Reaction of diketene with ethyl pyridineformimidates (Ia-e) resulted in the formation of 6-methyl-2-pyridyl-4H-1, 3-oxazin-4-one (IVa-c) and 2-ethoxy-6-methyl-2-pyridyl-2H-1, 3-oxazin-4 (3H)-one (IIIb, c). Similar reaction with ethyl 2-quinolineformimidate (Id) and methyl 2-pyridineacetimidate (Ie) gave 6-methyl-2-(2-quinolyl)-4H-1, 3-oxazine-4-one (IVd) and 2-methoxy-6-methyl-2-(2-pyridylmethyl)-2H-1, 3-oxazin-4 (3H)-one (IIIe), respectively. The products obtained were treated with ammonia to give 6-methyl-2-substituted-4 (3H)-pyrimidone (Va-e). Hydrolysis of IIIe gave 6-hydroxy-4-methyl-3 (or 5)-(2-pyridyl)-2 (1H)-pyridone (VIII).
二酮与
吡啶甲
亚胺酸
乙酯(Ia-e)反应生成 6-甲基-2-
吡啶基-4H-1, 3-恶嗪-4-酮(IVa-c)和 2-乙氧基-6-甲基-2-
吡啶基-2H-1, 3-恶嗪-4 (3H)-酮(IIIb, c)。与 2-
喹啉甲
亚胺乙酯(Id)和 2-
吡啶乙
酰亚胺甲酯(Ie)发生类似反应,分别得到 6-甲基-2-(2-
喹啉基)-4H-1, 3-恶嗪-4-酮(IVd)和 2-甲氧基-6-甲基-2-(2-
吡啶基甲基)-2H-1, 3-恶嗪-4 (3H)-酮(IIIe)。得到的产物经
氨水处理后得到 6-甲基-2-取代-4 (3H)-
嘧啶酮(Va-e)。
水解 IIIe 得到 6-羟基-4-甲基-3(或 5)-(2-
吡啶基)-2 (1H)-
吡啶酮(VIII)。