New approach toward the synthesis of deuterated pyrazolo[1,5-<i>a</i>]pyridines and 1,2,4-triazolo[1,5-<i>a</i>]pyridines

Vorob’ev, Aleksey Yu.; Supranovich, Vyacheslav I.; Borodkin, G. I.; Shubin, V. G.

doi:10.3762/bjoc.13.80

Cited by 9 publications

(3 citation statements)

References 34 publications

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“…Starting materials, unless otherwise noted, were obtained from commercial supplies and used without purification. O-(mesitylenesulfonyl)hydroxylamine (MSH) [52], mesitylenesulfonates of N-aminated heterocycles [52] and 1-aminopyridinium tetrafluoroborate [53] were obtained from previously published procedures. For the preparation of phenyl, alkyl and cycloalkyl alkynylphosphonates, Zhao's CuSO 4 -catalysed cross-coupling procedure was applied [54].…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2022

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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.

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Section: Methodsmentioning

confidence: 99%

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

et al. 2022

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“…These reactions require special conditions. They were carried out under heating [ 41 ], under pressure [ 40 , 42 ], in a microwave oven [ 43 ], by passing pure deuterium [ 40 ], or in deuterated solvents, more often D 2 O. Deuterium atoms were introduced by H/D exchange into α-aminopyridine derivatives by heating them to 80 °C in a solution of K 2 CO 3 in D 2 O [ 44 ]. Furthermore, by reaction with substituted acetylenes, the resulting deuterium derivatives were cyclized to pyrazolo[1,5- a ]pyridine derivatives containing deuterium atoms.…”

Section: Introductionmentioning

confidence: 99%

A Simple and Easily Implemented Method for the Regioselective Introduction of Deuterium into Azolo[1,5-a]pyrimidines Molecules

et al. 2023

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A method for the technically easy-to-implement synthesis of deuterium-labeled pyrazolo[1,5-a]pyrimidines and 1,2,4-triazolo[1,5-a]pyrimidines have been developed. The regioselectivity of such transformations has been shown. 1H NMR and mass spectrometric methods have proved the quantitative nature of such transformations and the kinetics of deuterium exchange has been studied. Spectrally, at different temperatures (+30 °C, −10 °C and −15 °C), the kinetics of the process was studied both in CD3OD and in deuterated alkali.

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“…Such imines were known to react with nitriles to yield [1,2,4] [26,27]. This reaction was applied to synthesis of deuterated [28] or 2-arylsubstituted derivatives library for antifungal [29] and anticancer [30] activity screening.…”

Section: Introductionmentioning

confidence: 99%

1,3-Dipolar cycloaddition of cyanopyridines to heterocyclic N-imines – combined experimental and theoretical studies

Vorob’ev¹,

Borodkin²,

Andreev³

et al. 2020

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Series of 2-pyridyl substituted [1,2,4]triazolo[1,5-a]azines have been synthesized by reaction of cyanopyridines with N-aminoazinium mesitylenesulfonates under basic conditions. The reaction proceeds smoothly with pyridinium, 1,10-phenanthrolinium and 8-oxyquinolinium salts. In case of quinolinium and isoquinolinium salts dimers of corresponding N-imines were isolated. Pyrazinium- and pyridazinium-N-imines didn’t possess any reactivity toward cyanopyridines. DFT studies give high activation barriers for 4-cyanopyridine cycloaddition to quinolinium and pyrazinium-N-imnes as well as highly negative free energy of dimerisation for quinolinium and isoquinolinium-N-imnes.

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New approach toward the synthesis of deuterated pyrazolo[1,5-a]pyridines and 1,2,4-triazolo[1,5-a]pyridines

Cited by 9 publications

References 34 publications

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

A Simple and Easily Implemented Method for the Regioselective Introduction of Deuterium into Azolo[1,5-a]pyrimidines Molecules

1,3-Dipolar cycloaddition of cyanopyridines to heterocyclic N-imines – combined experimental and theoretical studies

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