Potassium channels have a very wide distribution of single-channel conductance, with BK type Ca(2+)-activated K(+) channels having by far the largest. Even though crystallographic views of K(+) channel pores have become available, the structural basis underlying BK channels' large conductance has not been completely understood. In this study we use intracellularly applied quaternary ammonium co...

Main-chain chiral quaternary ammonium polymers were successfully synthesized by the quaternization polymerization of cinchonidine dimer with dihalides. The polymerization occurred smoothly under optimized conditions to give novel type of main-chain chiral quaternary ammonium polymers. The catalytic activity of the polymeric chiral organocatalysts was investigated on the asymmetric benzylation o...

The objective of this study was to answer the following question: are quaternary ammonium antibacterials suitable for dental materials? Reviewing the literature on quaternary ammonium compounds evidenced that this type of compounds is soluble in water. Our own findings also showed that they are well soluble in water and that their application as dental composites requires to check their solubil...

The synthesis and antibacterial activity of 1beta-methylcarbapenems with quaternary ammonium groups at the C-2 position have been studied. Two types of new carbapenem derivatives have been synthesized. These 1beta-methylcarbapenems, one type having a (2S,4S)-2-[1,1-dimethyl-2-(1-piperazinyl)carbonyl]pyrrolidinio-4-+ ++ylthio group and the other type having a (2S,4S)-2-(4-carbamoylmethyl-4-methy...

The effects of ionic analytes on the electrochemical properties of quaternary ammonium binaphthyl salts are described in this work. The stability of the binaphthyl radicals and hence the reversibility of the electrochemical response are discussed in terms of molecular structure. The ability of azacrown derivatised binaphthyl salts to act as amperometric receptors is ascribed to the strain impar...

The aim of this study was to develop a derivative of chitosan as pharmaceutical excipient used in sustained-release matrix tablets of poorly soluble drugs. A water-soluble quaternary ammonium carboxymethylchitosan was synthesized by a two-step reaction with carboxymethylchitosan (CMCTS), decylalkyl dimethyl ammonium and epichlorohydrin. The elemental analysis showed that the target product with...

Introduction A comprehensive review of gas-chromatographic methods for determining the concentration of circulating antiepileptic drug has been presented (1 ). Because most epileptic patients receive one or more drugs to control their seizures, it is therapeutically desirable to have a method for monitoring the concentrations of each of these drugs in serum. The chemistry of pyrolysis with meth...

The title compounds are a class of structurally simple analogues of quaternary benzo[c]phenanthridine alkaloids (QBAs). In order to develop novel QBA-like antifungal drugs, in this study, 24 of the title compounds with various substituents on the N-phenyl ring were evaluated for bioactivity against seven phytopathogenic fungi using the mycelial growth rate method and their SAR discussed. Almost...

The compounds Ln3Cu4P4O2ÿx (Ln = Pr, Sm) were prepared by annealing the elemental components in a NaCl/KCl flux. They crystallize with an ordered Zr3Cu4Si6-type structure (space group I4/mmm, Z = 2), which was refined from single-crystal X-ray data for both compounds; Pr3Cu4P4O2ÿx: a = 397.8(1), c = 2658.7(3) pm, R = 0.046 for 235 structure factors and 19 variable parameters; Sm3Cu4P4O2ÿx: a = ...