DBU Catalysis of N,N′-Carbonyldiimidazole-Mediated Amidations
摘要:
1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) has been found to catalyze the amidation of acyl Imidazoles. The rate acceleration is especially evident with traditionally unreactive, electron-deficient anilines. DBU is readily available and offers safety and cost advantages over more commonly employed catalysts such as 1-hydroxybenzotriazole.
A Comparison of Catalysts to Promote Imidazolide Couplings Including the Identification of 2-Hydroxy-5-nitropyridine as a New, Safe, and Effective Catalyst
摘要:
Five catalysts were compared with respect to their safety and catalytic effectiveness for promoting imidazolide couplings, Reaction rate enhancement, shock sensitivity, and differential scanning calorimetry (DSC) data were considered in this analysis. 6-Chloro-1-hydroxybenzotriazole, which has been described in the literature as a safe catalyst, was found to be shock sensitive. 2-Hydroxy-5-nitropyridine is a new catalyst for this type of reaction and was found to be safe, effective, readily available, and similar in price to that of the 1-hydroxybenzotriazole, a common catalyst for promoting acylation reactions.