Formation of <i>N</i>-acyl-<i>N,N′</i>-dicyclohexylureas from DCC and Arenecarboxylic Acids in the Presence of Hydroxybenzotriazole in CH<sub>2</sub>Cl<sub>2</sub> at Room Temperature
作者:Carlos R. Kaiser、Alessandra C. Pinheiro、Marcus V. N. de Souza、James L. Wardell、Solange M.S.V. Wardell
DOI:10.3184/030823408x333418
日期:2008.8
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
Substituent effect in reaction of dicyclohexylcarbodiimide with substituted benzoic acids
作者:Marek Ślebioda
DOI:10.1016/0040-4020(95)00400-3
日期:1995.7
A curved Hammett relationship was observed for the reaction of substituted benzoic acids with dicyclohexylcarbodiimide in buffered solution. The reaction is promoted by electon-withdrawing substituents because of larger concentration of the acid anion present in the reaction mixture. On the other hand, electron-donating substituents encourage nucleophilic attack of the acid anion on the protonated
Reactions of hydrazines with esters and carboxylic acids
作者:Richard Frederick Smith、Alvin C. Bates、Angello J. Battisti、Peter G. Byrnes、Christine T. Mroz、Thomas J. Smearing、Frederick X. Albrecht
DOI:10.1021/jo01266a085
日期:1968.2
One-Pot Reduction of Carboxylic Acids via <i>O</i>-Acylisoureas
作者:John M. Herbert、Alan T. Hewson、James E. Peace
DOI:10.1080/00032719808006479
日期:1998.3.1
A simple one-pot reduction of aliphatic carboxylic acids to primary alcohols, by treatment with dicyclohexylcarbodiimide followed by lithium borohydride, is reported. The same methodology applied to aromatic carboxylic acids is shown to give a mixture of the alcohols with N-cyclohexylcarboxamides.
Synthesis of Stable 1H-Azirines Reinvestigated: A Structural Corrigendum
作者:Klaus Banert、Manfred Hagedorn、Heiko Peisker
DOI:10.1055/s-0032-1317494
日期:——
The isoquinoline-catalyzed synthesis of pretended 1H-azirines from phenacyl bromides and N,N'-dialkylcarbodiimides was repeated. The products do not possess the structure of antiaromatic 1H-azirines, but simple N-acyl-N,N'-dialkylureas were formed instead. This structural corrigendum was confirmed by the independent synthesis of the known ureas and comparison of their H-1 NMR and C-13 NMR spectroscopic data in the case of six compounds. Thus, 1H-azirines keep their classification as very short-lived intermediates.