Synthesis of New Quinoxaline Derivatives

Abstract New quinoxaline derivatives were prepared by the reaction of 2-hydroxyquinoxaline 1 and alkyl or alkylaminoalkyl halides in dimethylformamide using potassium carbonate as a base. The hydroxyl group was readily converted into a thiol function by treatment with phosphorus pentasulfide and/or Lawesson's reagent in pyridine, and the subsequent alkylation of the thiol group was carried out under phase-transfer catalyst conditions. Chlorination of 1 was carried out with phosphorus oxychloride. Branching of alkylamino side chains to the 2-OH, 2-SH, and 2-Cl quinoxalines resulted in the synthesis of several compounds. Synthesis and alkylation of 2-hydroxy 7-nitroquinoxaline are also reported.