66600-05-3Relevant academic research and scientific papers
Method for preparing 2-chloro-5-substituted pyridine
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Paragraph 0061-0064; 0065-0067, (2021/09/21)
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.
Site-Selective, Modular Diversification of Polyhalogenated Aryl Fluorosulfates (ArOSO2F) Enabled by an Air-Stable PdI Dimer
Mendel, Marvin,Kalvet, Indrek,Hupperich, Daniel,Magnin, Guillaume,Schoenebeck, Franziska
supporting information, p. 2115 - 2119 (2020/01/02)
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.
Transition-metal-free decarboxylative halogenation of 2-picolinic acids with dihalomethane under oxygen conditions
Zhang, Xitao,Feng, Xiujuan,Zhang, Haixia,Yamamoto, Yoshinori,Bao, Ming
supporting information, p. 5565 - 5570 (2019/10/22)
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.
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
Keaveney, Sinead T.,Kundu, Gourab,Schoenebeck, Franziska
supporting information, p. 12573 - 12577 (2018/09/18)
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.
NOVEL COMPOUNDS
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Page/Page column 68; 69, (2017/09/08)
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
A new aromatic amine compound and its preparation and use (by machine translation)
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Paragraph 0085; 0086-0088, (2017/08/14)
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
Quinuclidine and DABCO Enhance the Radiofluorination of 5-Substituted 2-Halopyridines
Naumiec, Gregory R.,Cai, Lisheng,Lu, Shuiyu,Pike, Victor W.
, p. 6593 - 6603 (2017/09/12)
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.
Cobalt-Catalyzed Cross-Coupling Reactions of Arylboronic Esters and Aryl Halides
Duong, Hung A.,Wu, Wenqin,Teo, Yu-Yuan
supporting information, p. 4363 - 4366 (2017/12/05)
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.
Chemoselective Synthesis of Polysubstituted Pyridines from Heteroaryl Fluorosulfates
Zhang, Enxuan,Tang, Jiaze,Li, Suhua,Wu, Peng,Moses, John E.,Sharpless, K. Barry
, p. 5692 - 5697 (2016/04/20)
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.
