Traceless Synthesis of 3-N-Substituted-2-Thioxoquinazoline-4-Ones on a Soluble Polymeric Support

The synthesis of 3-N-substituted-2-thioxoquinazoline-4-ones is described with a traceless linker strategy using poly(ethylene glycol) (PEG) as a soluble polymeric support. Staudinger-Aza-Wittig reaction of PEG-supported azide with Ph3P and CS2 gave the corresponding PEG-supported phenyl isothiocyanate. Treatment of the phenyl isothiocyanate with different primary amines led, via intramolecular cyclization and simultaneous cleavage from PEG, to 2-thioxoquinazoline- 4-ones with of moderate to excellent yields.