- Synthesis and dopamine receptor pharmacological evaluations on ring C ortho halogenated 1-phenylbenzazepines
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A series of 1-phenylbenzazepines containing bromine or chlorine substituents at the ortho position of the appended phenyl ring (2′-monosubstituted or 2′,6′- disubstituted patterns) were synthesized and evaluated for affinity towards dopamine D1
- Alberts, Ian,Giri, Rajan,Harding, Wayne W.,Namballa, Hari K.,Sarker, Ananta
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Read Online
- Clomaalin hapten and artificial antigen as well as preparation method and application thereof
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The invention discloses clobetasine semiantigen and artificial antigen as well as a preparation method and application thereof. sum One of the clomastokinin artificial antigen is obtained by coupling the cloacalin hapten to a carrier protein. The chloropr
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Paragraph 0069-0071
(2021/09/11)
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- A new clade of styrene monooxygenases for (R)-selective epoxidation
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Styrene monooxygenases (SMOs) are excellent enzymes for the production of (S)-enantiopure epoxides, but so far, only one (R)-selective SMO has been identified with a narrow substrate spectrum. Mining the NCBI non-redundant protein sequences returned a new distinct clade of (R)-selective SMOs. Among them,SeStyA fromStreptomyces exfoliatus,AaStyA fromAmycolatopsis albispora, andPbStyA fromPseudonocardiaceaewere carefully characterized and found to convert a spectrum of styrene analogues into the corresponding (R)-epoxides with up to >99% ee. Moreover, site 46 (AaStyA numbering) was identified as a critical residue that affects the enantioselectivity of SMOs. Phenylalanine at site 46 was required for the (R)-selective SMO to endow excellent enantioselectivity. The identification of new (R)-selective SMOs would add a valuable green alternative to the synthetic tool box for the synthesis of enantiopure (R)-epoxides.
- Xiao, Hu,Dong, Shuang,Liu, Yan,Pei, Xiao-Qiong,Lin, Hui,Wu, Zhong-Liu
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p. 2195 - 2201
(2021/04/12)
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- Asymmetric azidohydroxylation of styrene derivatives mediated by a biomimetic styrene monooxygenase enzymatic cascade
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Enantioenriched azido alcohols are precursors for valuable chiral aziridines and 1,2-amino alcohols, however their chiral substituted analogues are difficult to access. We established a cascade for the asymmetric azidohydroxylation of styrene derivatives leading to chiral substituted 1,2-azido alcohols via enzymatic asymmetric epoxidation, followed by regioselective azidolysis, affording the azido alcohols with up to two contiguous stereogenic centers. A newly isolated two-component flavoprotein styrene monooxygenase StyA proved to be highly selective for epoxidation with a nicotinamide coenzyme biomimetic as a practical reductant. Coupled with azide as a nucleophile for regioselective ring opening, this chemo-enzymatic cascade produced highly enantioenriched aromatic α-azido alcohols with up to >99% conversion. A bi-enzymatic counterpart with halohydrin dehalogenase-catalyzed azidolysis afforded the alternative β-azido alcohol isomers with up to 94% diastereomeric excess. We anticipate our biocatalytic cascade to be a starting point for more practical production of these chiral compounds with two-component flavoprotein monooxygenases.
- Franssen, Maurice C. R.,Hollmann, Frank,Martínez-Montero, Lía,Paul, Caroline E.,Süss, Philipp,Schallmey, Anett,Tischler, Dirk
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p. 5077 - 5085
(2021/08/16)
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- Enantiomer Separation of Nitriles and Epoxides by Crystallization with Chiral Organic Salts: Chirality Switching Modulated by Achiral Acids
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Enantiomer separation of nitriles and epoxides by inclusion crystal formation with organic-salt type chiral hosts was achieved. The stereochemistry of the preferentially included nitrile could be switched only by changing the achiral carboxylic acid component. Crystallographic analysis of the inclusion crystals reveals that the hydrogen-bonding networks are controlled by the acidity of the phenol group of the acids, which results in chirality switching.
- Hirose, Takuji,Kodama, Koichi,Shimomura, Yuki
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p. 6552 - 6557
(2021/11/16)
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- Aerobic epoxidation of styrene over Zr-based metal-organic framework encapsulated transition metal substituted phosphomolybdic acid
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Catalytic epoxidation of styrene with molecular oxygen is regarded as an eco-friendly alternative to producing industrially important chemical of styrene oxide (STO). Recent efforts have been focused on developing highly active and stable heterogeneous catalysts with high STO selectivity for the aerobic epoxidation of styrene. Herein, a series of transition metal monosubstituted heteropolyacid compounds (TM-HPAs), such as Fe, Co, Ni or Cu-monosubstituted HPA, were encapsulated in UiO-66 frameworks (denoted as TM-HPA@UiO-66) by direct solvothermal method, and their catalytic properties were investigated for the aerobic epoxidation of styrene with aldehydes as co-reductants. Among them, Co-HPA@UiO-66 showed relatively high catalytic activity, stability and epoxidation selectivity at very mild conditions (313 K, ambient pressure), that can achieve 82 % selectivity to STO under a styrene conversion of 96 % with air as oxidant and pivalaldehyde (PIA) as co-reductant. In addition, the hybrid composite catalyst can also efficiently catalyze the aerobic epoxidation of a variety of styrene derivatives. The monosubstituted Co atoms in Co-HPA@UiO-66 are the main active sites for the aerobic epoxidation of styrene with O2/PIA, which can efficiently converting styrene to the corresponding epoxide through the activation of the in-situ generated acylperoxy radical intermediate.
- Hu, Dianwen,Song, Xiaojing,Zhang, Hao,Chang, Xinyu,Zhao, Chen,Jia, Mingjun
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- Synthesis of the β2-Agonist Tulobuterol and Its Metabolite 4-Hydroxytulobuterol
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Abstract: Alternative methods have been developed for the synthesis of theβ2-agonist tulobuterol and its metabolite4-hydroxytulobuterol with a similar activity. The proposed procedures utilizeavailable reagents, and the key stage in the synthesis is the formation ofintermediate oxirane according to the Corey–Chaykovsky reaction, followed byopening of the oxirane ring by the action of excess tert-butylamine. In the synthesis of 4-hydroxytulobuterol, thehydroxy group was protected by benzylation, and the protecting group was removedin the final stage by hydrogenation over carbon-supported palladium.
- Burdeinyi, M. L.,Glushkova, M. A.,Popkov, S. V.
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p. 390 - 394
(2020/04/27)
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- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
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supporting information
(2020/07/20)
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- Reprogramming Epoxide Hydrolase to Improve Enantioconvergence in Hydrolysis of Styrene Oxide Scaffolds
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Enantioconvergent hydrolysis by epoxide hydrolase is a promising method for the synthesis of important vicinal diols. However, the poor regioselectivity of the naturally occurring enzymes results in low enantioconvergence in the enzymatic hydrolysis of styrene oxides. Herein, modulated residue No. 263 was redesigned based on structural information and a smart variant library was constructed by site-directed modification using an “optimized amino acid alphabet” to improve the regioselectivity of epoxide hydrolase from Vigna radiata (VrEH2). The regioselectivity coefficient (r) of variant M263Q for the R-isomer of meta-substituted styrene oxides was improved 40–63-fold, and variant M263V also exhibited higher regioselectivity towards the R-isomer of para-substituted styrene oxides compared with the wild type, which resulted in improved enantioconvergence in hydrolysis of styrene oxide scaffolds. Structural insight showed the crucial role of residue No. 263 in modulating the substrate binding conformation by altering the binding surroundings. Furthermore, increased differences in the attacking distance between nucleophilic residue Asp101 and the two carbon atoms of the epoxide ring provided evidence for improved regioselectivity. Several high-value vicinal diols were readily synthesized (>88% yield, 90%–98% ee) by enantioconvergent hydrolysis using the reprogrammed variants. These findings provide a successful strategy for enhancing the enantioconvergence of native epoxide hydrolases through key single-site mutation and more powerful enzyme tools for the enantioconvergent hydrolysis of styrene oxide scaffolds into single (R)-enantiomers of chiral vicinal diols. (Figure presented.).
- Li, Fu-Long,Qiu, Yan-Yan,Zheng, Yu-Cong,Chen, Fei-Fei,Kong, Xu–Dong,Xu, Jian-He,Yu, Hui-Lei
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supporting information
p. 4699 - 4706
(2020/09/21)
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- Oxidovanadium(V) and dioxidomolybdenum(VI) Complexes of N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide: Synthesis, characterization, crystal structures and catalytic property
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N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide (H2L) was used to prepare oxidovanadium(V) complex [VOL(OEt)(MeOH)] (1) and dioxidomolybdenum(VI) complex [MoO2L(OH2)]·[MoO2L(EtOH)] (2). The complexes were characterized by IR, UV-Vis, NMR spectroscopy, and single crystal X-ray diffraction. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydroperoxide as oxidant.
- Liu, Huan-Yu,Yang, Luo-Ju,Ye, Ya-Fang,Yin, Yi-Shu,Zou, Xiao-Ling
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p. 130 - 136
(2020/03/30)
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- Synthesis, Characterization and Crystal Structures of Oxidovanadium(V) and Dioxidomolybdenum(VI) Complexes Derived from 2-bromo-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide with Catalytic Property
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Abstract: A hydrazone compound 2-bromo-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (H2L) was prepared and characterized by IR, UV-Vis and NMR spectra. Based on the hydrazone compound, a new oxidovanadium(V) and a new dioxidomolybdenum(VI) complexes, [VO(L)(OEt)(EtOH)] (I) and [MoO2(L)(OH2)] (II), were prepared and characterized by IR, UV-Vis, NMR spectra, and single crystal X-ray diffraction (CIF files nos. 1866755 (I) and 1866756 (II)). Complex I crystallizes as the monoclinic space group P21/c with unit cell dimensions a = 12.8733(12), b = 13.5088(13), c = 11.9262(11) ?, β = 91.765(2)°, V = 2073.0(3) ?3, Z = 4, R1 = 0.0524, wR2 = 0.1329, GOOF = 1.245. Complex II crystallizes as the monoclinic space group P21/c with unit cell dimensions a = 8.1140(9), b = 16.2975(19), c = 13.4318(15) ?, β = 106.456(2)°, V = 1703.4(3) ?3, Z = 4, R1 = 0.0296, wR2 = 0.0728, GOOF = 1.046. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydrogen peroxide as oxidant.
- Liu,Zou,Yang,Ye,Yang
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p. 809 - 816
(2019/11/11)
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- Highly selective and efficient olefin epoxidation with pure inorganic-ligand supported iron catalysts
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Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H2O2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH4)3[FeMo6O18(OH)6], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis.
- Zhou, Zhuohong,Dai, Guoyong,Ru, Shi,Yu, Han,Wei, Yongge
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supporting information
p. 14201 - 14205
(2019/10/02)
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- Kinetics of epoxidation by a Musa paradisiaca chloroperoxidase
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Epoxidations of indene, styrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, and naphthalene using Musa paradisiaca plant juice chloroperoxidase in the presence of H2O2 and t-butyl peroxide as oxidants have bee
- Yadav, Pratibha,Khare, Sunil K.,Sharma, Satyawati
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p. 602 - 609
(2019/05/16)
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- Peroxygenase-Catalysed Epoxidation of Styrene Derivatives in Neat Reaction Media
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Biocatalytic oxyfunctionalisation reactions are traditionally conducted in aqueous media limiting their production yield. Here we report the application of a peroxygenase in neat reaction conditions reaching product concentrations of up to 360 mM.
- Alcalde, Miguel,Arends, Isabel W. C. E.,Hollmann, Frank,Paul, Caroline E.,Rauch, Marine C. R.,Tieves, Florian
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- Arylruthenium(III) Porphyrin-Catalyzed C-H Oxidation and Epoxidation at Room Temperature and [RuV(Por)(O)(Ph)] Intermediate by Spectroscopic Analysis and Density Functional Theory Calculations
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The development of highly active and selective metal catalysts for efficient oxidation of hydrocarbons and identification of the reactive intermediates in the oxidation catalysis are long-standing challenges. In the rapid hydrocarbon oxidation catalyzed by ruthenium(IV) and -(III) porphyrins, the putative Ru(V)-oxo intermediates remain elusive. Herein we report that arylruthenium(III) porphyrins are highly active catalysts for hydrocarbon oxidation. Using catalyst [RuIII(TDCPP)(Ph)(OEt2)] (H2TDCPP = 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin), the oxidation of C-H bonds of various hydrocarbons with oxidant m-CPBA at room temperature gave alcohols/ketones in up to 99% yield within 1 h; use of [nBu4N]IO4 as a mild alternative oxidant avoided formation of lactone from cyclic ketone in C-H oxidation, and the catalytic epoxidation with up to 99% yield and high selectivity (no aldehydes as side product) was accomplished within 5 min. UV-vis, electrospray ionization-mass spectrometry, resonance Raman, electron paramagnetic resonance, and kinetic measurements and density functional theory calculations lend evidence for the formation of Ru(V)-oxo intermediate [RuV(TDCPP)(O)(Ph)].
- Shing, Ka-Pan,Cao, Bei,Liu, Yungen,Lee, Hung Kay,Li, Ming-De,Phillips, David Lee,Chang, Xiao-Yong,Che, Chi-Ming
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supporting information
p. 7032 - 7042
(2018/06/12)
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- Synthesis, Characterization, and Crystal Structures of Dioxomolybdenum(VI) Complexes Derived from Similar Tridentate Hydrazone Compounds with Catalytic Property
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Abstract: Two hydrazone compounds 2-chloro-N'-(2-hydroxy-4-methoxybenzylidene)benzohydrazide (H2L1) and N'-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide (H2L2) were prepared and characterized by IR, UV-Vis and 1H NMR spectra. Based on the hydrazone compounds, two new structurally similar dioxomolybdenum(VI) complexes, [MoO2L1(CH3OH)] (I) and [MoO2L2(CH3OH)] (II), were prepared and characterized by IR and UV-Vis spectra, and single crystal X-ray diffraction (CIF files nos. 1566491 (I) and 1566492 (II)). Complex I crystallizes as the triclinic space group (Formula presented.) with unit cell dimensions a = 8.0750(5), b = 10.5223(7), c = 10.8110(7) ?, α = 96.975(2)°, β = 97.909(2)°, γ = 104.497(2)°, V = 869.2(1) ?3, Z = 2, R1 = 0.0323, wR2 = 0.0620, GOOF = 1.089. Complex II crystallizes as the monoclinic space group P21/n with unit cell dimensions a = 11.680(1), b = 10.496(2), c = 14.879(2) ?, β = 98.862(2)°, V?= 1802.2(4) ?3, Z = 4, R1 = 0.0270, wR2 = 0.0675, GOOF = 1.111. X-ray analysis indicates that the complexes are mononuclear dioxomolybdenum(VI) species with the Mo atoms in octahedral coordination. The complexes were studied for their catalytic oxidation property on some olefins with tert-butyl hydrogen peroxide as oxidant.
- Liu,Yang,Diao,Ye,Zou
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p. 572 - 578
(2018/09/11)
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- Dearomative [2,3] sigmatropic rearrangement of ammonium ylides followed by 1,4-elimination to form α-(ortho-vinylphenyl)amino acid esters
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A base-induced dearomative [2,3] sigmatropic rearrangement of amino acid ester-derived ammonium salts followed by 1,4-elimination produced α-(ortho-vinylphenyl)amino acid esters. The reaction of azetidine-2-carboxylic acid-derived ammonium salt, (1S,2S,1′R)-3b, proceeded with a perfect N-to-C chirality transfer to afford α-(ortho-vinylphenyl)azetidine-2-carboxylic acid ester, (R)-5 (99% ee). On the other hand, the reaction of glycine-derived ammonium salt (R)-6a, which involves an efficient chirality transfer from a chiral benzylic carbon to an α-carbon of an ester carbonyl giving the optically active α-(ortho-vinylphenyl)glycine ester, (R)-8a (85% ee), was demonstrated. Although this dearomative [2,3] rearrangement followed by 1,4-elimination has limitations with regard to the structures of the substrates, our method provides unique access to substituted α-arylamino acid derivatives.
- Tayama, Eiji,Sotome, Sho
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supporting information
p. 4833 - 4839
(2018/07/15)
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- Synthesis of cyclic organic carbonates via catalytic oxidative carboxylation of olefins in flow reactors
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Methodology for direct catalytic conversion of olefins into cyclic carbonates using peroxide and carbon dioxide under relatively mild conditions is demonstrated. The protocol utilizes packed bed flow reactors in series to couple rhenium catalyzed olefin epoxidation and aluminum catalyzed epoxide carboxylation in a single sequence.
- Sathe, Ajay A.,Nambiar, Anirudh M. K.,Rioux, Robert M.
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- Potassium phosphate-catalyzed one-pot synthesis of 3-aryl-2-oxazolidinones from epoxides, amines, and atmospheric carbon dioxide
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Potassium phosphate was found to be a highly active catalyst in the three-component cycloaddition of amines, epoxides, and carbon dioxide in DMF at ambient temperature to form 3-aryl-2-oxazolidinones. Atmospheric CO2 and a broad range of amines were employed in this transformation. Aryl isocyanate and 1,2-aminoalcohol were generated in situ as key intermediates. This one-pot reaction is applicable to a variety of terminal epoxides and amines. The key advantages are high yields, simple work-up, inexpensive catalysts, and a practical ten gram-scale synthesis.
- Seo, Ue Ryung,Chung, Young Keun
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supporting information
p. 803 - 808
(2017/08/15)
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- Diastereoselective C?H Bond Amination for Disubstituted Pyrrolidines
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We report herein the improved diastereoselective synthesis of 2,5-disubstituted pyrrolidines from aliphatic azides. Experimental and theoretical studies of the C?H amination reaction mediated by the iron dipyrrinato complex (AdL)FeCl(OEt2) provided a model for diastereoinduction and allowed for systematic variation of the catalyst to enhance selectivity. Among the iron alkoxide and aryloxide catalysts evaluated, the iron phenoxide complex exhibited superior performance towards the generation of syn 2,5-disubstituted pyrrolidines with high diastereoselectivity.
- Iovan, Diana A.,Wilding, Matthew J. T.,Baek, Yunjung,Hennessy, Elisabeth T.,Betley, Theodore A.
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supporting information
p. 15599 - 15602
(2017/11/16)
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- Synthesis, crystal structures, and catalytic properties of two oxidovanadium(V) complexes with tridentate Schiff bases
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Two new oxidovanadium(V) complexes, [VO2L1] (I) and [VO2L2] (II), where L1 and L2 are the deprotonated forms of 4-methyl-2-[(2-morpholin-4-ylethylimino)methyl]phenol (HL1) and 2-[(2-isopropylaminoethylimino) methyl]-4-trifluoromethoxyphenol (HL2), respectively, have been prepared and characterized by physico chemical methods and single crystal X-ray diffraction (CIF files CCDC nos. 1443671 (I), 1443672 (II)). The V atom in each complex is coordinated by the phenolate oxygen, imino nitrogen and amino nitrogen of the Schiff base ligand, and two oxo groups, forming trigonal-bipyramidal geometry. The oxidation of olefins with the complexes as catalyst was evaluated, which indicated that both complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates by using tert-butyl hydrogen peroxide as oxidant.
- Peng
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p. 404 - 410
(2017/06/19)
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- Photocatalytic Asymmetric Epoxidation of Terminal Olefins Using Water as an Oxygen Source in the Presence of a Mononuclear Non-Heme Chiral Manganese Complex
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Photocatalytic enantioselective epoxidation of terminal olefins using a mononuclear non-heme chiral manganese catalyst, [(R,R-BQCN)MnII]2+, and water as an oxygen source yields epoxides with relatively high enantioselectivities (e.g., up to 60% enantiomeric excess). A synthetic mononuclear non-heme chiral Mn(IV)-oxo complex, [(R,R-BQCN)MnIV(O)]2+, affords similar enantioselectivities in the epoxidation of terminal olefins under stoichiometric reaction conditions. Mechanistic details of each individual step of the photoinduced catalysis, including formation of the Mn(IV)-oxo intermediate, are discussed on the basis of combined results of laser flash photolysis and other spectroscopic methods.
- Shen, Duyi,Saracini, Claudio,Lee, Yong-Min,Sun, Wei,Fukuzumi, Shunichi,Nam, Wonwoo
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supporting information
p. 15857 - 15860
(2016/12/23)
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- Catalytic Enantioselective Conversion of Epoxides to Thiiranes
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A highly efficient and enantioselective Br?nsted acid catalyzed conversion of epoxides to thiiranes has been developed. The reaction proceeds in a kinetic resolution, furnishing both epoxide and thiirane in high yields and enantiomeric purity. Heterodimer formation between the catalyst and sulfur donor affords an effective way to prevent catalyst decomposition and enables catalyst loadings as low as 0.01 mol %.
- Liao, Saihu,Leutzsch, Markus,Monaco, Mattia Riccardo,List, Benjamin
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supporting information
p. 5230 - 5233
(2016/05/19)
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- Synthesis method for compound tulobuterol
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The invention relates to a synthesis method for compound tulobuterol. The technical problems that potential safety hazards exist in an existing method, and cost is high are solved. The method includes the following steps of a, an olefination reaction, wherein 1-(2-chlorphenyl)-1-ethyl alcohol serves as an initial raw material, and in the presence of a catalyst and acid, a heating reaction is conducted to generate 2-chloro-styrene; b, a cyclization reaction, wherein 2-chloro-styrene serves as a raw material, and in the presence of alkali and an oxidizing agent, an epoxidation reaction is conducted to obtain 2-(2-chlorphenyl) ethylene oxide; c, a ring-opening reaction, wherein 2-(2-chlorphenyl) ethylene oxide serves as a raw material and reacts with tert-butylamine to obtain compound 1-(2-chlorphenyl)-2-tert-butylamino ethanol. The synthesis method can be used for preparing tulobuterol.
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Paragraph 0056; 0057
(2016/10/17)
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- An ionic liquid immobilized copper complex for catalytic epoxidation
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This article brings into focus an in situ strategy of immobilization of a copper complex onto an ionic liquid support. A practical method of olefin and terpene epoxidation by immobilizing a copper complex and 1-ethyl-3-methylimidazolium hexafluorophosphate and using H2O2 as the terminal oxidant is developed. The advantageous properties of this catalytic system redefine an exceptionally clean environment for catalytic epoxidations.
- Dileep,Rudresha
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p. 65870 - 65873
(2015/08/18)
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- Chiral electron deficient ruthenium helical coordination polymer as a catalyst for the epoxidation of substituted styrenes
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An air and moisture stable ruthenium(III) formate complex [Ru(HCO2)Cl2]n has been synthesized and examined in the epoxidation of substituted styrenes. X-ray crystallographic data of this complex were determined and showed that the formate ligand coordinates to the ruthenium centers in a μ2-η2 fashion (syn, syn). Its asymmetric unit contains one Ru(III) ion together with the half of a formate ligand and one chloride anion, which are bridged between the metal centers, forming a 1-D chain coordination polymer. This electron deficient helical coordination polymer was employed in the epoxidation of para-fluorostyrene, affording the epoxide product in 92% yield. Natural chirality of this coordination polymer is applicable in asymmetric epoxidation reactions.
- Jahromi, Bahareh Tamaddoni,Kharat, Ali Nemati,Zamanian, Sara
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p. 137 - 140
(2015/01/30)
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- Synthesis, structure, and catalytic oxidation of a molybdenum(VI) complex [MoO2(CH3OH)L]
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A new molybdenum(VI) complex, [MoO2(CH3OH)(L)] (L = N′-(4-diethylamino-2-hydroxybenzylidene)-4-hydroxybenzohydrazide), was prepared and characterized by spectroscopy methods and single crystal X-ray diffraction (CIF file CCDC no. 1038153). The crystal of the complex, C19H23MoN3O6, crystallizes in the triclinic space group P1 with unit cell dimensions a = 6.9824(9), b = 10.206(1), c = 15.302(2) ?, α = 94.399(2)°, β = 101.877(2)°, γ = 104.062(2)°, V = 1025.9(2) ?3, Z = 2, R1 = 0.0317, wR2 = 0.0796, S = 1.060. The Mo atom in the complex is in an octahedral coordination with phenolate O, imino N, enolate O atoms of the ligand L, and one oxo O in the equatorial plane, and with one methanol O and the other oxo O in the axial sites. Crystals of the complex are stabilized by hydrogen bonds. The complex was studied for its catalytic oxidation property on some olefins, with tert-butyl hydrogen peroxide as oxidant.
- Liu,Zang,Lv
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p. 451 - 455
(2015/07/01)
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- Continuous and convergent access to vicinyl amino alcohols
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Five active pharmaceutical ingredients (APIs) containing the vicinyl amino alcohol moiety were synthesized using a convergent chemical assembly system. The continuous system is composed of four flow reaction modules: biphasic oxidation, Corey-Chaykovsky epoxidation, phenol alkylation, and epoxide aminolysis. Judicious choice of reagents and module order allowed for two classes of β-amino alcohols, aryl and aryloxy, to be synthesized in good (27-69%) overall yields.
- Nobuta, Tomoya,Xiao, Guozhi,Ghislieri, Diego,Gilmore, Kerry,Seeberger, Peter H.
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supporting information
p. 15133 - 15136
(2015/10/12)
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- Vanadium(V) complexes with hydrazone and benzohydroxamate ligands: Synthesis, structures and catalytic epoxidation
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Two structurally similar vanadium(V) complexes, [VOL1L] (1) and [VOL2L] (2), where L1 is the dianionic form of N'-(3,5-dibromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide, L2 is the dianionic form of N'-(3,5-dibromo-2-hydroxybenzylidene)nicotinohydrazide, and L is benzohydroxamate, were prepared and characterized by elemental analysis, infrared spectra, and single crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/c, with unit cell dimensions a = 12.0262(7), b = 16.5629(9), c = 12.3449(8) A, β = 105.160(2)°, V = 2373.4(2) A3, Z = 4, R1 = 0.0376, wR2 = 0.0844, GOOF = 1.058; 2 crystallizes in the monoclinic space group P2 1/c, with unit cell dimensions a = 10.6439(7), b = 16.1968(9), c = 13.1108(8) A, β = 104.180(2)°, V = 2191.4(2) A3, Z = 4, R1 = 0.0521, wR2 = 0.1142, GOOF = 1.018. X-ray analysis indicates that vanadium in the complexes are coordinated by phenolate oxygen, imino nitrogen, and enolate oxygen of the hydrazone, two oxygens of the benzohydroxamate, and one oxo, generating octahedral coordination. Oxidations of olefins with the complexes as catalysts were evaluated. The complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant. 2014
- Li, An-Mei
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p. 2076 - 2085
(2014/08/18)
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- Synthesis and structures of two molybdenum(VI) complexes derived from similar benzohydrazone ligands with catalytic properties
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Two new structurally similar molybdenum(VI) complexes, [MoO 2L1(CH3OH)] (1) and [MoO2L 2(CH3OH)] (2), where L1 is the dianionic form of N′-(2-hydroxy-5-nitrobenzylidene)-2-methylbenzohydrazide and L 2 is the dianionic form of N′-(2-hydroxy-4-methoxybenzylidene)- 2-methylbenzohydrazide, were prepared and structurally characterized by elemental analysis, infrared spectra, and single-crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/c, with unit cell dimensions a = 7.941(1), b = 14.337(2), c = 15.141(2) A, β = 92.782(2)°, V = 1721.8(4) A3, Z = 4, R1 = 0.0286, wR2 = 0.0650, GOOF = 1.028. 2 crystallizes in the triclinic space group P-1, with unit cell dimensions a = 8.003(1), b = 10.608(1), c = 10.880(1) A, α = 95.745(2)°, β = 97.627(2)°, γ = 105.762(2)°, V = 872.0(2) A3, Z = 2, R1 = 0.0226, wR2 = 0.0595, GOOF = 1.116. X-ray analysis indicates that Mo in the complexes are coordinated by the phenolate oxygen, imino nitrogen, and enolate oxygen of the benzohydrazone, methanol, and two oxo groups, generating octahedral coordination. The oxidation of olefins with the complexes as catalysts was evaluated, indicating that the complexes showed excellent catalytic efficiency in oxidation of most aliphatic and aromatic substrates under mild conditions using tert-butyl hydrogen peroxide as oxidant. 2014
- Li, An-Mei
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p. 1022 - 1031
(2014/05/20)
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- N′-(3-Bromo-2-hydroxybenzylidene)isonicotinohydrazide and its oxovanadium(V) complex: Synthesis, structures, and catalytic properties
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A new hydrazone N′-(3-bromo-2-hydroxybenzylidene)isonicotinohydrazide (H2L) and its oxovanadium(V) complex, [VOLL′]·2H2O (L′ = 2-hydroxybenzohydroxamate), were prepared and structurally characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. The hydrazone coordinates to V through the phenolate oxygen, imino nitrogen, and enolate oxygen. The hydroxamate coordinates to V through the carbonyl oxygen and deprotonated hydroxyl oxygen. Vanadium in the complex is octahedral. The oxidation of olefins with the complex as catalyst was evaluated, which indicated that the complex showed catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant.
- Xiong, Yan,Li, Wen-Hui
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p. 3279 - 3287
(2015/10/20)
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- Hydroxylated sulfamides exhibiting neuroprotective action and their method of use
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Pharmaceutical compositions of the invention include hydroxylated sulfamide derivatives having a disease-modifying action in the treatment of diseases associated with excitotoxicity and accompanying oxidative stress that include epilepsy, Alzheimer's dise
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Page/Page column 18
(2014/02/15)
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- Syntheses, crystal structures, and catalysis by polymeric dioxomolybdenum(VI) complexes with similar (iso)nicotinohydrazones
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Polymeric dioxomolybdenum(VI) complexes, [MoO2L]n(L= L1= N'-(2-hydroxybenzylidene) nicotinohydrazide for 1, L=L 2= N'-(2-hydroxy-5-methoxybenzylidene)isonicotinohydrazide for 2), were prepared and characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. Complex 1 crystallizes in the orthorhombic space group P212121with a=7.6568(4), b =11.6315(7), c = 15.2211(9)A, V= 1355.59(13) A3, Z = 4, R1= 0.0181, wR2= 0.0464, and S = 1.097. Complex 2 crystallizes in the monoclinic space group P21/n with a=11.2516(6), b=11.8134(7), c= 12.4371(6) A, β = 116.2210(10)°, V=1483.02(14) A3, Z= 4, R1= 0.0399, wR2= 0.0874, and S=1.096. X-ray analysis indicates that Mo in each complex is octahedral with two oxo groups and N2O2donor set of the nicotinohydrazone or isonicotinohydrazone. The complexes are efficient catalysts for oxidation of olefins.
- Xu, Wei-Xiu,Yuan, Yong-Mei,Li, Wen-Hui
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p. 2726 - 2735
(2014/02/14)
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- Novel Ethanediamone Hepcidine Antagonists
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The present invention relates to novel hepcidin antagonists of formula (I), pharmaceutical compositions comprising them and the use thereof as medicaments, in particular for treatment of disorders in iron metabolism, such as, in particular, iron deficiency diseases and anaemias, in particular anaemias in connection with chronic inflammatory diseases (ACD: anaemia of chronic disease and AI: anaemia of inflammation).
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- NOVEL SULFAMIDES EXHIBITING NEUROPROTECTIVE ACTION AND METHODS FOR USE THEREOF
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Pharmaceutical compositions of the invention include sulfamide derivatives having a disease-modifying action in the treatment of diseases associated with excitotoxicity and accompanying oxidative stress that include epilepsy, Alzheimer's disease, and any
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Page/Page column 20
(2011/09/14)
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- Synthesis and antibacterial activities of cyclodimers of styrene oxides
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A simple synthetic procedure for preparation of 1,4-dioxanes or 1,3-dioxolanes from styrene oxides is described. Electron-donating groups on the aromatic ring of the styrene oxides were found to favour formation of 1,4-dioxanes while electron-withdrawing
- Mazimba, Ofentse,Majinda, Runner R.,Masesane, Ishmael B.
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experimental part
p. 299 - 304
(2012/05/04)
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- The Ru-catalyzed enantioselective preparation of chiral halohydrins and their application in the synthesis of (R)-clorprenaline and (S)-sotalol
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The asymmetric transfer hydrogenation of a series of halo-substituted aryl methyl ketones, including those substituted in both α-methyl and aryl rings, was studied for the preparation of chiral halohydrins. Up to 99.7% ee was obtained with 2-chloro-1-(2-chlorophenyl)ethanone as the substrate and Ru-CsDPEN as the catalyst in an HCOONa/H2O system. (R)-Clorprenaline, a drug used in the treatment of respiratory disorders, such as bronchitis and asthma, and (S)-sotalol, a class-III antiarrhythmic compound, were prepared with these chiral halohydrins.
- Lu, Chuanjun,Luo, Zonghua,Huang, Ling,Li, Xingshu
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p. 722 - 727
(2011/08/06)
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- Iron-catalyzed epoxidation of olefins using hydrogen peroxide
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A practical method of olefin epoxidation was developed by combining FeCl3·6H2O and 1-methylimidazole in acetone using H2O2 as the terminal oxidant. This system showed very good reactivity toward epoxidation of both terminal and substituted alkenes. The use of tridentate and tetradentate amine-bis(phenolate) ligands as additives was also examined. Modest improvement in selectivity was achieved if a bulky tridentate ligand was used. Generally, however, the simple catalyst system involving ferric chloride, 1-methylimidazole and dilute H2O 2 in acetone proved most successful in achieving good to excellent yields of epoxide products for a number of substrates, including aromatic and aliphatic alkenes.
- Hasan, Kamrul,Brown, Nicole,Kozak, Christopher M.
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experimental part
p. 1230 - 1237
(2011/06/27)
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- CALCILYTIC COMPOUNDS
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Novel calcilytic compounds, pharmaceutical compositions, methods of synthesis and methods of using them are provided
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Page/Page column 61-62
(2010/04/27)
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- Catalytic (asymmetric) methylene transfer to aldehydes
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[Chemical equation presented] An investigation Into the poor activity of sulfides as catalysts for sulfonium-ylide-mediated methylene transfer to aldehydes has indicated that ylide formation is the problematic catalytic cycle step. Alkylation with traditional electrophiles does not proceed with sufficient efficiency to allow the sulfide to be used catalytically. Methyl triflate rapidly alkylates cyclic thiolanes under mild conditions, allowing their use in efficient aldehyde epoxidation reactions (in conjunction with phosphazene bases) at loadings as low as 10 mol %.
- Piccinini, Alessandro,Kavanagh, Sarah A.,Connon, Paul B.,Connon, Stephen J.
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supporting information; experimental part
p. 608 - 611
(2010/05/18)
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- Asymmetric dihydroxylation of aryl olefins by sequential enantioselective epoxidation and regioselective hydrolysis with tandem biocatalysts
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Chiral aryl vicinal diols were obtained in high ee and yield by asymmetric dihydroxylation of aryl olefins with tandem biocatalysts: one contains an enantioselective styrene monooxygenase, and the other contains a regioselective epoxide hydrolase.
- Xu, Yi,Jia, Xin,Panke, Sven,Li, Zhi
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supporting information; experimental part
p. 1481 - 1483
(2009/09/06)
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- An unexpected 1,2-hydride shift in phosphoric acid-promoted cyclodimerization of styrene oxides under solvent-free conditions. A synthetic route towards 2,4-disubstituted 1,3-dioxolanes
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A 1,2-hydride shift in the phosphoric acid-promoted cyclodimerization of styrene oxide and its chloro derivatives under solvent-free conditions leading to 2,4-disubstituted 1,3-dioxolanes is described. Methoxy substituents on the aromatic ring of the styr
- Mazimba, Ofentse,Majinda, Runner R.,Masesane, Ishmael B.
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scheme or table
p. 5927 - 5929
(2010/01/11)
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- Urea derivatives are highly active catalysts for the base-mediated generation of terminal epoxides from aldehydes and trimethylsulfonium iodide
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N,N′-Diarylureas have been shown to efficiently catalyse sulfonium ylide-mediated aldehyde epoxidation reactions for the first time. These processes are of broad scope and can be coupled with a subsequent Cu(ii) ion-catalysed Meinwald rearrangement to give an efficient and convenient protocol for aldehyde homologation without intermediate purification. The Royal Society of Chemistry.
- Kavanagh, Sarah A.,Piccinini, Alessandro,Fleming, Eimear M.,Connon, Stephen J.
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supporting information; experimental part
p. 1339 - 1343
(2008/10/09)
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- Biocatalytic cleavage of alkenes with O2 and Trametes hirsuta G FCC 047
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Alkenes possessing a C=C double bond adjacent to an aromatic ring were cleaved to yield the corresponding carbonyl compounds by use of molecular oxygen as the sole oxidant and a cell-free extract of the wood-degrading fungus Trametes hirsuta FCC 047 as catalyst. The oxygen pressure required was optimized. Special adapted equipment allowed 96 reactions to be performed in parallel under controlled oxygen pressure. A broad spectrum of aryl-alkenes was successfully converted into the corresponding ketones/aldehydes with excellent chemoselectivity under a controlled oxygen atmosphere (2 bar). Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Lara, Miguel,Mutti, Francesco G.,Glueck, Silvia M.,Kroutil, Wolfgang
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scheme or table
p. 3668 - 3672
(2009/05/07)
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- Biomimetic iron-catalyzed asymmetric epoxidation of aromatic alkenes by using hydrogen peroxide
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A novel and general biomimetic non-heme Fe-catalyzed asymmetric epoxidation of aromatic alkenes by using hydrogen peroxide is reported herein. The catalyst consists of ferric chloride hexahydrate (FeCl3·OH 2O), pyridine-2,6-dicarboxylic acid (H2-(pydic)), and readily accessible chiral N-arenesulfonyl-N′-benzyl-substituted ethylenediamine ligands. The asymmetric epoxidation of styrenes with this system gave high conversions but poor enantiomeric excesses (ee), whereas larger alkenes gave high conversions and ee values. For the epoxidation of trans-stilbene (1a), the ligands (S,S)-N-(4-toluenesulfonyl)-1,2- diphenylethylenediamine ((S,S)-4a) and its N′-benzylated derivative ((S,S)-5a) gave opposite enantiomers of trans-stilbene oxide, that is, (S,S)-2a and (R,R)-2a, respectively. The enantioselectivity of alkene epoxidation is controlled by steric and electronic factors, although steric effects are more dominant. Preliminary mechanistic studies suggest the in situ formation of several chiral Fe-complexes, such as [FeCl(L*)2-(pydic)] ·HCl (L* = (S,S)-4a or (S,S)-5a in the catalyst mixture), which were identified by ESIMS. A UV/Vis study of the catalyst mixture, which consisted of FeCl3·6H2O, H2(pydic), and (S,S)-4a, suggested the formation of a new species with an absorbance peak at λ = 465 nm upon treatment with hydrogen peroxide. With the aid of two independent spin traps, we could confirm by EPR spectroscopy that the reaction proceeds via radical intermediates. Kinetic studies with deuterated styrenes showed inverse secondary kinetic isotope effects, with values of k H/kD = 0.93 for the β carbon and kH/k D=0.97 for the a carbon, which suggested an unsymmetrical transition state with stepwise O transfer. Competitive epoxidation of para-substituted styrenes revealed a linear dual-parameter Hammett plot with a slope of 1.00. Under standard conditions, epoxidation of la in the presence of ten equivalents of H218O resulted in an absence of the isotopic label in (S,S)-2a. A positive non-linear effect was observed during the epoxidation of la in the presence of (S,S)-5a and (R,R)-5a.
- Gelalcha, Feyissa Gadissa,Anilkumar, Gopinathan,Tse, Man Kin,Brueckner, Angelika,Beller, Matthias
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experimental part
p. 7687 - 7698
(2009/08/07)
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- A novel method for the synthesis of chiral epoxides from styrene derivatives using chiral acids in presence of Pseudomonas lipase G6 [PSL G6] and hydrogen peroxide
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Chiral epoxidation of styrene and its derivatives was carried out using series of chiral acids and urea hydrogen peroxide (UHP) or aqueous hydrogen peroxide (50%) in two phases under the catalytic influence of immobilized Pseudomonas lipase G6 [PSL G6] at 25-55 °C. A moderate to good yield and enantioselectivities of chiral epoxides were obtained.
- Sarma, Kuladip,Bhati, Nishi,Borthakur, Naleen,Goswami, Amrit
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p. 8735 - 8741
(2008/02/09)
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- Novel biomimetic iron-catalysts for environmentally benign epoxidations of olefins
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A new selective and easily manageable epoxidation method is presented using an inexpensive and efficient FeCl3·6H2O and imidazole derivatives as catalysts. Aqueous hydrogen peroxide as an environmentally benign oxidant is utilized. This novel Fe/imidazole system gives moderate to excellent yields toward aromatic mono-, di-, and tri-substituted olefins.
- Schr?der, Kristin,Tong, Xiaofeng,Bitterlich, Bianca,Tse, Man Kin,Gelalcha, Feyissa Gadissa,Brückner, Angelika,Beller, Matthias
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p. 6339 - 6342
(2008/02/10)
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- Enantioconvergent hydrolysis of styrene epoxides by newly discovered epoxide hydrolases in mung bean
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Two novel epoxide hydrolases were discovered in mung bean (Phaseolus radiatus L.) for the first time, either of which can catalyze enantioconvergent hydrolysis of styrene epoxides. Their regioselectivity coefficients are more than 90% for the p-nitrostyrene oxide. Furthermore, the crude mung bean powder was also shown to be a cheap and practical biocatalyst, allowing a one-step asymmetric synthesis of chiral (R)-diols from racemic epoxides, in up to >99% ee and 68.7% overall yield (after recrystallization).
- Xu, Wei,Xu, Jian-He,Pan, Jiang,Gu, Qing,Wu, Xin-Yan
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p. 1737 - 1740
(2007/10/03)
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- METHOD FOR PRODUCING SINGLE ENANTIOMER EPOXIDES BY THE ADH REDUCTION OF ALPHA-LEAVING GROUP-SUBSTITUTED KETONES AND CYCLISATION
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The invention relates to a method for producing single enantiomer epoxides by reducing a-leaving group-substituted ketones with (R)- or (S)-selective alcohol dehydrogenases in the presence of a cofactor and optionally a suitable system for regenerating the oxidised cofactor, to produce the corresponding single enantiomer alcohols and subsequently, by means of cyclisation induced by a base, the corresponding single enantiomer epoxides (EQUATION 1 ), wherein in EQUATION 1 LG may stand for F, CI, Br, I, OSO2Ar, OSO2CH3, OSO2R or OP(O)OR2, and R1, R2 and R3, independently of one another, stand for hydrogen, a branched or unbranched, optionally substituted C1-C2O- alkyl radical, symbolise an optionally randomly substituted C3-C10- cycloalkyl or alkenyl radical or a randomly substituted carbo- or heterocyclic aryl radical, or corresponds to a radical from the group CO2R, CONR2, COSR, CS2R, C(NH)NR2, CN, CHaI3, ArO, ArS, RO, RS, CHO, OH, NHR, NR2, Cl, F, Br, I or SiR3.
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Page/Page column 8
(2008/06/13)
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- Bacterial monooxygenase mediated preparation of nonracemic chiral oxiranes: Study of the effects of substituent nature and position
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Monooxygenation of styrene derivatives using recombinant E. coli biocatalyst is an efficient way to prepare the corresponding oxiranes. The electronic and geometric effects of the ring substituents are described and show the relaxed specificity of the enzyme and its high stereoselectivity.
- Bernasconi, Silvana,Orsini, Fulvia,Sello, Guido,Di Gennaro, Patrizia
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p. 1603 - 1606
(2007/10/03)
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