84539-36-6Relevant academic research and scientific papers
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.
PHOTOLYSIS OF PYRIDYL, QUINOLYL, AND ISOQUINOLYL AZIDES IN HYDROHALOGENOIC ACIDS
Sawanishi, Hiroyuki,Hirai, Toyoko,Tsuchiya, Takashi
, p. 1043 - 1046 (2007/10/02)
Photolysis of 4-azido-pyridine and -quinoline in hydrohalogenoic acids gave the 3-amino-4-halogeno compounds (2) via azirine or azacycloheptatetraene intermediates, whereas their N-oxides (4), under similar conditions, gave the 4-amino-3-halogeno compounds (5) presumably via nitrenium ion intermediates.In the 3-azidoquinoline and 4-azidoisoquinoline series, both free bases (6a, 8a) and N-oxides (6b, 8b) gave similar results to 4-azidopyridine and -quinoline N-oxides (4).
