Detalle de: Reaction of 4-hydrazinoquinolines with β-diketones. Synthesis and spectroscopy ( 1 h, 13 c nmr, ms) of some pyrazolylquinolines

A series of 4‐pyrazolylquinolines have been prepared from 4‐hydrazinoquinolines and β‐dicarbonyl compounds and the previously proposed diazepine structure for the reaction products has been ruled out. A 13 C nmr study established the 3‐position of the methyl group when two isomers were possible. Finally, a careful 1 H nmr study of 2‐ and 4‐pyrazolylquinolines led to the conclusion that intramolecular hydrogen bonds between aromatic (or heteroaromatic) C‐H and pyridine like nitrogens is the factor that determines the conformation of these compounds.