874 R. Nasielski-Hinkens, M. Benedek-Vamos and D. Maetens Vol. 17 required prolonged heating in concentrated refluxing pyridine to be successful. The nitration has been perform- ed with fuming nitric acid in acetic acid at 60° to yield 5,6-bis(iV-j3-toluenesulonamido)-8(7)-nitroquinoxaline (10). The hydrolysis and ring closure have been realized in the same conditions as mentioned previously and lead to 9-nitro-TAP (Id). The reduction of the nitro group could easily be ...