21 research outputs found
Synthesis, Fluorescence and NMR Spectroscopic Studies of a Novel Phosphinoxido-18-crown-6 Ether Containing an Anthracene Fluorophore Unit
The synthesis of the (R,R) and (S,S) enantiomers of a new enantiopure monophospha-18-crown-6 ether (1), which contains an anthracene fluorophore unit and methyl groups at its stereogenic centers, was accomplished. The structure of one enantiomer ((S,S)-1) was studied using one-dimensional (1H, 13C{1H}, and 31P{1H}) and two-dimensional NMR spectra. Because (R,R)-1 and (S,S)-1 can act as new fluorescent chemosensors, we examined their enantiomeric differentiation abilities toward the enantiomers of protonated chiral primary amines and amino acid esters (PEA, 1-NEA, PGME, PAME) using UV-Vis and fluorescence spectroscopies. These monophospha-crown ethers showed moderate enantiomeric discrimination abilities
Comparison of Cinchona Catalysts Containing Ethyl or Vinyl or Ethynyl Group at Their Quinuclidine Ring
Synthesis, complex formation and corneal permeation of cyclodextrin-modified, thiolated poly(aspartic acid) as self-gelling formulation of dexamethasone
Synthesis and determination of pKa values of new enantiopure pyridino- and piperidino-18-crown-6 ethers
Synthesis, experimental and theoretical studies on the factors influencing the pKa values of new crown ethers containing a diarylphosphinic acid unit
Abstract Synthesis of acidic new crown ethers containing a diarylphosphinic acid unit has been accomplished. The aromatic rings of the crown ethers were substituted with tert-butyl and nitro groups. Nitro substitution of the crown ethers was investigated. pKa determination of the new proton-ionizable crown ethers has been performed, showing the effect of the substituents of the aromatic rings on the acidity. An anomaly was discovered in the pKa values and an explanation was given based on quantum mechanical calculations and molecular dynamics simulations
Synthesis, complex formation and corneal permeation of cyclodextrin-modified, thiolated poly(aspartic acid) as self-gelling formulation of dexamethasone
Cornea-PAMPA as an Orthogonal in Vitro Physicochemical Model of Corneal Permeability
The present study was aimed to investigate the relationships between permeability and membrane retention values (logPe and MR) of the in vitro non-cellular permeability assay, corneal-PAMPA in comparison with experimental Caco-2 permeability data and calculated physicochemical properties (MW, clogP, clogD7.4 , TPSA). For the investigation, 50 structurally and physicochemically diverse drugs were selected and measured in PAMPA model optimized for corneal permeability. The results showed corneal-PAMPA model's orthogonality in terms of passive diffusion to the FDA approved Caco-2 as a gastrointestinal absorption model, while the comparison with physicochemical properties revealed trends between logPe , MR and the lipophilicity descriptors and TPSA