Nitrile Oxide [3 + 2] Cycloaddition: Application to the Synthesis of 6-Substituted 3(2H)-Pyridazinones and 6-Substituted 4,5-Dihydro-4-hydroxy-3(2H)-pyridazinones
Pyridazine and Pyrrole Compounds, Processes For Obtaining Them and Uses
申请人:Dubreuil Didier Max
公开号:US20100298562A1
公开(公告)日:2010-11-25
The present invention relates to nonlinear oligopyridazine compounds, to processes for obtaining them, to their uses, and also to their reduction to oligopyrroles and to the uses of the pyridazinylpyrrole and oligopyrrole compounds obtained. The invention relates in particular to the uses as medicaments, in particular for treating pathologies such as cancer, bacterial infections or parasitic infections, and also the uses in the materials, environmental, electronics and optics field.
Nitrile Oxide [3 + 2] Cycloaddition: Application to the Synthesis of 6-Substituted 3(2<i>H</i>)-Pyridazinones and 6-Substituted 4,5-Dihydro-4-hydroxy-3(2<i>H</i>)-pyridazinones
作者:P. G. Baraldi、A. Bigoni、B. Cacciari、C. Caldari、S. Manfredini、G. Spalluto
DOI:10.1055/s-1994-25663
日期:——
An efficient method for the preparation of 6-substituted 3(2H)-pyridazinones and 6-substituted 4,5-dihydro-4-hydroxy-3(2H)-pyridazinones starting from 3,5-disubstituted 4,5-dihydroisoxazoles is described. N-O bond cleavage of the isoxazoline ring promoted by molybdenum hexacarbonyl or by catalytic hydrogenation afforded the α-hydroxy γ-keto esters 4a-f which were converted into 6-substituted 4,5-dihydro-4-hydroxy-3(2H)-pyridazinones 5a-f or 6-substituted 3(2H)-pyridazinones 6a-f on treatment with hydrazine hydrate at room temperature or reflux in high yield starting from 4a-f. The flexibility of this protocol has been demonstrated by the synthesis of the C-nucleoside 7 starting from the known β-ribofu-ranosylnitromethane 8. Moreover, an intramolecular version of this methodology has been developed to prepare the known antiulcer tricyclic 3(2H)-pyridazinone 12.