81416-21-9Relevant articles and documents
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
