- Selective Halogenation of Pyridines Using Designed Phosphine Reagents
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Halopyridines are key building blocks for synthesizing pharmaceuticals, agrochemicals, and ligands for metal complexes, but strategies to selectively halogenate pyridine C-H precursors are lacking. We designed a set of heterocyclic phosphines that are installed at the 4-position of pyridines as phosphonium salts and then displaced with halide nucleophiles. A broad range of unactivated pyridines can be halogenated, and the method is viable for late-stage halogenation of complex pharmaceuticals. Computational studies indicate that C-halogen bond formation occurs via an SNAr pathway, and phosphine elimination is the rate-determining step. Steric interactions during C-P bond cleavage account for differences in reactivity between 2- and 3-substituted pyridines.
- Alegre-Requena, Juan V.,Levy, Jeffrey N.,Liu, Renrong,McNally, Andrew,Paton, Robert S.
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supporting information
p. 11295 - 11305
(2020/07/13)
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- ARYL TRIAZINE COMPOUND AND ORGANIC ELECTROLUMINESCENT ELEMENT USING THE SAME
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PROBLEM TO BE SOLVED: To provide an electron transporting material that achieves excellent life characteristics and current efficiency in an organic electroluminescent element. SOLUTION: A triazine compound represented by formula (1) is provided. In the f
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Paragraph 0098-0101
(2019/09/06)
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- SHMT INHIBITORS AND USES THEREOF
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The present invention provides compounds, compositions thereof, and methods of using the same.
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Paragraph 00258
(2018/06/30)
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- Scope and limitation for FeSO4-mediated direct arylation of heteroarenes with arylboronic acids and its synthetic applications
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FeSO4-mediated direct arylation of heteroarenes with arylboronic acids in the presence of K2S2O8 has been developed. A slow addition of an aqueous solution of an iron complex was crucial in the arylation. Scope and limitation of the heteroarenes and arylboronic acids are discussed. Furthermore, the direct arylation was applied to the formal total synthesis botryllazine B and sodium channel inhibitor.
- Komeyama, Kimihiro,Nagao, Yuya,Abe, Manabu,Takaki, Ken
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p. 301 - 313
(2014/03/21)
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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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