Synthesis of carbazole, acridine, phenazine, 4H-benzo[def]carbazole and their derivatives by thermal cyclization reaction of aromatic amines

✍ Scribed by Takaaki Horaguchi; Takako Oyanagi; Evelyn Cuevas Creencia; Kiyoshi Tanemura; Tsuneo Suzuki

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2004
• Tongue: English
• Weight: 209 KB
• Volume: 41
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570410101

✦ Synopsis

Abstract

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 4__H__‐benzo[def]carbazole 15 in 61% yield.