Triphenylphosphine-mediated reductive cyclization of 2-nitrobiphenyls: a practical and convenient synthesis of carbazoles.
J Org Chem
; 70(13): 5014-9, 2005 Jun 24.
Article
em En
| MEDLINE
| ID: mdl-15960500
ABSTRACT
The synthesis of a series of substituted carbazoles from the corresponding 2-nitrobiphenyl derivatives using a novel modification of the Cadogan reaction is described. Cyclization of the 2-nitrobiphenyls was achieved via reductive deoxygenation of the nitro groups using a slight excess of triphenylphosphine in a suitable solvent. We have observed a temperature dependence on the extent of conversion under these conditions, with higher boiling solvents affording higher yields across a range of substrates. The new reaction conditions are very straightforward and convenient to execute, tolerate a broad range of functional groups, and yield carbazole products in the absence of unwanted side products.
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Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article