Discovery and application of doubly quaternized cinchona-alkaloid-based phase-transfer catalysts was written by Xiang, Bangping;Belyk, Kevin M.;Reamer, Robert A.;Yasuda, Nobuyoshi. And the article was included in Angewandte Chemie, International Edition in 2014.Quality Control of 2-Bromo-5-fluoro-3-methylpyridine This article mentions the following:
Novel N,N’-disubstituted cinchona alkaloids were reported as efficient phase-transfer catalysts for the assembly of stereogenic quaternary centers. In comparison to traditional cinchona-alkaloid-based phase-transfer catalysts, these new catalysts afford substantial improvements in enantioselectivity and reaction rate for intramol. spirocyclization reactions of 3-[2-(chloromethyl)aryl]-γ-lactams with catalyst loadings as low as 0.3 mol% under mild conditions. In the experiment, the researchers used many compounds, for example, 2-Bromo-5-fluoro-3-methylpyridine (cas: 38186-85-5Quality Control of 2-Bromo-5-fluoro-3-methylpyridine).
2-Bromo-5-fluoro-3-methylpyridine (cas: 38186-85-5) belongs to pyridine derivatives. Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1.The molecular electric dipole moment is 2.2 debyes. The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase and 140.4 kJ·mol−1 in the gas phase. Pyridine derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.Quality Control of 2-Bromo-5-fluoro-3-methylpyridine