66600-05-3Relevant articles and documents
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.
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.