- Enantioselective ring-opening reaction of epoxides with MeOH catalyzed by homochiral metal-organic framework
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Two new copper metal-organic frameworks containing 2,2′-dihydroxy-1, 1′-binaphthalene-5,5′-dicarboxylic acid (5,5′-H 2BDA) and 2,2′-dihydroxy-1,1′-binaphthalene-4,4′- dicarboxylic acid (4,4′-H2BDA) have been prepared. X-ray structure determination of [Cu2(5,5′-BDA)2(H 2O)2]·MeOH·2H2O (MOF-1) and [Cu2(4,4′-BDA)2(H2O)2] ·4H2O (MOF-2) revealed similar 2D sheet structures, containing square-grid coordination networks, but differences in the stacking motif. The desolvated MOF-1 and -2 were used as Lewis acid catalysts in the asymmetric ring-opening reaction of epoxides with MeOH.
- Tanaka, Koichi,Otani, Ken-Ichi,Murase, Takanori,Nishihote, Shyota,Urbanczyk-Lipkowska, Zofia
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- Enhancement of CO2 Adsorption and Catalytic Properties by Fe-Doping of [Ga2(OH)2(L)] (H4L = Biphenyl-3,3′,5,5′-tetracarboxylic Acid), MFM-300(Ga2)
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Metal-organic frameworks (MOFs) are usually synthesized using a single type of metal ion, and MOFs containing mixtures of different metal ions are of great interest and represent a methodology to enhance and tune materials properties. We report the synthesis of [Ga2(OH)2(L)] (H4L = biphenyl-3,3′,5,5′-tetracarboxylic acid), designated as MFM-300(Ga2), (MFM = Manchester Framework Material replacing NOTT designation), by solvothermal reaction of Ga(NO3)3 and H4L in a mixture of DMF, THF, and water containing HCl for 3 days. MFM-300(Ga2) crystallizes in the tetragonal space group I4122, a = b = 15.0174(7) ? and c = 11.9111(11) ? and is isostructural with the Al(III) analogue MFM-300(Al2) with pores decorated with -OH groups bridging Ga(III) centers. The isostructural Fe-doped material [Ga1.87Fe0.13(OH)2(L)], MFM-300(Ga1.87Fe0.13), can be prepared under similar conditions to MFM-300(Ga2) via reaction of a homogeneous mixture of Fe(NO3)3 and Ga(NO3)3 with biphenyl-3,3′,5,5′-tetracarboxylic acid. An Fe(III)-based material [Fe3O1.5(OH)(HL)(L)0.5(H2O)3.5], MFM-310(Fe), was synthesized with Fe(NO3)3 and the same ligand via hydrothermal methods. [MFM-310(Fe)] crystallizes in the orthorhombic space group Pmn21 with a = 10.560(4) ?, b = 19.451(8) ?, and c = 11.773(5) ? and incorporates μ3-oxo-centered trinuclear iron cluster nodes connected by ligands to give a 3D nonporous framework that has a different structure to the MFM-300 series. Thus, Fe-doping can be used to monitor the effects of the heteroatom center within a parent Ga(III) framework without the requirement of synthesizing the isostructural Fe(III) analogue [Fe2(OH)2(L)], MFM-300(Fe2), which we have thus far been unable to prepare. Fe-doping of MFM-300(Ga2) affords positive effects on gas adsorption capacities, particularly for CO2 adsorption, whereby MFM-300(Ga1.87Fe0.13) shows a 49% enhancement of CO2 adsorption capacity in comparison to the homometallic parent material. We thus report herein the highest CO2 uptake (2.86 mmol g-1 at 273 K at 1 bar) for a Ga-based MOF. The single-crystal X-ray structures of MFM-300(Ga2)-solv, MFM-300(Ga2), MFM-300(Ga2)·2.35CO2, MFM-300(Ga1.87Fe0.13)-solv, MFM-300(Ga1.87Fe0.13), and MFM-300(Ga1.87Fe0.13)·2.0CO2 have been determined. Most notably, in situ single-crystal diffraction studies of gas-loaded materials have revealed that Fe-doping has a significant impact on the molecular details for CO2 binding in the pore, with the bridging M-OH hydroxyl groups being preferred binding sites for CO2 within these framework materials. In situ synchrotron IR spectroscopic measurements on CO2 binding with respect to the -OH groups in the pore are consistent with the above structural analyses. In addition, we found that, compared to MFM-300(Ga2), Fe-doped MFM-300(Ga1.87Fe0.13) shows improved catalytic properties for the ring-opening reaction of styrene oxide, but similar activity for the room-temperature acetylation of benzaldehyde by methanol. The role of Fe-doping in these systems is discussed as a mechanism for enhancing porosity and the structural integrity of the parent material.
- Krap, Cristina P.,Newby, Ruth,Dhakshinamoorthy, Amarajothi,García, Hermenegildo,Cebula, Izabela,Easun, Timothy L.,Savage, Mathew,Eyley, Jennifer E.,Gao, Shan,Blake, Alexander J.,Lewis, William,Beton, Peter H.,Warren, Mark R.,Allan, David R.,Frogley, Mark D.,Tang, Chiu C.,Cinque, Gianfelice,Yang, Sihai,Schr?der, Martin
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p. 1076 - 1088
(2016/02/09)
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- Graphene oxide as an acid catalyst for the room temperature ring opening of epoxides
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The minute amount of hydrogen sulfate groups introduced into the graphene oxide (GO) obtained by Hummers oxidation of graphite renders this material as a highly efficient, recyclable acid catalyst for the ring opening of epoxides with methanol and other primary alcohols as nucleophile and solvent.
- Dhakshinamoorthy, Amarajothi,Alvaro, Mercedes,Concepcion, Patricia,Fornes, Vicente,Garcia, Hermenegildo
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supporting information; experimental part
p. 5443 - 5445
(2012/07/28)
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- Quinuclidine compounds and drugs containing the same as the active ingredient
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The present invention provides an excellent squalene synthesizing enzyme inhibitor. Specifically, it provides a compound (I) represented by the following formula, a salt thereof or a hydrate of them. In which R1 represents (1) hydrogen atom or (2) hydroxyl group; HAr represents an aromatic heterocycle which may be substituted with 1 to 3 groups; Ar represents an optionally substituted aromatic ring; W represents a chain represented by (1) —CH2—CH2— which may be substituted, (2) —CH=CH— which may be substituted, (3) —C≡C—, (4) —NH—CO—, (5) —CO—NH—, (6) —NH—CH2—, (7) —CH2—NH—, (8) —CH2—CO—, (9) —CO—CH2—, (10) —NH—S(O)l—, (11) —S(O)l—NH—, (12) —CH2—S(O)— or (13) —S(O)l—CH2— (l denotes 0, 1 or 2); and X represents a chain represented by (1) a single bond, (2) an optionally substituted C1-6 alkylene chain, (3) an optionally substituted C2-6 alkenylene chain, (4) an optionally substituted C2-6 alkynylene chain, (5) a formula —Q— (wherein Q represents oxygen atom, sulfur atom, CO or N(R2) (wherein R2 represents a C1-6 alkyl group or a C1-6 alkoxy group)), (6) —NH—CO—, (7) —CO—NH—, (8) —NH—CH2—, (9) —CH2—NH—, (10) —CH2—CO—, (11) —CO—CH2—, (12) —NH—S(O)m—, (13) —S(O)m—NH—, (14) —CH2—S(O)m—, (15) —S(O)m—CH2— (wherein m denotes 0, 1 or 2) or (16) —(CH2)n—O— (wherein n denotes an integer from 1 to 6).
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- Sodium borohydride and vinyl triflates of α-keto esters: A new combination toward monoalkylated 1,2-diols
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NaBH4 converts a range of methyl 2-trifluoromethanesulfonyloxy 3-substituted propenoates to the corresponding monoalkylated 1,2-diols smoothly with total regiocontrol.
- Dalla, Vincent,Decroix, Bernard
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p. 1657 - 1660
(2007/10/03)
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- Bis-chlorodibutyltin oxide as a new reagent for a mild, versatile and regioselective ring-opening of epoxides
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A convenient and efficient procedure for the ring-opening of epoxides by means of alcohols and bis-chlorodibutyltin oxide is described. The cleavage of the oxiranes is found to proceed regioselectively under mild reaction conditions. Thus, several haloalkanols, useful intermediates toward biological active molecules, are easily obtained in very good yields.
- Salomon
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- Alcoxymethyltributyletains precurseurs d'alcoxymethyllithiums: application a la synthese de monoethers d'α-glycols et a l'homologation de cetones en aldehydes
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Ethoxymethyltributyltin (obtained from diethoxymethyltributyltin, acetyl chloride and tributyltin hydride) and methoxymethyltributyltin (obtained from chloromethyl-methyl ether and tributylstannylmagnesium chloride) have been transmetallated with butyllithium to give the corresponding alkoxymethyl lithium reagents.This reaction, although usually performed in ether, is possible in a variety of other solvents thus simplifying some of the problems encountered during isolation of the products.The alkoxymethyllithiums obtained react with aldehydes and ketones to give cleanly the corresponding monoprotected α-glycols.Stereochemical trends were observed for hydratropaldehyde and 4-tertiarybutylcyclohexanone, while regiochemical trends were evaluated in the case of cyclohexen-2-one.Syntheis of aldehydes has been achieved in good yields from tertiary monoprotected α-glycols using conventional methods.
- Duchene, Alain,Mouko-Mpegna, David,Quintard, Jean-Paul
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p. 787 - 793
(2007/10/02)
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- Conveniant Method for Replacement of Tertiary N-Methyl by Other Alkyl Groups: Application to Morphine Alkaloids
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The replacement of N-methyl of N-methylpiperidine (1), 4-methylmorpholine (4), 2-methyl-1,2,3,4-tetrahydroisoquinoline (7) and tropine (10) by n-propyl, n-butyl and isopropyl groups (3a-3c, 6c, 9a-9c and 12a-12c) has been achieved in high yields by quaternization of the respective tertiary amine with appropriate alkyl halide and demethylation of the resulting quaternary salt with thiophenoxide.It has been established that demethylation is strongly favoured over the removal of n-propyl and n-butyl groups, whereas deisopropylation occurs to some extent.Surprisingly, in the case of 11c, deisopropylation predominates.This method has been applied to morphine (13b), codeine (13d) and thebaine (14b) for similar replacements.The rapid quaternization of thebaine (14b) has been assigned to the absence of H-14 in this alkaloid.The fact that quaternary salts of thebaine, which are susceptible to aromatization of the nucleus by extrusion of the ethanamine chain, are smoothly demethylated to N-alkylnorthebaines (18a-18c) in good yields indicates that demethylation, a bimolecular nucleophilic displacement, competes very successfully with elimination reaction.
- Manoharan, T. Samuel,Madyastha, K. Madhava,Singh, B. B.,Bhatnagar, S. P.,Weiss, Ulrich
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