143616-19-7Relevant articles and documents
Type II flavin-containing monooxygenases: A new class of biocatalysts that harbors baeyer-villiger monooxygenases with a relaxed coenzyme specificity
Riebel, Anette,Fink, Michael J.,Mihovilovic, Marko D.,Fraaije, Marco W.
, p. 1112 - 1117 (2014/05/06)
Within a newly identified set of flavin-containing monooxygenases (FMOs) from Rhodococcus jostii RHA1, we have identified three monooxygenases (FMO-E, FMO-F, and FMO-G) that are effective in catalyzing Baeyer-Villiger oxidations. These type II FMOs display relaxed coenzyme specificity by accepting both NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) and NADH (reduced form of nicotinamide adenine dinucleotide), as a coenzyme, which is a novel and attractive feature among biocatalysts capable of conducting Baeyer-Villiger oxidations. We purified FMO-E and determined that the Michaelis constants for both coenzymes were in the micromolar range, whereas the activity was highest for NADH. By using the stopped-flow technique, formation of a peroxyflavin-enzyme intermediate was observed, which indicated that type II FMOs follow a catalytic mechanism similar to that of other class B flavoprotein monooxygenases. A set of cyclobutanones and cyclohexanones were used to probe the regio- and enantioselectivity of all three recombinant monooxygenases. The biocatalysts readily accepted small cyclic ketones, which enabled the conversion of previously poorly accepted substrates by other monooxygenases (especially norcamphor), and exhibited excellent and unique regio- and enantioselectivities. Sequence analysis revealed that type II FMOs that act as Baeyer-Villiger monooxygenases contain a unique N-terminal domain. Sequence conservation in this protein domain can be used to identify new NADH-dependent Baeyer-Villiger monooxygenases, which would facilitate future biocatalyst discovery efforts. New kid on the block: Members of a newly recognized group of sequence-related flavin-containing monooxygenases can perform Baeyer-Villiger oxidations. Their coenzyme indifference and unique specificity make them attractive biocatalysts.
Total Syntheses of the Metabolites of Schizandrin
Tanaka, Masahide,Ikeya, Yukinobu,Mitsuhashi, Hiroshi,Maruno, Masao,Wakamatsu, Takeshi
, p. 11703 - 11724 (2007/10/02)
The total syntheses of the metabolites of schizandrin were achieved.The tetracyclic lactone intermediates (13a-e) were prepared in optically pure form by the oxidative coupling reaction of the corresponding 3-benzyl-2-benzylidenebutyrolactones.Mukaiyama hydration of 13b afforded hydroxylactone (14), which was converted into SZ-M3 (4).The introduction of C6,7-diol moiety, which is common to the metabolites (4-11), was carried out by the successive double bond migration to 15a-e, lactone ring reduction ot the allylic diols (32a-e), and glycol formation.Then, reduction of the mesylates 33 completed the syntheses of the metabolites.
Process for the preparation of polycyclic compounds using ferric perchlorate and acid trifluoroacidic
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, (2008/06/13)
Polycyclic compounds (I) can be prepared in accordance with the following reaction formula: STR1 wherein R1 -R8 each represents a hydrogen atom, a hydroxyl group, an alkoxyl group or a substituted or unsubstituted benzyloxy group or
