Collect. Czech. Chem. Commun. 1980, 45, 2417-2424

Pyrazolidine derivatives from the condensation reaction of hydrazobenzene with aliphatic aldehydes

Vladimír Hanuša, Milan Hrazdirab and Otto Exnerc

a The J. Heyrovský Institute of Physical Chemistry and Electrochemistry, Czechoslovak Academy of Sciences, 121 38 Prague 2
b Department of Organic Chemistry, Institute of Chemical Technology, 532 10 Pardubice
c Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


The condensation reaction of hydrazobenzene with ethanal yields products of the pyrazolidine structure, III or V, according to whether it is carried out in the absence or presence of alcohols, respectively. Propanal reacts similarly to VIII while no reaction could be achieved with butanal. The structural evidence is based mainly on the mass and 1H NMR spectra which disprove the structures IV and VI, originally suggested by Rassow. The reaction is analogous to the condensation of aliphatic aldehydes with N-phenylhydroxylamine yielding 1,2-oxazolidine derivatives VII.