65780-54-3

Upstream product

• 49568-65-2 3-oxo-3,4-dihydro-quinoxaline-2-carbaldehyde 
• 100-63-0 phenylhydrazine 
• 62235-61-4 2-bromomethyl-3-oxo-3,4-dihydroquinoxaline 
• 1222-71-5 3-(D_r-1t_F,2c_F,3r_F,4-tetrahydroxy-but-cat_F-yl)-1H-quinoxalin-2-one 
• 1222-71-5 3-(L_r-1c_F,2t_F,3r_F,4-tetrahydroxy-but-cat_F-yl)-1H-quinoxalin-2-one 
• 14003-34-0 3-methyl-2-oxo-1,2-dihydroquinoxaline 
• 62-53-3 aniline 
• 95-54-5 1,2-diamino-benzene 
• 1222-71-5 3-(1,2,3,4-tetrahydroxy-butyl)-1H-quinoxalin-2-one 

Relevant academic research and scientific papers

Substituent Effects on the Tautomer Ratios between the Hydrazone Imine and Diazenyl Enamine Forms in 3-(Arylhydrazono)methyl-2-oxo-1,2-dihydroquinoxalines. Correlation of the Hammett Constants ?p with the Tautomeric Equilibrium Constants KT

The 3-(arylhydrazono)methyl-2-oxo-1,2-dihydroquinoxalines 1a-e and 2a-i showed tautomeric equilibria between the hydrazone imine A and diazenyl enamine B forms in dimethyl sulfoxide media.The substituent effects on the tautomer ratios of A to B in compounds 1a-e and 2a-i were studied by the nmr spectroscopy.The electron-donating or electron-withdrawing p-substituents R1 in compounds 2a-i represented a tendency to increase the ratios of the tautomer A or the tautomer B, respectively, exhibiting the linear correlation of the Hammett constants ?p (-0,17 to +0.78)with the tautomer ratios of A to B or the tautomeric equilibrium constants KT.However, the presence of the ester group R2 in compounds 1a-e induced the exclusive existence of the tautomer A regardless of the nature of the p-substituents R1.In the tautomeric thermodynamic study, the elevating temperature increased the ratios of the hydrazone imine tautomer A in compounds 2a-i.The tautomeric thermodynamic parameters ΔGO, ΔHO and ΔSO were derieved from the van't Hoff plots for compounds 2a,b,h,i, wherein the entropy term dominated the free energy difference between the A and B tautomers.