R. Brehme, E. Gründemann, Matthias F. Schneider
Jul 1, 2003
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0
Influential Citations
5
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Journal
Synthesis
Abstract
1,3-Disubstituted 1H-pyrazole-4-carbaldehyde-N,N-di-methylhydrazones 1 reacted with the Vilsmeier-Haack reagent, corresponding to the aza-enamine concept, in an electrophilic substitution reaction at the azomethine C-atomyielding the 1,4,5-triaza-pentadienium salts 2. These were hydrolysed to give 2-hydrazono-2-( 1H-pyrazole-4-yl)ethanals 3. The electrophilic attack did not take place at the vinylogous position 5' of the pyrazoles.