title: Synthesis and stereochemistry of dispiro substituted pyridazines: application of ellipticity-absorbance ratio spectra for proving enantiomeric relationship by HPLC-CD/UV detection.
abstract: The aim of our study was to synthesize vinylic and pyrido-fused pyridazines with a spirano moiety and to investigate their stereochemistry by spectroscopic and HPLC analyses. The vinylic compounds 5 were obtained by Knoevenagel condensation of cyclohexylidene malonates 1 with pyridazinecarbaldehyde 2. Compound 5b exhibits geometric isomerism identified by NMR, HPLC, and X-ray methods. The thermal rearrangement reactions of compounds 5 easily led to the pyridopyridazine derivatives 6. In the case of 6b, possessing both central and axial chirality, both diastereomers and the respective enantiomers were detected. Their stereochemical relationships could be determined by HPLC-CD/UV analyses with application of anisotropy spectra in a novel way.
authors: Department of Organic Chemistry, Semmelweis University, Budapest, Hungary.
authors: Gyula
authors: G
authors: Beke
authors: András
authors: A
authors: Gergely
authors: György
authors: G
authors: Szász
authors: Aletta
authors: A
authors: Szentesi
authors: József
authors: J
authors: Nyitray
authors: Orsolya
authors: O
authors: Barabás
authors: Veronika
authors: V
authors: Harmath
authors: Péter
authors: P
authors: Mátyus