Preparation and pyrolysis of 1-(pyrazol-5-yl)-1,2,3-triazoles and related compounds 1
作者:David Clarke、Richard W. Mares、Hamish McNab
DOI:10.1039/a700421d
日期:——
1-(Pyrazol-5-yl)-1,2,3-triazoles 8a, 9a and 10 are prepared by
cycloaddition of 5-azidopyrazoles with methyl prop-2-ynoate. The
regiochemistry of the process is confirmed by synthesis of 9a using an
authentic route from ethyl 2-formyl-2-diazoacetate 13. Flash vacuum
pyrolysis of 8a, 9a and 10 gives
5-methoxypyrazolo[1,5-a]pyrimidin-7-ones 16–18 by a
mechanism involving an unexpected oxoketenimine–imidoyl ketene
rearrangement as the key step. The mechanism is supported by a
13C labelling experiment. A general route to
pyrazolo[1,5-a]pyrimidin-7-ones from pyrazolylaminomethylene
Meldrum's acid derivatives (e.g. 30–32) is also
reported.
An unusual Fluorodinitroethylation Reaction of 3-Azidopyrazole
作者:Aleksei G. Gladyshkin、Aleksei B. Sheremetev
DOI:10.1007/s10593-019-02535-0
日期:2019.8
It was discovered for the first time that a two-step protocol involving dinitroethylation–fluorination of azoles can lead to double C- and N-fluorodinitroethylation of the pyrazole ring of 3-azidopyrazole.
Nitrogen‐rich quantumdots (N‐dots) were serendipitously synthesized in methanol or aqueous solution at a reaction temperature as low as 50 °C. These N‐dots have a small size (less than 10 nm) and contain a high percentage of the element nitrogen, and are thus a new member of quantum‐dot family. These N‐dots show unique and distinct photoluminescenceproperties with an increasing percentage of nitrogen
A novel entry to the imidoylketene–oxoketenimine energy surface
作者:David Clarke、Richard W. Mares、Hamish McNab
DOI:10.1039/c39930001026
日期:——
Gas-phase pyrolysis of the 1,2,3-triazoles 3â6 gives the pyrazolopyrimidinones 11â13 and the quinolinone 14 respectively: the mechanism involves an oxoketenimineâimidoylketene rearrangement.
作者:A. G. Gladyshkin、A. A. Anisimov、I. V. Ananyev、A. N. Pivkina、I. L. Dalinger、A. B. Sheremetev
DOI:10.1007/s11172-022-3580-5
日期:2022.8
Conditions for the introduction of the nitro group at the position 4 of N-(fluorodinitroethyl)pyrazoles bearing an electron-withdrawing substituent at the position 3 were found. The structures of the products were established by multinuclear NMR spectroscopy and X-ray crystallographic analysis.