Synthesis and characterization of functional six-membered ring carbonates for the preparation of orthogonal couplers

On the basis of commercially available trimethylolpropane (TMP) three six-membered ring carbonates were prepared, substituted with reactive side groups: a chloroformate (2a), an imidazolyl carbamate (2b) and a phenyl carbonate (2c). Their synthesis and characterizations are described and compared to known ring carbonates with reactive side groups. Starting from 2a-c orthogonal couplers 3a and 3b were synthesized for conversion under mild reaction conditions. In a model reaction 2-azidoethyl 2-N-acetylamino-2-deoxy- β-D-glucopyranose and tert-butyl-N-(3-aminopropyl) carbamate were linked with coupler 3a via a 1,3-dipolar cycloaddition and a nucleophilic ring-opening reaction. This coupling principle can be used for the preparation of multifunctional polymers or surface coatings at ambient conditions.