the reaction of 4-chloro-3-vinylcoumarins 3a-d with primary amines 4a-h. The coumarin derivatives 5 (except 5k) underwent an unusual pyridine ring closure under Vilsmeier conditions to form the benzopyrano[4,3-b]pyridines 6. When the aminoaldehydes 7 were treated with the Wittig reagent 2b the fused N-alkyl-2(1H)-pyridinones 8 have been obtained as expected.
从4-
氯香豆素-3-
甲醛(1)和维蒂希( Wittig )膦烷2a-d开始,已经通过四步顺序合成了标题化合物6a-c。通过4-
氯-3-
乙烯基香豆素3a-d与
伯胺4a-h的反应制备了
中间体4-烷基
氨基-3-
乙烯基香豆素5a-k。
香豆素衍
生物5(5k除外)在Vilsmeier条件下经历了异常的
吡啶环闭合,以形成
苯并
吡喃并[4,3- b ]
吡啶6。用维蒂希试剂2b处理
氨基醛7时如所期望的,获得了稠合的N-烷基-2 (1 H) -
吡啶酮8。