Darstellung und Struktur von Pyrazolyl-Kationen mit Polymethin- und Methan-Gerüst

摘要

The 4-pyrazoline-3-one1reacts with 4-dimethylaminobenzaldehyde to yield the stable asymmetric cyanine dye2bwhich reacts with1to give the colorless (aryl) (dipyrazolyl) methane3b. Using aldehydes with less cationstabilizing groups the polymethines2are not isolated but only the methanes3. The structures of2band3are discussed by1H,13C and Hetero NMR spectra.