Discrete, self-immolative N-substituted oligourethanes and their use as molecular tags

Abstract

Here, we first report a straightforward solution-phase approach for the synthesis of N-substituted oligourethanes. Using this protocol, discrete oligomers could be rapidly obtained on a multigram scale by solely utilizing liquid/liquid extractions, avoiding the need for excessive purification steps or the requirement for a solid or soluble support. In addition, structure elucidation of the obtained oligourethanes with the help of ESI- or LC-MS analysis was achieved by relying on the controlled depolymerization of these oligomers. Essential to this process is the presence of the terminal hydroxy moiety that can participate in an intramolecular cyclization. This intramolecular reaction was studied with a series of model compounds in order to determine the parameters that can be used to either enhance or inhibit its rate. In a last step of the study, the applicability of these chemically sequenceable macromolecules as molecular tags was demonstrated by their incorporation in a crosslinked polyurethane material. This study, hence, opens new avenues for the utilization of sequence-defined macromolecules for anti-counterfeiting purposes.