Urea and Polyurea Production: An Innovative Solvent-and Catalyst-Free Approach through Catechol Carbonate

The peculiar reactivity of catechol carbonate (CC) with amines and polyamines in both solvent-and catalyst-free conditions is herein described. In all the tests performed at room temperature, CC conversion reached 100% in a few seconds leading to the selective formation of the corresponding 2-hydroxyphenylcarbamate. This compound is further rapidly converted to the disubstituted urea by the consecutive nucleophilic attack of another amine. Noteworthy, the application of this approach can be successfully extended to the one-pot bioamine-based synthesis of polyurea as herein proposed for the first time in the literature. The reaction is of general purpose for primary amines, and catechol can be easily recovered by sublimation as pure crystals ready to be recycled for the synthesis of new CC. An exception is related to the reactivity of secondary amine, which leads to the selective formation of substituted phenolic carbamates (e.g., 2-hydroxyphenyl diethylcarbamate), suitable as intermediates in medicinal chemistry.