Curtius rearrangement of aromatic carboxylic acids to access protected anilines and aromatic ureas.
The reaction of a chloroformate or di-tert-butyl dicarbonate and sodium azide with an aromatic carboxylic acid produces the corresponding acyl azide, presumably through the formation of an azidoformate. The acyl azide undergoes a Curtius rearrangement to form an isocyanate derivative which is trapped either by an alkoxide or by an amine to form the aromatic carbamate or urea. The reaction conditions are compatible with a variety of functional groups and allow the synthesis of a number of aniline derivatives containing alkyl, halide, nitro, ketone, ether, and thioether substituents. [reaction: see text]
Lebel
Hélène
H
Département de chimie, Université de Montréal, P.O. Box 6128, Station Downtown, Montréal, Québec, Canada, H3C 3J7. helene.lebel@umontreal.ca
Leogane
Olivier
O
D000814:Aniline Compounds / Q000737:chemistry*; D001565:Benzoates / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D007202:Indicators and Reagents; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry*
D000814:Aniline Compounds; D001565:Benzoates; D002264:Carboxylic Acids; D007202:Indicators and Reagents; D014508:Urea