- Direct Amination of Isohexides via Borrowing Hydrogen Methodology: Regio- and Stereoselective Issues
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The regio and diastereoselective direct mono or diamination of bio-based isohexides (isosorbide and isomannide) has been developed through borrowing hydrogen (BH) methodology using a cooperative catalysis between an iridium complex and a Br?nsted acid. The access to chiral amino-alcohol (NH2-OH) and diamine (NH2-NH2), interesting optically pure bio-based monomers, was also proposed using BH strategy as a sustainable route for their obtention.
- Bahé, Florian,Grand, Lucie,Cartier, Elise,Jacolot, Ma?wenn,Moebs-Sanchez, Sylvie,Portinha, Daniel,Fleury, Etienne,Popowycz, Florence
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supporting information
p. 599 - 608
(2020/02/04)
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- Unravelling the Mechanism of the Ru/C-Catalysed Isohexide and Ether Isomerization by Hydrogen Isotope Exchange
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In this article we show that the catalytic isomerization of isohexide sugar alcohols as well as their respective ethers can occur by a hydride-based mechanism rather than a dehydrogenation/re-hydrogenation. C?H bonds in α-position to hydroxy and ether groups are activated using Ru/C as solid catalyst at temperatures as high as 160 °C and above. Hydrogen isotope exchange experiments proved that a full hydride exchange and isomerization is possible for isohexides but unexpectedly also for their methyl ethers. This is of great importance as it proves the co-existence of the both mechanisms for reactions that were so far assumed to occur solely by a dehydrogenation/re-hydrogenation. Hence, this co-existence should be taken into account for kinetic investigations of such reaction systems especially in the conversion of biomass-based chemicals under hydrogenation conditions. (Figure presented.).
- Engel, Rebecca V.,Niemeier, Johannes,Fink, Anja,Rose, Marcus
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p. 2358 - 2363
(2018/05/08)
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- Is water a suitable solvent for the catalytic amination of alcohols?
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The catalytic conversion of biomass and biogenic platform chemicals typically requires the use of solvents. Water is present already in the raw materials and in most cases a suitable solvent for the typically highly polar substrates. Hence, the development of novel catalytic routes for further processing would profit from the optimization of the reaction conditions in the aqueous phase mainly for energetic reasons by avoiding the initial water separation. Herein, we report the amination of biogenic alcohols in aqueous solutions using solid Ru-based catalysts and ammonia as a reactant. The influence of different support materials and bimetallic catalysts is investigated for the amination of isomannide as a biogenic diol. Most importantly, the transferability of the reaction conditions to various other primary and secondary alcohols is successfully proved. Hence, water appears to be a suitable solvent for the sustainable production of biogenic amines and offers great potential for further process development.
- Niemeier, Johannes,Engel, Rebecca V.,Rose, Marcus
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supporting information
p. 2839 - 2845
(2017/07/24)
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- One-Pot Preparation of Dimethyl Isosorbide from d-Sorbitol via Dimethyl Carbonate Chemistry
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Direct synthesis of dimethyl isosorbide (DMI) from d-sorbitol via dimethyl carbonate (DMC) chemistry is herein first reported. High yield of DMI was achieved using the nitrogen superbase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst and performing the reaction in a stainless steel autoclave by increasing the temperature from 90 to 200 °C. In this procedure, DMC features its full capacity acting in the different steps of the process as carboxymethylating, leaving-group (cyclization), and methylating agent; DMC is also employed as the reaction media.
- Aricò,Aldoshin,Tundo
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- ISOIDIDE MANUFACTURE AND PURIFICATION
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Methods are provided for the conversion of isosorbide to isoidide, wherein the isosorbide contains sorbitan impurities. The impurities in the isosorbide subjected to epimerization are converted to hydrodeoxygenation products. A method for synthesizing isoidide, comprising, providing an isosorbide containing one or more sorbitans; and, epimerizing the isosorbide to form an epimerization product comprising isoidide and hydrodeoxygenation products.
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Paragraph 00108-00109
(2016/09/22)
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- METHOD OF MAKING ISOIDIDE
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Disclosed is a process for the preparation of isoidide from isosorbide. An aqueous solution of isosorbide is subjected to epimerization in the presence of hydrogen under the influence of a catalyst comprising ruthenium on a support, preferably a carbon support. The process of the invention can be conducted using a relatively low hydrogen pressure, and leads to a desired distribution of epimers, favoring isoidide over isomannide and isosorbide.
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Paragraph 0041 - 0055
(2015/01/06)
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- Sustainable polyacetals from isohexides
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A single step synthetic protocol to access a small family of renewable diacetals was established. The resultant chiral diacetals are valuable building blocks in pharmaceuticals and materials science. To demonstrate their synthetic competence, isohexide-diacetals (2a-c) were subjected to acetal metathesis polymerization and the corresponding polymers (poly2a-c) were isolated as white solids with molecular weights in the range 3200-27 600 (g mol-1). The semi-crystalline polymers displayed glass transition temperatures between 38-65 °C and melting temperatures in the range 103-156 °C. The isohexide derived polyacetals are stable under practical washing and rinsing conditions but degrade in slightly acidic media. This journal is the Partner Organisations 2014.
- Rajput,Gaikwad,Menon,Chikkali
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supporting information
p. 3810 - 3818
(2014/08/05)
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- Direct amination of bio-alcohols using ammonia
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A slightly adapted catalyst system has been successfully applied in the direct amination of primary and secondary alcohols. Moreover, the applicability to diols has been shown, giving high selectivity towards the primary diamines. It was found that the Ru/P ratio as well as the amount of ammonia used are highly important in this system, especially for higher substrate loadings. The catalyst was employed on a larger batch scale for the conversion of isomannide to the corresponding diamine. Additionally, it was shown that the catalyst is stable for at least six consecutive runs. No significant loss of activity and selectivity was observed.
- Pingen, Dennis,Diebolt, Olivier,Vogt, Dieter
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p. 2905 - 2912
(2013/10/21)
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- Isolation of anhydro sugar hexitols by selective adsorbents
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A method is disclosed for recovering anhydrosugar alcohols from a mixture comprising closely related compounds, such as sugar alcohols. In the method the mixture is contacted with an adsorbent, whereby the anhydrosugar alcohols are selectively adsorbed. The anhydrosugar alcohols can be recovered by desorption from the adsorbent, using a desorbing solvent.
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Paragraph 0109
(2013/07/25)
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- ISOLATION OF ANHYDRO SUGAR ALCOHOLS BY SELECTIVE ADSORBENTS
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A method is disclosed for recovering anhydrosugar alcohols from a mixture comprising closely related compounds, such as sugar alcohols. In the method the mixture is contacted with an adsorbent, whereby the anhydrosugar alcohols are selectively adsorbed. The anhydrosugar alcohols can be recovered by desorption from the adsorbent, using a desorbing solvent.
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Paragraph 00111
(2013/07/31)
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- Synthesis of isoidide through epimerization of isosorbide using ruthenium on carbon
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A highly efficient procedure for obtaining resin-grade isoidide through catalytic epimerization of isosorbide using a ruthenium- on-carbon (Ru/C) catalyst is reported. A comprehensive reaction- parameter variation study involving substrate concentration, catalyst (type of metal, support, and loading), initial pH value, hydrogen pressure, solvent, and reaction temperature demonstrates that superior performance and high selectivity can be achieved. Epimerization of isosorbide in water (pH 8) at 220 °C, under 40 bar of hydrogen, and using a Ru/C catalyst (5% Ru) for 2 h results in a thermodynamic equilibrium mixture containing 55% isoidide, 40% isosorbide, and 5% isomannide. In comparison with previously reported nickel-based catalysts, the Ru/C catalyst is advantageous because it is highly active (as low as 360 ppm Ru) and recyclable. High purity isoidide is obtained by high-vacuum distillation of an equilibrium mixture on a 200 g scale. The high substrate loading (50 wt% in water), high selectivity, and the possibility for substrate reuse makes this procedure highly atom efficient and therefore, highly attractive for industrial use.
- N?tre, Jér?me Le,Van Haveren, Jacco,Van Es, Daan S.
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p. 693 - 700
(2013/07/27)
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- Isosorbide-based cholinesterase inhibitors; replacement of 5-ester groups leading to increased stability
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Isosorbide-2-carbamate-5-esters are highly potent and selective butyrylcholinesterase inhibitors with potential utility in the treatment of Alzheimer's Disease (AD). They are stable in human plasma but in mouse plasma they undergo hydrolysis at the 5-ester group potentially attenuating in vivo potency. In this paper we explore the role of the 5-position in modulating potency. The focus of the study was to increase metabolic stability while preserving potency and selectivity. Dicarbamates and 5-keto derivatives were markedly less potent than the ester class. The 2-benzylcarbamate-5-benzyl ether was found to be potent (IC50 52 nM) and stable in the presence of mouse plasma and liver homogenate. The compound produces sustained moderate inhibition of mouse butyrylcholinesterase at 1 mg/kg, IP.
- Dillon, Gerald P.,Gaynor, Joanne M.,Khan, Denise,Carolan, Ciaran G.,Ryder, Sheila A.,Marquez, Juan F.,Reidy, Sean,Gilmer, John F.
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scheme or table
p. 1045 - 1053
(2010/04/26)
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- DIURETICS
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A compound having the structure wherein X is selected from the group consisting of:a bond, —NHCH2(CH2)nCH2OC(O)—, —CH2NHC(O)CH2NHC(O)—, —CH2OC(O)—, —OCH(CH3)OC(O)—, —OCH2OC(O)—,—O—, —NR1—, —CR1R3—, —(CH2)p—, —(CH2)qNR1C(O)—, —CHR5NR2C(O)—, —(CH2)qC(O)—, —(CH2)qC(O)—, —(CH2)qC(O)NR1—, or a pharmaceutically acceptable salt thereof, and methods of using the compounds for treating, hypertension.
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Page/Page column 25
(2010/03/02)
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- NITRIC OXIDE DONOR COMPOUNDS
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The invention relates to nitric oxide donors of the formula (I) and pharmaceutically acceptable salts or stereoisomers thereof : wherein A and A' are independently selected from the group consisting of H and -(X)s-Y with the proviso that at least one of A or A' is not H; wherein s is 0 or 1; X is selected from the group consisting of : -CO-, -COO-, -CONH- and -SO2- or (A); Y is straight or branched C1-C20 alkyl chain, preferably C1- C10 alkyl chain, substituted with one or two -ONO2; or C1-C6 alkylenoxy- C1-C5 alkyl wherein the alkyl group is substituted by one or two -ONO2 groups. The invention also provides novel compositions comprising at least one compound of the invention and at least one therapeutic agent.
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Page/Page column 41; 42
(2009/10/09)
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- ANGIOTENSIN II RECEPTOR ANTAGONISTS
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A compound having the structure (I) wherein R is an angiotensin II receptor antagonist selected from the group consisting of (IIa)- (IIh); A is (Formula) wherein Rl and R2 are independently selected from the group consisting of hydrogen and C1-4 alkyl. Y is X0-Z wherein X0 is selected from the group consisting of: -O-, -O-CO-, -OCOO-, -OCONH- and -OSO2-; Z is a nitric oxide releasing moiety, or a pharmaceutically acceptable salt thereof.
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Page/Page column 81
(2010/01/07)
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- D-Isomannide in synthesis: Asymmetric Diels-Alder reactions with novel homochiral bis-imine Cu2+-catalysts
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The synthesis of a set of novel homochiral bis-imine ligands 4 derived from D-isomannide 6, and their application in the Cu2+-catalyzed asymmetric Diels-Alder reaction of cyclopentadiene and N-tert-crotonoyloxazolidinone 1 is reported.
- De Coster, Gert,Vandyck, Koen,Van der Eycken, Erik,Van der Eycken, Johan,Elseviers, Myriam,Roeper, Harald
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p. 1673 - 1679
(2007/10/03)
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- THE STRUCTURE OF ADDUCTS OF THE THREE DIASTEREOISOMERIC 1,4:3,6-DIANHYDROHEXITOLS AND LANTHANIDE CHELATES IN ACETONE
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Gd(dpm)3 induced 1H and 13C relaxation rate enhancements showed that 1,4:3,6-dianhydro-D-glucitol (containing both a threo and an erythro -O-C-C-OH moiety) acts as a bidentate ligand for Gd(dpm)3.Coordination occurs selectively with the erythro -O-C-C-OH moiety, involving the endohydroxyl group at C5 and the neighbouring ether oxygen.From a comparison of the Eu(fod)3 induced 1H shifts of 1,4:3.6-dianhydro-D-glucitol with those of 1,4:3,6-dianhydro-D-mannitol and 1,4:3,6-dianhydro-L-iditol it is concluded that the mannitol derivative (containing two erythro -O-C-C-OH moieties) forms analogous adducts, whereas the iditol derivative (containing two threo -O-C-C-OH moeities) has a low association constant.
- Peters, J. A.,Bovee, W. M. M. J.,Kieboom, A. P. G.
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p. 2885 - 2891
(2007/10/02)
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