A solid phase traceless synthesis of quinoxalinones

A solid-phase traceless synthesis of quinoxalinones in three combinatorial steps is reported. An aldehyde functionalized polystyrene resin was reductively alkylated by amino acid methyl esters, and then the resin bound secondary amines were reacted with o-fluoronitrobenzenes. The resulting o-nitroanilines were reduced by tin chloride to the dianilines, which spontaneously cyclized. The amide nitrogen of the dihydroquinoxalinones obtained was alkylated by alkyl halides. After cleavage from the resin, the dihydroquinoxalinones were air oxidized to quinoxalinones.