One-Pot Synthesis and Photochemical Diversification of Pyrazolo[1,2-a]pyridazinones into 3D-Rich Scaffolds
Ines Babnik1, Nejc Petek1, Uroš Grošelj1
1Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia.
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We report a one-pot, three-component synthesis of pyrazolo[1,2-a]pyridazinones from tetrahydropyridazines, a transformation that was historically challenging due to competing ring contractions. The resulting compounds undergo photoinduced transformations, without the need for external photocatalysts, to afford diverse 3D-rich derivatives, including tricyclic cyclobutenes and γ-(pyrazol-1-yl)butanals. Enabled by mild conditions, this strategy offers an efficient, atom-economical route to structurally diverse pyrazolo[1,2-a]pyridazinones and their derivatives.
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