A solid-phase traceless synthesis of tetrahydroquinoxalines

A solid-phase traceless synthesis of tetrahydroquinoxalines with three comb inatorial steps is reported. An aldehyde functionalized polystyrene resin w as reductively aminated by amino alcohols, and then the resin bound seconda ry amines were reacted with o-fluoronitrobenzenes. The hydroxy group was me sylated and the nitro group was reduced by tin(II) chloride to the anilines , which spontaneously cyclized. The secondary aniline nitrogen of the resul ting tetrahydroquinoxalines was further derivatized with acyl chlorides and isocyanates. After acidolytic cleavage from the resin, tetrahydroquinoxali nes with three points of diversity were obtained. (C) 2001 Elsevier Science Ltd. All rights reserved.