Synthesis, characterization, and application of a bifunctional coupler containing a five- and a six-membered ring carbonate

5-Ethyl-5-(((2-oxo-1,3-dioxolan-4-yl)methoxy)methyl)-1,3-dioxan-2-one (BC56) bearing a five- and six-membered ring carbonate was successfully synthesized and characterized. In model reactions it was shown that BC56 reacts selectively with 1 eq. of a primary amine at low temperature, only/mainly the six-membered ring carbonate is converted. Ionic, hydrophilic and hydrophobic amines were used to prepare functional couplers. Reaction of the functional couplers with a second primary amine group under more severe reaction conditions results in a coupling product. Both, polycondensation of BC56 with diamines in a one-step procedure (Procedure A) or in a two-step reaction (Procedure B) yielded poly(hydroxyl urethane) or its oligomers. Different reaction conditions were tested for the synthesis of poly(hydroxyl urethane)s with higher molecular weight. Solvents have the most significant influence to the molecular weight of the resulting polymer. In solvents with low polarity (e.g. THF and CHCl3), polymers with relative high molecular weight (M¯w≈10,000g/mol) were obtained; in solvents with high polarity (e.g. DMAc and DMF) oligomers (2000