Synthesis of novel 1,2,4-triazino[5,6-b]quinoxalines and their tri-N-oxides

Article abstract of DOI:10.1055/s-1991-26387

Reaction of [1,2,5]oxadiazolo[3,4-b]quinoxaline 1-oxides with stable nitrile oxides in refluxing dichloromethane affords good yields of 1,2,4-triazino[5,6-b]quinoxaline 1,2,4-tri-N-oxides, a novel class of compounds of containing the pyrazino[2,3-e]triazine skeleton and also bearing three N-oxides in the same triazine ring. The tri-N-oxides are reduced with triphenylphosphine or sodium dithionite to the corresponding 5,10-dihydro-1,2,4-triazino[5,6-b] quinoxalines, which are converted to 1,2,4-triazino[5,6-b] quinoxalines upon oxidation with iodosobenzene bis(trifluoroacetate).