Click chemistry with O-dimethylpropargylcarbamate for preparation of pH-sensitive functional groups. A case study.

Click chemistry has became an important tool for molecular constructs such as biopolymers. During the development of biodegradable multifunctional poly(ethylene oxide) (PEO) polymers suitable for click chemistry in water, an unexpected reaction leading to a mixture of triazole cycloadducts was observed. This result was attributed to an intramolecular ligand effect, and alternative conditions were evaluated. An efficient method was then implemented allowing the access in high yields to the expected triazolylcarbamate. pH sensitivity of the obtained isopropyltriazolylcarbamate was demonstrated at acidic pH.