The reaction of β-alkylpyridine N-oxides (I) with phenyl isocyanate (II) in dimethyl-formamide at 110° gave the cycloadducts (III and IV), although it was noticed that the reaction of pyridine N-oxide with II directly affords α-anilinopyridine. The duration at elevated temperature resulted in an increased yield of the anilino derivatives, while the cycloadducts tended to decrease. The effect by using various sorts of solvents demonstrated that dimethylformamide and dimethylsulfoxide are suitable for the formation of cycloadducts.
                                    β-烷基
吡啶 N-氧化物 (I) 与
异氰酸苯酯 (II) 在二甲基甲酰胺中于 110° 反应得到环加合物(III 和 IV),尽管注意到
吡啶 N-氧化物与 II 的反应直接得到α-苯
氨基吡啶。高温持续时间导致
苯胺衍
生物的产率增加,而环加合物的产率趋于减少。使用各种溶剂的效果表明,二甲基甲酰胺和
二甲亚砜适合形成环加合物。