An anomalous course of the reduction of 2-(3-oxo-3,4-dihydroquinoxalin-2-yl)benzene diazonium salt: a reinvestigation.
The 1H,13C and 15N NMR spectra of the reduction product of 2-(3-oxo-3,4-dihydroquinoxalin-2-yl)benzene diazonium salt with sodium sulfite were measured and analysed. It is shown that the reaction product corresponds to 1-(indazol-3-yl)-1,2-dihydro-benzimidazol-2-on and not 6H-quinoxalino[1,2-c] [1,2,3]benzotriazin-12(13H)-one as published previously. The correctness of the structure was confirmed by an independent synthesis. The observed 15N chemical shifts were compared with the predicted ones using the ACD/NNMR 9.01 program.
Lycka
Antonín
A
Research Institute for Organic Syntheses, Rybitví 296, CZ-532 18 Pardubice 20, Czech Republic. antonin.lycka@vuosas.cz
Frysová
Iveta
I
Slouka
Jan
J