- A new and efficient synthesis of indenone
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Reaction of dichloroketone 2 with NEt3 gave indenone (4) in high yield. Catodic reaction of 2 in the presence of C/Pt electrodes afforded the rearranged product 3 in high yield besides a small amount of chlorohydroxyketone 5. Reaction of rearranged dichloroketone 3 with NEt3 provided indenone (4) as the sole product. The mechanism of these reaction was discussed.
- Zengin,Dastan,Balci
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- Allylic oxidation of cyclohexene and indene by cis-[Ru(IV)(bpy)2 (py)(O)]2+
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The kinetics of oxidation of cyclohexene, cyclohexen-1-ol, and indene by cis-[Ru(IV)(bpy)2(py)(O)]2+ (bpy = 2,2'-bipyridine and py = pyridine) have been studied in CH3CN. The reactions are first-order in both Ru(IV)=O2+ and substrate in an initial, rapid stage in which Ru(IV) is reduced to Ru(III). The rate constants are 0.16 ± 0.01, 1.10 ± 0.02, and 5.74 ± 0.74 M-1 s-1 for cyclohexene, cyclohexen-l-ol, and indene, respectively. A k(α,α'-H4)/k(α,α'-D4) kinetic isotope effect of 21 ± 1 is observed for the oxidation of cyclohexene. At a 2:1 ratio of Ru(IV)=O2+ to olefin, the reactions of Ru(IV)=O2+ with either cyclohexene or indene give Ru(II)- NCCH32+ and the 4-electron ketone products, 2-cyclohexen-l-one and indenone, respectively, as identified by GC-MS. As the ratio of cyclohexene to Ru(IV)=O2+ is increased, cyclohexen-l-ol becomes an increasingly competitive product. The mechanisms of these reactions are highly complex. They involve two distinct stages and the formation and subsequent reactions of Ru(III)-substrate bound intermediates.
- Stultz, Laura K.,Huynh, My Hang V.,Binstead, Robert A.,Curry, Maria,Meyer, Thomas J.
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- Discovery and pharmacological characterization of a novel potent inhibitor of diacylglycerol-sensitive TRPC cation channels
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Background and Purpose The cation channel transient receptor potential canonical (TRPC) 6 has been associated with several pathologies including focal segmental glomerulosclerosis, pulmonary hypertension and ischaemia reperfusion-induced lung oedema. We set out to discover novel inhibitors of TRPC6 channels and investigate the therapeutic potential of these agents. Experimental Approach A library of potential TRPC channel inhibitors was designed and synthesized. Activity of the compounds was assessed by measuring intracellular Ca2+ levels. The lead compound SAR7334 was further characterized by whole-cell patch-clamp techniques. The effects of SAR7334 on acute hypoxic pulmonary vasoconstriction (HPV) and systemic BP were investigated. Key Results SAR7334 inhibited TRPC6, TRPC3 and TRPC7-mediated Ca2+ influx into cells with IC50s of 9.5, 282 and 226 nM, whereas TRPC4 and TRPC5-mediated Ca2+ entry was not affected. Patch-clamp experiments confirmed that the compound blocked TRPC6 currents with an IC50 of 7.9 nM. Furthermore, SAR7334 suppressed TRPC6-dependent acute HPV in isolated perfused lungs from mice. Pharmacokinetic studies of SAR7334 demonstrated that the compound was suitable for chronic oral administration. In an initial short-term study, SAR7334 did not change mean arterial pressure in spontaneously hypertensive rats (SHR). Conclusions and Implications Our results confirm the role of TRPC6 channels in hypoxic pulmonary vasoregulation and indicate that these channels are unlikely to play a major role in BP regulation in SHR. SAR7334 is a novel, highly potent and bioavailable inhibitor of TRPC6 channels that opens new opportunities for the investigation of TRPC channel function in vivo.
- Maier,Follmann,Hessler,Kleemann,Hachtel,Fuchs,Weissmann,Linz,Schmidt,L?hn,Schroeter,Wang,Rütten,Strübing
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- Cyclopentadienones via a Tandem C-Cyclopropylnitrone Cyclization-Cycloreversion Sequence
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Aldonitrones derived from spiro[2.4]hepta-4,6-diene-1-carbaldehyde and its benzo analog undergo a tandem uncatalyzed intramolecular cyclopropane–nitrone cyclization-5,6-dihydro-1,2-oxazine cycloreversion to give cyclopentadienones. Similarly, the NH-nitrone generated in situ from spiro[cyclopropane-1,1′-indene]carbaldehyde oxime leads to benzocyclopentadienone (1H-inden-1-one) by the same mechanism. DFT calculations are in favor of a concerted yet highly asynchronous pathway for the cyclizations. Control experiments with the dihydro and tetrahydro derivatives show that the spirocyclopentadiene unit is essential for the success of the reaction, invoking spiroconjugative effects for increased cyclopropane reactivity.
- Erden, Ihsan,G?rtner, Christian,Ma, Jingxiang,Cabrera, Gabriel,Markham, Kate,Azimi, Saeed,Gronert, Scott
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- A bioinspired oxoiron(iv) motif supported on a N2S2macrocyclic ligand
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A mononuclear oxoiron(iv) complex1-transbearing two equatorial sulfur ligations is synthesized and characterized as an active-site model of the elusive sulfur-ligated FeIVO intermediates in non-heme iron oxygenases. The introduction of sulfur ligands weakens the Fe-O bond and enhances the oxidative reactivity of the FeIVO unit with a diminished deuterium kinetic isotope effect, thereby providing a compelling rationale for nature's use of thecis-thiolate ligated oxoiron(iv) motif in key metabolic transformations.
- Deutscher, Jennifer,Gerschel, Philipp,Warm, Katrin,Kuhlmann, Uwe,Mebs, Stefan,Haumann, Michael,Dau, Holger,Hildebrandt, Peter,Apfel, Ulf-Peter,Ray, Kallol
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supporting information
p. 2947 - 2950
(2021/03/24)
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- Mild Darzens Annulations for the Assembly of Trifluoromethylthiolated (SCF3) Aziridine and Cyclopropane Structures
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We report mild new annulation approaches to trisubstituted trifluoromethylthiolated (SCF3) aziridines and cyclopropanes via Darzens inspired protocols. The products of these anionic annulations, rarely studied previously, possess attractive features rendering them valuable building blocks for synthesis platforms. In this study, trisubstituted acetophenone nucleophiles bearing SCF3 and bromine substituents in their α position were shown to undergo [2 + 1] annulations with vinyl ketones and tosyl-protected imines under mild reaction conditions.
- Delost, Michael D.,Njardarson, Jon T.
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supporting information
p. 6121 - 6125
(2021/08/16)
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- Liquid-phase oxidation of olefins with rare hydronium ion salt of dinuclear dioxido-vanadium(V) complexes and comparative catalytic studies with analogous copper complexes
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Homogeneous liquid-phase oxidation of a number of aromatic and aliphatic olefins was examined using dinuclear anionic vanadium dioxido complexes [(VO2)2(salLH)]? (1) and [(VO2)2(NsalLH)]? (2) and dinuclear copper complexes [(CuCl)2(salLH)]? (3) and [(CuCl)2(NsalLH)]? (4) (reaction of carbohydrazide with salicylaldehyde and 4-diethylamino salicylaldehyde afforded Schiff-base ligands [salLH4] and [NsalLH4], respectively). Anionic vanadium and copper complexes 1, 2, 3, and 4 were isolated in the form of their hydronium ion salt, which is rare. The molecular structure of the hydronium ion salt of anionic dinuclear vanadium dioxido complex [(VO2)2(salLH)]? (1) was established through single-crystal X-ray analysis. The chemical and structural properties were studied using Fourier transform infrared (FT-IR), ultraviolet–visible (UV–Vis), 1H and 13C nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS), electron paramagnetic resonance (EPR) spectroscopy, and thermogravimetric analysis (TGA). In the presence of hydrogen peroxide, both dinuclear vanadium dioxido complexes were applied for the oxidation of a series of aromatic and aliphatic alkenes. High catalytic activity and efficiency were achieved using catalysts 1 and 2 in the oxidation of olefins. Alkenes with electron-donating groups make the oxidation processes easy. Thus, in general, aromatic olefins show better substrate conversion in comparison to the aliphatic olefins. Under optimized reaction conditions, both copper catalysts 3 and 4 fail to compete with the activity shown by their vanadium counterparts. Irrespective of olefins, metal (vanadium or copper) complexes of the ligand [salLH4] (I) show better substrate conversion(%) compared with the metal complexes of the ligand [NsalLH4] (II).
- Maurya, Abhishek,Haldar, Chanchal
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- Design, synthesis, and biological evaluation of novel sulindac derivatives as partial agonists of PPARγ with potential anti-diabetic efficacy
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Peroxisome proliferator-activated receptor gamma (PPARγ) is a valuable drug target for diabetic treatment and ligands of PPARγ have shown potent anti-diabetic efficacy. However, to overcome the severe side effects of current PPARγ-targeted drugs, novel PPARγ ligands need to be developed. Sulindac, an identified ligand of PPARγ, is widely used in clinic as a non-steroidal anti-inflammatory drug. To explore its potential application for diabetes, we designed and synthesized a series of sulindac derivatives to investigate their structure-activity relationship as PPARγ ligand and potential anti-diabetic effect. We found that meta-substitution in sulindac's benzylidene moiety was beneficial to PPARγ binding and transactivation. Z rather than E configuration of the benzylidene double bond endowed derivatives with the selectivity of PPARγ activation. The indene fluorine is essential for binding and regulating PPARγ. Compared with rosiglitazone, compound 6b with benzyloxyl meta-substitution and Z benzylidene double bond weakly induced adipogenesis and PPARγ-targeted gene expression. However, 6b potently improved glucose tolerance in a diabetic mice model. Unlike rosiglitazone, 6b was devoid of apparent toxicity to osteoblastic formation. Thus, we provided some useful guidelines for PPARγ-based optimization of sulindac and an anti-diabetic lead compound with less side effects.
- Huang, Fengyu,Zeng, Zhiping,Zhang, Weidong,Yan, Zhiqiang,Chen, Jiayun,Yu, Liangfa,Yang, Qian,Li, Yihuan,Yu, Hongyu,Chen, Junjie,Wu, Caisheng,Zhang, Xiao-kun,Su, Ying,Zhou, Hu
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- Modification of MnFe2O4 surface by Mo (VI) pyridylimine complex as an efficient nanocatalyst for (ep)oxidation of alkenes and sulfides
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In this current paper, we report a new type of heterogeneous molybdenum (+6) complex, prepared by covalent grafting of cis-dioxo?molybdenum (VI) pyridylimine complex on the surface of MnFe2O4 nanoparticles (NP) and characterized using various physicochemical techniques. The recyclable prepared nanocatalyst was tested for sulfoxidation of sulfides and epoxidation of alkenes under solvent-free condition. The catalyst exhibited high turnover frequency for the oxidization of cyclooctene and cyclohexene (10,850 h?1) and thioanisole and dimethyl sulfide (41,250 h?1). The synthesized catalyst was found highly efficient, retrievable and eco-friendly catalyst for the (ep)oxidation of alkenes and sulfides in excellent yields in a short time. Furthermore, the synthesized nanocatalyst can be reused for four runs without apparent loss of its catalytic activity in the oxidation reaction.
- Bouzari, Narges,Bezaatpour, Abolfazl,Babaei, Behnam,Amiri, Mandana,Boukherroub, Rabah,Szunerits, Sabine
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- Anchoring of a terpyridine-based Mo(VI) complex on manganese ferrite as a recoverable catalyst for epoxidation of olefins under solvent-free conditions
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A magnetically separable heterogeneous nanocatalyst was obtained by anchoring a terpyridine-based Mo(VI) complex on modified MnFe2O4 nanoparticles and characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and diffuse reflectance spectroscopies (DRS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analysis. The catalytic activity of the supported molybdenum based catalyst was evaluated in the selective epoxidation of various olefins (cyclooctene, limonene, 1-dodecane, 1-heptene, styrene, 1-indene, α-pinene, cyclohexene) with tert-butyl hydroperoxide (TBHP) as an oxidant under solvent-free conditions. This nanocatalyst was easily separated by using an external magnetic field and reused consecutively at least five times with no significant loss in selectivity and catalytic activity. The short reaction time, simple preparation, high conversion, good physicochemical stability and magnetic recycling of the catalysts are beneficial.
- Fadaei Sarabi, Mahsa,Bezaatpour, Abolfazl,Mahmoudi, Ali
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p. 1597 - 1612
(2021/03/29)
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- Stoichiometric Formation of an Oxoiron(IV) Complex by a Soluble Methane Monooxygenase Type Activation of O2 at an Iron(II)-Cyclam Center
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In soluble methane monooxygenase enzymes (sMMO), dioxygen (O2) is activated at a diiron(II) center to form an oxodiiron(IV) intermediate Q that performs the challenging oxidation of methane to methanol. An analogous mechanism of O2 activation at mono-or dinuclear iron centers is rare in the synthetic chemistry. Herein, we report a mononuclear non-heme iron(II)-cyclam complex, 1-trans, that activates O2 to form the corresponding iron(IV)-oxo complex, 2-trans, via a mechanism reminiscent of the O2 activation process in sMMO. The conversion of 1-trans to 2-trans proceeds via the intermediate formation of an iron(III)-superoxide species 3, which could be trapped and spectroscopically characterized at-50 °C. Surprisingly, 3 is a stronger oxygen atom transfer (OAT) agent than 2-trans; 3 performs OAT to 1-trans or PPh3 to yield 2-trans quantitatively. Furthermore, 2-trans oxidizes the aromatic C-H bonds of 2,6-di-tert-butylphenol, which, together with the strong OAT ability of 3, represents new domains of oxoiron(IV) and superoxoiron(III) reactivities.
- Kass, Dustin,Corona, Teresa,Warm, Katrin,Braun-Cula, Beatrice,Kuhlmann, Uwe,Bill, Eckhard,Mebs, Stefan,Swart, Marcel,Dau, Holger,Haumann, Michael,Hildebrandt, Peter,Ray, Kallol
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supporting information
p. 5924 - 5928
(2020/05/08)
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- Engineering P450LaMO stereospecificity and product selectivity for selective C-H oxidation of tetralin-like alkylbenzenes
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The P450-mediated asymmetric hydroxylation of inert C-H bonds is a chemically challenging reaction. Self-sufficient P450LaMO from the CYP116B subfamily could catalyze the transformation of 1,2,3,4-tetrahydronaphthalene to (S)-tetralol, despite its poor enantioselectivity (er 66:34) and product selectivity (the ratio of alcohol and ketone, ak, 76:24). To improve the selectivity, phenylalanine scanning and further protein engineering were performed to reshape the active pocket of P450LaMO, resulting in a mutant (T121V/Y385F/M391L) with not only improved (S)-enantioselectivity (er 98:2) but also excellent product selectivity (ak 99:1), in contrast to another mutant L97F/T121F/E282V/T283Y with complementary (R)-enantioselectivity (er 23:77). Moreover, the enantiopure (S)-alcohols formed by the P450LaMO-catalyzed oxidation of a series of alkylbenzenes are potentially important building blocks in the pharmaceutical industry. This Phe-based enantioselectivity engineering used for reshaping the active pocket of P450s could provide a guide to the protein evolution of other CYP116B members.
- Li, Ren-Jie,Li, Aitao,Zhao, Jing,Chen, Qi,Li, Ning,Yu, Hui-Lei,Xu, Jian-He
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p. 4638 - 4644
(2018/09/29)
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- Controlling the C(sp3)-C(sp2) Axial Conformation in the Enantioselective Friedel-Crafts-Type Alkylation of β-Naphthols with Inden-1-ones
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The Friedel-Crafts-type reaction between properly functionalized inden-1-ones and 2-naphthols generates a hindered single bond which displays a unique preference for an antiperiplanar conformational diastereoisomer. The steric hindrance and the presence of an enantioenriched stereogenic center control the distribution of the two diastereomeric conformers at equilibrium and increase the energy for the rotation of the C(sp3)-C(sp2) single bond.
- Di Iorio, Nicola,Filippini, Giacomo,Mazzanti, Andrea,Righi, Paolo,Bencivenni, Giorgio
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supporting information
p. 6692 - 6695
(2017/12/26)
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- HETEROCYCLIC COMPOUND AND ORGANIC LIGHT EMITTING DEVICE USING THE SAME
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The present specification provides a heterocyclic compound and an organic light-emitting element using the same. The heterocyclic compound is represented by chemical formula 1. The heterocyclic compound is used for an organic light-emitting element to reduce a driving voltage of the organic light-emitting element, improve light efficiency, and improve the lifespan characteristics of the element by thermal stability of the compound.COPYRIGHT KIPO 2017
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Paragraph 0104-0108
(2018/03/23)
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- Fe3O4 magnetic nanoparticles (MNPs) as an efficient catalyst for selective oxidation of benzylic and allylic C-H bonds to carbonyl compounds with tert-butyl hydroperoxide
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Fe3O4 magnetic nanoparticles (MNPs) were prepared by a co-precipitation method with oleic acid as a surfactant and characterized by FT-IR, TEM, DLS, XRD, VSM techniques. XRD, DLS and TEM analysis of this catalyst clearly showed the formation of cubic structure Fe3O4 MNPs, with a mean size of 16 nm. Moreover, a magnetization measurement revealed that the Fe3O4 MNPs had superparamagnetic behaviour and the saturation magnetization of the catalyst was 54.6 emu g-1. The Fe3O4 MNPs in combination with tert-butyl hydroperoxide catalyzed the oxidation of various benzylic and allylic C-H bonds to the corresponding carbonyl compounds in excellent yields. These oxidation reactions were effectively and economically performed under mild conditions, and therefore the dual challenge of cost effectiveness and benign nature of the processes was met.
- Zarghani, Monireh,Akhlaghinia, Batool
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p. 38592 - 38601
(2016/05/24)
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- Aza-Morita-Baylis-Hillman reactions catalyzed by a cyclopropenylidene
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Catalysis using a bis(dialkylamino)cyclopropenylidene (BAC) has been developed, which relies on a formal umpolung activation of Michael acceptor pro-nucleophiles. Various aza-Morita-Baylis-Hillman reactions between aromatic, heteroaromatic, or aliphatic imines and acyclic or cyclic α,β-unsaturated ketones and carboxylic acid derivatives have been catalyzed by a BAC under mild conditions. Functionalities such as unprotected amino and hydroxy groups have been tolerated. The catalyst loading was decreased to 1 mol% without loss of activity. The BAC catalyst was shown to be substantially more active than a cyclic (alkyl)(amino) carbene (CAAC), N-heterocyclic carbenes (NHCs), and P- or N-centered Lewis bases.
- Lu, Xun,Schneider, Uwe
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supporting information
p. 12980 - 12983
(2016/11/09)
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- Rapid Access to Orthogonally Functionalized Naphthalenes: Application to the Total Synthesis of the Anticancer Agent Chartarin
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We report the synthesis of orthogonally functionalized naphthalenes from simple, commercially available indanones in four steps. The developed method proceeds through a two-step process that features a thermally induced fragmentation of a cyclopropane indanone with simultaneous 1,2-chloride shift. Migration of the chloride substituent occurs in a regioselective manner to preferentially afford the para-chloronaphthol substitution pattern. The obtained naphthols are versatile building blocks that can be selectively modified and used for the efficient construction of biologically active molecules. This has enabled the total synthesis of the potent anticancer natural product chartarin through a highly convergent retrosynthetic bond disconnection.
- Unzner, Teresa A.,Grossmann, Adriana S.,Magauer, Thomas
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supporting information
p. 9763 - 9767
(2016/08/10)
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- Synthesis of benzo[c]fluorenone through a one-pot cascade reaction using inden-1-one derivatives
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A novel one-pot thermal cycloaddition of two indenones followed by a decarbonylation and dehydrogenation cascade afforded benzo[c]fluorenones regioselectively. Various substituted indenone derivatives were converted into their corresponding benzo[c]fluorenones in good to excellent yields.
- Zheng, Shuyan,Tan, Hongsheng,Zhang, Xiaoguang,Yu, Chunhui,Shen, Zhengwu
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supporting information
p. 975 - 978
(2015/02/02)
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- A scalable procedure for light-induced benzylic brominations in continuous flow
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A continuous-flow protocol for the bromination of benzylic compounds with N-bromosuccinimide (NBS) is presented. The radical reactions were activated with a readily available household compact fluorescent lamp (CFL) using a simple flow reactor design based on transparent fluorinated ethylene polymer (FEP) tubing. All of the reactions were carried out using acetonitrile as the solvent, thus avoiding hazardous chlorinated solvents such as CCl4. For each substrate, only 1.05 equiv of NBS was necessary to fully transform the benzylic starting material into the corresponding bromide. The general character of the procedure was demonstrated by brominating a diverse set of 19 substrates containing different functional groups. Good to excellent isolated yields were obtained in all cases. The novel flow protocol can be readily scaled to multigram quantities by operating the reactor for longer time periods (throughput 30 mmol h-1), which is not easily possible in batch photochemical reactors. The bromination protocol can also be performed with equal efficiency in a larger flow reactor utilizing a more powerful lamp. For the bromination of phenylacetone as a model, a productivity of 180 mmol h -1 for the desired bromide was achieved.
- Cantillo, David,De Frutos, Oscar,Rincon, Juan A.,Mateos, Carlos,Oliver Kappe
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supporting information
p. 223 - 229
(2014/01/17)
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- Synthesis of benzo[c]fluorenone through a one-pot cascade reaction using inden-1-one derivatives
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A novel one-pot thermal cycloaddition of two indenones followed by a decarbonylation and dehydrogenation cascade afforded benzo[c]fluorenones regioselectively. Various substituted indenone derivatives were converted into their corresponding benzo[c]fluorenones in good to excellent yields.
- Zheng, Shuyan,Tan, Hongsheng,Zhang, Xiaoguang,Yu, Chunhui,Shen, Zhengwu
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supporting information
p. 975 - 978
(2014/02/14)
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- 2,6-Dicarboxypyridinium fluorochromate-promoted oxidation of alkyl-arenes into carbonyl compounds under nonaqueous and aprotic conditions
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Benzylic C-H oxidation of a wide variety of alkyl- and cycloalkyl arenes employing 2,6-dicarboxypyridinium fluorochromate under mild reaction conditions is described. The corresponding carbonyl compounds are obtained in good to excellent yields. Taylor & Francis Group, LLC.
- Sarrafi, Yaghoub,Tajbakhsh, Mahmood,Hosseinzadeh, Rahman,Sadatshahabi, Marzieh,Alimohammadi, Kamal
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experimental part
p. 678 - 685
(2011/12/21)
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- The effect of encapsulated Zn-POM on the catalytic activity of MIL-101 in the oxidation of alkenes with hydrogen peroxide
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Zinc monosubstituted Keggin heteropolyanion [PZnMo2W 9O39]5- was electrostatically bound to nanocages of MIL-101 polymer matrix. The Zn-POM@MIL-101 catalyst was characterized by XRD, N2 adsorption, atomic absorption (AAS), and FT-IR spectroscopic methods. The catalytic activity of the new composite material, Zn-POM@MIL-101, was assessed in the oxidation of alkenes using aqueous hydrogen peroxide as oxidant. Zn-POM@MIL-101/H2O2 catalytic system demonstrated good catalytic activity in the oxidation reactions. Zn-POM@MIL-101 was reusable for three catalytic cycles. While the MIL-101 matrix is an active catalyst in these oxidation reactions, the presence of Zn-POM significantly changed the selectivity and reaction times. Copyright
- Saedi, Zahra,Tangestaninejad, Shaharm,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 463 - 473
(2012/05/20)
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- [PZnMo2W9O39]5- immobilized on ionic liquid-modified silica as a heterogeneous catalyst for epoxidation of olefins with hydrogen peroxide
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The epoxidation of alkenes with hydrogen peroxide catalyzed by [PZnMo 2W9O39]5-, ZnPOM, supported on ionic liquid-modified silica, Im-SiO2, is reported. The immobilized catalyst, [ZnPOM@Im-SiO2] was characterized by elemental analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR and UV-Vis spectroscopic methods. This new synthesized hybrid catalyst was applied for efficient epoxidation of various olefins with aqueous H2O2 in acetonitrile under reflux conditions. This solid catalyst can be easily recovered by simple filtration and reused several times without significant loss of its catalytic activity.
- Hajian, Robabeh,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Khosropour, Ahmad Reza
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p. 975 - 979
(2013/02/22)
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- Synthesis of optically pure 1-amino-3-aryl indanes exemplified by (+)-indatraline
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A versatile procedure for the synthesis of optically pure 1-amino-3-aryl indanes is presented, exemplified by the synthesis of the triple uptake inhibitor (+)-indatraline (1). Georg Thieme Verlag Stuttgart · New York.
- N?rager, Niels Gr?n,Lorentz-Petersen, Linda Luise Reeh,Lyngs?, Lars Ole,Kehler, Jan,Juhl, Karsten
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supporting information; experimental part
p. 1753 - 1755
(2011/09/16)
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- Synthesis of cyclic enones via direct palladium-catalyzed aerobic dehydrogenation of ketones
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α,β-Unsaturated carbonyl compounds are versatile intermediates in the synthesis of pharmaceuticals and biologically active compounds. Here, we report the discovery and application of Pd(DMSO)2(TFA)2 as a catalyst for direct dehydrogenation of cyclohexanones and other cyclic ketones to the corresponding enones, using O2 as the oxidant. The substrate scope includes heterocyclic ketones and several natural-product precursors.
- Diao, Tianning,Stahl, Shannon S.
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supporting information; experimental part
p. 14566 - 14569
(2011/10/17)
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- Synthesis and characterization of supported heteropolymolybdate nanoparticles between silicate layers of Bentonite with enhanced catalytic activity for epoxidation of alkenes
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A new heterogeneous catalyst (PVMo/Bentonite) consisting of vanadium substituted heteropolymolybdate with Keggin-type structure Na 5[PV2Mo10O40]·14H 2O (PVMo) supported between silicate layers of bentonite has been synthesized by impregnation method and characterized using X-ray diffraction, Fourier-transformed infrared spectroscopy, scanning electron microscopy, UV-vis diffuse reflectance spectroscopy, transmission electron microscopy and elemental analysis. X-ray diffraction and scanning electron microscopy analysis indicated that PVMo was finely dispersed into layers of bentonite as support. The PVMo/Bentonite used as an efficient heterogeneous catalyst for epoxidation of alkenes. Various cyclic and linear alkenes were oxidized into the corresponding epoxides in high yields and selectivity with 30% aqueous H2O 2. The catalyst was reused several times, without observable loss of activity and selectivity. The obtained results showed that the catalytic activity of the PVMo/Bentonite was higher than that of pure heteropolyanion (PVMo).
- Salavati, Hossein,Rasouli, Nahid
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scheme or table
p. 1853 - 1859
(2011/11/05)
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- Olefin epoxidation with tert-BuOOH catalyzed by vanadium polyoxometalate immobilized on ionic liquid-modified MCM-41
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Preparation and characterization of vanadium-containing polyphosphomolybdates supported on ionic liquid-modified MCM-41, MCM-41-Im, are reported. The catalyst, [PVMo@MCM- 41-Im], was characterized by elemental analysis, X-ray diffraction, scanning electron microscopy and also FT-IR, and UV-Vis spectroscopic methods. This heterogeneous catalytic system was applied for efficient epoxidation of various olefins in the presence of tert-BuOOH in 1,2-dichloroethane under reflux. The catalyst can be reused several times without apparent loss of its catalytic performance.
- Hajian, Robabeh,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Khosropour, Ahmad Reza
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scheme or table
p. 4134 - 4144
(2012/03/26)
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- Zirconia-supported Keggin phosphomolybdovanadate nanocomposite: A heterogeneous and reusable catalyst for alkene epoxidation under thermal and ultrasonic irradiation conditions
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Keggin phosphomolybdovanadate, PVMo, was supported on a zirconia matrix by the wet impregnation method. The phase and chemical structure, optical absorption, surface physicochemical properties and morphology of PVMo-ZrO 2 composite were studied by X-ray diffraction (XRD) technique, FT-IR and diffuse reflectance UV-vis spectroscopic (DR UV-vis) methods, and scanning electron microscopy (SEM), which indicated that the primary Keggin structure has remained intact after formation of the composite. Moreover, the obtained nanocomposite was used as an efficient catalyst of olefins under reflux and ultrasonic irradiation conditions. The catalyst was reused several times, without observable loss of activity and selectivity. Indeed, the catalytic activity of the PVMo-ZrO2 was compared with pure Keggin phosphomolybdovanadate.
- Salavati, Hossein,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 588 - 596
(2012/05/20)
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- An unprecedented method for the generation of tert -butylperoxy radical using DIB/TBHP protocol: Solvent effect and application on allylic oxidation
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Figure presented Tert-Butylperoxy radical was generated with PhI(OAc) 2 and tBuOOH. Ester solvent was found to be critical and the protocol was applied in the allylic oxidation of various olefinic substrates, which gave the corresponding α,β-unsaturated enones in good yield and regioselectivity.
- Zhao, Yi,Yeung, Ying-Yeung
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supporting information; experimental part
p. 2128 - 2131
(2010/08/05)
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- Photolysis of 1,2-naphthoquinone in oxygen-doped argon matrix at low temperature
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Photolysis of 1,2-naphthoquinone (1) in argon matrix either with or without oxygen at 10K was investigated by IR spectroscopy in combination with DFT calculations. The results indicate that 1 gave bis(ketene) 2 as a main product along with a small amount
- Itoh, Takayoshi,Tatsugi, Jiro,Tomioka, Hideo
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scheme or table
p. 737 - 742
(2009/12/08)
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- Benzylic carbon oxidation by an in situ formed o-iodoxybenzoic acid (IBX) derivative
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Benzylic C-H bonds are selectively oxidized to the corresponding carbonyl functionalities using catalytic quantities of 2-iodobenzoic acid (2IBAcid) and Oxone. The reported procedure tolerates different functional groups and operates under mild conditions. A radical mechanism is proposed for the transformation and evidence supporting the proposed mechanism is also presented. Georg Thieme Verlag Stuttgart.
- Ojha, Lawanya R.,Kudugunti, Shashi,Maddukuri, Padma P.,Kommareddy, Amitha,Gunna, Meena R.,Dokuparthi, Praveen,Gottam, Hima B.,Botha, Kiran K.,Parapati, Divya R.,Vinod, Thottumkara K.
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scheme or table
p. 117 - 121
(2009/05/30)
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- NOVEL INDANE COMPOUNDS
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The invention provides novel indane compounds which are useful in the treatment of affective disorders, pain disorders, attention deficit hyperactivity disorder (ADHD), cognitive disorders, substance abuse, smoking cessation and stress urinary incontinence.
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Page/Page column 13
(2008/06/13)
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- Syntheses and pyrolyses of benzofuran analogues of α-oxo-o- quinodimethane. A study on vinylcarbene-cyclopropene rearrangement
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(Chemical Equation Presented) Flash vacuum pyrolyses (FVP) of benzoic 3-methyl-2-benzofurancarboxylic anhydride (12) and benzoic 2-methyl-3- benzofurancarboxylic anhydride (13) at 550°C and ca. 10-2 torr both give methylenebenzocyclobutenone (21) as the major product and indenone (22) as the minor one. A mechanism involving generation of α-oxo-o- quinodimethane 11 as the primary pyrolysis product from FVP of 13, followed by elimination of a CO molecule to give carbene 24, which undergoes a vinylcarbene-cyclopropene rearrangement and a ring contraction of the resulting carbene 23, is proposed to account for the observed results. The proposed mechanism is further supported by a deuterium-labeling study on FVP of (2-benzofuryl)methyl-α,α-d2 benzoate (28-d2).
- Tseng, Pen-Wen,Yeh, Su-Wen,Chou, Chin-Hsing
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p. 3481 - 3485
(2008/09/21)
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- Organic photochemical rearrangements of triplets and zwitterions; mechanistic and exploratory organic photochemistry
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There has been some controversy about the mechanisms of reactions of enones and dienones. The question has been whether a zwitterion or diradical is involved as the intermediate. In the case of ground state species it has not been recognized that zwitterions may have diradical character. In triplet reactions there is the question of whether the rearrangements take place at the initial T1 stage or subsequently as S0 ground state zwitterions or diradicals. We now have some new rearrangements bearing on these questions. In some cases it is the triplet which rearranges, while in others it is the SO zwitterion. The zwitterion vs. diradical nature of the S0 species has been assessed by both experimental as well as theoretical means. Similarly, both experiment and computational theory have been used to determine at what stage the triplet rearrangements occur and to determine the characteristics of the rearranging species. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Zimmerman, Howard E.,Suryanarayan, Vijay
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p. 4091 - 4102
(2008/02/13)
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- Tetrafluoro-IBA and-IBX: Hypervalent iodine reagents
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Fluorine makes the difference: FIBX (see structure), the tetrafluoro derivative of the hypervalent iodine reagent, is more soluble and has higher reactivity than its nonfluorinated counterpart. An efficient synthesis of FIBX and initial reactions are presented. Some of these reactions can be conducted in standard organic solvents. Owing to the increased reactivity, new transformations and catalytic reactions may be possible. (Chemical Equation Presented).
- Richardson, Robert D.,Zayed, Jameel M.,Altermann, Sabine,Smith, Daniel,Wirth, Thomas
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p. 6529 - 6532
(2008/09/16)
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- Stereochemistry of the tetrabutylammonium cyanide-catalyzed cyanosylilation of cyclic α,β-epoxyketones - Dependence of the diastereoselectivity on the ring size
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The diastereoselective Bu4NCN-catalyzed addition of TMSCN to cyclic α,β-epoxyketones has been considered. Good diastereoselectivities were found, depending on the ring size of the starting material. Computational studies account for the observed diastereoselectivities. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Aljarilla, Ana,Cordoba, Ruben,Csaky, Aurelio G.,Fernandez, Israel,Ortiz, Fernando Lopez,Plumet, Joaquin,Gomez, Gloria Ruiz
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p. 3969 - 3976
(2007/10/03)
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- Oxidation of C-H bonds by [(bpy)2(py)RuIVO] 2+ occurs by hydrogen atom abstraction
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Anaerobic oxidations of 9,10-dihydroanthracene (DHA), xanthene, and fluorene by [(bpy)2(py)RuIVO]2+ in acetonitrile solution give mixtures of products including oxygenated and non-oxygenated compounds. The products include those formed by organic radical dimerization, such as 9,9′-bixanthene, as well as by oxygen-atom transfer (e.g., xanthone). The kinetics of these reactions have been measured. The kinetic isotope effect for oxidation of DHA vs DHA-d4 gives k H/kD ≥ 35 ± 1. The data indicate a mechanism of initial hydrogen-atom abstraction forming radicals that dimerize, disproportionate and are trapped by the oxidant. This mechanism also appears to apply to the oxidations of toluene, ethylbenzene, cumene, indene, and cyclohexene. The rate constants for H-atom abstraction from these substrates correlate well with the strength of the C-H bond that is cleaved. Rate constants for abstraction from DHA and toluene also correlate with those for oxygen radicals and other oxidants. The rate constant for H-atom transfer from toluene to [(bpy)2(py)RuIVO]2+ appears to be close to that predicted by the Marcus cross relation, using a tentative rate constant for hydrogen atom self-exchange between [(bpy)2(py)Ru IIIOH]2+ and [(bpy)2(py)RuIVO] 2+.
- Bryant, Jasmine R.,Mayer, James M.
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p. 10351 - 10361
(2007/10/03)
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- Synthesis of enantiopure angularly condensed [2.2]paracyclophanes containing five-membered rings
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Optically active angularly condensed [2.2]paracyclophanes containing five-membered rings have been synthesized by a two-step approach based on the Diels-Alder cycloaddition of (S)-(+)-4-vinyl[2.2]paracyclophane. Structural analysis by NMR spectroscopy is presented. These helicenophanes containing a cyclopentane ring show extraordinarily high specific rotations. This phenomenon has been discussed in terms of structural modifications caused by the replacement of the benzene unit with a cyclopentane ring.
- Minuti, Lucio,Taticchi, Aldo,Marrocchi, Assunta,Lanari, Daniela,Broggi, Alessandra,Gacs-Baitz, Eszter
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p. 481 - 487
(2007/10/03)
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- New polycyclic indanylimidazoles with alpha2 adrenergic activity
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A compound of formula I 1wherein R1 to R3, —A—, m and t are as defined in claim 1, or a pharmaceutically acceptable salt or ester thereof, useful as an alpha2 adrenergic agent.
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- Oxidation of silyl enol ethers by using IBX and IBX·N-oxide complexes: A mild and selective reaction for the synthesis of enones
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α,β-Unsaturated carbonyl compounds can be prepared by the oxidation of trimethylsilyl enol ethers with IBX (1) or IBX·MPO (2). A diverse set of carbonyl compounds can be dehydrogenated with ease by using this method. Trimethylsilyl enol ethers such as 4, which are formed in situ by the addition of an organometallic species to an enone, can be dehydrogenated with 1 or 2 to give a functionalized enone (e. g. 3 → 5). IBX = iodoxybenzoic acid; MPO = 4-methoxypyridine-N-oxide.
- Nicolaou,Gray, David L. F.,Montagnon, Tamsyn,Harrison, Scott T.
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p. 996 - 1000
(2007/10/03)
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- HIO3 and I2O5: Mild and selective alternative reagents to IBX for the dehydrogenation of aldehydes and ketones
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Economic and convenient: Iodic acid (1) and iodine pentoxide (2) form complexes 3 and 4, respectively, with DMSO when heated at 80°C for 1 h. The complexes are efficient agents for the dehydrogenation of ketones and aldehydes at 45-65°C. X-ray crystallographic analysis (see picture) shows that the iodine pentoxide. DMSO complex 4 self-assembles into a remarkable helix in the solid state.
- Nicolaou,Montagnon, Tamsyn,Baran, Phil S.
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p. 1386 - 1389
(2007/10/03)
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- Role of phenoxy radicals in PCDD/F formation
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In this work, the role of phenoxy radicals in polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) formation was investigated by studying the slow oxidation of 2-chlorophenol (2-CP) and 2-chloroanisole (2-CA) at a gas-phase concentration of 4 ppm (~2.1 × 104 μg/m3) over a temperature range of 400-800°C. Residence times were maintained at 2.0 ± 0.10 s. PCDD/F reaction products were dibenzofuran, dibenzo-p-dioxin, 4-chlorodibenzofuran, 1-chlorodibenzo-p-dioxin, 4,6-dichlorodibenzofuran, and 1,6-dichlorodibenzo-p-dioxin (1,6-DCDD). Major products observed in these experiments were 2,6-dichlorophenol, 3-phenyl-2-propenal, 1-indanone, 1,3-isobenzofurandione, and 3-phenyl-2-propenoyl chloride. The 2-CP and 2-CA experiments, along with the variable concentration 2-CA experiments, showed that the concentration of radicals present in the oxidation system has a significant effect on the PCDD/F product distribution and ultimately the PCDD/PCDF ratio. Also, the observation of dichlorinated phenoxy phenol and dichlorinated dihydroxybiphenyl, the proposed intermediate species in the radical-radical mechanism, suggests that radical-radical mechanism dominates gas-phase PCDD/F formation. This information will be helpful in constructing a detailed kinetic mechanism of PCDD/F formation/destruction in combustor postcombustion zone.
- Sidhu, Sukh,Edwards, Phil
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p. 531 - 541
(2007/10/03)
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- Efficient enzymatic kinetic resolution of 4-hydroxytetralone and 3-hydroxyindanone
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Both enantiomers of 4-acetoxy- and 4-hydroxytetralone have been obtained with high enantiomeric purity by kinetic resolution using enzymes. 3-Hydroxyindanone was successfully resolved using enzymatic transesterification. The absolute configuration of the products were established by literature precedence.
- Joly,Nair, Mangalam S.
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p. 2283 - 2287
(2007/10/03)
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- Enantioselective epoxidation with chiral MnIII(salen) catalysts: Kinetic resolution of aryl-substituted allylic alcohols
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A set of aryl-substituted allylic alcohols rac-2 has been epoxidized by chiral Mn(salen*) complexes 1 as the catalyst and iodosyl benzene (PhIO) as the oxygen source. Whereas one enantiomer of the allylic alcohol 2 is preferentially epoxidized to give the threoor cis-epoxy alcohol 3 (up to 80% ee) as the main product (dr up to >95:5), the other enantiomer of 2 is enriched (up to 53% ee). In the case of 1,1-dimethyl-1,2-dihydronaphthalen-2-ol (2c), the CH oxidation to the enone 4c proceeds enantioselectively and competes with the epoxidation. The absolute configurations of the allylic alcohols 2 and their epoxides 3 have been determined by chemical correlation or CD spectroscopy. The observed diastereo- and enantioselectivities in the epoxidation reactions are rationalized in terms of a beneficial interplay between the hydroxy-directing effect and the attack along the Katsuki trajectory.
- Adam,Humpf,Roschmann,Saha-Moeller
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p. 5796 - 5800
(2007/10/03)
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- Facile synthesis of indenones from indanones: A new procedure
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A two-step procedure for the conversion of indanones to indenones is described.
- Hauser,Zhou,Sun
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- A highly chemoselective oxidation of alcohols to carbonyl products with iodosobenzene diacetate mediated by chromium(III)(salen) complexes: Synthetic and mechanistic aspects
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The catalytic oxidation of the allylic alcohols 1d-n with iodosobenzene diacetate, mediated by the [CrIII(salen)]X complex, affords the respective enones in excellent chemoselectivity for Cl- as counterion [complex A(Cl)], while for the counterions TfO- [complex A(TfO)] and PF6- [complex A(PF6)] nearly equal amounts of enone and epoxide are observed. This counterion-dependent oxidation of allylic alcohols by CrIII(salen) complexes is rationalized in terms of Lewis acid catalysis by the complex A(Cl) and redox catalysis for A(TfO) and A(PF6).
- Adam, Waldemar,Hajra, Saumen,Herderich, Markus,Saha-M?ller, Chantu R.
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p. 2773 - 2776
(2007/10/03)
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- Chemoselective C-H oxidation of alcohols to carbonyl compounds with iodosobenzene catalyzed by (Salen)chromium complex
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Primary and secondary alcohols with benzylically and allylically activated C-H bonds are chemoselectively oxidized to the corresponding carbonyl compounds by the (salen)Cr(III) complex I as the catalyst and iodosobenzene as the oxygen source; the oxidizing species is the Cr(V) oxo complex. Allylic alcohols with fully substituted double bonds give appreciable amounts of epoxides besides the C-H oxidation products enones, while saturated alcohols are less readily oxidized.
- Adam, Waldemar,Gelalcha, Feyissa Gadissa,Saha-Moeller, Chantu R.,Stegmann, Veit R.
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p. 1915 - 1918
(2007/10/03)
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- Synthesis and DNA binding of spirocyclic model compounds related to the neocarzinostatin chromophore.
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[formula: see text] Spirocyclic model compounds which mimic the molecular architecture of one of the decomposition products of the antitumor agent NCS-chrom have been synthesized. These readily accessible molecules bind with remarkable efficiency to bulged DNA oligonucleotides, offering potential for the design of therapeutic agents.
- Xi,Jones,Qabaja,Wright,Johnson,Goldberg
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p. 1375 - 1377
(2008/02/09)
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- 3-(Trifluoromethyl)indenyl Cation: Ion Pair Return in the Formation of an Antiaromatic and Electron-Deficient Doubly Destabilized Carbocation
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The solvolysis of 3-(trifluoromethyl)-3-indenyl tosylate (15) occurs with extensive isomerization to 1-(trifluoromethyl)-3-indenyl tosylate (16), which reacts in a slower process to give the substitution product 17. Kinetic analysis of a model involving an intermediate allyl cation/tosylate ion pair 18 gave a partitioning ratio in CD3CO2D at 99.6°C for 18 of 7.7 for return with allylic rearrangement compared with solvent capture. Studies of 15 with specific 18O labeling show no scrambling in recovered 15 and partial scrambling in rearrangement to 16. The m value measuring the dependence of the reactivity of 15 on the solvent-ionizing parameter YOTs is 0.78, which is significantly less than that of 1.23 for the analogous 9-(trifluoromethyl)-9-fluorenyl tosylate 7. Normal salt effects in CF3CO2H predominate for 15, and the special salt effect involves no more than 14% capture of solvent-separated ion pairs by 0.551 M KO2CCF3. The substrate 15 has a net diminution in reactivity of more than 109 relative to the secondary indanyl tosylate 22, with factors of 106 and 103 attributable to antiaromaticity and to the electron-withdrawing CF3 group, respectively. The solvolysis of 15 is proposed to occur by formation of an ion pair with significant nucleophilic solvation at the relatively unhindered allylic carbon, but internal return occurs in preference to solvent or salt capture. Solvolysis of the rearranged tosylate 16 occurs with a strong rate retardation by the γ-CF3 group, a large extent of internal return, and with a normal salt effect.
- Allen, Annette D.,Fujio, Mizue,Mohammed, Nageib,Tidwell, Thomas T.,Tsuji, Yutaka
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p. 246 - 252
(2007/10/03)
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- Study of the pyrolytic chemistry of isobenzofurylmethyl benzoates
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Pyrolysis of (1-isobenzofuryl)methyl benzoate (9a), produced in situ from flash vacuum pyrolysis of (7-oxa-1-benzonorbornenyl)methyl benzoate (10a), gave methylenebenzocyclobutenone (4), 2-ethynylbenzaldehyde (5) and benzocyclopentadienone (6). The deuterium-labeled study indicated that the mechanism for the formation of these products involved the double migrations of benzoate group in 9a. Pyrolysis of (3-methyl-1-isobenzofuryl)methyl benzoate (9c) gave 1,3-dimethylene-1,3-dihydroisobenzofuran (33), which is stable in benzene and hydrolyzed rapidly in chloroform to give 1,2-diacetylbenzene (35).
- Chen, Ping-Shu,Chou, Chin-Hsing
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p. 17115 - 17126
(2007/10/03)
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