Reactions of Cyclic Oxalyl Compounds, 26. Cyclocondensation Reaction of 4,5-substituted Thiophene- and N-Alkylpyrrol-2,3-diones with o-Phenylendiamine

Article abstract of DOI:10.1007/BF00810263

4-Benzoyl-5-phenylthiophene-2,3-dione (1) reacts with o-phenylendiamine to give the quinoxaline derivative 2 which cyclizes either to the furo<2,3-b>quinoxaline 4 or to the thieno<2,3-b>quinoxaline 5 depending on the reaction conditions.On the other hand,