19069-63-7Relevant articles and documents
Selective Halogenation of Pyridines Using Designed Phosphine Reagents
Alegre-Requena, Juan V.,Levy, Jeffrey N.,Liu, Renrong,McNally, Andrew,Paton, Robert S.
supporting information, p. 11295 - 11305 (2020/07/13)
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.
SHMT INHIBITORS AND USES THEREOF
-
Paragraph 00258, (2018/06/30)
The present invention provides compounds, compositions thereof, and methods of using the same.
Site-Selectivity in the Reaction of 3-Substituted Pyridine 1-Oxides with Phosphoryl Chloride
Yamanaka, Hiroshi,Araki, Tomio,Sakamoto, Takao
, p. 2244 - 2247 (2007/10/02)
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