A variety of nitrogen-containing heterocycles were synthesized by passing vapors of aromatic amines over calcium oxide at 450–650 °C under nitrogen carrier gas. Reaction of 2-aminobiphenyl 3a at 560 °C gave carbazole 4 in 80% yield. Reaction of 2, 2′-diaminobiphenyl 3b afforded a mixture of carbazole 4 and 4-aminocarbozole 6b. In the case of 2-amino-2′-nitrobiphenyl 3c, benzo[c]cinnoline 7 was obtained along with carbazole 4. Reaction of 2-amino-2′-methoxybiphenyl 3d gave four products of carbazole 4,4-hydroxycarbazole 6e, phenanthridine 8 and dibenzofuran 9. Reaction of 2-aminodiphenylmethane 5a afforded acridine 10. In the case of 2-aminobenzophenone 5b, acridone 11 was obtained as a major product. Reaction of 2-aminobenzhydrol 5c gave acridine 10. When 2-aminodiphenylamine 5d was reacted, phenazine 12 was obtained in good yield. In contrast, reaction of 2-aminodiphenyl ether 5e produced only 2-hydroxydiphenylamine 13. Reaction of 4-aminophenanthrene 14 produced 4H-benzo[def]carbazole 15 in 61% yield.

中文翻译：

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芳香胺的热环化反应合成咔唑，a啶，吩嗪，4 H-苯并[ def ]咔唑及其衍生物

在450-650°C的氮载气下，通过芳族胺的蒸气通过氧化钙，可以合成出各种含氮杂环。2-氨基联苯3a在560°C下反应生成咔唑4，收率80％。2，2'-二氨基联苯3b的反应得到咔唑4和4-氨基咔唑6b的混合物。在2-氨基-2'-硝基联苯3c的情况下，苯并[ c与咔唑4一起获得] cinnoline7。2-氨基-2'-甲氧基联苯3d反应得到咔唑4,4-羟基咔唑6e，菲啶8和二苯并呋喃9的四种产物。2-氨基二苯基甲烷5a反应得到a啶10。在2-氨基二苯甲酮5b的情况下，获得了as啶酮11作为主要产物。2-氨基苯甲酸5c的反应得到a啶10。当2-氨基二苯胺5d反应时，以良好的产率获得吩嗪12。相反，2-氨基二苯醚5e的反应仅产生2-羟基二苯胺13。4-氨基菲14的反应产生61％产率的4 H-苯并[ def ]咔唑15。