%0 Journal Article %J Angewandte Chemie-International Edition %D 2007 %T Novel reaction of the “huisgen zwitterion” with chalcones and dienones: an efficient strategy for the synthesis of pyrazoline and pyrazolopyridazine derivatives %A Nair, Vijay %A Biju, Akkattu T. %A Mathew, Smitha C. %A Eringathodi, Suresh %K chalcones; nitrogen heterocycles; pyrazolines; synthetic methods; zwitterions %X

Two unexpected transformations: The reaction of the Huisgen zwitterion derived from triphenylphosphane and diisopropyl azodicarboxylate (DIAD) with chalcones affords functionalized pyrazolines. In contrast, the reaction with dienones affords pyrazolopyridazines, presumably by Diels–Alder reaction of the initially formed pyrazoline with excess DIAD (see scheme).

%B Angewandte Chemie-International Edition %V 46 %P 2070–2073 %8 MAR %G eng %N 12 %9 Article %2

Council of Scientific & Industrial Research (CSIR) - India

%3 Foreign %4 11.709 %R 10.1002/anie.200604025