Traceless synthesis of 3H-quinazolin-4-ones via a combination of solid-phase and solution methodologies

A solid-phase traceless synthesis of quinazolin-4-ones is described. An aldehyde functionalized resin was reductively aminated with primary amines, and the resin-bound secondary amine acylated with o-nitro-benzoic acids. The nitro group was reduced with tin(II) chloride, and the aniline acylated with acid anhydrides. Acidolytic cleavage afforded a diamide, which was cyclized in solution phase to the 3H-quinazolin-4-one removing the trace of the linker.