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Zwitterionic Compound (zwitterionic + compound)
Selected AbstractsSynthesis of Zwitterionic Compounds: Fully Saturated Pyrimidinylium and 1,3-Diazepinylium Derivatives via the Novel Rearrangement of 3-Oxobutanoic Acid Thioanilide Derivatives.CHEMINFORM, Issue 47 2002Barbara Zaleska Abstract For Abstract see ChemInform Abstract in Full Text. [source] The Zwitterion Effect in Ionic Liquids: Towards Practical Rechargeable Lithium-Metal Batteries,ADVANCED MATERIALS, Issue 20 2005N. Byrne Practical lithium-metal batteries are the ultimate goal of battery researchers. The addition of a zwitterionic compound (see Figure) to an ionic liquid electrolyte doped with a lithium salt results in a 100% enhancement of the current densities achieved in the cycling of a lithium-metal cell. This phenomenon arises due to increased lithium-ion mobility or a reduced solid electrolyte interphase layer resistance. [source] In-vitro and in-vivo studies of cefpirom using bile salts as absorption enhancersJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2003Yahya Mrestani ABSTRACT Cephalosporins have to be administered by injection because of the poor intestinal absorption of the orally delivered drugs. Because of the obvious drawbacks of drug delivery by injection, the development of alternatives with enhanced oral bioavailability is receiving much attention in pharmaceutical research. Cefpirom (Cp) is a new semi-synthetic amino-2-thiazolyl-methoxyimino cephalosporin that has been substituted in position 3 with a cyclopenteno-pyridinium group in order to create a zwitterionic compound. It exhibits highly hydrophilic properties, as shown from its extremely low partition coefficient, and therefore its lipophilicity was increased using bile salts. The effect of this on the partition coefficients determined in the n-octanol/buffer system was confirmed using an in-vitro transport model with artificial and biological membranes. The pharmacokinetic properties of Cp were investigated in rabbits after intraduodenal administration with and without bile salts. Furthermore, the physiological compatibility of the bile salts was investigated using active D-glucose transport. [source] Imidazol(in)ium-2-carboxylates as N-Heterocyclic Carbene Precursors for the Synthesis of Second Generation Ruthenium Metathesis CatalystsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Xavier Sauvage Abstract Five well-known ruthenium-N-heterocyclic carbene (NHC) catalysts for olefin metathesis and related reactions, including the second generation Grubbs and Hoveyda,Grubbs catalysts, were prepared by phosphane exchange between first generation ruthenium-benzylidene or indenylidene complexes and NHCs generated in situ upon thermolysis of imidazol(in)ium-2-carboxylates. Because N-heterocyclic carbene carbon dioxide adducts (NHC,CO2) are stable zwitterionic compounds that can be stored and handled with no particular precautions, this procedure is particularly attractive from a practical point of view. Reaction courses were conveniently monitored by 31P,NMR spectroscopy and the experimental conditions were carefully adjusted to obtain high yields of pure products within short periods of time. [source] | ||||||||||