Oxidative [3+2]Cycloaddition of Alkynylphosphonates with Heterocyclic N-Imines: Synthesis of Pyrazolo[1,5-a]Pyridine-3-phosphonates Full article
| Journal |
Molecules
, E-ISSN: 1420-3049 |
||||
|---|---|---|---|---|---|
| Output data | Year: 2022, Volume: 27, Number: 22, Pages: 7913 Pages count : 1 DOI: 10.3390/molecules27227913 | ||||
| Tags | alkynes; cycloaddition; heterocycles; oxidation; iron | ||||
| Authors |
|
||||
| Affiliations |
|
Abstract:
A series of pyrazolo[1,5-a]pyridine-3-ylphosphonates were prepared with moderate to good yields by the oxidative [3+2]cycloaddition of 2-subtituted ethynylphosphonates with in situ generated pyridinium-N-imines and their annulated analogs. 2-Aliphatic and 2-Ph acetylenes demonstrate low activity, and the corresponding pyrazolopyridines were achieved with a moderate yield in the presence of 10 mol% Fe(NO3)3·9H2O. At the same time, tetraethyl ethynylbisphosphonate, diethyl 2-TMS- and 2-OPh-ethynylphosphonates possess much greater reactivity and the corresponding pyrazolo[1,5-a]pyridines, and their annulated derivatives were obtained with good to excellent yields without any catalyst. 2-Halogenated ethynylphosphonates also readily reacted with pyridinium-N-imines, forming complex mixtures containing poor amounts of 2-halogenated pyrazolopyridines.
Cite:
Philippov I.
, Gatilov Y.
, Sonina A.
, Vorob’ev A.
Oxidative [3+2]Cycloaddition of Alkynylphosphonates with Heterocyclic N-Imines: Synthesis of Pyrazolo[1,5-a]Pyridine-3-phosphonates
Molecules. 2022. V.27. N22. P.7913. DOI: 10.3390/molecules27227913 WOS РИНЦ OpenAlex
Oxidative [3+2]Cycloaddition of Alkynylphosphonates with Heterocyclic N-Imines: Synthesis of Pyrazolo[1,5-a]Pyridine-3-phosphonates
Molecules. 2022. V.27. N22. P.7913. DOI: 10.3390/molecules27227913 WOS РИНЦ OpenAlex
Dates:
| Submitted: | Oct 20, 2022 |
| Accepted: | Nov 4, 2022 |
| Published online: | Nov 16, 2022 |
Identifiers:
| Web of science: | WOS:000887304000001 |
| Elibrary: | 57651109 |
| OpenAlex: | W4309604975 |