Preparation and evaluation of bipyridyl-tagged reagents and scavengers

The synthesis of three bipyridyl-tagged reagents and one scavenger is described. Of the three reagents, the carbodiimide derivative proved to be effective as a coupling reagent for amide formation and the removal of the coupling side product from the reaction mixture by complexation onto a Cu-derivatised resin has been successfully demonstrated. This purification process was thoroughly optimised using a DOE approach and the procedure subsequently applied to the use of a bipyridyl-tagged amine as an isocyanate scavenger. Preliminary results clearly demonstrate the potential of using chelation tags such as bipyridine units as a means for removing solution phase reagents and scavengers from reaction mixtures providing an attractive alternative to their resin-bound and fluorous-tagged counter-parts.