Automated Parallel, Multi-Step Polymer-Assisted Solution Phase (PASP) Synthesis of Substituted Benzimidazole Derivatives

The automated polymer-assisted solution phase (PASP) synthesis of a 72 member library of 2- alkylthio-benzimidazoles 16 and benzimidazolin-2-ones 17 using commercially available robotic workstations is described. By incorporating both automated aqueous work-ups, in-line scavenging and 'catch and release' protocols the desired compounds were obtained directly in good yields and excellent purities without the need for conventional chromatographic purification. The synthesis described demonstrates how both manual and automated equipment may be utilised together to provide a versatile approach that facilitates parallel compound synthesis.