Xi:Irritant;
106-24-1Relevant articles and documents
Selective Hydrogenation of Aldehydes Using a Well-Defined Fe(II) PNP Pincer Complex in Biphasic Medium
Weber, Stefan,Brünig, Julian,Zeindlhofer, Veronika,Schr?der, Christian,St?ger, Berthold,Limbeck, Andreas,Kirchner, Karl,Bica, Katharina
, p. 4386 - 4394 (2018)
A biphasic process for the hydrogenation of aldehydes was developed using a well-defined iron (II) PNP pincer complex as model system to investigate the performance of various ionic liquids. A number of suitable hydrophobic ionic liquids based on the N(Tf)2? anion were identified, allowing to immobilize the iron (II) catalyst in the ionic liquid layer and to facilitate the separation of the desired alcohols. Further studies showed that targeted Br?nsted basic ionic liquids can eliminate the need of an external base to activate the catalyst.
Characterization of the Rv3378c gene product, a new diterpene synthasefor producing tuberculosinol and (13R, S)-isotuberculosinol (nosyberkol), from the mycobacterium tuberculosis H37Rv genome
Nakano, Chiaki,Ootsuka, Takahiro,Takayama, Kazutoshi,Mitsui, Toshiaki,Sato, Tsutomu,Hoshino, Tsutomu
, p. 75 - 81 (2011)
The Rv3377c and Rv3378c genes from Mycobacterium tuberculosis are specifically found in the virulent Mycobacterium species, but not in the avirulent species. The Rv3378c-encoded enzyme produced tuberculosinol 2 (5(6), 13(14)-halimadiene-15-ol), 13R-5a and 13Sisotuberculosinol 5b (5(6), 14(15)-halimadiene-13-ol) as its enzymatic products from tuberculosinyl diphosphate 3, indicating that the Rv3378c enzyme catalyzed the nucleophilic addition of a water molecule after the release of a diphosphate moiety. The three enzymatic products 2, 5a, and 5b were produced irrespective of the N- and C-terminal His-tagged Rv3378c enzymes, and of the maltose-binding protein fusion enzyme; the product distribution ratio was identical between the enzymes as 1:1 for 2:5, and 1:3 for 5a:5b. The successful separation of 5a and 5b by a chiral HPLC column provided the first complete assignments of 1H- and 13C-NMR data for 5a and 5b. The enzymatic mechanism for producing 2, 5a, and 5b is proposed here, and the optimal catalytic conditions and kinetic parameters, in addition to the divalent metal effects, are described. Site-directed mutagenesis of Asp into Asn, targeted at the DDXXD motif, resulted in significantly decreased enzymatic activity.
Labeling of polyprenylated macromolecules using mild Ene reactions
Zhang, Jingwen,Zhao, Jizhong,Wang, Li,Hu, Hongmei,Wang, Sheng,Yu, Ping,Wang, Rui
, (2021)
Protein posttranslational modifications play pivotal roles in a wide range of functions such as gene expression regulation, differentiation, cell migration, various human diseases and so on. Polyprenylated group are a lipid modification only found in the Ras super family protein. It was demonstrated that farnesyl, geranylgeranyl groups are covalently attached into sulfur atom on cysteine of Caxx motif, playing essential roles in anchoring on plasma membrane and signal transduction etc. We first reported a straightforward chemical approach to labelling of polyprenylated macromolecules. Our method mainly relied on a novel fluorination/Ene reaction, exhibiting application potential in the study of proteome-wide mapping of protein prenylation target.
Large Pore Bifunctional Titanium-Aluminosilicates: the Inorganic Non-enzymatic Version of the Epoxidase Conversion of Linalool to Cyclic Ethers
Corma, A.,Iglesias, M.,Sanchez, F.
, p. 1635 - 1636 (1995)
Bifunctional aluminosilicate catalysts containing framework Ti are prepared, with two different topologies and pore sizes; these samples contain both acid and oxidizing catalytic sites and are highly selective for carrying out multistep reactions with selectivities close to those obtained with epoxidases, this is shown to occur for the oxidation of linalool to cyclic hydroxy ethers.
Gold catalysis for selective hydrogenation of aldehydes and valorization of bio-based chemical building blocks
Silva, Rerison J. M.,Fiorio, Jhonatan L.,Vidinha, Pedro,Rossi, Liane M.
, p. 2162 - 2169 (2019)
Gold catalysts are best known for their selectivity in oxidation reactions, however, there is a promising future for gold in selective hydrogenations. Herein, the hydrogenation of several aldehydes and important bio-based chemical building blocks, namely 5-hydroxymethylfurfural (5-HMF), furfural and vanillin, was performed throughout the combination of Au nanoparticles with Lewis bases. The Au-amine ligand (e.g., 2,4,6-trimethylpyridine) catalytic system could reduce the aldehyde carbonyl group selectively, without reducing alkene moieties or opening the furanic ring that occur on most traditional catalysts. Otherwise, the reduction of nitro group is preferential and the catalytic system was used for the synthesis of furfurylamines, important intermediates in the synthesis of different pharmaceuticals (e.g., furosemide), through the selective reductive amination of furfural starting from nitro-compounds. Moreover, a fully heterogeneous gold catalyst embedded in N-doped carbon (Au@N-doped carbon / TiO2) was able to perform these reactions in successive recycles without the addition of ligands, with impact in the development of a continuous flow process for biomass valorization.
Tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP): A novel catalyst for selective deacetylation
Yoshimoto, Kazuya,Kawabata, Hirotoshi,Nakamichi, Natsuki,Hayashi, Masahiko
, p. 934 - 935 (2001)
Chemo-and stereoselective deacetylation was achieved by the use of a catalytic amount of tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP).
Cloning and characterization of Pfl-1841, a 2-methylenebornane synthase in Pseudomonas fluorescens PfO-1
Chou, Wayne K.W.,Ikeda, Haruo,Cane, David E.
, p. 6627 - 6632 (2011)
The pfl-1841 gene from Pseudomonas fluorescens PfO-1 is the only gene in any of the three sequenced genomes of the Gram-negative bacterium P. fluorescens, that is, annotated as a putative terpene synthase. The predicted Pfl-1841 protein, which harbors the two strictly conserved divalent metal binding domains found in all terpene cyclases, is closely related to several known or presumed 2-methylisoborneol synthases, with the closest match being to the MOL protein of Micromonaspora olivasterospora KY11048 that has been implicated as a 2-methylenebornane synthase. A synthetic gene encoding P. fluorescens Pfl-1841 and optimized for expression in Escherichia coli was expressed and purified as an N-terminal His6-tagged protein. Incubation of recombinant Pfl-1841 with 2-methylgeranyl diphosphate produced 2-methylenebornane as the major product accompanied by 1-methylcamphene as well as other minor, monomethyl-homomonoterpene hydrocarbons and alcohols. The steady-state kinetic parameters for the Pfl-1841-catalyzed reaction were K M=110±13 nM and kcat=2.4±0.1×10 -2 s-1. Attempts to identify the P. fluorescens SAM-dependent 2-methylgeranyl diphosphate synthase have so far been unsuccessful.
Asymmetric bioreduction of activated alkenes using cloned 12-oxophytodienoate reductase isoenzymes OPR-1 and OPR-3 from Lycopersicon esculentum (tomato): A striking change of stereoselectivity
Hall, Melanie,Stueckler, Clemens,Kroutil, Wolfgang,Macheroux, Peter,Faber, Kurt
, p. 3934 - 3937 (2007)
(Chemical Equation Presented) Tomato source: 12-Oxophytodienoate reductase isoenzymes OPR1 and OPR3 from tomato possess a broad substrate spectrum for the asymmetric bioreduction of α,β-unsaturated enals, enones, dicarboxylic acids, and N-substituted male-imides (see scheme). Stereocomplementary behavior of both isoenzymes was observed in the reduction of a nitroalkene that led to the formation of opposite stereoisomers in high enantiomeric excess.
Diisopropoxytitanium(III) Tetrahydroborate: A Highly Useful Reagent for the Remarkably Selective 1,2-Reduction of α,β-Unsaturated Carbonyl Compounds
Ravikumar, K. S.,Baskaran, Sundarababu,Chandrasekaran, Srinivasan
, p. 5981 - 5982 (1993)
Diisopropoxytitanium(III) tetrahydroborate formed by the reaction of diisopropoxytitanium dichloride and benzyltriethylammonium borohydride (1:2) reacts with a variety of α,β-unsaturated carbonyl compounds in dichloromethane (-20 deg C) very readily to yield exclusively the corresponding allylic alcohols in excellent yields.
SELECTIVE REDUCTION OF ALDEHYDES IN PRESENCE OF A KETONE WITH CHLOROTRIMETHYLSILANE AND NICKEL BORIDE
Borbaruah, M.,Barua, N. C.,Sharma, R. P.
, p. 5741 - 5742 (1987)
It has been shown that a combination of chlorotrimethylsilane and nickel boride effects the chemoselective reduction of an aldehyde in presence of a ketonic carbonyl group.
