Affinity separation based on hydrogen bonding

Abstract

The purification - work up and separation from other compounds - of chemical reactions is a crucial step in the synthesis of organic molecules. Therefore, organic chemists have developed a variety of work up and purification techniques throughout the last centuries, and novel methods are being explored every day. In recent years, a novel technique making use of controllable, non-covalent interactions was designed. In this so called affinity separation methodology, a starting material is equipped with a tag that has a (strong) affinity for a different medium than the other reagents present. After chemical reaction, addition of this affinity medium and subsequent phase separation yields the pure product, which can be obtained after cleavage from the tag. In this thesis, a novel affinity separation method based on hydrogen bonding is described. A self-complementary ureidopyrimidinone-tag is used to functionalise a solid resin, which can be used to abstract compounds that bear the same hydrogen bonding tag, from an apolair solution. Using this method, different products were isolated from crude reaction mixtures in high yield and with good purity. Also, a tagged catalyst was abstracted from solution, and this metal-based calatic complex was reused in three reaction cycles without loss of activity