Nucleophilic transformations of heterocyclic derivatives of 4-heteryl-2,4-dioxobutanoic acids

Proceeding from 4-heteryl-2,4-dioxobutanoic acids were prepared (Z)-3-heteroylmethylene1,2,3,4-tetrahydro-2-quinoxalones that when treated with oxalyl chloride afforded 3-heteroyl-1,2,4,5-tetrahydropyrrolo[1,2-a]quinoxaline-1,2,4-triones. The latter took in reactions with o-aminophenol and o-phenylenediamine two different directions.