Redox transformations of 2-formylquinoxaline hydrate and diethylacetal N,N?-dioxides

Quinoxaline 1,4-Dioxides: Advances in Chemistry and Chemotherapeutic Drug Development

“…Reduction and rearrangements occurring in the 1,4-dioxide core are often observed under basic conditions [ 69 , 70 , 71 , 72 , 73 ], by treatment of nucleophiles [ 74 , 75 , 76 ] or acid halides [ 77 , 78 , 79 ], which frequently reduce the yield of the target products and limit the possibility of transforming the functional groups of quinoxaline 1,4-dioxides. At the same time, the electron-withdrawing nature of the N -oxide fragments in the quinoxaline nucleus makes it possible to carry out a nucleophilic substitution of the leaving groups in positions 2, 3 and 6, 7 of the heterocyclic core under relatively mild conditions.…”

“…In particular, 2-substituted quinoxaline 1,4-dioxides 28a,b isomerize to 3-oxoquinoxaline 1-N-oxides 30a and 30b in high yield through the intermediate oxaziridines 29 under photolysis of their aqueous solutions (Scheme 8) [68]. Reduction and rearrangements occurring in the 1,4-dioxide core are often observed under basic conditions [69][70][71][72][73], by treatment of nucleophiles [74][75][76] or acid halides [77][78][79], which frequently reduce the yield of the target products and limit the possibility of transforming the functional groups of quinoxaline 1,4-dioxides. At the same time, the electron-withdrawing nature of the N-oxide fragments in the quinoxaline nucleus makes Reduction and rearrangements occurring in the 1,4-dioxide core are often observed under basic conditions [69][70][71][72][73], by treatment of nucleophiles [74][75][76] or acid halides [77][78][79], which frequently reduce the yield of the target products and limit the possibility of transforming the functional groups of quinoxaline 1,4-dioxides.…”

“…Reduction and rearrangements occurring in the 1,4-dioxide core are often observed under basic conditions [69][70][71][72][73], by treatment of nucleophiles [74][75][76] or acid halides [77][78][79], which frequently reduce the yield of the target products and limit the possibility of transforming the functional groups of quinoxaline 1,4-dioxides. At the same time, the electron-withdrawing nature of the N-oxide fragments in the quinoxaline nucleus makes Reduction and rearrangements occurring in the 1,4-dioxide core are often observed under basic conditions [69][70][71][72][73], by treatment of nucleophiles [74][75][76] or acid halides [77][78][79], which frequently reduce the yield of the target products and limit the possibility of transforming the functional groups of quinoxaline 1,4-dioxides. At the same time, the electronwithdrawing nature of the N-oxide fragments in the quinoxaline nucleus makes it possible Pharmaceuticals 2023, 16, 1174 9 of 39 to carry out a nucleophilic substitution of the leaving groups in positions 2, 3 and 6, 7 of the heterocyclic core under relatively mild conditions.…”