An MT-sulfone group was converted to a trifluoromethyl group by treatment with IF(5) after an alkylation reaction. Therefore, an MT-sulfone anion can be used as a trifluoromethyl anion equivalent. The formal asymmetric Michael-addition of a trifluoromethyl anion to crotonaldehyde was also performed.

O-Demethylabierixin, a new polyether antibiotic, was isolated from a Streptomyces spp. Its structure elucidation was carried out with fast atom bombardment mass spectrometry (FAB-MS) and fast atom bombardment mass spectrometry-mass spectrometry (FAB-MS/MS) by comparing spectral patterns with those of structurally similar polyether compounds, nigericin and abierixin. The collision-induced dissoc...

Our recent work with cyclic and acyclic polyether self-assembled monolayers (SAMs) on gold is presented. A series of dithia-crown-tetrathiafulvalene derivatives with one or two disulfide groups has been prepared, and their SAMs on gold have been characterized by electrochemistry and by reflection-absorption infrared spectroscopy. These SAMs are extremely stable on repeated electrochemical poten...

Introduction: The aim of this study was to evaluate and compare the long-term dimensional measurement accuracy of recent polyether and addition silicone monophase impression materials after their immersion in three disinfectants (dual phenol, 2% glutaraldehyde and 0.5% sodium hypochlorite) for 10 minutes and 1 hour. Methodology: Two standardized stainless steel dies were prepared (ADA specifica...

BACKGROUND This study evaluated in vivo the accuracy of metal (Smart®) and plastic (Triple Tray®) dual-arch trays used with vinyl polysiloxane (Flexitime®), in the putty/wash viscosity, as well as polyether (Impregum Soft®) in the regular viscosity. MATERIALS AND METHODS In one patient, an implant-level transfer was screwed on an implant in the mandibular right first molar, serving as a patte...

Abstract Six different types of polyamic acids were synthesized by reacting 1,2,4,5-cyclohexanetetracarboxylic dianhydride with the diamine monomers 3,4-oxydianiline, 1,3-bis(3-aminopheno- xy )benzene, 1,4-bis(4-amino-phenoxy)benzene, m -bis[4-(3-aminophenoxy)phenyl]sulfone, p -bis[4-(4-aminophenoxy)-phenyl]sulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane. Thereafter, polyimide (...

PURPOSE To evaluate the dimensional accuracy of the resultant (duplicative) casts made from two different impression materials (polyvinyl siloxane and polyether) in parallel and angulated implants. MATERIALS AND METHODS Three definitive master casts (control groups) were fabricated in dental stone with three implants, placed at equi-distance. In first group (control), all three implants were ...

A new polyether macrocyclic of 1-pyrazolylbenzimidazol-2-ones 5-6 have been synthesized by the reaction of dichloro(poly)ethylene glycol in phase transfer catalysis conditions. The structure of these compounds were identified by H NMR, C NMR, IR spectroscopy and Mass spectrometry. The formation of Li, Na, and K complexes with compounds 5-6 has been investigated by UV-visible spectroscopy. It wa...

In this study, the efficacy of electron beam irradiation versus chemical coupling for yielding polyethersulfone (PES) membranes with antibacterial properties was investigated. For the surface coating, a recently discovered lead compound, IL-KKA, comprising a short peptide sequence functionalized with imidazolium groups, was used. For better integration within the membrane, several novel variant...