Quality Control of 1-MethylpyrazoleOn March 25, 2021, Shi, Xinzhe; Sosa Carrizo, E. Daiann; Cordier, Marie; Roger, Julien; Pirio, Nadine; Hierso, Jean-Cyrille; Fleurat-Lessard, Paul; Soule, Jean-Francois; Doucet, Henri published an article in Chemistry – A European Journal. The article was 《C-H Bond Arylation of Pyrazoles at the β-Position: General Conditions and Computational Elucidation for a High Regioselectivity》. The article mentions the following:
Direct arylation of most five-membered ring heterocycles are generally easily accessible and strongly favored at the α-position using classical palladium-catalysis. Conversely, regioselective functionalization of such heterocycles at the concurrent β-position remains currently very challenging. Herein, authors report general conditions for regioselective direct arylation at the β-position of pyrazoles, while C-H α-position is free. By using aryl bromides as the aryl source and a judicious choice of solvent, the arylation reaction of variously N-substituted pyrazoles simply proceeds via β-C-H bond functionalization. The β-regioselectivity is promoted by a ligand-free palladium catalyst and a simple base without oxidant or further additive, and tolerates a variety of substituents on the bromoarene. DFT calculations revealed that a protic solvent such as 2-ethoxyethan-1-ol significantly enhances the acidity of the proton at β-position of the pyrazoles and thus favors this direct β-C-H bond arylation. This selective pyrazoles β-C-H bond arylation was successfully applied for the straightforward building of π-extended poly(hetero)aromatic structures via further Pd-catalyzed combined α-C-H intermol. and intramol. C-H bond arylation in an overall highly atom-economical process. The results came from multiple reactions, including the reaction of 1-Methylpyrazole(cas: 930-36-9Quality Control of 1-Methylpyrazole)
1-Methylpyrazole(cas: 930-36-9) belongs to pyrazoles. Pyrazoles and their related multiring analogs are common elements of a wide variety of bioactive compounds. These ring structures are rare in nature. A consequence of this is that they have previously been thought to be poor moieties to include in potential new drugs. Quality Control of 1-Methylpyrazole
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics