65698-90-0Relevant academic research and scientific papers
Application of Photoclick Chemistry for the Synthesis of Pyrazoles via 1,3-Dipolar Cycloaddition between Alkynes and Nitrilimines Generated In Situ
Remy, Richard,Bochet, Christian G.
, p. 316 - 328 (2018/01/27)
The photochemical extrusion of gaseous nitrogen from 2,5-disubstituted tetrazoles to generate reactive nitrilimines in situ represents an efficient and attractive way to form dipoles that can be used to provide useful chemicals via 1,3-dipolar cycloadditions. The concept of “photoclick chemistry” already inspired numerous researchers, who exploited photochemical processes involving alkenes for the synthesis of adducts or the functionalization of biocompatible materials. The approach requires bioorthogonality, ease of access to the starting materials and operational simplicity. We report herein our investigations toward a photoclick reaction involving 2,5-disubstituted tetrazoles and alkynes as the dipolarophile for the synthesis of pyrazole derivatives. In addition to the numerous reports recently published on the synthesis of pyrazoles, we wish to add to the list a photochemical procedure that represents a mild and atom-economical alternative. Moreover, considering that such nitrilimines precursors can be accessed in one step from inexpensive and abundant starting materials and given the commercial availability of a broad spectrum of alkynes, we examined the scope of the photoclick reaction with respect to reactive partners, enabling the synthesis of a library of useful heteroaromatics.
PhIO promoted synthesis of nitrile imines and nitrile oxides within a micellar core in aqueous media: A regiocontrolled approach to synthesizing densely functionalized pyrazole and isoxazoline derivatives
Pal, Gargi,Paul, Sanjay,Ghosh, Partha Pratim,Das, Asish R.
, p. 8300 - 8307 (2014/02/14)
A highly efficient and general protocol has been developed for the facile synthesis of highly diversified 1,3,5-trisubstituted pyrazoles and 3,5-disubstituted 2-isoxazolines through one-pot tandem intermolecular, as well as intramolecular, dipolar [3 + 2] cycloaddition reactions. Chemoselective oxidation of aldohydrazone to nitrile imine and aldoximes to nitrile oxides by iodosobenzene in neutral aqueous media was performed. The scope of the reactions in regiocontrolled dipolar cycloaddition with olefins in the presence of PhIO toward highly substituted pyrazole and isoxazoline derivatives has been demonstrated. SDS converted the initially floating reaction mass and the organo-oxidant PhIO into a homogeneous mixture, which on stirring became a turbid emulsion. The micellar arrangement was confirmed by dynamic light scattering and optical microscopy. The new, green and metal free synthetic method enabled the execution of regiocontrolled tandem cycloaddition oxidation sequences leading to a library of pyrazole and isoxazoline derivatives.
Intramolekulare 1,3-dipolare Cycloadditionen von Diarylnitriliminen aus 2,5-Diaryltetrazolen
Meier, Hansruedi,Heimgartner, Heinz
, p. 1283 - 1300 (2007/10/02)
Alkenyl-substituted diaryl-nitrile-imines - generated by photolysis or thermolysis of alkenyl-substituted 2,5-diaryl-tetrazoles - undergo a regioselective intramolecular cycloaddition to yield new heterocyclic compounds, e.g. fused 2-pyrazolines.Wit
CYCLOADDITIONS INTRAMOLECULAIRES CATIONIQUE 3+ + 2 ET DIPOLAIRE-1,3 DE PHENYLHYDRAZONES.
Fouchet, B.,Joucla, M.,Hamelin, J.
, p. 1333 - 1336 (2007/10/02)
In acidic medium, alkenyl phenylhydrazones lead, probably via a 3+ + 2 cationic cycloaddition, to fused ring system, which are difficult to obtain as primary products of thermal 1,3 dipolar cycloaddition.
