Synthesis, complete NMR assignment and structural study of a steroidal dimer of 17α-ethynyl-5α,10α-estran-17β-ol with diethynylbenzene spacer.

A phenylene-bridged steroidal dimer derived from 17α-ethynyl-5α,10α-estran-17β-ol with molecular rotor-like architecture was synthesized to investigate the supramolecular interactions directing the crystallization of these systems. Structures with varying importance in complementarity between H-bonding and hydrophobic interactions can be observed directing the packing of the obtained crystals, depending on the synthetic stage, though conserving the same space group for both systems. Such behavior clearly shows the versatility achievable using steroids as crystal packing directors. Alongside this structural study, the complete NMR assignment is presented for the dimer, and precursors, in which the steroids present an unconventional and noteworthy A-B ring fusion.