palladium(I) Dimer
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Full control over multiple competing coupling sites would enable straightforward access to densely functionalized compound libraries. Historically, the site selection in Pd0-catalyzed functionalizations of poly(pseudo)halogenated arenes has been unpredictable, being dependent on the employed catalyst, the reaction conditions, and the substrate itself. Building on our previous report of C?Br-selective functionalization in the presence of C?OTf and C?Cl bonds, we herein complete the sequence and demonstrate the first general arylations and alkylations of C?OTf bonds (in I dimer. This allowed the realization of the first general and triply selective sequential C?C coupling (in 2D and 3D space) of C?Br followed by C?OTf and then C?Cl bonds.
- Keaveney, Sinead T.,Kundu, Gourab,Schoenebeck, Franziska
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supporting information
p. 12573 - 12577
(2018/09/18)
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- Collagen
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PROBLEM TO BE SOLVED: To provide a collagen producing promoter preferable for preventing or improving wrinkle formation.SOLUTION: There is provided a collagen producing promoter made of a compound expressed by the following general formula and an external
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Paragraph 0067
(2018/07/04)
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- Quinuclidine and DABCO Enhance the Radiofluorination of 5-Substituted 2-Halopyridines
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Positron emission tomography (PET) is an important molecular imaging technique for medical diagnosis, biomedical research and drug development. PET tracers for molecular imaging contain β+-emitting radionuclides, such as carbon-11 (t1/2 = 20.4 min) or fluorine-18 (t1/2 = 109.8 min). The [18F]2-fluoropyridyl moiety features in a few prominent PET radiotracers, not least because this moiety is usually resistant to unwanted radiodefluorination in vivo. Various methods have been developed for labeling these radiotracers from cyclotron-produced no-carrier-added [18F]fluoride ion, mainly based on substitution of a leaving group, such as halide (Cl or Br), or preferably a better leaving group, such as nitro or trimethylammonium. However, precursors with a good leaving group are sometimes more challenging or lengthy to prepare. Methods for enhancing the reactivity of more readily accessible 2-halopyridyl precursors are therefore desirable, especially for early radiotracer screening programs that may require the quick labeling of several homologous radiotracer candidates. In this work, we explored a wide range of additives for beneficial effect on nucleophilic substitution by [18F]fluoride ion in 5-substituted 2-halopyridines (halo = Cl or Br). The nucleophilic cyclic tertiary amines, quinuclidine and DABCO, proved effective for increasing yields to practically useful levels (> 15 %). Quinuclidine and DABCO likely promote radiofluorination through reversible formation of quaternary ammonium intermediates.
- Naumiec, Gregory R.,Cai, Lisheng,Lu, Shuiyu,Pike, Victor W.
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p. 6593 - 6603
(2017/09/12)
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- A new aromatic amine compound and its preparation and use (by machine translation)
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The invention discloses a novel aromatic amine compound, and the compound molecule of the general formula: Wherein R1 , R2 , R3 Are hydrogen atom or the carbon atom number 1 - 30 alkyl or the carbon atom number 6 - 50 car
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Paragraph 0085; 0086-0088
(2017/08/14)
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- Cobalt-Catalyzed Cross-Coupling Reactions of Arylboronic Esters and Aryl Halides
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An efficient cobalt catalyst system for the Suzuki-Miyaura cross-coupling reaction of arylboronic esters and aryl halides has been identified. In the presence of cobalt(II)/terpyridine catalyst and potassium methoxide, a diverse array of (hetero)biaryls have been prepared in moderate to excellent yields.
- Duong, Hung A.,Wu, Wenqin,Teo, Yu-Yuan
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supporting information
p. 4363 - 4366
(2017/12/05)
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- NOVEL COMPOUNDS
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The present invention relates to novel compounds of formula (I) and methods for the manufacture of inhibitors of deubiquitylating enzymes (DUBs). In particular, the invention relates to the inhibition of ubiquitin C-terminal hydrolase 30 or ubiquitin spec
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Page/Page column 68; 69
(2017/09/08)
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- Chemoselective Synthesis of Polysubstituted Pyridines from Heteroaryl Fluorosulfates
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A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib. A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib.
- Zhang, Enxuan,Tang, Jiaze,Li, Suhua,Wu, Peng,Moses, John E.,Sharpless, K. Barry
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p. 5692 - 5697
(2016/04/20)
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- Iridium complexes with aza-benzo fused ligands
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Novel iridium complexes containing phenylpyridine and pyridyl aza-benzo fused ligands are described. These complexes are useful as light emitters when incorporated into OLEDs.
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Paragraph 0201; 0202
(2014/05/24)
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- METHOD FOR PRODUCING 6-HALOGENO-3-ARYLPYRIDINE DERIVATIVE
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[Problem] The present invention provides an industrially advantageous production method of a 6-halogeno-3-arylpyridine derivative in which cryogenic condition is not required, production step is short, and an isomer difficult to be separated is not produced as a by-product. [Solution] A production method of a 6-halogeno-3-arylpyridine derivative represented by the general formula (III) comprising: the first step reacting a 2, 5-dihalogenopyridine derivative represented by the general formula (I) with a magnesiation reagent; and the second step reacting the product obtained from the above-described first step, in the presence of a palladium compound, with a halogenoaryl derivative represented by the general formula (II).
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Page/Page column 8
(2010/09/17)
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- Naphthidine di(radical cation)s-stabilized palladium nanoparticles for efficient catalytic Suzuki-Miyaura cross-coupling reactions
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Stable Pd(0) nanoparticles were prepared at room temperature in 1,4-dioxane from PdCl2 using N,N′-bis(4-methoxyphenyl)-(1,1′-binaphthyl)-4,4′-diamine (naphthidine) as reducing and stabilizing agent. This procedure resulted in Pd(0) particles possessing an average diameter of ca. 25 nm stabilized against aggregation due to a barrier of the naphthidine di(radical cation) Napht2.2+. These particles were evaluated for their capability to act as catalysts in Suzuki-Miyaura coupling reactions. The Pd(0)/Napht2.2+ provides a general and convenient method to prepare biaryls from aryl bromides or iodides and boronic acids with a broad range of functional groups in 1,4-dioxane at 80 °C and under aerobic conditions.
- Desmarets, Christophe,Omar-Amrani, Rafik,Walcarius, Alain,Lambert, Jacques,Champagne, Beno?t,Fort, Yves,Schneider, Rapha?l
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p. 372 - 381
(2008/04/01)
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- A versatile method for suzuki cross-coupling reactions of nitrogen heterocycles
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(Chemical Equation Presented) A wide-ranging study of Suzuki reactions which use nitrogen-containing heterocycles is described (see scheme; dba = dibenzylideneacetone, Cy = cyclohexyl). This method is highly versatile (a single procedure was used for all substrates, including boronate esters and trifluoroborates), compatible with a variety of unprotected functionalities (e.g., NH2-and OH-substituted substrates), and efficient even with unactivated aryl chlorides.
- Kudo, Noriaki,Perseghini, Mauro,Fu, Gregory C.
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p. 1282 - 1284
(2007/10/03)
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- Arylpiperaszine derivatives, to the process for the production thereof and to the use thereof as therapeutic agents
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The invention relates to compounds of the general formula (I): to the process for preparing them, and to the use thereof as a therapeutic agent.
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Page/Page column 11
(2008/06/13)
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- Combining enabling techniques in organic synthesis: Solid-phase-assisted catalysis under microwave conditions using a stable Pd(II)-precatalyst
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The catalytic activity of a 2-pyridinealdoxime-based Pd(II)-complex covalently anchored via the oxime moiety to a glass/polymer composite material was evaluated in Suzuki-Miyaura cross-coupling reactions of aryl and heteroaryl halides, including arylchlorides, with aryl and heteroaryl boronic acids both under thermal as well as microwave irradiating conditions in water. The stability and reusability of this Pd-precatalyst is part of the present study.
- Dawood, Kamal M.,Kirschning, Andreas
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p. 12121 - 12130
(2007/10/03)
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- Ruthenium-Catalyzed Heck-Type Olefination and Suzuki Coupling Reactions: Studies on the Nature of Catalytic Species
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Ruthenium-catalyzed Heck olefination and Suzuki cross coupling reactions have been developed. When starting with a ruthenium complex [RuCl 2(p-cymene)]2 as a homogeneous catalyst precursor, induction periods were observed and ruthenium colloids of zero oxidation state were generated under catalytic conditions. Isolated ruthenium colloids carried out the olefination, implying that active catalytic species are ruthenium nanoclusters. To support this hypothesis, ruthenium nanoparticles stabilized with dodecylamine were independently prepared via a hydride reduction procedure, and their catalytic activity was subsequently examined. Olefination of iodobenzene with ethyl acrylate was efficiently catalyzed by the ruthenium nanoparticles under the same conditions, which could be also reused for the next runs. In poisoning experiments, the conversion of the olefination was completely inhibited in the presence of mercury, thus supporting our assumption on the nature of catalytic species. No residual ruthenium was detected from the filtrate at the end of the reaction. On the basis of the postulation, a heterogeneous catalyst system of ruthenium supported on alumina was consequently developed for the Heck olefination and Suzuki cross coupling reactions for the first time. It turned out that substrate scope and selectivity were significantly improved with the external ligand-free catalyst even under milder reaction conditions when compared to results with the homogeneous precatalyst. It was also observed that the immobilized ruthenium catalyst was recovered and reused up to several runs with consistent efficiency. Especially in the Suzuki couplings, the reactions could be efficiently carried out with as low as 1 molpercent of the supported catalyst over a wide range of substrates and were scaled up to a few grams without any practical problems, giving coupled products with high purity by a simple workup procedure.
- Na, Youngim,Park, Soyoung,Han, Soo Bong,Han, Hoon,Ko, Sangwon,Chang, Sukbok
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p. 250 - 258
(2007/10/03)
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- Cross-coupling of triallyl(aryl)silanes with aryl bromides and chlorides: An alternative convenient biaryl synthesis
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Cross-coupling of a diverse range of aryl bromides with triallyl(aryl)silanes is effective in the presence of PdCl2/PCy 3 and tetrabutylammonium fluoride (TBAF) in DMSO-H2O to give various biaryls in good yields. It is worthwhile to note that the all-carbon-substituted arylsilanes, stable towards moisture, acid, and base and easily accessible, serve as a highly practical alternative to their aryl(halo)silane counterparts. A catalyst system consisting of [η3-C3H5)PdCl]2 and 2-[2,4,6-(i-Pr)3C6Ha]-C6H4PCy 2 and use of TBAF· 3 H2O in THF-H2O are effective especially for the cross-coupling with aryl chlorides. Both of the catalyst systems tolerate a broad spectrum of common functional groups. The high efficiency of reactions is presumably due to the ready cleavage of the allyl groups upon treatment with TBAF·3 H2O and an appropriate amount of water. Diallyl(diphenyl)silane also cross-couples with various aryl bromides and chlorides in good yields, whereas allyl(triphenyl)silane gives the cross-coupled products in only moderate yields. Through sequential cross-coupling of bromochlorobenzenes with different arylsilanes, a range of unsymmetrical terphenyls are accessible in good overall yields.
- Sahoo, Akhila K.,Oda, Takuro,Nakao, Yoshiaki,Hiyama, Tamejiro
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p. 1715 - 1727
(2007/10/03)
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- Synthesis of 5-substituted 2,2′-bipyridines from substituted 2-chloropyridines by a modified Negishi cross-coupling reaction
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A new and practical approach to a number of differently 5-substituted 2,2′-bipyridines starting from substituted 2-chloropyridines has been found through the application of modified Negishi cross-coupling conditions. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Luetzen, Arne,Hapke, Marko
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p. 2292 - 2297
(2007/10/03)
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- Photolysis of Tetraarylmethanes and 3-(Triarylmethyl)pyridines
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Upon UV irradiation in benzene-methanol (1:2) tetraarylmethanes or 3-(triarylmethyl)pyridines underwent an α,α-elimination of two aryl groups to give biaryls or 3-arylpyridine, and two corresponding carbene intermediates.The latters afforded methyl ethers by O-H insertion to methanol.
- Shi, Min,Okamoto, Yoshiki,Takamuku, Setsuo
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p. 2731 - 2733
(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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