BACKGROUND AND PURPOSE Data on the epidemiology of OXA-type extended-spectrum beta (beta)-lactamases (ESBLs) are limited due to difficulty of identification by routine microbiology laboratories. We determined the prevalence rate of OXA-type beta-lactamases among extended-spectrum cephalosporin (ESC)-non-susceptible Pseudomonas aeruginosa isolates at a university hospital in southern Taiwan. M...

A formal [4+3] epoxide cascade protocol utilizing ambiphilic sulfonamides and a variety of epoxides (masked ambiphiles) has been developed for the generation of benzothiaoxazepine-1,1'-dioxides and oxathiazepine-1,1'-dioxides. This protocol combines an epoxide ring-opening with either an S(N)Ar or oxa-Michael cyclization pathway.

Two novel protocols for the chemical valorization of polyhydroxybutyrate (PHB) were developed, aiming at production two bio-based molecules: methyl 3-hydroxybutyrate (MHB) and 3-methoxybutyrate (MMB). Optimized reaction conditions applied to pure PHB inclusions inside bacterial cells as starting materials. MHB was synthesized through a single-step catalytic methanolysis, while MMB three-step pr...

The reaction of 1-alkenoylcyclopropane carboxylic acids with NBS or NIS was investigated, which provides an efficient route to biologically important 7-halogenated furo[3,2-c]pyran-4-ones in a one-pot transformation. The major pathway for the formation of the O-O heterocycles was proposed as a halo-oxa-cyclization, HBr elimination, cyclopropane ring-opening and recyclization (intramolecular oxa...

We report the O-alkylation of oximes with Michael acceptors using Cs2CO3 as catalyst. The transformation proceeds stereospecifically retention oxime configuration. Irradiation visible light in presence diphenyl anthracene and cerium complexes affects E to Z configuration ratio ether products, but a complete stereocontrol was not achieved. operationally simple protocol allows synthesis various O...

Lactol carbocyclisations provide a succinct method of constructing the oxabicyclo[3.2.1]octane scaffold, motif present in various natural products medicinal interest. Lactols containing an unsaturated ketone or ester were prepared by olefin cross-metathesis; electrophilic alkene derived from methyl vinyl underwent concomitant terminal α-methylenation and oxa-Michael addition to give bridged lac...

Production of Extended spectrum β-lactamases (ESBLs) is a common mechanism of resistance in multidrug- Pseudomonas aeruginosa, but the frequency of different ESBLs may vary significantly in different parts of the world. The aim of this study was to investigate the prevalence of OXA-2/OXA-10 type ESBLs and class 1 integron among clinical isolates of P. aeruginosa in Ta...

BACKGROUND Detection of carbapenem hydrolyzing class D beta lactamase OXA-181, (a variant of OXA-48) in Enterobacteriaceae, is important, to institute appropriate therapy and to initiate preventive measures. This study was done to determine the presence of OXA 48 and its derivative OXA-181 in Enterobacteriaceae of pathogenic significance. MATERIAL AND METHODS One hundred and eleven non-repeti...