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call loadScript javascripts\jsmol\core\package.js call loadScript javascripts\jsmol\core\core.z.js -- required by ClazzNode call loadScript javascripts\jsmol\J\awtjs2d\WebOutputChannel.js Jmol JavaScript applet jmolApplet0_object__1978764490589091__ initializing getValue debug = null getValue logLevel = null getValue allowjavascript = null AppletRegistry.checkIn(jmolApplet0_object__1978764490589091__) call loadScript javascripts\jsmol\core\corestate.z.js viewerOptions: { "name":"jmolApplet0_object","applet":true,"documentBase":"https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:15977","platform":"J.awtjs2d.Platform","fullName":"jmolApplet0_object__1978764490589091__","display":"jmolApplet0_canvas2d","signedApplet":"true","appletReadyCallback":"Jmol._readyCallback","statusListener":"[J.appletjs.Jmol.MyStatusListener object]","codeBase":"https://www.ebi.ac.uk/chebi/javascripts/jsmol/","syncId":"1978764490589091","bgcolor":"#000" } (C) 2012 Jmol Development Jmol Version: 13.2.7 $Date: 2013-10-01 11:35:15 -0500 (Tue, 01 Oct 2013) $ java.vendor: j2s java.version: 0.0 os.name: j2s Access: ALL memory: 0.0/0.0 processors available: 1 useCommandThread: false appletId:jmolApplet0_object (signed) starting HoverWatcher_1 getValue emulate = null defaults = "Jmol" getValue boxbgcolor = null getValue bgcolor = #000 backgroundColor = "#000" getValue ANIMFRAMECallback = null getValue APPLETREADYCallback = Jmol._readyCallback APPLETREADYCallback = "Jmol._readyCallback" getValue ATOMMOVEDCallback = null getValue CLICKCallback = null getValue ECHOCallback = null getValue ERRORCallback = null getValue EVALCallback = null getValue HOVERCallback = null getValue LOADSTRUCTCallback = null getValue MEASURECallback = null getValue MESSAGECallback = null getValue MINIMIZATIONCallback = null getValue PICKCallback = null getValue RESIZECallback = null getValue SCRIPTCallback = null getValue SYNCCallback = null getValue STRUCTUREMODIFIEDCallback = null getValue doTranslate = null language=en_US getValue popupMenu = null getValue script = null Jmol applet jmolApplet0_object__1978764490589091__ ready call loadScript javascripts\jsmol\core\corescript.z.js call loadScript javascripts\jsmol\J\script\FileLoadThread.js starting QueueThread0_2 script 1 started starting HoverWatcher_3 starting HoverWatcher_4 The Resolver thinks Mol A2Q - Ideal conformer Mrv1927 05202109373D starting HoverWatcher_5 Time for openFile(A2Q - Ideal conformer Mrv1927 05202109373D 15 15 0 0 0 0 999 V2000 -1.0360 0.0260 -0.0570 C 0 0 0 0 0 0 0 0 0 0 0 0 -0.2730 -1.2410 -0.3820 C 0 0 1 0 0 0 0 0 0 0 0 0 1.0530 -1.1870 0.3900 C 0 0 1 0 0 0 0 0 0 0 0 0 1.8590 0.0190 -0.0900 C 0 0 1 0 0 0 0 0 0 0 0 0 1.0450 1.2770 -0.0210 C 0 0 0 0 0 0 0 0 0 0 0 0 -0.2820 1.2840 -0.0100 C 0 0 0 0 0 0 0 0 0 0 0 0 -2.2310 0.0030 0.1530 O 0 0 0 0 0 0 0 0 0 0 0 0 -0.8490 -2.1120 -0.0690 H 0 0 0 0 0 0 0 0 0 0 0 0 -0.0770 -1.2920 -1.4530 H 0 0 0 0 0 0 0 0 0 0 0 0 -0.8120 2.2240 0.0330 H 0 0 0 0 0 0 0 0 0 0 0 0 0.8500 -1.0890 1.4560 H 0 0 0 0 0 0 0 0 0 0 0 0 1.6190 -2.1000 0.2070 H 0 0 0 0 0 0 0 0 0 0 0 0 2.7430 0.1310 0.5380 H 0 0 0 0 0 0 0 0 0 0 0 0 2.1730 -0.1470 -1.1210 H 0 0 0 0 0 0 0 0 0 0 0 0 1.5640 2.2230 0.0220 H 0 0 0 0 0 0 0 0 0 0 0 0 1 2 1 0 0 0 0 1 6 1 0 0 0 0 1 7 2 0 0 0 0 2 3 1 0 0 0 0 3 4 1 0 0 0 0 4 5 1 0 0 0 0 5 6 2 0 0 0 0 2 8 1 0 0 0 0 2 9 1 0 0 0 0 6 10 1 0 0 0 0 3 11 1 0 0 0 0 3 12 1 0 0 0 0 4 13 1 0 0 0 0 4 14 1 0 0 0 0 5 15 1 0 0 0 0 M END): 15 ms reading 15 atoms ModelSet: haveSymmetry:false haveUnitcells:false haveFractionalCoord:false 1 model in this collection. Use getProperty "modelInfo" or getProperty "auxiliaryInfo" to inspect them. Default Van der Waals type for model set to Babel 15 atoms created ModelSet: not autobonding; use forceAutobond=true to force automatic bond creation Script completed Jmol script terminated
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| InChI=1S/C6H8O/c7-6-4-2-1-3-5-6/h2,4H,1,3,5H2 |
| FWFSEYBSWVRWGL-UHFFFAOYSA-N |
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Outgoing
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cyclohex-2-enone
(CHEBI:15977)
is a
cyclohexenone
(CHEBI:48951)
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|
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Incoming
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(4R,5S,6R)-2,4,5,6-tetrahydroxycyclohex-2-en-1-one
(CHEBI:4077)
has functional parent
cyclohex-2-enone
(CHEBI:15977)
5D-(5/6)-2,6-dihydroxy-5-(hydroxymethyl)cyclohex-2-en-1-one
(CHEBI:16694)
has functional parent
cyclohex-2-enone
(CHEBI:15977)
|
|
1-cyclohexen-3-one
|
NIST Chemistry WebBook
|
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2-cyclohexen-1-one
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ChEBI
|
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2-Cyclohexen-1-one
|
KEGG COMPOUND
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2-cyclohexenone
|
NIST Chemistry WebBook
|
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3-oxocyclohexene
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ChemIDplus
|
|
Cyclohex-2-enone
|
KEGG COMPOUND
|
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cyclohex-2-enone
|
UniProt
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cyclohexen-3-one
|
NIST Chemistry WebBook
|
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1280477
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Reaxys Registry Number
|
Reaxys
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|
2792
|
Gmelin Registry Number
|
Gmelin
|
|
930-68-7
|
CAS Registry Number
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ChemIDplus
|
|
930-68-7
|
CAS Registry Number
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NIST Chemistry WebBook
|
Peschel MT, Kabaciński P, Schwinger DP, Thyrhaug E, Cerullo G, Bach T, Bach T, Hauer J, de Vivie-Riedle R (2021)
Activation of 2-Cyclohexenone by BF3 Coordination: Mechanistic Insights from Theory and Experiment.
Angewandte Chemie (International ed. in English) 60, 10155-10163 [PubMed:33595902]
[show Abstract]
Lewis acids have recently been recognized as catalysts enabling enantioselective photochemical transformations. Mechanistic studies on these systems are however rare, either due to their absorption at wavelengths shorter than 260 nm, or due to the limitations of theoretical dynamic studies for larger complexes. In this work, we overcome these challenges and employ sub-30-fs transient absorption in the UV, in combination with a highly accurate theoretical treatment on the XMS-CASPT2 level. We investigate 2-cyclohexenone and its complex to boron trifluoride and analyze the observed dynamics based on trajectory calculations including non-adiabatic coupling and intersystem crossing. This approach explains all ultrafast decay pathways observed in the complex. We show that the Lewis acid remains attached to the substrate in the triplet state, which in turn explains why chiral boron-based Lewis acids induce a high enantioselectivity in photocycloaddition reactions. | Kosari M, Seayad AM, Xi S, Kozlov SM, Borgna A, Zeng HC (2020)
Synthesis of Mesoporous Copper Aluminosilicate Hollow Spheres for Oxidation Reactions.
ACS applied materials & interfaces 12, 23060-23075 [PubMed:32345013]
[show Abstract]
Hollow functional metal silicate materials have received the most interest due to their large inner space, permeable and functional shell, lighter density, and better use of material compared to their solid counterparts. While tremendous success has been made in the synthesis of individual metal silicates with uniform morphology, the synthesis of multiphase hollow silicates has not been explored yet, although their direct applications could be promising. In this study, mesoporous aluminosilicate spheres (MASS) are transformed to submicrometer copper aluminosilicate hollow spheres (CASHS) via a one-pot hydrothermal process. CASHS has a hollow interior with Cu-Al-Si thorn-like moieties in a lamellar structure on its outer shell. The structure and morphology of CASHS are unique and different from the previously reported tubular copper silicates that are emanated from Stöber silica spheres. Herein, we also demonstrate that the extent of hollowing in CASHS can be attained by controlling the aluminum content of pristine MASS, highlighting the existence of parameters for in situ controlling the shell thickness of hollow materials. The application of CASHS as a potential heterogeneous catalyst has been directed to important oxidation processes such as olefin oxidation and the advanced oxidation process (AOP). In cyclohexene oxidation, for instance, high selectivity to cyclohex-2-en-1-one is achieved under moderate conditions using tert-butyl hydroperoxide as the oxidant. CASHS is a robust heterogeneous catalyst and recyclable for this reaction. CASHS-derived catalysts also favor AOP and enhance the removal of cationic dyes together with H2O2 through an adsorption-degradation process. | Xu Z, Miao C, Dong F, Jia L, Li W, Wang M, Liu W, Zheng QH (2020)
Radiosynthesis of a carbon-11 labeled tetrahydrobenzisoxazole derivative as a new PET probe for γ-secretase imaging in Alzheimer's disease.
Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine 155, 108915 [PubMed:31590101]
[show Abstract]
To develop PET radiotracers for imaging of Alzheimer's disease, a new carbon-11 labeled potent and selective γ-secretase modulator (GSM) has been synthesized. The reference standard tetrahydrobenzisoxazole derivative 8 and its desmethylated precursor 9 were synthesized from cyclohex-2-en-1-one and 3-hydroxy-4-nitrobenzaldehyde in eight and nine steps with 11% and 5% overall chemical yield, respectively. The radiotracer [11C]8 was prepared from its corresponding precursor 9 with [11C]CH3OTf through O-11C-methylation and isolated by RP-HPLC combined with SPE in 45-50% radiochemical yield, based on [11C]CO2 and decay corrected to EOB. The radiochemical purity was >99%, and the molar activity (Am) at EOB was 555-740 GBq/μmol. | Zhou HQ, Li L, Zhao Y, Wang HG, Zheng X (2019)
A combined experimental and density functional theory investigation of the hydrogen bonding of 2-cyclohexen-1-one and 3-methyl- 2-cyclohexen-1-one in solvents.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 208, 32-39 [PubMed:30290292]
[show Abstract]
Hydrogen bonding is a weak chemical interaction widely existed in the variety of organic and biological molecules. As an important structural motif of pyrimidine bases, the solvent effect of the hydrogen bonding of 2-cyclohexen-1-one (CHO) and 3-methyl- 2-cyclohexen-1-one (3MCHO) and its effect on the frequency shift of the CO stretching mode were investigated by using the FT-Raman and UV absorption spectra and density functional theory calculations. The electronic transitions associated with the UV absorptions in different solvents were calculated at B3LYP-TD/6-31++G(d,p) level of theory and employing SCIPCM solvent model. The vibrational spectra of CHO and 3MCHO were assigned on the basis of the FT-Raman spectra in neat liquid and different solvents, the calculated vibrational spectra of monomer and CHO dimers, and the concentration dependent experiments of the band pair intensities. Hydrogen bonding energies of CHO-(H2O)n (n = 1,2) clusters were predicted. The results reveal that the CHO-(H2O)2 cluster and CHO monomer are respectively the major source of spectral observation in water and cyclohexane, while CHO dimmer and CHO monomer coexist in acetonitrile. The difference in the frequency of the νC=O stretching mode between 3MCHO monomer and CHO monomer in cyclohexane were explored. | Liu J, Ma D (2018)
A Unified Approach for the Assembly of Atisine- and Hetidine-type Diterpenoid Alkaloids: Total Syntheses of Azitine and the Proposed Structure of Navirine C.
Angewandte Chemie (International ed. in English) 57, 6676-6680 [PubMed:29611891]
[show Abstract]
A tetracyclic dinitrile was synthesized in twelve steps from cyclohex-2-en-1-one by using a chelation-triggered conjugate addition to a γ-hydroxy-substituted α,β-unsaturated nitrile and an oxidative dearomatization/Diels-Alder cycloaddition cascade as the key steps. The first total synthesis of azitine (in 17 steps) was achieved through a simple reductive cyclization of this intermediate and subsequent transformations while the total synthesis of the proposed structure of navirine C (in 19 steps) was accomplished by a hydrogen-atom-transfer reaction of the tetracyclic dinitrile, Pd/C-catalyzed reductive cyclization, and subsequent functional group manipulation. | Sankaralingam M, Lee YM, Nam W, Fukuzumi S (2017)
Selective Oxygenation of Cyclohexene by Dioxygen via an Iron(V)-Oxo Complex-Autocatalyzed Reaction.
Inorganic chemistry 56, 5096-5104 [PubMed:28422498]
[show Abstract]
An iron complex with a tetraamido macrocyclic ligand, [(TAML)FeIII]-, was found to be an efficient and selective catalyst for allylic oxidation of cyclohexene by dioxygen (O2); cyclohex-2-enone was obtained as the major product along with cyclohexene oxide as the minor product. An iron(V)-oxo complex, [(TAML)FeV(O)]-, which was formed by activating O2 in the presence of cyclohexene, initiated the autoxidation of cyclohexene with O2 to produce cyclohexenyl hydroperoxide, which reacted with [(TAML)FeIII]- to produce [(TAML)FeV(O)]- by autocatalysis. Then, [(TAML)FeV(O)]- reacted rapidly with [(TAML)FeIII]- to produce a μ-oxo dimer, [(TAML)FeIV(O)FeIV(TAML)]2-, which was ultimately converted to [(TAML)FeV(O)]- when [(TAML)FeIII]- was not present in the reaction solution. An induction period was observed in the autocatalytic production of [(TAML)FeV(O)]-. The induction period was shortened with increasing catalytic amounts of [(TAML)FeV(O)]- and cyclohexenyl hydroperoxide, whereas the induction period was prolonged by adding catalytic amounts of a spin trapping reagent such as 5,5-dimethyl-1-pyrroline N-oxide (DMPO). The allylic oxidation of cycloalkenes was also found to depend on the allylic C-H bond dissociation energies, suggesting that the hydrogen atom abstraction from the allylic C-H bonds of cycloalkenes is the rate-determining radical chain initiation step. In this study, we have shown that an iron(III) complex with a tetraamido macrocyclic ligand is an efficient catalyst for the allylic oxidation of cyclohexene via an autocatalytic radical chain mechanism and that [(TAML)FeV(O)]- acts as a reactive intermediate for the selective oxygenation of cyclohexene with O2 to produce cyclohex-2-enone predominantly. | Zeng M, Murphy SK, Herzon SB (2017)
Development of a Modular Synthetic Route to (+)-Pleuromutilin, (+)-12-epi-Mutilins, and Related Structures.
Journal of the American Chemical Society 139, 16377-16388 [PubMed:29048164]
[show Abstract]
We describe the development of an enantioselective synthetic route to (+)-pleuromutilin (1), (+)-12-epi-mutilin, and related derivatives. A key hydrindanone was prepared in three steps and 48% overall yield from cyclohex-2-en-1-one. 1,4-Hydrocyanation provided a nitrile (53%, or 85% based on recovered starting material) that was converted to the eneimide 57 in 80% yield by the 1,2-addition of methyllithium to the nitrile function, cyclization, and in situ acylation with di-tert-butyldicarbonate. The eneimide 57 was employed in a 2-fold neopentylic coupling reaction with an organolithium reagent derived from the alkyl iodides (R)- or (S)-30, which contain the C11-C13 atoms of the target, to provide diastereomeric diketones in 60% or 48% yield (for coupling with (R)- or (S)-30, respectively). The diketone derived from (S)-30 contains the (S)-C12 stereochemistry found in pleuromutilin and was elaborated to an alkynylaldehyde. Nickel-catalyzed reductive cyclization of this alkynylaldehyde, to construct the eight-membered ring of the target, unexpectedly provided a cyclopentene (67%), which arises from participation of the C12-α-olefin in the transformation. The diketone derived from the enantiomeric C12-fragment (R)-30 underwent reductive cyclization to provide the desired product in 60% yield. This was elaborated to 12-epi-mutilin by a four-step sequence (39% overall). Installation of the glycolic acid residue followed by C12 epimerization (Berner et al. Monatsh. Chem. 1986, 117, 1073) generated (+)-pleuromutilin (1). (+)-12-epi-Pleuromutilin and (+)-11,12-di-epi-pleuromutilin were prepared by related sequences. This work establishes a convergent entry to the pleuromutilins and provides a foundation for the production of novel antibiotics to treat drug-resistant and Gram-negative infections. | Mooneyham AE, McDonnell MP, Drucker S (2017)
Cavity Ringdown Spectrum of 2-Cyclohexen-1-one in the CO/Alkenyl CC Stretch Region of the S1(n, π*)-S0 Vibronic Band System.
The journal of physical chemistry. A 121, 2343-2352 [PubMed:28260378]
[show Abstract]
The 2-cyclohexen-1-one (2CHO) molecule serves as a prototype for understanding the photochemical properties of conjugated enones. We have recorded the cavity ringdown (CRD) absorption spectrum of 2CHO vapor at room temperature over the 360-380 nm range. This portion of the spectrum encompasses the S1(n,π*) ← S0 vibronic band system in the region of the C═C and C═O stretch fundamentals. We have assigned about 40 vibronically resolved features in the spectrum, affording fundamental frequencies for 7 different vibrational modes in the S1(n,π*) state, including the C═C (1554 cm-1) and OC-CH (1449 cm-1) stretch modes. The C═O stretch character is spread over at least four different vibrational modes in the S1(n,π*) state, with fundamentals spanning the 1340-1430 cm-1 interval. This finding stems from a significant reduction in C═O bond order upon excitation, which leads to near-coincidence of the C═O stretch and several CH2 wag frequencies. Such complexities make 2CHO an ideal candidate for testing excited-state computational methods. We have used the present spectroscopic results to test EOM-EE-CCSD harmonic-frequency predictions for the S1(n,π*) state. We have also benchmarked the performance of less costly computational methods, including CIS(D) and TDDFT. For certain density functionals (e.g., B3LYP and PBE0), we find that the accuracy of TDDFT frequency predictions can approach but not meet that of EOM-EE-CCSD. | Reich S, Nestl BM, Hauer B (2016)
Loop-Grafted Old Yellow Enzymes in the Bienzymatic Cascade Reduction of Allylic Alcohols.
Chembiochem : a European journal of chemical biology 17, 561-565 [PubMed:27037735]
[show Abstract]
The enzymatic reduction of C=C bonds in allylic alcohols with Old Yellow Enzymes represents a challenging task, due to insufficient activation through the hydroxy group. In our work, we coupled an alcohol dehydrogenase with three wild-type ene reductases-namely nicotinamide-dependent cyclohex-2-en-1-one reductase (NCR) from Zymomonas mobilis, OYE1 from Saccharomyces pastorianus and morphinone reductase (MR) from Pseudomonas putida M10-and four rationally designed β/α loop variants of NCR in the bienzymatic cascade hydrogenation of allylic alcohols. Remarkably, the wild type of NCR was not able to catalyse the cascade reaction whereas MR and OYE1 demonstrated high to excellent activities. Through the rational loop grafting of two intrinsic β/α surface loop regions near the entrance of the active site of NCR with the corresponding loops from OYE1 or MR we successfully transferred the cascade reduction activity from one family member to another. Further we observed that loop grafting revealed certain influences on the interaction with the nicotinamide cofactor. | Clay D, Winkler CK, Tasnádi G, Faber K (2014)
Bioreduction and disproportionation of cyclohex-2-enone catalyzed by ene-reductase OYE-1 in 'micro-aqueous' organic solvents.
Biotechnology letters 36, 1329-1333 [PubMed:24563324]
[show Abstract]
The bioreduction and disproportionation of cyclohex-2-enone catalyzed by Old Yellow Enzyme 1 was investigated in presence of organic (co)solvents. Whereas the NADH-dependent bioreduction activity strongly decreased at elevated co-solvent concentrations due to the insolubility of the nicotinamide-cofactor, the NADH-free disproportionation was significantly improved in water-immiscible organic co-solvents at 90 % (v/v) with near-quantitative conversion. This positive effect was attributed to removal of the inhibiting co-product, phenol, from the enzyme's active site. The best co-solvents show high lipophilicity (logP) and a high potential to solubilize phenol (Kphenol). As a predictive parameter, the ratio of logP/Kphenol should be preferably ≥100. | Clay D, Winkler CK, Tasnádi G, Faber K (2014)
Bioreduction and disproportionation of cyclohex-2-enone catalyzed by ene-reductase OYE-1 in ‘micro-aqueous’ organic solvents
Biotechnology letters 36, 1329-1333 [Agricola:IND500890908]
[show Abstract]
The bioreduction and disproportionation of cyclohex-2-enone catalyzed by Old Yellow Enzyme 1 was investigated in presence of organic (co)solvents. Whereas the NADH-dependent bioreduction activity strongly decreased at elevated co-solvent concentrations due to the insolubility of the nicotinamide-cofactor, the NADH-free disproportionation was significantly improved in water-immiscible organic co-solvents at 90 % (v/v) with near-quantitative conversion. This positive effect was attributed to removal of the inhibiting co-product, phenol, from the enzyme’s active site. The best co-solvents show high lipophilicity (logP) and a high potential to solubilize phenol (Kₚₕₑₙₒₗ). As a predictive parameter, the ratio of logP/Kₚₕₑₙₒₗshould be preferably ≥100. | Steinkellner G, Gruber CC, Pavkov-Keller T, Binter A, Steiner K, Winkler C, Lyskowski A, Schwamberger O, Oberer M, Schwab H, Faber K, Macheroux P, Gruber K (2014)
Identification of promiscuous ene-reductase activity by mining structural databases using active site constellations.
Nature communications 5, 4150 [PubMed:24954722]
[show Abstract]
The exploitation of catalytic promiscuity and the application of de novo design have recently opened the access to novel, non-natural enzymatic activities. Here we describe a structural bioinformatic method for predicting catalytic activities of enzymes based on three-dimensional constellations of functional groups in active sites ('catalophores'). As a proof-of-concept we identify two enzymes with predicted promiscuous ene-reductase activity (reduction of activated C-C double bonds) and compare them with known ene-reductases, that is, members of the Old Yellow Enzyme family. Despite completely different amino acid sequences, overall structures and protein folds, high-resolution crystal structures reveal equivalent binding modes of typical Old Yellow Enzyme substrates and ligands. Biochemical and biocatalytic data show that the two enzymes indeed possess ene-reductase activity and reveal an inverted stereopreference compared with Old Yellow Enzymes for some substrates. This method could thus be a tool for the identification of viable starting points for the development and engineering of novel biocatalysts. | Trapp O, Weber SK, Bauch S, Bäcker T, Hofstadt W, Spliethoff B (2008)
High-throughput kinetic study of hydrogenation over palladium nanoparticles: combination of reaction and analysis.
Chemistry (Weinheim an der Bergstrasse, Germany) 14, 4657-4666 [PubMed:18384020]
[show Abstract]
The hydrogenation of 1-acetylcyclohexene, cyclohex-2-enone, nitrobenzene, and trans-methylpent-3-enoate catalyzed by highly active palladium nanoparticles was studied by high-throughput on-column reaction gas chromatography. In these experiments, catalysis and separation of educts and products is integrated by the use of a catalytically active gas chromatographic stationary phase, which allows reaction rate measurements to be efficiently performed by employing reactant libraries. Palladium nanoparticles embedded in a stabilizing polysiloxane matrix serve as catalyst and selective chromatographic stationary phase for these multiphase reactions (gas-liquid-solid) and are coated in fused-silica capillaries (inner diameter 250 microm) as a thin film of thickness 250 nm. The palladium nanoparticles were prepared by reduction of palladium acetate with hydridomethylsiloxane-dimethylsiloxane copolymer and self-catalyzed hydrosilylation with methylvinylsiloxane-dimethylsiloxane copolymer to obtain a stabilizing matrix. Diphenylsiloxane-dimethylsiloxane copolymer (GE SE 52) was added to improve film stability over a wide range of compositions. Herein, we show by systematic TEM investigations that the size and morphology (crystalline or amorphous) of the nanoparticles strongly depends on the ratio of the stabilizing polysiloxanes, the conditions to immobilize the stationary phase on the surface of the fused-silica capillary, and the loading of the palladium precursor. Furthermore, hydrogenations were performed with these catalytically active stationary phases between 60 and 100 degrees C at various contact times to determine the temperature-dependent reaction rate constants and to obtain activation parameters and diffusion coefficients. | He L, Jian TY, Ye S (2007)
N-heterocyclic carbene catalyzed aza-Morita-Baylis-Hillman reaction of cyclic enones with N-tosylarylimines.
The Journal of organic chemistry 72, 7466-7468 [PubMed:17705547]
[show Abstract]
N-Heterocyclic carbenes (NHCs) prove to be efficient catalysts for the aza-Morita-Baylis-Hillman (aza-MBH) reaction of cyclopent-2-en-1-one or cyclohex-2-en-1-one with a variety of N-tosylarylimines to give the aza-MBH adduct in high yields. Crossover experiments show NHC can add to N-tosylarylimines in a reversible manner, which allows the addition of NHC to cyclic enones and thus catalyzes the aza-Mortia-Baylis-Hillman reaction. | Rosamilia AE, Scott JL, Strauss CR (2005)
Preparation of 2- and 4-arylmethyl N-substituted and N,N-disubstituted anilines via a "green", multicomponent reaction.
Organic letters 7, 1525-1528 [PubMed:15816743]
[show Abstract]
[reaction: see text] A new, green, regioselective, one-step, multicomponent reaction of an aldehyde possessing a nonenolizable carbonyl function, cyclohex-2-enone (or a derivative thereof), and primary or secondary amines afforded 2-N-substituted arylmethyl anilines or 4-N,N-disubstituted arylmethyl anilines, respectively. Yields and regioselectivities were good. Evidence for a pathway involving imine and iminium intermediates is presented along with examples demonstrating amenability of the process to combinatorial chemistry. | Khan H, Harris RJ, Barna T, Craig DH, Bruce NC, Munro AW, Moody PC, Scrutton NS (2002)
Kinetic and structural basis of reactivity of pentaerythritol tetranitrate reductase with NADPH, 2-cyclohexenone, nitroesters, and nitroaromatic explosives.
The Journal of biological chemistry 277, 21906-21912 [PubMed:11923299]
[show Abstract]
The reaction of pentaerythritol tetranitrate reductase with reducing and oxidizing substrates has been studied by stopped-flow spectrophotometry, redox potentiometry, and X-ray crystallography. We show in the reductive half-reaction of pentaerythritol tetranitrate (PETN) reductase that NADPH binds to form an enzyme-NADPH charge transfer intermediate prior to hydride transfer from the nicotinamide coenzyme to FMN. In the oxidative half-reaction, the two-electron-reduced enzyme reacts with several substrates including nitroester explosives (glycerol trinitrate and PETN), nitroaromatic explosives (trinitrotoluene (TNT) and picric acid), and alpha,beta-unsaturated carbonyl compounds (2-cyclohexenone). Oxidation of the flavin by the nitroaromatic substrate TNT is kinetically indistinguishable from formation of its hydride-Meisenheimer complex, consistent with a mechanism involving direct nucleophilic attack by hydride from the flavin N5 atom at the electron-deficient aromatic nucleus of the substrate. The crystal structures of complexes of the oxidized enzyme bound to picric acid and TNT are consistent with direct hydride transfer from the reduced flavin to nitroaromatic substrates. The mode of binding the inhibitor 2,4-dinitrophenol (2,4-DNP) is similar to that observed with picric acid and TNT. In this position, however, the aromatic nucleus is not activated for hydride transfer from the flavin N5 atom, thus accounting for the lack of reactivity with 2,4-DNP. Our work with PETN reductase establishes further a close relationship to the Old Yellow Enzyme family of proteins but at the same time highlights important differences compared with the reactivity of Old Yellow Enzyme. Our studies provide a structural and mechanistic rationale for the ability of PETN reductase to react with the nitroaromatic explosive compounds TNT and picric acid and for the inhibition of enzyme activity with 2,4-DNP. | Shi M, Xu YM (2001)
Lewis base effects in the Baylis-Hillman reaction of imines with cyclohex-2-en-1-one and cyclopent-2-en-1-one.
Chemical communications (Cambridge, England)1876-1877 [PubMed:12240358]
[show Abstract]
In the Baylis-Hillman reaction of N-benzylidene-4-methyl-benzenesulfonamide with cyclohex-2-en-1-one or cyclopent-2-en-1-one, we found that, in the presence of a catalytic amount of DMAP, the Baylis-Hillman reaction can be greatly accelerated to give the normal Baylis-Hillman adduct 1 or 3 in good or very high yields: moreover, using PBu3 as a Lewis base in the reaction of N-benzylidene-4-methylbenzenesulfonamide with cyclopent-2-en-1-one, the normal Baylis-Hillman adducts 3 could be obtained in very high yields within 5 h, however, using PBu3 or DBU as a Lewis base in the reaction of N-benzylidene-4-methyl-benzenesulfonamide with cyclohex-2-en-1-one, beside the normal Baylis-Hillman adduct 1 abnormal Baylis-Hillman adduct 3-aryl-2-[(4-methylphenyl)sulfonyl]-2-azabicyclo[2.2.2]octan-5-one 2 was formed at the same time; the substituent's effects were also examined. | Nilsson AM, Gäfvert E, Salvador L, Luthman K, Bruze M, Gruvberger B, Nilsson JL, Karlberg AT (2001)
Mechanism of the antigen formation of carvone and related alpha, beta-unsaturated ketones.
Contact dermatitis 44, 347-356 [PubMed:11380545]
[show Abstract]
In the present study, the mechanism for the antigen formation of alpha, beta-unsaturated ketones was investigated. A series of analogues of carvone ((5R)-5-isopropenyl-2-methyl-2-cyclohexenone) with altered chemical reactivity and with retained overall structure or with retained reactivity and altered three-dimensional structure were synthesized. These analogues were tested for cross-reactivity in carvone-sensitized animals. Cross-reactivity was observed for analogue 3 ((5R)-5-isopropyl-2-methyl-2-cyclohexen-1-one). No cross-reactions were observed for analogues 1 ((2R,5R)-5-isopropenyl-2-methyl cyclohexanone) and 4 ((5R)-2,3-dimethyl-5-isopropenyl-2-cyclohexene-1-one). Both those compounds also failed to induce sensitization. These findings demonstrate that alpha, beta-unsaturated ketones form antigens after a nucleophilic attack at the beta-carbon with soft nucleophiles such as thiol in cysteine and not with the formation of a Schiff's base after a nucleophilic attack at the carbonyl carbon with nitrogen nucleophiles. Furthermore, no cross-reactivity was observed between R- and S-carvone indicating the importance of the 3-dimensional structure of haptens (and antigens) in T-cell recognition. The analogues were also tested for cross-reactivity on patients allergic to carvone. The results from the animal study were confirmed. | Maume D, Le Bizec B, Marchand P, Montrade MP, Andre F (1998)
N-methyl-N-alkylsilyltrifluoroacetamide-I2 as a new derivatization reagent for anabolic steroid control.
The Analyst 123, 2645-2648 [PubMed:10435317]
[show Abstract]
Analytical methods for the control of growth promoters have to be specific and sensitive. At low concentration levels, it is difficult to identify some molecules unambiguously even with the improved performance of analytical methods. GC-MS analysis of 17 beta-trenbolone and its major metabolite, 17 alpha-trenbolone, is a good example. A new derivatization agent has been developed which is based on silylation of the 3- and 17-oxygenated functions and nucleophilic substitution in the 4-position. The structure of the derivatized products was demonstrated using a simple model, cyclohex-2-en-1-one, by NMR and MS spectrometry. In contrast to data found in the literature, this derivative permitted specific mass spectra for trenbolone, sensitive signals for high mass ions and reproducible gas chromatograms to be obtained. The addition of an N(CH3)COCF3 radical to the steroid nucles allowed highly specific detection in GC-high resolution MS even following extraction from complex matrices; sensitive responses were also observed in the negative chemical ionization mode. Moreover, there are significant differences in the electron ionization mass spectra of the two stereoisomers, 17 alpha- and 17 beta-trenbolone. These preliminary results and those obtained for androsta-1,4-dien-3-one and pregna-4,6-dien-3-one indicate useful advances for the determination of steroids and potential applications for metabolism studies on such compounds. | Bellucci G, Chiappe C, Pucci L, Gervasi PG (1996)
The mechanism of oxidation of allylic alcohols to alpha,beta-unsaturated ketones by cytochrome P450.
Chemical research in toxicology 9, 871-874 [PubMed:8828923]
[show Abstract]
The oxidation of cyclohex-2-en-1-ol, a simple model substrate for allylic alcohols, is catalyzed by several P450 isoenzymes and leads exclusively to cyclohex-2-en-1-one. No double bond epoxidation or C(4) hydroxylation have been observed. The large primary kinetic isotope effect measured using [2H]-1-cyclohex-2-en-1-ol is consistent with an at least partially rate limiting breaking of the C(1)-H bond. The mass spectrometric analysis of cyclohex-2-en-1-one obtained from [18O]cyclohex-2-en-1-ol has established that a gem-diol intermediate is involved, even if a dual hydrogen abstraction pathway may contribute to the reaction. |
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