Synthesis, crystal structure and NMR investigation of a new type of cyclic steroidal dimer based on brassinosteroids

A new type of cyclic steroidal dimer based on brassinosteroids has been synthesized via the reaction of 24-epibrassinolide with 1,4-phenylenediboronic acid and structurally characterized by single-crystal X-ray diffraction and 2D NMR analysis. The crystal structure of the dimer was found to contain rather large solvent accessible voids.

► The reaction of 24-epibrassinolide with 1,4-phenylenediboronic acid has been studied.
► A cyclic dimer product 3 with steroid units joined head-to-tail has been isolated.
► The absolute configuration of 3 has been determined by single-crystal X-ray.
► The total cell volume was filled with disordered solvent.