In 2017,Li, Zhao; Gelbaum, Carol; Campbell, Zachary S.; Gould, Paul C.; Fisk, Jason S.; Holden, Bruce; Jaganathan, Arvind; Whiteker, Gregory T.; Pollet, Pamela; Liotta, Charles L. published 《Pd-Catalyzed Suzuki coupling reactions of aryl halides containing basic nitrogen centers with arylboronic acids in water in the absence of added base》.New Journal of Chemistry published the findings.Synthetic Route of C5H5BrN2 The information in the text is summarized as follows:
The Pd-catalyzed Suzuki coupling reactions of a series of aryl chlorides and aryl bromides containing basic nitrogen centers with arylboronic acids in water in the absence of added base were reported. The reactions proceeded either partially or entirely under acidic conditions. After surveying twenty-two phosphorus ligands, high yields of products were obtained with aryl chlorides only when a bulky ligand, 2-(di-tert-butyl-phosphino)-1-phenyl-1H-pyrrole (cataCXiumPtB) was used. In contrast, aryl bromides produced high yields of products in the absence of both added base and added ligand. In order to explore the Suzuki coupling process entirely under acidic conditions, a series of reactions were conducted in buffered acidic media using several model substrates. 4-Chlorobenzylamine, in the presence of cataCXiumPtB, produced high yields of product at buffered pH 6.0; the yields dropped off precipitously at buffered pH 5.0 and lower. The fall-off in yield was attributed to the decomposition of the Pd-ligand complex due to the protonation of the ligand in the more acidic aqueous media. In contrast, in the absence of an added ligand, 4-amino-2-chloropyridine produced quant. yields at buffered pH 3.5 and 4.5 while 4-amino-2-bromopyridine produced quant. yields in a series of buffered media ranging from pH 4.5 to 1.5. These substrates were only partially protonated in acidic media and could behave as active Pd ligands in the Suzuki catalytic cycle.6-Bromopyridin-3-amine(cas: 13534-97-9Synthetic Route of C5H5BrN2) was used in this study.
6-Bromopyridin-3-amine(cas: 13534-97-9) belongs to anime. Amines characteristically form salts with acids; a hydrogen ion, H+, adds to the nitrogen. With the strong mineral acids (e.g., H2SO4, HNO3, and HCl), the reaction is vigorous. Salt formation is instantly reversed by strong bases such as NaOH. Neutral electrophiles (compounds attracted to regions of negative charge) also react with amines; alkyl halides (R′X) and analogous alkylating agents are important examples of electrophilic reagents.Synthetic Route of C5H5BrN2