The author of 《Catalytic enantioselective pyridine N-oxidation》 were Hsieh, Sheng-Ying; Tang, Yu; Crotti, Simone; Stone, Elizabeth A.; Miller, Scott J.. And the article was published in Journal of the American Chemical Society in 2019. COA of Formula: C5H3BrClN The author mentioned the following in the article:
The catalytic, enantioselective N-oxidation of substituted pyridines is described. The approach is predicated on a biomol.-inspired catalytic cycle wherein high levels of asym. induction are provided by aspartic-acid-containing peptides as the aspartyl side chain shuttles between free acid and peracid forms. Desymmetrizations of bis(pyridine) substrates bearing a remote pro-stereogenic center substituted with a group capable of hydrogen bonding to the catalyst are demonstrated. Our approach presents a new entry into chiral pyridine frameworks in a heterocycle-rich mol. environment. Representative functionalizations of the enantioenriched pyridine N-oxides further document the utility of this approach. Demonstration of the asym. N-oxidation in two venerable drug-like scaffolds, Loratadine and Varenicline, show the likely generality of the method for highly variable and distinct chiral environments, while also revealing that the approach is applicable to both pyridines and 1,4-pyrazines. In the experiment, the researchers used many compounds, for example, 5-Bromo-2-chloropyridine(cas: 53939-30-3COA of Formula: C5H3BrClN)
5-Bromo-2-chloropyridine(cas: 53939-30-3) belongs to pyridine. Pyridine is very deactivated towards electrophilic substitution with respect to benzene. For this reason classical formylation, using methods such as the Gattermann or Vilsmeier reactions, are not generally successful. COA of Formula: C5H3BrClN