betadex and per-6-amino-beta-cyclodextrin

The highly anionic synthetic pentasaccharide fondaparinux (FDPX) - representing the antithrombin binding sequence of heparin - is in clinical use as a potent anticoagulant. Contrary to the unfractionated heparin, FDPX lacks potent antidote completely reversing its anticoagulant activity, therefore it is of great importance to identify new structures exhibiting strong intermolecular interactions towards FDPX. The polycationic heptakis(6-amino-6-deoxy)-beta-cyclodextrin (NH

Topics: beta-Cyclodextrins; Fondaparinux; Heparin; Magnetic Resonance Spectroscopy

The synthesis of 2-aryl-2,3-dihydro-4-quinolones in the presence of per-6-amino-β-cyclodextrin (per-6-ABCD) as catalyst can improve selectivity and yield. The interaction between per-6-ABCD and benzaldehyde or o-aminoacetophenone plays an important role in this reaction. This paper studies the complexes of per-6-ABCD with benzaldehyde and o-aminoacetophenone using density functional theory (DFT) method. The reaction process is investigated by studying the energy of the reactants and the product. Hydrogen bonds are researched on the basis of natural bonding orbital (NBO) analysis, the results propose the donor-acceptor interactions of complex. The Mulliken charge and frontier orbital are employed for revealing the charge distribution. In addition, (13)C nuclear magnetic resonance ((13)CNMR) spectroscopy shows that the carbon atom on the aldehyde group for benzaldehyde, carbonyl group and the carbon atom connected with carbonyl group for o-aminoacetophenone are apparently activated in the cavity of per-6-ABCD. The probable catalytic mechanism of per-6-ABCD is discussed in terms of the calculated parameters.

Topics: 4-Quinolones; Acetophenones; Benzaldehydes; beta-Cyclodextrins; Catalysis; Computer Simulation; Energy Transfer; Hydrogen Bonding; Models, Chemical; Models, Molecular; Molecular Structure; Proton Magnetic Resonance Spectroscopy; Structure-Activity Relationship

A highly efficient one-pot synthesis of enantiomerically enriched 2-aryl-2,3-dihydroquinolin-4(1H)-ones has been carried out for the first time using per-6-ABCD as a supramolecular host, chiral base catalyst, and a reusable promoter to give the corresponding scaffold with high yield (up to 99%) and enantiomeric excess (up to 99%). The catalyst is recovered and reused without loss in its activity.

Topics: 4-Quinolones; beta-Cyclodextrins; Catalysis; Molecular Structure; Stereoisomerism

A unique, efficient, highly sensitive and selective fluorescent chemosensor for fenitrothion has been reported for the first time using per-6-amino-β-cyclodextrin:Eu(III) complex. Among the various pesticides, the sensitivity response is found to be in the order, fenitrothion>>>quinalphos>methylparathion>parathion>methylparaoxon>paraoxon>fenchlorphos>profenofos>malathion. A detection limit as low as 1 × 10(-12)M for fenitrothion sensing is realized with a 2.4% relative standard deviation (RSD) of three consecutive runs. The per-6-amino-β-cyclodextrin:Eu(III):pesticide complexes and their sensing mechanism are evidenced from emission, NMR, FT-IR, binding constant measurement, Job's plot, ICD spectra, ESI-MS, lifetime measurements and molecular modeling studies. The proposed sensing is a consequence of Absorption Energy Transfer Emission (AETE) process as a result of better encapsulation of fenitrothion inside the cavity of per-6-amino-β-cyclodextrin:Eu(III) complex. The remarkable sensitivity and selectivity of fenitrothion compared to other OPs, is attributed to a more deeper binding and tighter fit of fenitrothion inside the CD cavity, which is evident from binding constant values and molecular modeling studies. This tighter fit ensures the replacement of two coordinating water molecules on Eu(III) ion, which may have contributed to the more selective sensing of fenitrothion.

Topics: beta-Cyclodextrins; Binding Sites; Biosensing Techniques; Europium; Fenitrothion; Fluorescence; Limit of Detection; Organophosphorus Compounds; Pesticides; Sensitivity and Specificity

A highly efficient enantioselective Henry reaction has been carried out using per-6-ABCD as a supramolecular chiral host and promoter to give the corresponding adduct with high yield (up to 99%) and enantiomeric excess (up to 99%). Per-6-ABCD also promotes the diastereoselective Henry reaction in a syn-selective manner to give the adduct up to 99% yield with 99:1 syn/anti selectivity. The enantiomeric excess of the syn-adduct is 99%. The catalyst is recovered and reused without loss in its activity.

Topics: Aldehydes; beta-Cyclodextrins; Catalysis; Molecular Structure; Stereoisomerism

Per-6-amino-beta-cyclodextrin (per-6-ABCD), acting simultaneously as a supramolecular ligand for CuI and host for aryl bromides, catalyzes N-arylation of imidazole with aryl bromides under mild conditions. This simple method proceeds with excellent yield for the coupling of imidazole with various substituted aryl bromides demonstrating good tolerance of other functionalities.

Topics: beta-Cyclodextrins; Bromine; Catalysis; Copper; Imidazoles; Ligands; Nitrogen