Synthesis of Novel 1,2,4-Triazino[5,6-<i>b</i>]quinoxalines and Their Tri-<i>N</i>-oxides
作者:John K. Gallos、Nicolaos G. Argyropoulos
DOI:10.1055/s-1991-26387
日期:——
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 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).
在回流的二氯甲烷中,[1,2,5]噁二唑并[3,4-b]喹喔啉 1-氧化物与稳定的腈氧化物发生反应,可以得到产率很高的 1,2,4-三嗪并[5,6-b]喹喔啉 1,2,4-三-N-氧化物,这是一类含有吡嗪并[2,3-e]三嗪骨架的新型化合物,在同一个三嗪环中还含有三个 N-氧化物。三-N-氧化物用三苯基膦或二亚硫酸钠还原成相应的 5,10-二氢-1,2,4-三嗪并[5,6-b]喹喔啉,再用碘代苯二(三氟乙酸)氧化成 1,2,4-三嗪并[5,6-b]喹喔啉。