1430100-72-3Relevant academic research and scientific papers
A reinvestigation of reaction of 2-hydrazino-3-phenylquinoxaline with 1,3-diketones: Synthesis and characterization of regioisomeric 1-(3′-phenylquinoxalin-2′-yl)-3,5-disubstitutedpyrazoles and 1,2,4-triazolo[4,3-a]quinoxalines
Eakta,Aggarwal, Ranjana,Sumran, Garima
, p. 273 - 281 (2013/05/09)
A reinvestigation into the reaction of 2-hydrazino-3-phenylquinoxaline 1 with several 1,3-diketones 2a-g reveals that a mixture of regioisomeric 1-(3′-phenylquinoxalin-2′-yl)-3,5-disubstitutedpyrazoles 3a-g and 4a-e and 1-methyl-4-phenyl/methyl-1,2,4-triazolo[4,3-a]quinoxalines 5a,b is formed as reaction products rather than erroneously reported exclusive formation of triazole 5 in case of aryl alkyl-1,3-diketones or 1-(3′- phenylquinoxalin-2′-yl)-3-alkylpyrazoles 4 in case of dialkyl and diaryl-1,3-diketones. Structural elucidation of the regioisomeric pyrazoles has been established by the spectroscopic data (1H, 13C NMR, COSY experiments and HRMS) and minimum energy 3-D diagrams.
Facile and efficient regioselective synthesis of 1-(3′-substituted quinoxalin-2′-yl)-3-aryl/heteroaryl-5-methylpyrazoles
Aggarwal, Ranjana,Masan, Eakta,Sumran, Garima
, p. 1842 - 1848 (2013/05/21)
This report describes an efficient and practical approach for regioselective synthesis of 1-(3′-substituted quinoxalin-2′-yl)-3- aryl/heteroaryl-5-methylpyrazoles (3a-j). Reaction of 2-chloro-3-substituted quinoxalines (1) with 3(5)-methyl-5(3)-aryl-1H-pyrazoles (2) in the presence of sodium hydride furnished the title compounds in excellent yields with good levels of regioselectivity. The present protocol is superior to the existing method, which yielded a mixture of regioisomeric pyrazoles (I, II) and triazolo[4,3-a]quinoxalines (III). Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
