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Kinetic analyses of intramolecular dehydration of hexitols in high-temperature water
Intramolecular dehydration of the biomass-derived hexitols D-sorbitol, D-mannitol, and galactitol was investigated. These reactions were performed in high-temperature water at 523–573 K without added acid catalyst. The rate constants for the dehydration steps in the reaction networks were determined at various reaction temperatures, and the activation energies and pre-exponential factors were calculated from Arrhenius plots. The yield of each product was estimated as a function of reaction time and temperature using the calculated rate constants and activation energies. The maximum yield of each product from the dehydration reactions was predicted over a range of reaction time and temperature, allowing the selective production of these important platform chemicals.
Yamaguchi, Aritomo,Mimura, Naoki,Shirai, Masayuki,Sato, Osamu
(2019/11/29)

Direct Amination of Isohexides via Borrowing Hydrogen Methodology: Regio- and Stereoselective Issues
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
supporting information
p. 599 - 608
(2020/02/04)

Efficient and selective aqueous photocatalytic mono-dehydration of sugar alcohols using functionalized yttrium oxide nanocatalysts
The mono-dehydration of sugar alcohols such as d-sorbitol and d-mannitol generates 1,4-sorbitan and 1,4-mannitan, respectively, which are relevant platform molecules for the synthesis of detergents and pharmaceuticals. Most reported catalytic systems provided access to di-dehydrated products, while mono-dehydration required special efforts, particularly regarding selectivity and reaction temperature. A series of functionalized yttrium oxides were prepared via sol-gel synthesis in this work, which not only showed an interesting micropipe-like morphology, but also contained functional components. These materials were investigated as photocatalysts in the dehydration of d-sorbitol and d-mannitol, exhibiting high selectivity to mono-dehydration. The effects of solvent, temperature and catalyst were fully discussed. A catalytic mechanism was proposed based on the experimental results and calculations.
Cheng, Yu,Fan, Chao,Guo, Lina,Huang, Benhua,Li, Xiaoyong,Luque, Rafael,Ma, Xiaomo,Meng, Xu,Pan, Cheng,Sun, Yang,Yang, Juncheng,Zhang, Junjie,Zhang, Weining,Zheng, Aqun
p. 5333 - 5344
(2020/09/17)

A strategy of ketalization for the catalytic selective dehydration of biomass-based polyols over H-beta zeolite
Biomass contains plentiful hydroxyl groups that lead to an oxygen-rich structure compared to petroleum-based chemicals. Dehydration is the most energy-efficient technique to remove oxygen; however, multiple similar vicinal hydroxyl groups in sugar alcohols impose significant challenges for their selective dehydration. Here, we present a novel strategy to control the etherification site in sugar alcohols by the ketalization of the vicinal-diol group for the highly selective formation of tetrahydrofuran derivatives. A ketone firstly reacts with terminal vicinal hydroxyl groups to form the 1,3-dioxolane structure. This structure of the constrained 1,3-dioxolane ring would improve the accessibility of reactive groups to facilitate intramolecular etherification. As a better leaving group than water, the ketone can also promote intramolecular etherification. Consequently, a range of tetrahydrofuran derivatives are produced in excellent yields with the H-beta zeolite catalyst under mild reaction conditions. This strategy opens up new opportunities for the efficient upgrading of biomass via the modification or protection of hydroxyl groups.
Che, Penghua,Lu, Fang,Si, Xiaoqin,Ma, Hong,Nie, Xin,Xu, Jie
supporting information
p. 634 - 640
(2018/02/14)

Unravelling the Mechanism of the Ru/C-Catalysed Isohexide and Ether Isomerization by Hydrogen Isotope Exchange
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
supporting information
p. 2358 - 2363
(2018/05/08)

One-Pot Preparation of Dimethyl Isosorbide from d-Sorbitol via Dimethyl Carbonate Chemistry
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
p. 53 - 57
(2017/01/17)

Selective Dehydration of Mannitol to Isomannide over Hβ Zeolite
Isomannide is a potential feedstock for the production of super engineering plastics. A prospective route to obtain isomannide is dehydration of mannitol derived from lignocellulosic biomass, but homogeneous acid catalysts reported in the literature produce a large amount of 2,5-sorbitan as a byproduct in the dehydration reaction. In this work, we initially studied the mechanism of proton-induced dehydration of mannitol by density functional theory calculations, which suggested that local steric hindrance around acid sites designed at the angstrom level can tune the selectivity toward isomannide formation. Based on this prediction, we found that the precisely defined microporous confinement offered by Hβ provides improved selectivity and high catalytic activity for the production of isomannide, where 1,4-dehydration is favored by 20 kJ mol-1 of activation energy. The optimization of the Si/Al ratio of Hβ to balance the acid amount and hydrophobicity improved the catalytic activity and achieved 63% yield of isomannide, far exceeding the best result reported previously (35% yield).
Yokoyama, Haruka,Kobayashi, Hirokazu,Hasegawa, Jun-Ya,Fukuoka, Atsushi
p. 4828 - 4834
(2017/07/24)

Is water a suitable solvent for the catalytic amination of alcohols?
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
supporting information
p. 2839 - 2845
(2017/07/24)

PROCESS FOR PRODUCING ISOHEXIDES
A process is described for producing an isohexide by a base catalyzed conversion of a 1,2:5,6-diacetal of a hexitol to the isohexide.
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Paragraph 0036; 0037

(2017/12/15)

METHOD FOR PURIFYING ANHYDROUS SUGAR ALCOHOL, ANHYDROUS SUGAR ALCOHOL AND RESIN
Provided are an anhydrosugar alcohol purification method, etc. with which an anhydrosugar alcohol can be efficiently purified and an anhydrosugar alcohol of excellent storage stability can be obtained, and which can limit discoloration and reduction of glass transition temperature of a resin obtained using said anhydrosugar alcohol. The anhydrosugar alcohol purification method is provided with a step for distilling an anhydrosugar alcohol from a substance to be distilled comprising active carbon and the anhydrosugar alcohol.
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Paragraph 0077; 0078

(2017/01/19)

ISOIDIDE MANUFACTURE AND PURIFICATION
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)

Synthesis of five- and six-membered heterocycles by dimethyl carbonate with catalytic amounts of nitrogen bicyclic bases
A catalytic amount of a nitrogen bicyclic base, i.e., DABCO, DBU or TBD, is effective for the one-pot synthesis of heterocycles from 1,4-, 1,5-diols and 1,4-bifunctional compounds via dimethyl carbonate chemistry under neat conditions. Nitrogen bicyclic bases that were previously shown to have enhanced the reactivity of DMC in methoxycarbonylation reaction by a BAc2 mechanism are herein used for the first time as efficient catalysts for cyclization reactions encompassing both BAc2 and BAl2 pathways. This synthesis procedure was also applied to a large scale synthesis of cyclic sugars, isosorbide and isomannide, starting from d-sorbitol and d-mannitol, respectively. The resulting anhydro sugar alcohols were obtained as pure crystalline compounds that did not require any further purification or crystallization. This journal is
Aricò,Evaristo,Tundo
p. A1176 - A1185
(2015/03/04)

METHOD OF MAKING ISOIDIDE
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)

Sustainable polyacetals from isohexides
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
supporting information
p. 3810 - 3818
(2014/08/05)

Intramolecular dehydration of mannitol in high-temperature liquid water without acid catalysts
Intramolecular dehydration of mannitol in high-temperature liquid water without adding any hazardous acid catalysts and its kinetic analyses were carried out. The dehydration behavior of mannitol was compared with that of sorbitol. 2,5-Anhydromannitol and 1,4-anhydromannitol were major products from the mannitol monomolecular dehydration in contrast with the only major product, 1,4-anhydrosorbitol, from the sorbitol monomolecular dehydration.
Yamaguchi, Aritomo,Sato, Osamu,Mimura, Naoki,Shirai, Masayuki
p. 45575 - 45578
(2014/12/12)

Direct amination of bio-alcohols using ammonia
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
p. 2905 - 2912
(2013/10/21)

Isolation of anhydro sugar hexitols by selective adsorbents
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)

ISOLATION OF ANHYDRO SUGAR ALCOHOLS BY SELECTIVE ADSORBENTS
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)

Synthesis of isoidide through epimerization of isosorbide using ruthenium on carbon
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.
p. 693 - 700
(2013/07/27)

DIURETICS
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)

Isosorbide-based cholinesterase inhibitors; replacement of 5-ester groups leading to increased stability
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.
scheme or table
p. 1045 - 1053
(2010/04/26)

NITRIC OXIDE DONOR COMPOUNDS
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)

ANGIOTENSIN II RECEPTOR ANTAGONISTS
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)

Method for purifying a composition containing at least one internal dehydration product of a hydrogenated sugar
The invention concerns a method for purifying a composition containing at least a product for internal dehydration of a hydrogenated sugar. The invention is characterised in that it comprises: (a) an optional step whereby said composition is treated, whether after re-dissolving or not, with at least a discoloration means; (b) a subsequent step whereby the composition, optionally treated with discoloration means, is treated with at least ion-exchanging means; (c) a subsequent step whereby the resulting composition is treated with at least discoloration means. Said method is in particular applicable to isohexide compositions, in particular isosorbide or isomannide. The resulting compositions, which exhibit particular characteristics in terms of purity and proportion of some impurities, constitute novel products for use in chemical, pharmaceutical, cosmetology and food industries.
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Page 6

(2008/06/13)

The Use of a Mannitol-Derived Fused Oxacycle as a Combinatorial Scaffold
An efficient and high-yielding solid-phase synthesis of a small library of compounds containing a cis-fused pyranofuran structural motive is descibed. With use of the cheap and readily available D-(+)-mannitol, a highly functionalized sugar template was synthesized and immobilized on a solid support via an olefinic linker. Modification of this two-point molecular scaffold and subsequent ring-closing metathesis/cleavage gave access to a series of functionalized conformationally constrained fused oxacycles.
Timmer, Mattie S. M.,Verdoes, Martijn,Sliedregt, Leo A. J. M.,Van Der Marel, Gijsbert A.,Van Boom, Jacques H.,Overkleeft, Herman S.
p. 9406 - 9411
(2007/10/03)

D-Isomannide in synthesis: Asymmetric Diels-Alder reactions with novel homochiral bis-imine Cu2+-catalysts
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
p. 1673 - 1679
(2007/10/03)

The solvent-free thermal dehydration of hexitols on zeolites.
Dehydration of galactitol, D-glucitol and D-mannitol at high temperature in the presence of molecular sieves without solvent under an argon atmosphere is described. Cyclodehydration products with retention or inversion of the configuration at asymmetric carbon atoms, were observed. Reaction of galactitol yielded racemic 1,4-anhydrogalactitol in a first step and then racemic 1,4:3,6-dianhydroiditol. Complete analytical separations of exhaustively O-acetylated reaction products were achieved by GC and structures were assigned using co-injection with standards.
Kurszewska, Maria,Skorupowa, Eugenia,Madaj, Janusz,Konitz, Antoni,Wojnowski, Wieslaw,Wisniewski, Andrzej
p. 1261 - 1268
(2007/10/03)

Synthesis and structure of 1,4:3,6-dianhydro-2-O-p-tosyl-D-mannitol
1,4:3,6-Dianhydro-2-O-p-tosyl-D-mannitol (3) has been isolated from the reaction of 1,4:3,6-dianhydro-D-mannitol (2) and p-toluenesulfonyl chloride (1:2 mole ratio) in pyridine in 19% yield after fractional crystallization. It crystallizes in the orthorhombic space group P212121 (Z = 4) with a = 6.064(2), b = 8.347(1) and c = 26.455(16) A. Disorder associated with the unsubstituted furanose ring provides two arrangements, rings B and C, with two sets of sites for both the hydroxyl group and a ring carbon atom: the relative occupancy of ring B: ring C = 0.53(1):0.47(1). Distinct H-bonding situations (both intra- and inter-molecular) are associated with the two arrangements. The conformations of the unsubstituted furanose ring with the weaker intramolecular H-bonding (ring B) and the tosyl-substituted ring (ring A) are very similar, being 1:2 mixtures of envelope [3E] and twist forms [3T4]: the stronger H-bonding in ring C results instead in a conformation made up from a 30:70 mixture of E0 and 4T0 forms. The 1H-NMR spectrum for 3 indicates that the average solution conformation is also a mixture of envelope and twist forms and is similar to that of the A/B solid-state arrangement.
Marr, Andrew,Wardell, James L.,Cox, Philip J.
p. 161 - 166
(2007/10/03)

A simple conversion of polyols into anhydroalditols
A simple procedure, which consists of direct heating of pyridinium chloride and the starting material, is described for the dehydration of alditols. Anhydroalditols, of great interest for various applications, are thus obtained, and the selectivity of the reaction is discussed. Some selective protections for further uses of these products are studied.
Duclos,Fayet,Gelas
p. 1087 - 1090
(2007/10/02)

Acyloxonium ions in the high-yielding synthesis of oxolanes from alditols, hexoses, and hexonolactones catalysed by carboxylic acids in anhydrous hydrogen fluoride
Treatment of D-glucono-1,5- or D-mannono-1,4-lactone with anhydrous hydrogen fluoride catalysed by formic or acetic acid yields 3,6-anhydro-D-glucono- and -D-mannono-1,4-lactone, respectively.Similarly, D-mannitol is converted into 1,4-anhydro-D-mannitol and subsequently into the 1,4:3,6-dianhydride, whereas D-glucitol forms exclusively the 3,6-anhydride and, on further reaction, 1,4:3,6-dianhydro-D-glucitol.D-Glucose and 2-acetamido-2-deoxy-D-glucose are also converted into the corresponding 3,6-anhydrides by reaction with hydrogen fluoride and formic acid.13C-N.m.r. spectroscopy indicates that the reactions involve intermediate dioxolanyium ions.
Defaye, Jacques,Gadelle, Andree,Pedersen, Christian
p. 191 - 202
(2007/10/02)

THE STRUCTURE OF ADDUCTS OF THE THREE DIASTEREOISOMERIC 1,4:3,6-DIANHYDROHEXITOLS AND LANTHANIDE CHELATES IN ACETONE
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.
p. 2885 - 2891
(2007/10/02)

1,4:3,6-DIANHYDRO-2,5-DIDEOXY-2,5-BIS(DIPHENYLPHOSPHINO)-L-IDITOL. A NEW CHIRAL LIGAND FOR ASYMMETRIC HYDROGENATION WITH RHODIUM COMPLEXES AS CATALYSTS
A new chiral 1,4-diphosphine, 1,4:3,6-dianhydro-2,5-dideoxy-2,5-bis(diphenylphosphino)-L-iditol, has been prepared from D-mannitol.Rhodium complexes of this ligand are asymmetric homogeneous hydrogenation catalysts for dehydroamino acids, giving (S)-amino acids in 21-58percent optical yields.
Bakos, Jozsef,Heil, Balint,Marko, Laszlo
p. 249 - 252
(2007/10/02)

Acid Catalyzed Dehydration of Alditols. Part I. D-Glucitol and D-Mannitol
The acid catalyzed dehydration of D-glucitol and D-mannitol has been studied using 13C NMR spectroscopy to monitor the reactions.The products formed were identified and rate constants were measured.Dehydration of (1S)-1-2H-D-mannitol with 3 M sulfuric acid was shown to yield (1R)-1-2H-1,4:3,6-dianhydro-D-mannitol, showing that dehydration of D-mannitol to 1,4-anhydro-D-mannitol and, subsequently, to the 1,4:3,6-dianhydride takes place with inversion at the primary carbon atom.
Bock, Klaus,Pedersen, Christian,Thoegersen, Henning
p. 441 - 450
(2007/10/02)

Preparation of bicyclic hexitol anhydrides by using acidic cation-exchange resin in a binary solvent. 13C-N.m.r. spectroscopy confirms configurational inversion in chloride displacement of methanesulfonate in isomannide and isosorbide derivatives
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Goodwin, James C.,Hodge, John E.,Weisleder, David
p. 133 - 141
(2007/10/02)