84539-34-4Relevant articles and documents
Synthesis of pyridinium betaine azo chromophores
Kreicberga,Laipniece,Bērzi?a,Kampars
, p. 438 - 444 (2014/05/06)
New chromophores have been synthesized and investigated containing as acceptor a quaternized pyridine unit with mobile bromine in the structure conjugated with two donor units - the indan-1,3-dione anion and the dihydroxyethylamino group through a π-conju
Bromination of Some Pyridine and Diazine N-Oxides
Paudler, William W.,Jovanovic, Misa V.
, p. 1064 - 1069 (2007/10/02)
Selected monosubstituted pyridines, pyrazines, pyrimidines, and their N-oxides, having an electron-donating substituent, were successfully brominated under very mild conditions.The N-oxide function itself is not sufficient to cause these ?-deficient systems to undergo electrophilic aromatic halogenation.Only strongly electron-donating substituents (amino groups) activate the heterocyclic nucleus toward bromination.These substituents direct the electrophilic substitution ortho/para to them with or without the N-oxide group present.Pyridine and diazines with moderately activating substituents such as alkoxy groups are brominated only when their ortho/para activation is augmented by the activation of the N-oxide funtion.Failure to brominate 5-methoxypyrimidine 1-oxide may well reflect the greater ? deficiency of the pyrimidine ring.