Thermal transformations of 3-azido-4H-quinolizin-4-ones 4a,b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d, available from the corresponding heteroarylamines 2a–d, were studied. The reaction products were mostly dependent on the solvent. Thus, heating of 3-azido-1-cyano-4H-quinolizin-4-one (4a) in toluene afforded 2-(pyridin-2-yl)fumaronitrile 5a, whereas 3-amino-1-cyano-4H-quinolizin-4-one (8) was obtained on treatment of 4a in a mixture of toluene and trifluoroacetic anhydride. However, heating of 4a in acetic anhydride and in acetic acid resulted in a ring contraction to produce 3-(diacetylamino)indolizine-1-carbonitrile 6a and 3-(acetylamino)indolizine-1-carbonitrile 7a, respectively. Similarly, ring contractions took place on heating ethyl 3-azido-4-oxo-4H-quinolizin-1-carboxylate 4b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d in acetic anhydride or acetic acid to produce the N-acetylated 3-aminoindolizine derivatives 6b, 7b and 3-aminoimidazo[1,2–x]azine derivatives 6c,d in 30–89% yields. The structures of compounds 5–8 were determined by NMR spectroscopy and X-ray diffraction.
研究了由相应的杂芳基胺 2a-d 制得的 3-叠氮-4H-喹嗪-4-酮 4a,b 和 3-叠氮-4H-叠氮并[1,2-x]嘧啶-4-酮 4c,d 的热转化。反应产物主要取决于溶剂。因此,在甲苯中加热 3-叠氮-1-氰基-4H-喹嗪-4-酮(4a)可得到 2-(吡啶-2-基)烟腈 5a,而在甲苯和三氟乙酸酐的混合物中处理 4a 则可得到 3-氨基-1-氰基-4H-喹嗪-4-酮(8)。然而,在乙酸酐和乙酸中加热 4a 会导致环收缩,分别生成 3-(二乙酰氨基)吲哚利嗪-1-甲腈 6a 和 3-(乙酰氨基)吲哚利嗪-1-甲腈 7a。同样,在乙酸酐或乙酸中加热 3-叠氮-4-氧代-4H-喹嗪-1-羧酸乙酯 4b 和 3-叠氮-4H-叠氮并[1,2-x]嘧啶-4-酮 4c、d 会发生环收缩,生成 N-乙酰化的 3-氨基吲嗪衍生物 6b、7b 和 3-氨基咪唑并[1,2-x]嗪衍生物 6c、d,产率为 30-89%。化合物 5-8 的结构是通过核磁共振光谱和 X 射线衍射确定的。