65169-36-0Relevant academic research and scientific papers
Preparation of nitropyridines by nitration of pyridines with nitric acid
Katritzky, Alan R.,Scriven, Eric F. V.,Majumder, Suman,Akhmedova, Rena G.,Vakulenko, Anatoliy V.,Akhmedov, Novraz G.,Murugan, Ramiah,Abboud, Khalil A.
, p. 538 - 541 (2007/10/03)
Preparation of nitropyridines by nitration of pyridines with nitric acid was discussed. Trifluoroacetic anhydride was chilled in an ice bath and the pyridine or substituted pyridines were slowly added and stirred at chilled conditions for 2 h. Relative amounts of the reactants were required for the nitration of pyridine were characterized by 1H and Nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. It was observed that the yields of β-nitropyridines obtained using the standard protocol were generally higher than those obtained using N2O3.
The synthesis of β-nitropyridine compounds
Bakke, Jan M.,Ranes, Eli,Riha, Jaroslav,Svensen, Harald
, p. 141 - 144 (2007/10/03)
Pyridine and a number of substituted pyridines have been nitrated by reaction with N2O5 followed by reaction with an aqueous solution of SO2xH2O or NaHSO3. The dependence of the yields on the pH of the aqueous reaction medium, on the concentration of SO2xH2O-HSO3-, on addition of methanol to the aqueous phase, and on the reaction temperature were investigated. The yields obtained with NaHSO3 were: 3-nitropyridine 77%, 2-methyl-5-nitro-pyridine 36%, 3-methyl-5-nitropyridinc 24%, 3-acetyl-5-nitropyridine 18%, 5-nitropyridine-3-carboxylic acid 15%, 3-chloro-5-nitropyridine 11%, 4-methyl-3-nitropyridine 39%, 4-acetyl-3-nitropyridine 67%, 4-cyano-3-nitropyridine 45%, 4-phenyl-3-nitropyridine 68%, 4-formyl-3-nitropyridine 62% (from reaction in liquid SO2), 3-nitropyridine-4-carboxylic acid 48%, methyl 3-nitropyridine-4-carboxylate 75%, 2,3-dimethyl-5-nitropyridine 37%, 2,4-dimethyl-5-nitropyridine 64%, 3-nitroquinoline 10% and 4-nitroisoquinoline 42%.
Nitration of Aromatic and Heteroaromatic Compounds by Dinitrogen Pentaoxide
Bakke, Jan M.,Hegbom, Ingrid,Oevreeide, Elin,Aaby, Kjersti
, p. 1001 - 1006 (2007/10/02)
Nitration of benzene and monosubstituted benzenes in liquid SO2 by dinitrogen pentaoxide at - 11 deg C gave the corresponding nitroarenes with substitution patterns similar to those obtained by nitrations with HNO3-H2SO4.For acetophenone an o/m ratio of 0.94 was obtained.The yields were dependent on the substituents.With a 1:1 ratio of arene: N2O5 the yields varied from 73percent for toluene to 0.4percent for nitrobenzene as substrates.From competition experiments and the nitration of bibenzyl it was concluded that the reaction was faster than the macroscopic rate of mixing.The qualitative order of reactivity for PhX was X = OCH3>CH3>H>Cl>CH3CO>NO2.Nitration with N2O5 in liquid CO2 gave similar results.Nitration of pyrimidine, pyrrole, imidazole and indole with N2O5-SO2 gave no nitrated products.With thiophene, 2- (34percent) and 3-nitrothiophene (5percent) together with 2,4-(16percent) and 2,5-dinitrothiophene (8percent) were obtained.With pyridine, mono- and di-methylpyridines, quinoline, isoquinoline and 4-phenylpyridine nitration of the pyridine ring was obtained.The yields varied from ca. 70percent to 16percent, except for 3,5-, 2,5- and 2,6-dimethylpyridine for which only traces of nitro-dimethylpyridines were obtained.The reaction with the pyridines appears to be intramolecular both in the SO2 phase and in the water phase used for quenching the reaction.The reaction was proposed to proceed by a complex formed in liquid SO2:
