Authors: De Souza, M.V.N.; Kaiser, C.R.; Pinheiro, A.C.; Wardell, S.M.S.V.; Wardell, J.L.
Source: Journal of Chemical Research, 468-472, 2008
Publisher: Science Reviews 2000 Ltd
Abstract
The syntheses of N-acyl-N,N′-dicyclohexylureas from 1,3-dicyclohexylcarbodiimide and arenecarboxylic acids [p-XC6H4CO2H (X = H or NO2), 2-, 3- or 4-pyridinecarboxylic acid and pyrazinecarboxylic acid] in the presence of hydroxybenzotriazole in CH2Cl2 at room temperature are reported. The reactions proceed via the intermediacy of O-acyl-N,N′-dicyclohexylurea derivatives which undergo rapid O-acyl to N-acyl rearrangements. No acid anhydrides were detected. Under the same reaction conditions, the O-acyl derivative from the alkanecarboxylic acid, N-(benzyloxycarbonyl)-DL-pipecolic acid does not undergo rearrangement, as shown by the subsequent reaction with MeOH to give methyl N-(benzyloxycarbonyl)-DL-pipecolate. Characterisations were generally achieved by spectroscopic means, and specifically for N-(p-nitrobenzenecarbonyl)-N,N′-dicyclohexylurea by X-ray crystallography.Keywords: None Document Type: Research Article DOI: http://dx.doi.org/10.3184/030823408X333418 Publication date: 1 de Julho de 2008
