Synthesis of C 3h -symmetric benzotripyrrole derivatives as monomers for organic frameworks

Practical synthetic method for constructing C3h-symmetric benzotripyrrole core was developed starting from readily available 2,4,6-trihalobenzene-1,3,5-tricarbaldehydes by the reaction with N -benzylglycine esters followed by base-mediated cyclization. The pendant ester groups of the resulted benzotripyrrole derivatives were subjected to hydrolysis, aminolysis, and hydride reduction reactions. As a result, benzotripyrrole-2,5,8-tricarbaldehyde was obtained in two-step sequence, possessing the reactive functionalities required for construction of covalent organic frameworks. Spectral and optical properties of the newly synthesized derivatives were recorded.