Charge Migration in Dicationic Electrophiles and Its Application to the Synthesis of Aza-polycyclic Aromatic Compounds
摘要:
Superacid-promoted reactions of dicationic electrophiles have been studied, and the positive charge centers are found to migrate apart in a predictable manner. Using isotopic labeling the charge migration is found in one system to occur through successive deprotonation-reprotonation steps. The charge migration chemistry is the basis for new general synthetic route to aza-polycyclic aromatic compounds.
Superacid-promoted reactions of pyrazolecarboxaldehydes and the role of dicationic electrophiles
作者:Douglas A. Klumpp、Patrick J. Kindelin、Ang Li
DOI:10.1016/j.tetlet.2005.02.152
日期:2005.4
Pyrazolecarboxaldehydes react in the Bronsted superacid triflic acid (CF3SO3H, TfOH) to generate electrophilic intermediates capable of reacting with benzene in condensation reactions. Appropriately substituted pyrazoles may also undergo intramolecular Friedel-Crafts-type reactions. It is proposed that the pyrazolecarboxaldehydes and related systems form diprotonated intermediates in these reactions. (c) 2005 Elsevier Ltd. All rights reserved.
Synthesis and antimicrobial activity of 4-formylpyrazole N-acylhydrazones
作者:M. K. Bratenko、N. P. Voloshin、I. O. Petrunik、D. M. Livak、M. V. Vovk
DOI:10.1007/bf02580517
日期:1998.6
Microwave‐Assisted Synthesis of 3‐(4‐Pyrazolyl)propenoic Acids
作者:Vitaliy O. Chornous、Mykhaylo K. Bratenko、Mykhaylo V. Vovk
DOI:10.1081/scc-120027241
日期:2004.12.31
Under microwave activation, pyrazole-4-carboxaldehydes react with malonic acid in the presence of a small amount of pyridine to give 3-(4-pyrazolyl)propenoic acids in high yields.