Oxidative [3+2]Cycloaddition of Alkynylphosphonates with Heterocyclic N-Imines: Synthesis of Pyrazolo[1,5-a]Pyridine-3-phosphonates

Oxidative [3+2]Cycloaddition of Alkynylphosphonates with Heterocyclic N-Imines: Synthesis of Pyrazolo[1,5-a]Pyridine-3-phosphonates Научная публикация

Журнал

Molecules
, E-ISSN: 1420-3049

Вых. Данные

Год: 2022, Том: 27, Номер: 22, Страницы: 7913 Страниц : 1 DOI: 10.3390/molecules27227913

Ключевые слова

alkynes; cycloaddition; heterocycles; oxidation; iron

Авторы

Philippov Igor ¹ , Gatilov Yuriy ¹ , Sonina Alina ¹ , Vorob’ev Aleksey ^1,2

Организации

1	Novosibirsk Institute of Organic Chemistry SB RAS
2	Department of Natural Science, Faculty of Organic Chemistry, Novosibirsk State University

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.

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

Поступила в редакцию:	20 окт. 2022 г.
Принята к публикации:	4 нояб. 2022 г.
Опубликована online:	16 нояб. 2022 г.

Web of science	WOS:000887304000001
РИНЦ	57651109
OpenAlex	W4309604975