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90. Synthesis of 10-Aryl-10H-naphtho[1,8a,8-fg]indazol-7-ones (Organic Azides in Heterocyclic Synthesis, Part 32)
Wolfgang Stadlbauer* and Gerhard Hojas J. Heterocyclic Chem, 40 (2003) 753-756.

Abstract: 3-Hydroxy-2-[1-(arylhydrazono)ethyl]-1H-phenalen-1-ones 3, obtained from 2-acetyl-3-hydroxy-1H-phenalen-1-one (1) and arylhydrazines 2, cyclize under acidic conditions to 8-methyl-10-aryl-10H-naphtho[1,8a,8-fg]indazol-7-ones 4. Indazoles 4 are also obtained from 2-acetyl-3-hydroxy-1H-phenalen-1-one (1) and arylhydrazines 2 in a one pot reaction. 2-Acetyl-3-azido-1H-phenalen-1-one (6) does not give 8-methyl-9-arylamino-9H-naphtho[1,8a,8-fg]indazol-7-ones via azide decomposition but gives again by nucleophilic replacement of the azide moiety in 6 indazoles 4.


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