Reductive metallation of 6-methyl-2,3-diphenylquinoxaline. Synthesis of 1,4-dihydro-1,4-diazine derivatives

Abstract

The reductive metallation of 6-methyl-2,3-diphenylquinoxaline 1 with sodium metal in tetrahydrofuran and inert atmosphere to a monomeric dianion 2 has been explored and the nucleophilicity of this disodium adduct was investigated with various alkylation and acylation reagents. An annulation of the pyrazine ring system was accomplished by treating the dianion with polymethylene chlorides, CI(CH2)(n)Cl, n = 3.4.