81416-34-4Relevant academic research and scientific papers
Reaction of Aromatic N-Oxides with Dipolarophiles. VIII. Carbamation Products of 2-Anilinopyridine Derivatives
Hisano, Takuzo,Harano, Kazunobu,Matsuoka, Toshikazu,Suematsu, Fumihiro,Ohizumi, Norihide
, p. 1869 - 1877 (2007/10/02)
In the 1,3-dipolar cycloaddition reaction of pyridine N-oxides with phenyl isocyanates, we have isolated 1,5-sigmatropy products of the primary cycloadduct and carbamation products of 2-anilinopyridines.In connection with the tautomerism of 2-anilinopyridines, the structure of the carbamation products is discussed in detail based on kinetic, molecular orbital calculation and spectral data.A comparison of the spectral data with those of structurally related compounds indicated that the carbamation does not occur at the ring nitrogen but at the exocyclic one.Keywords -- tautomerism; 2-anilinopyridine; molecular orbital theory; carbamation; phenyl isocyanate; 2-pyridone-imine; 1,3-dipolar cycloaddition; pyridine N-oxide; 2-(N-phenylcarbamoylanilino)pyridine
REACTION OF AROMATIC N-OXIDES WITH DIPOLAROPHILES. IV. FACTORS AFFECTING THE 1,3-CYCLOADDITION OF PYRIDINE 1-OXIDE WITH PHENYL ISOCYANATES
Hisano, Takuzo,Matsuoka, Toshikazu,Tsutsumi, Kazuhiro,Muraoka, Keiji,Ichikawa, Masataka
, p. 3706 - 3712 (2007/10/02)
Pyridine 1-oxide was subjected to 1,3-dipolar cycloaddition with phenyl isocyanates having an ortho, meta or para substituent group.The reaction conducted at 90 deg C in dimethylformamide gave the 2,3-dihydropyridine-form cycloadduct, although the reaction of pyridine 1-oxide with phenyl isocyanate directly affords 2-anilinopyridine.An increase of the reaction time led to increases in the yields of 2-anilinopyridine and 1-phenylcarbamoyl-2-phenylimino-1,2-dihydropyridine, while the yield of the cycloadduct tended to decrease.The reaction at 150 deg C resulted in an increased yield of 2-anilinopyridine.The reactions of 2-anilinopyridine and 5-methyl-2-anilinopyridine with phenyl isocyanate at room temperature afforded the corresponding 1-phenylcarbamoyl-2-phenylimino-1,2-dihydropyridines, whereas the reactions of 3-methyl- and 3,5-dimethyl-2-anilinopyridines with phenyl isocyanate at 90 deg C afforded 2-(N-phenylcarbamoylanilino)pyridine derivatives. - Keywords: 1,3-dipolar cycloaddition; 2,3-dihydropyridine-form cycloadducts; 2-anilinopyridines; 1-phenylcarbamoyl-2-phenylimino-1,2-dihydropyridines; 2-(N-phenylcarbamoylanilino)pyridines
