Pyridazine derivatives. Part 39: Reactivity of 5-iodopyridazin-3(2H)-ones in palladium-catalysed reactions
作者:Alberto Coelho、Eddy Sotelo、Héctor Novoa、Oswald M. Peeters、Norbert Blaton、Enrique Raviña
DOI:10.1016/j.tet.2004.10.014
日期:2004.12
antiplatelet agents, convenient and efficient methods for the preparation of 2,5-disubstituted pyridazin-3(2H)-ones are reported that utilise palladium-catalysed cross-coupling reactions. A post-coupling base-promoted isomerisation has been observed during Sonogashira alkynylation of 5-iodopyridazin-3(2H)-ones (3) with 1-phenyl-2-propyn-1-ol. Variable amounts of phthalazinones were isolated as by-products during
Design, Synthesis, and Structure–Activity Relationships of a Novel Series of 5-Alkylidenepyridazin-3(2<i>H</i>)-ones with a Non-cAMP-Based Antiplatelet Activity
5-Alkylidenepyridazin-3-ones with four points of diversity (R-2, R-6, X, Y) have been synthesized and evaluated as platelet aggregation inhibitors. Several derivatives eliciting antiplatelet activity in the low micromolar range (e.g., 14e, 14k, 14p, 14v, IC50 congruent to 1 mu M) were identified. Structure-activity relationships studies on these compounds revealed the key molecular determinants of this new family of antiplatelet agents: (a) two ester groups in the alkoxy moieties; (b) lipophilic substituents at the N2 position of the pyridazin-3-one. The preliminary results of a pharmacological study aimed at determining the mechanism of action of a set of representative compounds revealed that, unlike other pyridazinones, the documented antiplatelet effect is not a consequence of a PDE-III inhibitory activity.