Development of dinitrophenylated cyclodextrin derivatives for enhanced enantiomeric separations by high-performance liquid chromatography

Chiral Recognition Mechanism: Practical Considerations for Pharmaceutical Analysis of Chiral Compounds

“…Consequently, chiral separation with native CDs is quite rare in this mode. In contrast, derivatized CDs, particularly 2,6-dinitro-4-trifluoromethylphenyl ethersubstituted β-cyclodextrin [76,77], (R)-and (S)-1-(1-naphthyl)ethyl carbamoylated β-CDs [78,79], have shown good enantioselectivity under normal-phase conditions. It seems that both the CD cavity and substituent moieties may be involved in the chiral recognition process on these derivatized CD phases.…”

“…To promote π−π interaction, derivatized CD CSPs with aromatic substituents have been developed [76][77][78]82]. The aromatic groups can be π-electron rich (i.e., π-basic), such as naphthylethyl in the case of 1-(1-naphthyl)ethyl carbamoylated β-CDs [76,77] and dimethylphenyl in the case of 3,5-dimethylphenyl carbamoylated β-CD [82], or π-electron deficient (i.e., π-acidic), such as dinitrophenyl in the case of 2,6-dinitro-4-trifluoromethylphenyl ether-substituted β-cyclodextrin [78,79]. Furthermore, carbamate linkage can provide additional sites for H-bonding and dipole-dipole interactions.…”

NMR enantiodifferentiation of quaternary ammonium salts of Tröger base

“…[41][42][43][44][45][46][47][48][49] Many different types of Tröger bases have been prepared thanks to very modular synthetic routes to the tricyclic core, [50][51][52][53][54][55][56][57][58] and this for a variety of applications such as molecular recognition, 59-61 DNAinteracting probes, 62 biomimetic systems, 63 self-assembled structures, 64,65 or as analytes for chiral stationary phase chromatography. [66][67][68][69][70][71][72] However, in terms of stereochemistry, these compounds undergo relatively facile racemization in acidic media with moderate barriers of inversion (ca. 101 kJ/mol), 73,74 and their quaternary ammonium salts 8 racemize as well for that matter (ca.…”

The role of π‐acidic and π‐basic chiral stationary phases in the high‐performance liquid chromatographic enantioseparation of unusual β‐amino acids

“…In the new generation of cyclodextrin columns, pelectron-deficient dinitrotrifluoromethylphenyl groups are introduced on to the b-cyclodextrin ring (Cyclobond DNP). 30,31 The nitro group is a strong p-electron-withdrawing group. It has both resonance and inductive effects for p-electron-withdrawing.…”