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Telalovic, S. (author), Ramanathan, A. (author), Mul, G. (author), Hanefeld, U. (author)The three-dimensional sponge-like mesoporous material TUD-1 is straightforward to prepare. Its synthesis can readily be modified to introduce metals into the framework of TUD-1, imparting many different catalytic activities. M-TUD-1 catalysts have proven to be very active, unlimited by diffusion and very stable. By combining two metals into one...journal article 2009
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Schühle, D.T. (author), Poláek, M. (author), Luke, I. (author), Chauvin, T. (author), Tóth, E. (author), Schatz, J. (author), Hanefeld, U. (author), Stuart, M.C.A. (author), Peters, J.A. (author)A pyridine-N-oxide functionalized DOTA analogue has been conjugated to a calix[4]arene and the corresponding Gd-complex was characterized with respect to its suitability as MRI contrast agent. The compound forms spherical micelles in water with a cmc of 35 mMand a radius of 8.2 nm. The relaxivity of these aggregates is 31.2 s-1 mM-1 at 25ºC and...journal article 2009
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Hanefeld, U. (author), Paravidino, M. (author), Sorgedrager, M. (author), Orru, R.V.A. (author)Water concentration affects both the enantioselectivity and activity of enzymes in dry organic media. Its influence has been investigated using the hydrocyanation of benzaldehyde catalyzed by hydroxynitrile lyase cross-linked enzyme aggregate (MeHNL-CLEA) as a model reaction. The enzyme displayed higher enantioselectivity at higher water...journal article 2010
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Telalovic, S. (author), Hanefeld, U. (author)Different amorphous mesoporous TUD-1 catalysts were employed in cyanosilylation of acetophenone with trimethylsilylcyanide in dichloromethane at room temperature. Catalysts were monometallic Al-TUD-1, Zr-TUD-1 and bimetallic Na–Al-TUD-1 and Al–Zr-TUD-1's with constant Si/metal ratio but different Al/Zr ratios. Al-TUD-1 proved to be the most...journal article 2010
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Jin, J. (author), Straathof, A.J.J. (author), Pinkse, M.W.H. (author), Hanefeld, U. (author)A bifunctional hydratase/alcohol dehydrogenase was isolated from the cyclohexanol degrading bacterium Alicycliphilus denitrificans DSMZ 14773. The enzyme catalyzes the addition of water to ?,?-unsaturated carbonyl compounds and the subsequent alcohol oxidation. The purified enzyme showed three subunits in SDS gel, and the gene sequence revealed...journal article 2010
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Ten Dam, J. (author), Djanashvili, K. (author), Kapteijn, F. (author), Hanefeld, U. (author)Screening of four commercial catalysts (Pt/Al2O3, Pt/SiO2, Pd/Al2O3, and Pd/SiO2) and four acidic additives (hydrochloric, tungstic, phosphotungstic, and silicotungstic acids) shows that the combination of a platinum hydrogenation catalyst with tungsten containing acidic additives yields 1,3-propanediol from aqueous glycerol. The performance of...journal article 2012
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Hanefeld, U. (author)Hydroxynitrile lyases are a versatile group of enzymes that are applied both in the laboratory and on an industrial scale. What makes them particularly interesting is that to date five structurally unrelated categories of hydroxynitrile lyases have been discovered. Given their great importance they have often been immobilised utilising many...journal article 2013
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Ranoux, A. (author), Djanashvili, K. (author), Arends, I.W.C.E. (author), Hanefeld, U. (author)Novel amorphous mesoporous borosilicate, B-TUD-1, was prepared to test its performance for different sustainable reactions. The structure of the material, the effective incorporation of boron into the framework as well as the nature of incorporated boron were verified by N2-sorption, XRD, ICP-OES, TEM, NH3-desorption, MAS NMR and FTIR. The...journal article 2013
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Chen, B.S. (author), Otten, L.G. (author), Resch, V. (author), Muyzer, G. (author), Hanefeld, U. (author)Rhodococcus rhodochrous ATCC 17895 possesses an array of mono- and dioxygenases, as well as hydratases, which makes it an interesting organism for biocatalysis. R. rhodochrous is a Gram-positive aerobic bacterium with a rod-like morphology. Here we describe the features of this organism, together with the complete genome sequence and annotation....journal article 2013
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Resch, V. (author), Seidler, C. (author), Chen, B.S. (author), Degeling, I. (author), Hanefeld, U. (author)The use of water as a nucleophile for Michael additions is still a challenge in organic chemistry. In this report we describe the use of amino acids as catalysts for the Michael addition of water to ?,?-unsaturated ketones. All 20 proteinogenic amino acids were screened and L-lysine was identified as the best candidate. To obtain a better...journal article 2013
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Resch, V.A. (author), Jin, J. (author), Chen, B.S. (author), Hanefeld, U. (author)The Michael hydratase – alcohol dehydrogenase (MhyADH) from Alicycliphilus denitrificans was previously identified as a bi-functional enzyme performing a hydration of ?,?-unsaturated ketones and subsequent oxidation of the formed alcohols. The investigations of the bi-functionality were based on a spectrophotometric assay and an activity...journal article 2014
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Resch, V. (author), Hanefeld, U. (author)Water is omnipresent and essential. Yet at the same time it is a rather unreactive molecule. The direct addition of water to C[double bond, length as m-dash]C double bonds is therefore a challenge not answered convincingly. In this perspective we critically evaluate the selectivity and the applicability of the different catalytic approaches for...journal article 2014
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Chen, B.S. (author), Resch, V. (author), Otten, L.G. (author), Hanefeld, U. (author)The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important ?-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent...journal article 2014
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Vasudevan Srinivasan, V. (author), Ranoux, A. (author), Maheswari, R. (author), Hanefeld, U. (author), Ramanathan, A. (author), Subramaniam, B. (author)The acidity of Zr-incorporated large pore cubic mesoporous silicate, KIT-5, with Fm3m symmetry was explored as catalyst in the Hantzsch reaction for preparation of 1,4-dihydropyridine (DHP) derivatives, Meerwein–Ponndorf–Verley (MPV) reduction of 4-tert-butylcyclohexanone, and Prins reaction of citronellal. The catalyst showed ~82–94 %...journal article 2015
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Szymańska, K. (author), Odrozek, K. (author), Zniszczoł, A. (author), Torrelo, G. (author), Resch, V. (author), Hanefeld, U. (author), Jarzębskia, A.B. (author)Acyltransferase from Mycobacterium smegmatis (MsAcT) immobilised in continuous-flow microchannel (30-50 ?m dia.) reactors with hierarchical pore structure (4 cm3/g total pore volume) enabled quantitative, full and rapid transesterification of neopentylglycol with ethyl acetate in a biphasic 50/50 % system in less than one minute. MsAcT was...journal article 2016
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Bracco Garcia, M.P. (author), Busch, H. (author), von Langermann, J. (author), Hanefeld, U. (author)The first enantioselective synthesis was the selective addition of cyanide to benzaldehyde catalysed by a hydroxynitrile lyase (HNL). Since then these enzymes have developed into a reliable tool in organic synthesis. HNLs to prepare either the (R)- or the (S)-enantiomer of the desired cyanohydrin are available and a wide variety of reaction...journal article 2016
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Gjonaj, L. (author), Pinkse, M.W.H. (author), Fernandez Fueyo, E. (author), Hollmann, F. (author), Hanefeld, U. (author)Nitrile reductases catalyse a two-step reduction of nitriles to amines. This requires the binding of two NADPH molecules during one catalytic cycle. For the nitrile reductase from E. coli (EcoNR) mass spectrometry studies of the catalytic mechanism were performed. EcoNR is dimeric and has no Rossman fold. It was demonstrated that during...journal article 2016
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ten Dam, J. (author), Ramanathan, A. (author), Djanashvili, K. (author), Kapteijn, F. (author), Hanefeld, U. (author)The synthesis of a series of bifunctional catalysts (1 wt% Pt/W-TUD-1 (Technische Universiteit Delft-1) and 1 wt% Pt/WO<sub>3</sub>/TUD-1) with different tungsten loadings (5-30 wt% WO<sub>3</sub>) is described. They were characterized using ICP-OES, INAA, N<sub>2</sub> physisorption, XRD and TEM. Their catalytic performance (activity and...journal article 2017
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Marsden, S.R. (author), Gjonaj, L. (author), Eustace, S.J. (author), Hanefeld, U. (author)Transketolase catalyzes asymmetric C−C bond formation of two highly polar compounds. Over the last 30 years, the reaction has unanimously been described in literature as irreversible because of the concomitant release of CO2 if using lithium hydroxypyruvate (LiHPA) as a substrate. Following the reaction over a longer period of time however, we...journal article 2017
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Medici, R. (author), Stammes, J.K. (author), Otten, L.G. (author), Hanefeld, U. (author), Kwakernaak, Stender (author)α-Hydroxy ketones and vicinal diols constitute well-known building blocks in organic synthesis. Here we describe one enzyme that enables the enantioselective synthesis of both building blocks starting from diketones. The enzyme 2,3-butanediol dehydrogenase (BudC) from S. marcescens CECT 977 belongs to the NADH-dependent metal-independent short...journal article 2017