Abstract
Claisen-Schmidt-type aldol-crotonic condensation of 3-acetyl-5-nitropyridine derivatives with various aromatic aldehydes was used for the preparation of pyridylchalcones. Cyclization of the latter with hydrazine hydrate in acetic acid afforded the corresponding N-acetyl derivatives of 4,5-dihydro-1H-pyrazole.
Synthesis of 4,5-dihydro-1H-pyrazole derivatives based on 3-acetyl-5-nitropyridines