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Enantioselective Sulfoxidations Catalyzed by Chloroperoxidase and Horseradish Peroxidase
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Horseradish peroxidase catalysed sulfoxidation is enantioselective
No full textHorseradish peroxidase catalysed oxidation of aryl methyl sulfides by H2O2 preferentially gives (-)-(S)-sulfoxides, enantiomeric excess 30-68%
Enantioselective oxidations catalyzed by diketocamphane monooxygenase from Pseudomonas putida with macromolecular NAD in a membrane reactor
No full textSeveral sulfides and bicyclo[3.2.0]hept-2-en-6-one were enantioselectively oxidized to the corresponding sulfoxides and oxa lactones by a crude preparation of the two diketocamphane monooxygenases from Pseudomonas putida. The reactions were carried out in a membrane reactor with the use of poly(ethylene glycol)-N6-(2-aminoethyl)-NAD and coenzyme regeneration by the formate/formate dehydrogenase system
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Enantioselective oxidation of sulphides to sulphoxides in the presence of bovine serum albumin
No full textIn situ generated dioxiranes oxidize a series of prochiral sulphides to the corresponding sulphoxides with enantiomeric excess (e.e.) up to 89%, when bovine serum albumin (BSA) is used as chiral auxiliary. The degree of enantioselectivity, as well as yield and reaction times, depend upon the nature of the dioxirane. These are compared with enantioselectivities attainable for the same transformations by using peroxomonosulfate alone, i.e. in the absence of ketone. In the oxidation of prochiral keto sulphides (wherein the carbonyl functionality serves as precursor of dioxirane) with peroxomonosulfate, optically active keto sulphoxides are isolated in satisfactory chemical and optical yield (up to e.e. 84%)
Synthesis of chiral benzyl alkyl sulfoxides by cyclohexanone Monooxygenase from Acinetobacter NCIB 9871
No full textBenzylalkyl sulfides with alkyl groups from methyl to hexyl, para-alkylbenzyl groups from methyl to butyl, 2-phenylethyl methyl sulfide and 3-phenylpropyl methyl sulfide have been oxidized by cyclohexanonemonooxygenase from AcinetobacterNCIB9871. Sulfoxides with enantiomeric excesses ranging from 80% for the (R)-configuration to 96% ee for the (S)-configuration were obtained.
Cyclohexanonemonooxygenase (CMO) catalyzed the asymmetric oxidation of numerous benzylalkyl sulfides to sulfoxides with ee up to 96%
Enantioselective oxidation of sulfides to sulfoxides catalysed by bacterial cyclohexanone monooxygenases
No full textThis review article briefly introduces the applications of bacterial cyclohexanone monooxygenases to the enantioselective oxidations of organic sulfur compounds to sulfoxides. High enantioselectivities are observed in the sulfoxidation of alkyl aryl sulfides, disulfides, dialkyl sulfides, cyclic and acyclic 1,3-dithioacetals. The oxidation of alkyl aryl sulfides with flavin dependent microorganisms extends the synthetic interest of this class of enzymes
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