AN ALTERNATIVE APPROACH TO THE SYNTHESIS OF 5<i>H</i>-CHROMENO[4,3-<i>b</i>]PYRIDIN-5-ONE SYSTEM USING THE CLEAVAGE OF 5<i>H</i>,9<i>H</i>-PYRANO[2',3':5,6]CHROMENO[4,3-<i>b</i>]PYRIDINE-5,9-DIONES WITH BINUCLEOPHILES
DOI:
https://doi.org/10.1007/4211Keywords:
carbonyl compounds, condensed chromones, isoxazoles, , pyrazoles, cyclization, recyclizationAbstract
Hantzsch reaction has been successfully employed for a one-step assembling of pyranopyridine fragment to produce 5Н,9Н-pyrano[2',3':5,6]chromeno[4,3-b]pyridine-5,9-diones which upon treatment with binucleophiles undergo chemoselective γ-pyrone ring opening with the concomitant recyclization to give five-membered cycles, providing a concise route to 6-pyrazolyl(isoxazolyl)-5H-chromeno[4,3-b]pyridin-5-ones.
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Published
2018-02-16
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Short Communications