7189-03-9Relevant 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.
PROCESS FOR THE REGIOSELECTIVE SYNTHESIS OF PYRAZOLES
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, (2015/07/15)
A process is described for the synthesis of pyrazoles having general formula (I) which comprises the steps of mixing a compound having general formula (II) and a 1,2-disubstituted hydrazine having general formula (III) to form a reaction intermediate having general formula (IV) and the reaction mixture obtained in step i), in an acid environment, cyclizes to form a pyrazole having general formula (I), according to reaction scheme 1 Scheme 1.
Diastereoselective synthesis of pyrazolines using a bifunctional Bronsted acidic ionic liquid under solvent-free conditions
Safaei, Shirin,Mohammadpoor-Baltork, Iraj,Khosropour, Ahmad R.,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah
, p. 3095 - 3104 (2013/01/15)
An efficient protocol for the excellent diastereoselective synthesis of pyrazolines via a three-component reaction of aldehydes, hydrazines and dimethyl acetylenedicarboxylate (DMAD) in the presence of a bifunctional Bronsted acidic ionic liquid as a reus
One-pot synthesis of functionalized 3-aryl-1-phenyl-1H-pyrazoles from hydrazonoyl chlorides and acetylenic esters in the presence of Ph3P
Yavari, Issa,Khalili, Gholamhossein,Mirzaei, Anvar
experimental part, p. 277 - 280 (2010/05/15)
The zwitterionic 1 :1 intermediates generated by addition of Ph 3P to acetylenic esters is trapped by 1-[(aryl)chloromethylene]-2- phenylhydrazines (=N-phenylarenecarbohydrazonoyl chlorides) to yield functionalized 3-aryl-1-phenyl-1H-pyrazoles
