Comparing Methodologies in 2-2'-Bipyridine Synthesis
Abstract
The purpose of this study is to determine the most economical and efficient way to synthesize functionalized bipyridine adducts for future incorporation into ruthenium complexes. These complexes show promise in treating bladder cancer and their extensive conjugated system demonstrates strong photovoltaic activity.
Two distinct approaches will be contrasted. The first method uses several disubstituted 2-bromopyridine substrates in homo-coupling reactions to create functionalized bipyridines, at the expense of long reactions times. The second route utilizes unsubstituted 2,2’-bipyridines and functionalizes them in a symmetrical pattern using a microwave synthesizer, to attempt to drastically shorten reaction times.
The first mode utilizes deactivating groups on 2-bromopyridines, as prior studies done in our lab indicated they facilitate palladium catalyzed homo-coupling more efficiently. Thus, the efficiency of two catalysts, Pd[PPh3]4 and PdCl2(PPh3)2, will be compared with each the following substrates: 2-bromo-6(1H-pyrazol1-yl)-pyridine, methyl-6-bromopyridine carboxylate, 5-acetyl-2-bromopyridine, 2-bromopyridine-5- carboxaldehyde, and 6-bromo-2-pyridinecarbonitrile. Reactions are assembled and carried out under inert gas environment, using glovebox assembly and a Schlenk-line manifold for the duration. After 12-24h, product isolation is completed on a CombiFlash Rf 2000 Automated Flash Chromatography System. The second mode requires the development of a novel microwave synthesis protocol to brominate unsubstituted 2,2’-bipyridines using a Microwave Reaction System. Based on the nitrogen’s directing effect, we expect bromination to occur at the 5,5’-positions, with potential 3,3’-dibromination as well. In future studies dibrominated bipyridines will undergo a hetero-coupling process with either pyrazole or thiophene rings to extend the conjugated framework of the ligand. Products will be characterized by 1 HNMR in both routes.
Faculty Sponsors
Dr. Beatrix Aukszi
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-3-2024 12:30 PM
End Date
4-4-2024 1:30 PM
Comparing Methodologies in 2-2'-Bipyridine Synthesis
Alvin Sherman Library
The purpose of this study is to determine the most economical and efficient way to synthesize functionalized bipyridine adducts for future incorporation into ruthenium complexes. These complexes show promise in treating bladder cancer and their extensive conjugated system demonstrates strong photovoltaic activity.
Two distinct approaches will be contrasted. The first method uses several disubstituted 2-bromopyridine substrates in homo-coupling reactions to create functionalized bipyridines, at the expense of long reactions times. The second route utilizes unsubstituted 2,2’-bipyridines and functionalizes them in a symmetrical pattern using a microwave synthesizer, to attempt to drastically shorten reaction times.
The first mode utilizes deactivating groups on 2-bromopyridines, as prior studies done in our lab indicated they facilitate palladium catalyzed homo-coupling more efficiently. Thus, the efficiency of two catalysts, Pd[PPh3]4 and PdCl2(PPh3)2, will be compared with each the following substrates: 2-bromo-6(1H-pyrazol1-yl)-pyridine, methyl-6-bromopyridine carboxylate, 5-acetyl-2-bromopyridine, 2-bromopyridine-5- carboxaldehyde, and 6-bromo-2-pyridinecarbonitrile. Reactions are assembled and carried out under inert gas environment, using glovebox assembly and a Schlenk-line manifold for the duration. After 12-24h, product isolation is completed on a CombiFlash Rf 2000 Automated Flash Chromatography System. The second mode requires the development of a novel microwave synthesis protocol to brominate unsubstituted 2,2’-bipyridines using a Microwave Reaction System. Based on the nitrogen’s directing effect, we expect bromination to occur at the 5,5’-positions, with potential 3,3’-dibromination as well. In future studies dibrominated bipyridines will undergo a hetero-coupling process with either pyrazole or thiophene rings to extend the conjugated framework of the ligand. Products will be characterized by 1 HNMR in both routes.
