Chiral Discrimination of Ammonium Neurotransmitters by C₃‐Symmetric Enantiopure Hemicryptophane Hosts

Abstract

Enantiopure hemicryptophanes efficiently discriminate chiral ammonium neurotransmitters. The ephedrine and norephedrine molecules associate with hemicryptophane hosts to form 1:1 and 1:2 host-guest complexes. Binding constants are determined by fitting the ¹H nuclear magnetic resonance (NMR) titration curves to give β₁ and β₂ values, which are used to characterize the diastereomeric and enantiomeric discriminating potentials of the hosts.

Synthesis, resolution, and chiroptical properties of hemicryptophane cage controlling the chirality of propeller arrangement of a C3 triamide unit

“…Enantiopure hemicryptophanes can be obtained either by resolution of the racemic mixture or by diastereoselective synthesis . Besides their use as enantioselective receptors for carbohydrates and neurotransmitters, their C 3 symmetry has allowed to build molecular cages presenting a triple‐helical arrangement of the linkers . Indeed, the CTV unit is able to control the chirality of triple helices since the CTV with P (respectively M ) configuration induces a Δ (respectively, Λ ) propeller‐like arrangement of the linkers.…”

Large‐Scale Synthesis of Enantiopure Molecular Cages: Chiroptical and Recognition Properties

“…We thus focused on tren–hemicryptophanes containing the C 3 ‐symmetric tris(2‐aminoethyl)amine (tren) ligand, which exhibited substrate‐, diastereo‐, and enantioselective recognition properties toward neurotransmitters and carbohydrates ,. Moreover, encaged azatrane structures can be formed when a metal or heteroelement is introduced into the tren unit.…”

Cyclotriveratrylene-BINOL-Based Host Compounds: Synthesis, Absolute Configuration Assignment, and Recognition Properties

“…[25][26][27][28][29][30] The related hemicryptophanes combine a CTV moiety with another C 3 symmetrical unit and display chiral recognition properties towards molecules of biological interest like neurotransmitters and carbohydrates. [31][32][33][34][35][36] Although the efficiency and selectivity of these two classes of cage compounds were demonstrated, their quite complex and low yield syntheses raise the question about the potential applications of such sophisticated structures. [34][35][36][37][38][39] Thus, we decided to investigate the chiral recognition properties of "openshell" enantiopure CTV units: their synthesis avoids the macrocyclization step, and therefore should be easier and shorter.…”