Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc) oligomers and N,N-diacetyllactosamine (LacDiNAc) based on galactose oxidase treatment

• Christiane E. Kupper,
• Ruben R. Rosencrantz,
• Birgit Henßen,
• Helena Pelantová,
• Stephan Thönes,
• Anna Drozdová,
• Vladimir Křen and
• Lothar Elling

Beilstein J. Org. Chem. 2012, 8, 712–725, doi:10.3762/bjoc.8.80

• results regarding the formation of acid and α,β-unsaturated aldehyde into account, we chose pH 6 for further galactose oxidase reactions. Hydrogen peroxide is known to inhibit galactose oxidase activity [50][51]. Therefore, we tested reaction mixtures with catalase and a mixture of catalase and peroxidase

Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity

• Krzysztof M. Borys,
• Maciej D. Korzyński and
• Zbigniew Ochal

Beilstein J. Org. Chem. 2012, 8, 259–265, doi:10.3762/bjoc.8.27

• of 4-chlorothiophenol (2) with dimethyl sulfate, followed by treatment of the resulting product 5 with hydrogen peroxide and glacial acetic acid. Next, bromination of the methyl group of 4 was achieved by using either sodium hypobromite (Scheme 2, method B) or bromine chloride (Scheme 2, method C

Biocatalytic hydroxylation of n-butane with in situ cofactor regeneration at low temperature and under normal pressure

• Svenja Staudt,
• Christina A. Müller,
• Jan Marienhagen,
• Christian Böing,
• Stefan Buchholz,
• Ulrich Schwaneberg and
• Harald Gröger

Beilstein J. Org. Chem. 2012, 8, 186–191, doi:10.3762/bjoc.8.20

• Methylocystis sp. was used, a ratio of 58:42 was obtained for the product isomers 1- and 2-butanol, respectively [7]. However, use of the hydroxylase unit only, in combination with hydrogen peroxide, furnished exclusively 2-butanol. A perfect regioselectivity of 100% for 2-butanol was reported by the group of

Synthesis and oxidation of some azole-containing thioethers

• Andrei S. Potapov,
• Nina P. Chernova,
• Vladimir D. Ogorodnikov,
• Tatiana V. Petrenko and
• Andrei I. Khlebnikov

Beilstein J. Org. Chem. 2011, 7, 1526–1532, doi:10.3762/bjoc.7.179

• characterized. Oxidation of the pyrazole-containing thioether by hydrogen peroxide proceeds selectively to provide a sulfoxide or sulfone, depending on the amount of oxidant used. Oxidation of the benzotriazole derivative by hydrogen peroxide is not selective, and sulfoxide and sulfone form concurrently

• oxidation reactions. Oxidation of thioethers to sulfoxides and sulfones can be achieved by using different oxidants and catalysts [15], hydrogen peroxide being the most versatile and green among them [16]. Despite the simplicity of their preparation and potentially useful properties, azole-containing

• sulfoxides and sulfones are not described in the literature. The action of one mole of hydrogen peroxide on thioether 3 in acetic acid at room temperature for 2.5 h selectively gives sulfoxide 6 (85% yield, Scheme 3). Raising the temperature to the boiling point of acetic acid (118 °C) and using an excess of

Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• operation to an efficient continuous-flow process (Scheme 7) [28]. The process involves the lipase-catalyzed in situ formation of peracetic acid (20) from hydrogen peroxide and ethyl acetate (19), which oxidizes the model substrate 1-methylcyclohexene (18) to form the product 1-methylcyclohexene oxide (21

Bromine–lithium exchange: An efficient tool in the modular construction of biaryl ligands

• Laurence Bonnafoux,
• Frédéric R. Leroux and
• Françoise Colobert

Beilstein J. Org. Chem. 2011, 7, 1278–1287, doi:10.3762/bjoc.7.148

• -Dimethylamino-2',6-dibromobiphenyl (1c) was obtained in an overall yield of 79% in 3 steps (Scheme 1). To introduce the methoxy group, 2,2',6-tribromobiphenyl (1a) was successively subjected to lithiation, borylation with fluorodimethoxyborane·diethyl ether, followed by oxidation with hydrogen peroxide and O

Molecular rearrangements of superelectrophiles

• Douglas A. Klumpp

Beilstein J. Org. Chem. 2011, 7, 346–363, doi:10.3762/bjoc.7.45

• center of 76. The loss of hydrogen peroxide affords the oxygen-centered cation 78 and subsequent migration of the adjacent group gives dication 75. Whittaker and Carr have described a series of superacid-promoted reactions to prepare bicyclic lactones [28]. Several of the conversions involve

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• solution polymerization was demonstrated by Qi et al. who were able to polymerize styrene with horseradish peroxidase, hydrogen peroxide, and a β-diketone in aqueous direct miniemulsion [92]. Normally, only hydrophilic monomers can be polymerized with this initiating system in water or a co-solvent, e.g

• are shown in Figure 6. Aniline and anilium hydrochloride were polymerized in direct and in inverse miniemulsion, respectively [93]. The polymerization of anilium hydrochloride was initiated by hydrogen peroxide and gave highly crystalline emeraldine polyaniline. In direct miniemulsions, additional

Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate

• Michael North and
• Marta Omedes-Pujol

Beilstein J. Org. Chem. 2010, 6, 1043–1055, doi:10.3762/bjoc.6.119

• prepared by a 100% atom economical reaction between epoxides and CO2 (Scheme 2) [65]. The green credentials of propylene carbonate are enhanced by the commercialization of a low temperature synthesis of propylene oxide from propene and hydrogen peroxide [66][67][68][69][70], by the development of a greener

• synthesis of hydrogen peroxide [71], and by the combination of these processes into a one-pot synthesis of propylene oxide from propene, hydrogen and oxygen [72][73]. In addition, it has been shown that in the presence of an appropriate catalyst, the reaction between epoxides and carbon dioxide can be

Free radical homopolymerization of a vinylferrocene/cyclodextrin complex in water

• Helmut Ritter,
• Beate E. Mondrzik,
• Matthias Rehahn and
• Markus Gallei

Beilstein J. Org. Chem. 2010, 6, No. 60, doi:10.3762/bjoc.6.60

• polyvinylferricinium cation 6 takes place at 0.5 V and its reduction at −0.45 V (Figure 2). By contrast, irreversible oxidation occurred on heating the solution of complexed polyvinylferrocene 3 in aqueous hydrogen peroxide, which was accompanied with a change in color from yellow (Figure 3a) to green (Figure 3b). In

• cyclic voltammetry for the complexed PVFc/PVFc+-system 3/6: 1.0 × 10−3 M substance in Na2SO4 | Ag/AgCl. Redox behaviour of PVFc 3: (a) the complexed PVFc 3 mixed with aqueous hydrogen peroxide solution was heated to 50 °C. The orange 3 oxidized to green PVFc+ 6 cation (b), which is reduced to the PVFc 4

Anion receptors containing thiazine-1,1-dioxide heterocycles as hydrogen bond donors

• Hong-Bo Wang,
• James A. Wisner and
• Michael C. Jennings

Beilstein J. Org. Chem. 2010, 6, No. 50, doi:10.3762/bjoc.6.50

• these dithioethers to the disulfones 9 and 10 with urea-hydrogen peroxide (UHP) and trifluoroacetic anhydride (TFAA) in acetonitrile at room temperature proceeds in high yields. The final products 1 and 2 were obtained by the cyclization and dehydration of these intermediate disulfones with ammonium

The C–F bond as a conformational tool in organic and biological chemistry

• Luke Hunter

Beilstein J. Org. Chem. 2010, 6, No. 38, doi:10.3762/bjoc.6.38

• effect (analogous to Lewis-acid activation of 36) which makes 37 more reactive towards nucleophiles [34]. In intermediate 37, the fluorine atom aligns gauche to the positively-charged nitrogen atom (Figure 9, inset), resulting in a phenyl group shielding the top (re) face of the alkene. Hydrogen peroxide

Synthesis of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide – a tailor-made photoinitiator for dental adhesives

• Norbert Moszner,
• Iris Lamparth,
• Jörg Angermann,
• Urs Karl Fischer,
• Frank Zeuner,
• Thorsten Bock,
• Robert Liska and
• Volker Rheinberger

Beilstein J. Org. Chem. 2010, 6, No. 26, doi:10.3762/bjoc.6.26

• phenylphosphine dilithium solution was then added to a THF solution of 2. THF was evaporated from the intermediate bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine solution, the residue dissolved in toluene and oxidized with a 30 wt % hydrogen peroxide solution at 70 °C. After column

• ]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide For this stage all manipulations were carried out in brown glass apparatus or under yellow light. The residue from the latter step was dissolved in toluene (40 mL). Hydrogen peroxide solution (30%, 4.17 g, 36.8 mmol) was added dropwise under vigorous

On the functionalization of benzo[e][2,1]thiazine

• Kirill Popov,
• Tatyana Volovnenko and
• Julian Volovenko

Beilstein J. Org. Chem. 2009, 5, No. 42, doi:10.3762/bjoc.5.42

• oxidizing agents. Thus, oxidants such as sodium dichromate and potassium permanganate did not transform 1 into the corresponding carboxylic acids. Attempted oxidation of compounds 1 with hydrogen peroxide, peroxyacetic acid and m-chloroperoxybenzoic acid (mCPBA) was also unsuccessful. The desired oxidation

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• in 46% overall yield. Interestingly, oxidation with hydrogen peroxide gave predominantly the N-allylic system rather than the vinylic one. This is in accordance with the precedent established by the laboratory of K.B. Sharpless [80][81]. The overall yield from diazo-ester 67 was only 2% and was

The development and evaluation of a continuous flow process for the lipase- mediated oxidation of alkenes

• Charlotte Wiles,
• Marcus J. Hammond and
• Paul Watts

Beilstein J. Org. Chem. 2009, 5, No. 27, doi:10.3762/bjoc.5.27

• lipase B, Novozym® 435, in a preliminary investigation into the development of a continuous flow reactor capable of performing the chemo-enzymatic oxidation of alkenes in high yield and purity, utilising the commercially available oxidant hydrogen peroxide (100 volumes). Initial investigations focussed

• ; hydrogen peroxide; lipase; micro reactor; Novozym® 435; peracids; Introduction In addition to their synthetic value as intermediates in the preparation of diols, alcohols, hydroxyesters and alkenes, epoxides are a key raw material in many industrial processes, finding application in adhesives, polymers

• situ generated peracids derived from formic acid or acetic acid (1)/hydrogen peroxide (2). As H2O2 (2) is itself not sufficiently electrophilic to epoxidise a non-conjugated double bond directly, its use in the formation of a peracid has afforded a route to the epoxidation of alkenes in the presence of

Efficient 1,4-addition of α-substituted fluoro(phenylsulfonyl)methane derivatives to α,β-unsaturated compounds

• G. K. Surya Prakash,
• Xiaoming Zhao,
• Sujith Chacko,
• Fang Wang,
• Habiba Vaghoo and
• George A. Olah

Beilstein J. Org. Chem. 2008, 4, No. 17, doi:10.3762/bjoc.4.17

• . We first began with the preparation of nitro, cyano, ester, or acetyl-substituted (phenylsulfonyl)methanes from the corresponding (phenylthio)methane derivatives, the precursors of α-substituted fluoro(phenylsulfonyl)methane derivatives. Oxidation of (nitromethyl)(phenyl)sulfide with aqueous hydrogen

• peroxide [H2O2, 30% (wt)] was attempted in acetic acid at room temperature. Tuning the conditions by using 4-fold excess of H2O2 afforded 90% yield of (nitromethylsulfonyl)benzene overnight (Table 1, entry 1) [26][27][28]. 2a–c and 2e were prepared in 76–91% yields under the optimized condition and used

The Elbs and Boyland- Sims peroxydisulfate oxidations

• E. J. Behrman

Beilstein J. Org. Chem. 2006, 2, No. 22, doi:10.1186/1860-5397-2-22

• , although they obtained evidence for a peroxide, isolated only phenol (in substantial yield). Heller and Weiler [18] investigated a more stable analog, namely p-nitrophenyl hydroperoxide formed by ipso displacement of a nitro group from p-dinitrobenzene by the hydrogen peroxide anion.p-Nitrophenyl

The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives

• David O'Hagan,
• Henry S. Rzepa,
• Martin Schüler and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2006, 2, No. 19, doi:10.1186/1860-5397-2-19

• lead to poor conversions and a complex product mixture. As an alternative strategy ozonolysis in acetic acid, with a hydrogen peroxide work-up was explored [27][28], and this proved successful as illustrated in Scheme 8. For example, reaction of a 4:1 mixture of erythro- and threo- 13 led to the