- A decatungstate-based ionic liquid exhibiting a very low dielectric constant suitable for acting as a solvent and a catalyst for the oxidation of organic substrates
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In this contribution, a new POM-based ionic liquid, namely (P6,6,6,14)4[W10O32], was fully characterized. Its viscosity and its very low dielectric constant make this hybrid ionic liquid suitable to be used as a solvent for organic transformations. As a proof of concept, this unique ionic liquid having both solvent and catalyst properties was tested for the catalytic oxidation of various alcohols and alkenes in the presence of H2O2.
- Martinetto, Yohan,Pégot, Bruce,Roch-Marchal, Catherine,Haouas, Mohamed,Cottyn-Boitte, Betty,Camerel, Franck,Jeftic, Jelena,Morineau, Denis,Magnier, Emmanuel,Floquet, Sébastien
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p. 9751 - 9755
(2021/06/15)
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- Expanding the repertoire of nitrilases with broad substrate specificity and high substrate tolerance for biocatalytic applications
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Enzymatic conversion of nitriles to carboxylic acids by nitrilases has gained significance in the green synthesis of several pharmaceutical precursors and fine chemicals. Although nitrilases from several sources have been characterized, there exists a scope for identifying broad spectrum nitrilases exhibiting higher substrate tolerance and better thermostability to develop industrially relevant biocatalytic processes. Through genome mining, we have identified nine novel nitrilase sequences from bacteria and evaluated their activity on a broad spectrum of 23 industrially relevant nitrile substrates. Nitrilases from Zobellia galactanivorans, Achromobacter insolitus and Cupriavidus necator were highly active on varying classes of nitriles and applied as whole cell biocatalysts in lab scale processes. Z. galactanivorans nitrilase could convert 4-cyanopyridine to achieve yields of 1.79 M isonicotinic acid within 3 h via fed-batch substrate addition. The nitrilase from A. insolitus could hydrolyze 630 mM iminodiacetonitrile at a fast rate, effecting 86 % conversion to iminodiacetic acid within 1 h. The arylaliphatic nitrilase from C. necator catalysed enantioselective hydrolysis of 740 mM mandelonitrile to (R)-mandelic acid in 4 h. Significantly high product yields suggest that these enzymes would be promising additions to the suite of nitrilases for upscale biocatalytic application.
- Rayavarapu, Pratima,Shah, Shikha,Sunder, Avinash Vellore,Wangikar, Pramod P.
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p. 289 - 296
(2020/05/18)
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- Cobalt/N-Hydroxyphthalimide(NHPI)-Catalyzed Aerobic Oxidation of Hydrocarbons with Ionic Liquid Additive
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A highly efficient and solvent-free system of cobalt/NHPI-catalyzed aerobic oxidation of hydrocarbons was developed using imidazolium-based ionic liquid (IL) as an additive. These amphipathic ILs were found self-assemble at the interface between the organic hydrocarbons and the aqueous phase of catalyst combination (Co/NHPI), with forming a solution of reversed multilamellar vesicles for catalysis. The initial reaction rate was influenced by both the composition of microdomains and the structure of IL launched. Consequently, a proper water content (χH2O) of wet IL was requisite to reach the optimum reactivity. Besides, the interfacial boundary between aqueous and organic phase composed by C2-alkylated imidazolium ILs, such as [bdmim]SbF6 and [C12dmim]SbF6, not only has ternary aggregates (hydrocarbons/IL/H2O) of higher stability but renders O2 a faster diffusion rate and higher concentration, thereby offering a high reactivity of the protocol towards hydrocarbon oxidation.
- Mahmood, Sajid,Xu, Bao-Hua,Ren, Tian-Lu,Zhang, Zhi-Bo,Liu, Xiao-Min,Zhang, Suo-Jiang
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- Highly efficient oxidative cleavage of alkenes and cyanosilylation of aldehydes catalysed by magnetically recoverable MIL-101
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The catalytic activity of magnetically recoverable MIL-101 was investigated in the oxidation of alkenes to carboxylic acids and cyanosilylation of aldehydes. MIL-101 was treated with Fe3O4 and the prepared catalyst was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption measurements, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and inductively coupled plasma analysis. The catalytic active sites in this heterogeneous catalyst are Cr3+ nodes of the MIL-101 framework. This heterogeneous catalyst has the advantages of excellent yields, short reaction times and reusability several times without significant decrease in its initial activity and stability in both oxidation and cyanosilylation reactions. Its magnetic property allows its easy separation using an external magnetic field.
- Nourian, Maryam,Zadehahmadi, Farnaz,Kardanpour, Reihaneh,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
-
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- Nanocoating of Hydrophobic Mesoporous Silica around MIL-101Cr for Enhanced Catalytic Activity and Stability
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The metal-organic framework (MOF) MIL-101Cr was readily encapsulated by a very thin shell (around 30 nm) of hydrophobic mesoporous silica, which replicates the irregular shape of the MOF nanocrystals. Such a silica shell facilitates the diffusion of hydrophobic reactants with enhancement of the catalytic activity of the MOF and significantly improved catalytic stability of the MOF in the oxidation of indene.
- Ying, Jie,Herbst, Annika,Xiao, Yu-Xuan,Wei, Hao,Tian, Ge,Li, Zhaofei,Yang, Xiao-Yu,Su, Bao-Lian,Janiak, Christoph
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supporting information
p. 899 - 902
(2018/02/14)
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- Cyclic Hydroxamic Acid Analogues of Bacterial Siderophores as Iron-Complexing Agents prepared through the Castagnoli–Cushman Reaction of Unprotected Oximes
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The first application of multicomponent chemistry (the Castagnoli–Cushman reaction) toward the convenient one-step preparation of cyclic hydroxamic acids is described. Cyclic hydroxamic acids are close analogues of bacterial siderophores (iron-binding com
- Bakulina, Olga,Bannykh, Anton,Dar'in, Dmitry,Krasavin, Mikhail
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p. 17667 - 17673
(2017/12/26)
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- BIOREVERSABLE PROMOIETIES FOR NITROGEN-CONTAINING AND HYDROXYL-CONTAINING DRUGS
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Disclosed are promoieties of the following formula which can be used to form prodrugs of nitrogen-containing or hydroxyl-containing drug or a pharmaceutically active agent: (I) and pharmaceutical compositions comprising the prodrugs.
- -
-
Page/Page column 155; 156
(2015/06/18)
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- Synthesis and antitumor activity evaluation of 2-arylisoquinoline-1,3(2H, 4H)-diones in vitro and in vivo
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Six 2-(2-acylaminobenzothiazol-6-yl)isoquinoline-1,3(2H,4H)-diones (1a-1f) and five 2-arylisoquinoline-1,3(2H,4H)-diones (1g-1k) were synthesized by refluxing homophthalic anhydrides with 2-acylaminobenzothiazolyl-6-amine or substituted aniline in glacial acetic acid. The cytotoxic activities of 1a-1k were evaluated via MTT method against A431, A549, and PC3. Compound 1b relatively displayed a higher cytotoxic activity than the others. The antitumor effect of 1b were evaluated in established nude mice PANC-1 xenograft model. The results suggest that compound 1b could potentially inhibit tumor growth.
- Kang, Bo-Rui,Wang, Juan,Li, Huan,Li, Yan,Mei, Qi-Bing,Zhang, San-Qi
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p. 1340 - 1349
(2014/03/21)
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- HCV PROTEASE INHIBITORS
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The present invention discloses a compound of general formula (I); A is O, S, CH, NH or NR', when O links with Z3, Z1 is N or CRZ1, Z2 is CRZ2, when Z1 links with O, Z2 is CH, Z3 is C-Ar; Ra, Rb, Rc and Rd independently is H, OH, halogen or -Y1-Rm; A1 is NH or CH2; R1' is alkyl, aryl, cycloalkyl, heterocycloalkyl or heteroaryl; A2 is N, O or linking bond; R1 is hydrogen, or, R1 linking covalently with R3 forms C5-C9 saturated or unsaturated hydrocarbon chain substituted by O or N; R3 is alkyl, cycloalkyl, heterocycloalkyl, alkyl substituted by cycloalky etc; R4 is alkoxy-CO, alkyl-NHCO, (alkyl)2NCO, or formyl substituted by aryl, cycloalkyl, heterocycloalkyl.
- -
-
Paragraph 0127; 0128
(2014/06/24)
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- HCV Protease Inhibitors
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A compound of general formula (I); A is O, S, CH, NH or NR′, when O links with Z3, Z1 is N or CRZ1, Z2 is CRZ2, when Z1 links with O, Z2 is CH, Z3 is C—Ar; Ra, Rb, Rc and Rd independently is H, OH, halogen or —Y1—Rm; A1 is NH or CH2; R1′ is alkyl, aryl, cycloalkyl, heterocycloalkyl or heteroaryl; A2 is N, O or linking bond; R1 is hydrogen, or, R1 linking covalently with R3 forms C5-C9 saturated or unsaturated hydrocarbon chain substituted by O or N; R3 is alkyl, cycloalkyl, heterocycloalkyl, alkyl substituted by cycloalkyl etc; R4 is alkoxy-CO, alkyl-NHCO, (alkyl)2NCO, or formyl substituted by aryl, cycloalkyl, heterocycloalkyl.
- -
-
Paragraph 0251-0254
(2014/06/24)
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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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- MIL-101 metal-organic framework: A highly efficient heterogeneous catalyst for oxidative cleavage of alkenes with H2O2
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In the present work, a new and efficient method for direct oxidation of alkenes to carboxylic acids with H2O2 catalyzed by metal-organic framework MIL-101 is reported. In this transformation, the MIL-101 catalyzes the oxidation reactions by framework nodes and acts as a heterogeneous and reusable catalyst. The structure of MIL-101 was stable after three catalytic cycles.
- Saedi, Zahra,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 18 - 22
(2012/03/26)
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- Aqueous organotin chemistry: Part 3 - Triphenyltin hydride and di-n-butyltin dichloride mediated nucleophilic substitution of 2-iodobenzoates in water
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This paper demonstrates the nucleophilic displacement of the iodine in 2-iodobenzoates mediated by triphenyltin hydride and di-n-butyltin dichloride in water.
- Sarma,Maitra
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p. 1148 - 1150
(2007/10/03)
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- Laser flash photolysis study of the reactivity of α-ketenylbenzocyclobutenone with water and alcohols
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Photolysis of 2-diazo-1,3-indandione leads to ketene formation via the Wolff rearrangement. Ketene 2 hydrates to produce enol 3a that rearranges to 4a. Homophthalic acid 5a is formed by photodecomposition of 4a upon prolonged irradiation.
- De Lucas, Nanci Camara,Andraos, John,Netto-Ferreira,Scaiano
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p. 677 - 680
(2007/10/02)
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- Studies in the Cycloproparene Series: Reactions with Radicals
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The behaviour of 1H-cyclopropabenzene (1) and 1H-cyclopropanaphthalene (23) towards a variety of radicals results in opening of the three-membered ring to give ortho-substituted benzyl and 2-methylnaphthalene derivatives, e.g. (13) and (28), respectively.Ring expansion into the cycloheptatriene manifold by way of addition to the bridge bond and norcaradiene formation have not been observed.Analogous reactions with the methylidenecyclopropanaphthalenes (33) and (34) lead to much decomposition, and provide little evidence for the C 1 cycloproparenyl radicals (35) and (36).
- Chai, Christina L. L.,Christen, Detlev,Halton, Brian,Neidlein, Richard,Starr, Malcolm A. E.
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p. 577 - 592
(2007/10/02)
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- Fused s-Triazino Heterocycles. XV. 13H-4,6,7,13a,13c-Pentaazabenzochrysene, 13H-4,7,13a,13c-Tetraazabenzochrysene, and 7H-3,7,10,10b-Tetraazacycloheptanaphthalene, Three New Ring Systems
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The reaction of N-cyano-N'-(6-amino-2-pyridyl)acetamidine (5a) and homophthalic anhydride followed by ring closure of the 2--5-methyl-1,3,4,6,9b-pentaazaphenalene intermediate (4a) gave 5-methyl-13-oxo-13H-4,6,7,13a,13c-pentaazabenzochrysene (8a).An analogous series starting with 3-N-(6-amino-2-pyridyl)amino-2-cyano-2-butenenitrile (5b) in place of 5a gave in two steps 5-methyl-13-oxo-13H-4,7,13a,13c-tetraazabenzochrysene-6-carbonitrile (8b).Elemental analysis, ir and pmr spectra of 8a, 8b and several new model compounds aided in confirming the structures of 8a and 8b.The synthesis of one of these model compounds for 5b and phenylacetic anhydride led surprisingly to 2-methyl-9-phenyl-7H-3,7,10,10b-tetraazacycloheptanaphthalene (10) in addition to the expected 2-benzyl-4-cyano-5-methyl-1,3,6,9b-tetraazaphenalene (7b).
- Shaw, John T.,Corbett, Wendy L.,Layman, Deanna L.,Cuny, Gregory D.,Kerschner, Judith L.
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p. 1837 - 1840
(2007/10/02)
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- An Investigation of the Di-Grignard Approach to Metallabenzocyclobutenes of Group 14
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The reactions of 1,2-dihydro-1-magnesabenzocyclobutane (5) with dichlorodimethylsilane (12a), dichloromethylgermane (12b) and dichloromethylstannane (12C) are reported; 1,2-dihydro-1,1-dimethyl-1-silabenzocyclobutene (14a) and 1,2-dihydro-1,1-dimethyl-1-germabenzocyclobutene (14b) were formed in high yields, but the tin analogue was not obtained.Eight-membered ring species, the dimers 17 and 18, were isolated for all three metals.Other products gave useful indications of the probable course of these interesting and complex reactions.
- Boer, H. J. R. De,Akkerman, O. S.,Bickelhaupt, F.
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p. 291 - 306
(2007/10/02)
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- COBALT CARBONYL CATALYZED POLYCARBONYLATION OF POLYHALOGENATED AROMATICS UNDER PHOTOSTIMULATION
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Cobalt carbonyl catalyzed polycarbonylation of much less reactive polychlorobenzenes could be easily achieved under photostimulation in aqueous sodium hydroxide.All these reactions could be performed without any organic solvent(in some cases, ethanol was used as a co-solvent) and any phase transfer catalyst.
- Kashimura, Tsugunori,Kudo, Kiyoshi,Mori, Sadayuki,Sugita, Nobuyuki
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p. 299 - 302
(2007/10/02)
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- Sunlamp-Irradiated Phase-Transfer Catalysis. 1. Cobalt Carbonyl Catalyzed SRN1 Carbonylations of Aryl and Vinyl Halides
-
Cobalt carbonyl catalyzed carbonylation (1 atm) of aryl and vinyl halides may be easily achieved under phase-transfer-catalysis conditions provided that the reaction medium is irradiated.Irradiation may be achieved by a commercial sunlamp.Most of these reactions may also be performed without organic solvent and in some cases without a phase-transfer agent.Finally, this new, inexpensive carbonylation method allows very efficient synthesis of benzolactams and benzolactones.
- Brunet, Jean-Jacques,Sidot, Christian,Caubere, Paul
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p. 1166 - 1171
(2007/10/02)
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- Stereopopulation Control. 8. Rate and Equilibrium Enhancement in the Formation of Homophthalic Anhydrides
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The kinetics of cyclization of α,α,3,4,6-pentamethylhomophthalic acid have been measured in sovent acetonitrile at 28.5 deg C, using as catalysts a series of acids ranging in strength from perchloric to acetic.In the presence of 0.12 M HClO4, t1/2 for acid anhydride formation = 0.3 s.For the stronger acid catalysts, kcycl is a linear function of catalyst concentration; for the weak acids, however, a change in rate-limiting step is revealed by curvature in the plots of ktotobsd vs. .All the weak acids show the same limiting value, 6.45E-3 min-1; this value is considered to be the rate constant for uncatalyzed formation of the tetrahedral intermediate.Homoconjugate bases (HA2(-)) of the weak acids show a similar curvature in their dilution plots, and the same limiting rate constant as for weak acids.Two independent and competitive pathways for cyclization are proposed.For strong acid catalysis, an intermediate acylium ion is considered on the basis of Broensted α = -0.79, kH/kD ca. 1, and acceleration of anhydride hydrolysis by methyl substituents.A value of ΔSexcit. = -23 eu suggests that cyclization, rather than acylium ion formation, is rate limiting.For weak acid catalysis, α = -0.17, kH/kD = 4.3, ΔSexcit. = -31 eu, and methyl groups retard anhydride hydrolysis by electron release; for this pathway, catalyzed breakdown of a tetrahedral intermediate is considered rate limiting.The composite Broensted plot is curved because the two pathways follow different rate laws.In contrast to rate enhancement results for phenolic lactone formation, the pentamethylhomophthalic acid is only sevenfold as reactive as α,α-dimethylhomophthalic acid.For the catalyst acids, pK(acetonitrile) is shown to be a linear function of pK(H2O) over the entire range of acids examined.
- Hillery, Paul S.,Cohen, Louis A.
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p. 2760 - 2770
(2007/10/02)
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- EFFICIENT DEMETYLATION OF METHYL ESTERS WITH ANHYDROUS TRIFLUOROACETIC ACID
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Trifluoroacetic acid (TFA) is an effective reagent for the demethylation of methyl esters under anhydrous conditions, affording the parent acids and methyl trifluoroacetate.
- Tabor, Derrick C.,Evans, Slayton A.,Kenan, William Rand
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p. 855 - 864
(2007/10/02)
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- Convenient Preparation of Homophthalic Acids
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Preparation of homophthalic acids by peroxide oxidation of indan-1-one-2-glyoxalates is reported. Orientation of acetylation of methyl 3,5-dimethoxyphenylacetate has been established.
- Bhakta, C.,Mukherjee, Sanat K.
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p. 637 - 639
(2007/10/02)
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