4280-43-7Relevant academic research and scientific papers
Regioselective Synthesis of Trisubstituted Quinoxalines Mediated by Hypervalent Iodine Reagents
Ito, Ryota,Miura, Kasumi,Suzuki, Noriyuki,Suzuki, Yumiko,Takehara, Ren
, p. 16892 - 16900 (2021/12/06)
A facile and regioselective synthesis of quinoxalines, an important motif in medicinal chemistry and materials sciences, was developed. Despite their prospective utility, the regioselective preparation of trisubstituted quinoxalines has not been previously established. In the reported system, hypervalent iodine reagents catalyzed the annulation between α-iminoethanones ando-phenylenediamines in a chemo/regioselective manner to afford trisubstituted quinoxalines. Excellent regioselectivities (6:1 to 1:0) were achieved using [bis(trifluoroacetoxy)iodo]benzene and [bis(trifluoroacetoxy)iodo]pentafluorobenzene as annulation catalysts.
A novel palladium-catalyzed synthesis of 2-arylbenzimidazoles
Perry,Wilson
, p. 7016 - 7021 (2007/10/02)
A new method for the preparation of 2-arylbenzimidazoles based on the palladium-catalyzed carbonylation, coupling, and cyclization of haloaromatics and o-phenylenediamines is described. Reactions were run in DMAc at 145°C for 18 h, under 95 psig CO, with 1.5 mol% PdCl2L2 as catalyst and in the presence of 1.2 equiv of 2,6-lutidine to give 70-98% yield of desired products. This route is tolerant of a variety of functional groups and nicely complements the classical route where the desired benzoic acid derivatives are unavailable. The selection of an appropriate base is crucial for the formation of 2-arylbenzimidazoles. Intermolecular bis-acylation to form bisamides occurs if the base is too strong. Weak bases allow side reactions with amide solvents to occur, leading to substituted benzamides and alkyl benzimidazoles.
