Some synthetic applications of 2,3-dichloro-N-phenylmaleimide: A novel synthesis of 2-phenylpyrrolo[3,4-b]quinoxaline-1,3-diones. I

Article abstract of DOI:10.1016/S0040-4020(99)00672-9

2,3-Dichloro-N-phenylmaleimide 2 undergoes nucleophilic substitution reactions by a variety of nucleophiles giving either monosubstituted 5 or disubstituted 3 products. Treatment of 5 with sodium azide at room temperature results in cyclization to the corresponding 2-phenylpyrrolo[3,4- b]quinoxaline-1,3-diones 6, while at higher temperatures 5 is reduced to the 2-amino-amino-N-phenylmaleimides 7.