2-(2-Furfurylidene) acetylquinoxaline (Ia) and its 3-methyl analog (Ib) were cyclized to pyrrolo [1, 2-α] quinoxaline ring systems (IIa and IIb) by hydrochloric acid treatment. 2-(4-Methoxybenzylidene) acetylpyridine could be cyclized directly to the 2, 3-dihydroindolizine ring system (V) by treatment with perchloric acid. 2-Arylideneacetyl-3-methyl-quinoxalines (IX) also were cyclized to the corresponding pyrrolo [1, 2-α] quinoxaline systems by hydrochloric acid or perchloric acid. The cyclization of 2-(2-furfurylidene)-acetylquinoline (XI) was performed by using acetic anhydride in the presence of a catalytic amount of trifluoroacetic acid. 2-(2-Furfurylidene) acetylpyrazine (XIII) was cyclized easily by hydrochloric acid treatment. The structures of the adducts of these cyclic products with dimethyl acetylenedicarboxylate are discussed.
2-(2-
呋喃亚甲基)乙酰
喹啉(Ia)及其3-甲基类似物(Ib)通过
氯化氢处理环化形成
吡咯[1, 2-α]
喹啉环系(IIa和IIb)。2-(4-甲氧基苄亚甲基)乙酰
吡啶可以通过
高氯酸处理直接环化为2, 3-二氢
喹唑啉环系(V)。2-芳基
乙烯乙酰-3-甲基
喹唑啉(IX)也通过
氯化氢或
高氯酸环化为相应的
吡咯[1, 2-α]
喹啉体系。2-(2-
呋喃亚甲基)乙酰
喹啉(XI)的环化则使用
醋酸酐在微量
三氟乙酸的催化下进行。2-(2-
呋喃亚甲基)乙酰
吡嗪(XIII)通过
氯化氢处理容易环化。这些环状产物与二甲基
乙炔二
羧酸酯的加成物的结构进行了讨论。