- Reactivity–Stereoselectivity Mapping for the Assembly of Mycobacterium marinum Lipooligosaccharides
-
The assembly of complex bacterial glycans presenting rare structural motifs and cis-glycosidic linkages is significantly obstructed by the lack of knowledge of the reactivity of the constituting building blocks and the stereoselectivity of the reactions i
- Hansen, Thomas,Ofman, Tim P.,Vlaming, Joey G. C.,Gagarinov, Ivan A.,van Beek, Jessey,Goté, Tessa A.,Tichem, Jacoba M.,Ruijgrok, Gijs,Overkleeft, Herman S.,Filippov, Dmitri V.,van der Marel, Gijsbert A.,Codée, Jeroen D. C.
-
supporting information
p. 937 - 945
(2020/12/09)
-
- A Domino Epoxide Ring-Opening Xanthate Migration Reaction: An Alternative Entry to Thiosugars
-
A sterereospecific and efficient synthesis of thiosugars derived from levoglucosenone and methyl α-d-glucopyranoside was developed by a domino epoxide ring opening- xanthate migration to afford 1,3-oxathiolane-2-thiones in high yields. The stereochemical outcome of the new C–S bond was defined by the configuration of the starting materials. The 1,3-oxathiolane-2-thiones were subsequently submitted to a second tandem reaction affording the corresponding 2,3-episulfide alcohols. The thiosugars obtained are useful building blocks for the synthesis of thiooligosaccharides with potential biological properties.
- Comba, María B.,Mangione, María I.,Suárez, Alejandra G.,Sarotti, Ariel M.,Spanevello, Rolando A.
-
supporting information
p. 6848 - 6856
(2018/12/11)
-
- Hybridisation potential of 1′,3′-Di-O-methylaltropyranoside nucleic acids
-
In further study of our series of six-membered ring-containing nucleic acids, different 1′,3′-di-O-methyl altropyranoside nucleoside analogs (DMANA) were synthesized comprising all four base moieties, adenine, cytosine, uracil and guanine. Following assembly into oligonucleotides (ONs), their affinity for natural oligonucleotides was evaluated by thermal denaturation of the respective duplexes. Data were compared with results obtained previously for both anhydrohexitol (HNAs) and 3′-O-methylated altrohexitol modified ONs (MANAs). We hereby demonstrate that ONs modified with DMANA monomers, unlike some of our previously described analogues with constrained 6-membered hexitol rings, did not improve thermodynamic stability of dsRNA complexes, most probably in view of an energetic penalty when forced in the required 1C4 pairing conformation. Overall, a single incorporation was more or less tolerated or even positive for the adenine congener, but incorporation of a second modification afforded a slight destabilization (except for A), while a fully modified sequence displayed a thermal stability of -0.3°C per modification. The selectivity of pairing remained very high, and the new modification upon incorporation into a DNA strand, strongly destabilized the corresponding DNA duplexes. Unfortunately, this new modification does not bring any advantage to be further evaluated for antisense or siRNA applications.
- Venkatesham, Akkaladevi,Kachare, Dhuldeo,Schepers, Guy,Rozenski, Jef,Froeyen, Mathy,Van Aerschot, Arthur
-
p. 4020 - 4041
(2015/05/06)
-
- Diaminohexopyranosides as ligands in half-sandwich ruthenium(II), rhodium(III), and iridium(III) complexes
-
The syntheses of methyl 2,3-diamino-4,6-O-benzylidene-2,3-dideoxy-α-d-hexopyranosides of glucose, mannose, gulose, and talose and methyl 2-amino-4,6-benzylidene-2,3-dideoxy-3-tosylamido-α-d-glucopyranoside are exhaustively presented, as well as their application as ligands in half-sandwich ruthenium(II), rhodium(III), and iridium(III) complexes. The complex formation occurs highly diastereoselectively, creating a stereogenic metal center. The molecular structures of the ligands and their complexes were investigated by X-ray structure analysis, NMR spectroscopy, polarimetry, and DFT methods. The diamino monosaccharide complexes have been subjected to antitumor activity studies. In vitro tests of a few ruthenium complexes against different cancer cell types showed antiproliferative activities 4-10 times lower than that of cisplatin.
- B?ge, Matthias,Fowelin, Christian,Bednarski, Patrick,Heck, Jürgen
-
p. 1507 - 1521
(2015/05/13)
-
- α- and β-Lipomycin: Total syntheses by sequential stille couplings and assignment of the absolute configuration of all stereogenic centers
-
40 years ago spectroscopy, derivatization, and degradation revealed the structures of α-lipomycin and its aglycon β-lipomycin except for the configurations of their side-chain stereocenters. We synthesized all relevant β-lipomycin candidates: the (12R,13S
- Hofferberth, Max L.,Brückner, Reinhard
-
supporting information
p. 7328 - 7334
(2014/07/21)
-
- SUGAR-LINKER-DRUG CONJUGATES
-
The present disclosure relates to sugar-linker-drug conjugates, of the formula [A-B-]n-L-D, wherein A is a saccharide; B is a spacer, n is an integer selected from 1 to 3; L is a linker group and D is a drug having a chemically reactive functional group selected from the group consisting of a primary or secondary amine, hydroxyl, sulfhydryl, carboxyl, aldehyde and ketone. Pharmaceutical compositions comprising the conjugates and methods of using thern are also provided.
- -
-
Paragraph 0237
(2014/09/29)
-
- SACCHARIDE CONJUGATES
-
This invention relates to compounds comprising a saccharide conjugated to an imaging agent or a reporter group, compositions comprising them and methods of using them. Specifically BLM-disaccharide and BLM-monosaccharide conjugates containing different linker groups and an imaging agent or a reporter group are provided for the targeting and imaging of tumors.
- -
-
Paragraph 0228; 0230
(2014/10/04)
-
- AN EFFICIENT AND SCALABLE PROCESS FOR THE MANUFACTURE OF FONDAPARINUX SODIUM
-
The present invention relates to a process for the synthesis of the Factor Xa anticoagulent Fondaparinux and related compounds. The invention relates, in addition, to efficient and scalable processes for the synthesis of various intermediates useful in the synthesis of Fondaparinux and related compounds.
- -
-
Page/Page column 21; 22
(2013/08/15)
-
- Synthesis of ribo-hexopyranoside- and altrose-based azacrown ethers and their application in an asymmetric Michael addition
-
The synthesis of four new ribo-hexopyranoside-based chiral lariat ethers of monoaza-15-crown-5 type and two altropyranoside-based crown ethers were elaborated. Our syntheses utilized the regioselective ring opening of the oxiran moiety of the 2,3-anhydro sugars by nucleophilic reagents to afford the key intermediates. The reaction of methyl-2,3-anhydro-4,6-O-benzylidene-α-d- mannopyranoside with ethanolamine is especially of interest to afford a 3-substituted altropyranoside. One of the ribo-hexopyranoside-based lariat ethers with a 4-methoxyphenyl substituent induced an enantioselectivity of 80% when used as catalyst in the Michael addition of diethyl acetamidomalonate to trans-β-nitrostyrene under phase transfer catalytic conditions.
- Rapi, Zsolt,Bakó, Péter,Keglevich, Gy?rgy,Sz?llsy, áron,Drahos, László,Hegeds, László
-
-
- A scalable approach to obtaining orthogonally protected β-d-idopyranosides
-
A practical method to obtain orthogonally protected d-idopyranose from d-galactose has been developed, which is the first method to enable synthesis of the challenging β-d-idopyranoside linkage. The method relies on a key double inversion at O-2 and O-3 in an easily prepared d-galactose derivative, which proceeds regio- and stereoselectively through a 2,3-anhydrotalopyranoside; reaction using a selection of alkoxides affords exclusively the 3-O-alkylidopyranoside, which can be used to generate an orthogonally protected monosaccharide. The process is scalable and requires minimal purification, so it could be used to produce building blocks to aid in the synthesis of various β-idopyranose-containing oligosaccharide targets to further probe their biological functions.
- Hevey, Rachel,Morland, Alizee,Ling, Chang-Chun
-
p. 6760 - 6772
(2012/09/25)
-
- Synthesis of 3-amido-3-deoxy-β-d-talopyranosides: All-cis-substituted pyranosides as lectin inhibitors
-
3-Deoxy-3-amino-β-d-talopyranosides have been synthesized for the first time. The amines were obtained from galactopyranosides through 2,3-anhydrogulosides that were opened to idosides followed by an oxidation/reductive amination sequence. From the amines, 11 corresponding 3-deoxy-3-arylamido-β-talopyranosides have been synthesized and evaluated as inhibitors against galectin-1, -2, -3, -4C, -4N, -7, -8N and -9N. The synthesized talosamides showed selectivity for Galectin-4C with three of the monosaccharides having dissociation constants at around 100 μM against the lectin, which is more than two orders of magnitude better than methyl β-galactoside and significantly better than the previous best galectin-4C monosaccharide inhibitor.
- ?berg, Christopher T.,Noresson, Ann-Louise,Leffler, Hakon,Nilsson, Ulf J.
-
experimental part
p. 9164 - 9172
(2011/12/03)
-
- Assembly of digitoxin by gold(I)-catalyzed glycosidation of glycosyl o-alkynylbenzoates
-
Digitoxin, a clinically important cardiac trisaccharide, was assembled efficiently from digitoxigenin and 3,4-di-O-tert-butyldiphenylsilyl-d- digitoxosyl o-cyclopropylethynylbenzoate in 9 steps and 52% overall yield via alternate glycosylation and protecting group manipulation. The present synthesis showcases the advantage of the gold(I)-catalyzed glycosylation protocol in the synthesis of glycoconjugates containing acid-labile 2-deoxysugar linkages.
- Ma, Yuyong,Li, Zhongzhen,Shi, Hefang,Zhang, Jian,Yu, Biao
-
body text
p. 9748 - 9756
(2012/01/04)
-
- Stereoselective synthesis of 2,3-diamino-2,3-dideoxy-β-d- mannopyranosyl uronates
-
With the aim to find an efficient synthetic procedure for the construction of 2,3-diamino-2,3-dideoxy-β-d-mannuronic acids, we evaluated three mannosyl donors: (S)-phenyl 4,6-di-O-acetyl-2,3-diazido mannopyranoside, (S)-phenyl 2,3-diazido-4,6-O-benzylidene mannopyranoside, and (S)-phenyl 2,3-diazido mannopyranosyl methyl uronate. The first two mannosylating agents are rather unselective or slightly α-selective in their condensation with three different acceptors. The mannuronic acid donor on the other hand reliably provides the desired β-mannosidic linkage. A mechanistic rationale is put forward to account for the different behavior of the three donor types. Suitably protected 2,3-diazido mannuronic acids were employed to construct the all-cis-linked tetrasaccharide repeating unit of the capsular polysaccharide of Bacillus stearothermophilus, featuring two 2,3-diacetamido-2,3-dideoxy-β-d- mannuronic acids.
- Walvoort, Marthe T. C.,Moggre, Gert-Jan,Lodder, Gerrit,Overkleeft, Herman S.,Codee, Jeroen D. C.,Van Der Marel, Gijsbert A.
-
experimental part
p. 7301 - 7315
(2011/11/12)
-
- Chemoenzymatic synthesis of ring18O-labeled sialic acid
-
Methyl 4,6-O-benzylidene-α-D-glucopyranoside was converted into methyl 2-azido-2-deoxy-4,6-O-benzylidene-α-D-altropyranoside via a synthetic route that incorporated two inversions of configuration. Activation of the C-3 hydroxyl group as a triflate ester
- Indurugalla, Deepani,Bennet, Andrew J.
-
scheme or table
p. 1005 - 1009
(2009/02/08)
-
- Efficient formation and cleavage of benzylidene acetals by sodium hydrogen sulfate supported on silica gel
-
NaHSO4SiO2 was used as an efficient heterogeneous catalyst for both the formation and the cleavage of benzylidene acetals. This catalyst is compatible with many functional or protective groups. Under different solvent systems, either the formation or the cleavage of benzylidene acetals was carried out smoothly in excellent yields and with good chemoselectivity. Georg Thieme Verlag Stuttgart.
- Niu, Youhong,Wang, Ning,Cao, Xiaoping,Ye, Xin-Shan
-
p. 2116 - 2120
(2008/02/09)
-
- Base-promoted rearrangement of sugar epoxides to unsaturated sugars
-
(Chemical Equation Presented) A simple and efficient method for rearranging 2,3-anhydro carbohydrates to unsaturated sugars has been developed. The exceptionally mild reaction conditions and high stereoselectivity should make this an attractive method for the preparation of unsaturated carbohydrate derivatives.
- Wang, Yuan,Li, Qin,Cheng, Shuihong,Wu, Yanfen,Guo, Dongjie,Fan, Qiu-Hua,Wang, Xiaofang,Zhang, Li-He,Ye, Xin-Shan
-
p. 5577 - 5579
(2007/10/03)
-
- Enantioselective synthesis of phyllanthurinolactone, a leaf-closing substance of Phyllanthus urinaria L., and its analogs toward the development of molecular probes
-
We report enantioselective synthesis of phyllanthurinolactone (1), a leaf-closing substance of Phyllanthus urinaria L., and its analogs with sugars other than D-glucose. Structure-activity relationship study using them revealed that the structure of the sugar moiety did not affect their bioactivity at all. This result is very important for the development of molecular probes based on the structure of 1.
- Urakawa, Yoshifumi,Sugimoto, Takanori,Sato, Hirotaka,Ueda, Minoru
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p. 5885 - 5888
(2007/10/03)
-
- Synthesis of D-rubranitrose by using a novel method for constructing functionalized branched-chain structures
-
Convenient synthesis of D-rubranitrose from D-glucose was achieved by using simple and novel methods for deoxygenation and construction of functionalized branched-chain structures. The total yield of D-rubranitrose from methyl 4,6-O-benzylidene-α-D-glucop
- Sato, Ken-Ichi,Miyama, Daisuke,Akai, Shoji
-
p. 1523 - 1525
(2007/10/03)
-
- Neighboring-group participation in benzylidene acetal ring-opening of a 2-cyano-2-deoxypyranoside derivative by diethylaluminum cyanide
-
The oxirane ring-opening of an anhydro sugar with diethylaluminum cyanide (Et2AlCN) is a direct approach for obtaining a cyano derivative. Methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside showed anomalous chemical behavior when treated with Et2AlCN. The reaction afforded the corresponding β-cyanohydrin as the minor component from a mixture of compounds resulting from the benzylidene acetal ring-opening caused by the attack of ethyl or cyano groups.
- Mangione, Maria I.,Suarez, Alejandra G.,Spanevello, Rolando A.
-
p. 2177 - 2183
(2007/10/03)
-
- Synthetic approach to tetrahydrofuran units and five-membered ring lactones fused to hexopyranosides
-
A stereoselective synthesis of the miharamycin sugar moiety epimer at C-3′ was accomplished in high yield starting from an appropriate (Z)-Wittig product, synthesized by Wittig reaction of a 4,6-O-benzylidene protected hexopyranosid-3-ulose with [(ethoxycarbonyl)methylene]triphenylphosphorane followed by iodine promoted isomerisation of the (E)-Wittig product formed. Reduction of the (Z)-isomer obtained in quantitative yield, cyclisation and dihydroxylation with osmium tetroxide, gave the target molecule containing a cis-fused tetrahydrofuran ring in its structure. Synhesis of five-membered rings trans-fused to the hexopyranosidic units succeeded via two different synthetic pathways. Stereoselective Reformatsky reaction of a 2,6-di-O-pivaloyl protected hexopyranosid-3-ulose, followed by cyclisation with dimethylzinc gave a 3,4-trans-fused lactone. The approach using the reaction of 2,3-and 3,4-epoxides with the dianion of phenylselenoacetic acid led to low yield but novel phenylseleno derivatives of trans-fused five-membered rings, namely a phenylselenolactone 2,3-trans-fused to a 4,6-O-benzylidene-hexopyranoside and a phenylselenolactenol 3,4-trans-fused to a 6-O-pivaloyl-hexopyranoside.
- Rauter, Amelia P.,Oliveira, Olga,Canda, Tana,Leroi, Estelle,Ferreira, Humberto,Ferreira, Maria J.,Ascenso, Jose A.
-
p. 257 - 273
(2007/10/03)
-
- Application of focused microwaves to the scale-up of solvent-free organic reactions
-
A series of typical solvent-free reactions have been safely and beneficially scaled-up to several hundred grams in a larger batch reactor (Synthewave 1000) with yields equivalent to those obtained under similar conditions (temperature, reaction time) in laboratory-scale experiments (Synthewave 402). They concern potassium acetate alkylation, regioselective phenacylation of 1,2,4-triazole, deethylation of 2-ethoxy-anisole, and typical examples in carbohydrate chemistry (peracetylation, glycosylation, saponification, halogenation, and epoxidation of D-glucopyranosides).
- Cleophax,Liagre,Loupy,Petit
-
p. 498 - 504
(2013/08/07)
-
- Efficient synthesis of epoxides from vicinal diols via cyclic sulfates
-
Reaction of cyclic sulfates of vic-diols with sodium hydroxide in THF-MeOH produced the corresponding epoxides in excellent isolated yields at room temperature. Cyclic sulfates of trans-diols gave cis-epoxides, and cyclic sulfates of cis-diols afforded tr
- Jang,Joo,Cho
-
p. 4489 - 4494
(2007/10/03)
-
- Enantiospecific approach to a quinane skeleton related to pentalenolactones
-
A novel and general approach has been delineated for the enantiomerically pure synthesis of the angularly fused tricyclic system of the pentalenolactone family of compounds. D-Glucose is used as starting material and a diasteroselective Diels-Alder reaction sets the elements for the ring junctions.
- Pellegrinet, Silvina C.,Spanevello, Rolando A.
-
p. 8623 - 8626
(2007/10/03)
-
- One-pot conversion of 1,2-diols to epoxides: Convenient preparation of methyl 2,3-anhydro-5-O-trityl-β-D-lyxofuranoside and methyl 2,3,-anhydro-4,6-O-benzylidene-α-D-mannopyranoside
-
Tosyl chloride and sodium hydride are used to convert some 1,2-diols to epoxides in one-pot in enantiomerically/diastereomerically pure form.
- Srinivasa Murthy,Gaitonde,Prahlada Rao
-
p. 285 - 289
(2007/10/02)
-
- Chemistry of oxo-sugars. (2). Regio- and stereo-selective synthesis of methyl D-hexopyranosiduloses and identification of their forms existing in solutions
-
Sixteen oxo derivatives of methyl D-hexopyranosides with various regio-and stereo-chemistries were selectively synthesized by direct oxidation of non-protected methyl glycosides by the bistributyltin oxide-bromine method or by oxidation of partially protected glycosides followed by deprotection. The forms of these oxoglycosides existing in pyridine-d5 and in H2O (D2O) were investigated by means of 13C-NMR spectroscopy, and it was found that interconversion between oxo and hydrate forms of oxoglycosides readily takes place.
- Liu,Sato,Tsuda
-
p. 491 - 501
(2007/10/02)
-
- CYCLOADDITION OF CHIRAL AZOMETHINE YLIDES FROM AMINOSUGAR N-OXIDES. ENANTIOSELECTIVE SYNTHESIS OF 3,4-DISUBSTITUTED PYRROLIDINES
-
The base deprotonation method, applied to amino-sugar N-oxides prepared from methyl 2,3-anhydro-4,6-O-benzylidene-α-D-mannopyranoside (8) and methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside (9), allows the easy generation of complex and very reactive sugar azomethine ylides.Fair yields of the major diastereomeric pyrrolidines resulting from cycloaddition to stilbene are thus obtained with good asymmetric induction.The easy elimination of the chiral appendage as starting epoxides gives access to the enantiomerically enriched 3,4-diphenylpyrrolidines.
- Chastanet, Jacqueline,Fathallah, Hassana,Negron, Guillermo,Roussi, Georges
-
p. 1565 - 1572
(2007/10/02)
-
- Reactions of Some Pyranoside Diol Monotriflates with Nucleophiles and Bases
-
Reaction of pyranoside diol (equatorial) monotriflates with soft, nonbasic nucleophiles is a useful way to make axial heteroatom-substituted and "epimerized" pyranosides, particularly where a fused acetal ring inhibits ring contraction.Among the substrates examined (1,2,3,4,35), only 4 shows a strong tendency to give ring-contracted products.The reaction of 1-3 with more basic nucleophiles (F(1-), t-BuO(1-)) leads to the anhydrosugars 8, 25, and 26, respectively.The SN2 reaction of 35 with tetra n-butylammonium iodide forms the basis for a new synthesis of the Cerny epoxide 32.
- Knapp, Spencer,Naughton, Andrew B. J.,Jaramillo, Carlos,Pipik, Brenda
-
p. 7328 - 7334
(2007/10/02)
-
- Lithium aluminium hydride reduction of glycopyranoside-monosulfonates: Formation of branched furanosides
-
Lithium aluminum hydride reduction of glycopyranoside-monotosylates caused three reactions: (1) stereospecific 1,2-shift, producing branched furanosides (path A), (2) reductive O-S bond cleavage, producing the original glycosides (path B), and (3) reductive removal of the tosyloxy group, producing deoxyglycosides (path C). The path A reaction was particularly evident for the monotosylates at 2-O, 3-O, and 4-O: for example, methyl 2-O-tosyl-α-D-xylopyranoside gave methyl 2-deoxy-2-C-(hydroxymethyl)-α-D-α-erythrofuranoside in 60% yield. This reaction opens a new and efficient route to branched glycofuranosides of natural and unnatural type. Stereo-electronic requirements of this reaction in relation to the balance of the other two reactions are discussed.
- Tsuda,Nishimura,Ito
-
p. 1983 - 1989
(2007/10/02)
-
- The 'Off-template' Problem: Towards a General Solution
-
Wittig reaction of the t-butyldimethylsilylated C-3 ketone methyl 4,6-O-benzylidene-2-O-(t-butyldimethylsilyl)-α-D-ribo-hexopyranosid-3-uloside leads exclusively to C-2 alkenes, providing an efficient synthesis of these potentially useful intermediates.Alternatively, the corresponding t-butyldiphenylsilyl ether, prepared with complete regiospecificity from methyl 4,6-O-benzylidene-α-D-glucopyranoside, gives a C-3 alkene on oxidation and Wittig reaction.Deprotection, hydrogenation and cyclization of this product leads to the cis-fused butyrolactone, methyl 4,6-O-benzylidene-3-deoxy-3-(ethoxycarbonyl)-2,3-butyrolactone-α-D-allopyranoside, which is alkylated stereospecifically to give methyl 4,6-O-benzylidene-3-deoxy-3-(prop-2-yloxycarbonyl)-2,3-butyrolacto-α-D-allopyranoside.This procedure provides a general solution of the 'off-template' problem of carbohydrate-based natural product synthesis.
- Rashid, Abdul,Taylor, G. Mark,Wood, William W.,Alker, David
-
p. 1289 - 1296
(2007/10/02)
-
- Tripyranoside Precursors for Ansamycins. Pyranosidic Homologation. 6.
-
The primary and secondary alcohols of the dipyranoses 6 and 9a are used as implements for elaborating the upper pyranoside rings of the tripyranoses 27 and 28, respectively.Compounds 27 contains seven of the eight chiral centers of rifamycin S, while 28 fixes seven of the nine chiral centers of streptovaricin A.For the synthetic procedures, the primary alcohol is oxidized to an aldehyde, which is subjected to olefination with a phosphorane of the type PH3P=CHCH(OR)2.Treatment with pyridinium p-toluenesulfonate, specifically, in the presence of an alcohol causes cycliz ation with secondary the alcohol, resulting in a hexenepyranoside, which is glycositated in situ by the alcohol.The resulting hexenepyranoside is then epoxidized, and for this process, a new procedure was developed that involves hydroxylation with osmium tetroxide and treatment of the cis diol so formed with phosgene iminium chloride (Viehe's salt> to give a chloro carbamate, which then reacts with methoxide to give the desired epoxide.Opening of the ring with dimethylmagnesium then completes the requirements for the upper ring.
- Fraser-Reid, Bert,Molino, Bruce F.,Magdzinski, Leon,Mootoo, David R.
-
p. 4505 - 4511
(2007/10/02)
-
- The Synthesis and Attempted Cyclization of Some α-Acyloxy Carbohydrate Epoxides
-
The preparation of eight α-acyloxy carbohydrate epoxides is described, together with attempts to cyclize these compounds.
- Jones, Keith,McEvoy, John,Wood, William W.,Scott, Ian L.
-
p. 1774 - 1790
(2007/10/02)
-
- Phase Transfer-Catalyzed Preparation of Oxiranes
-
Oxiranes 3 are prepared in 70-85percent yields by treating 1,2-diols 1 with one molar equivalent of p-toluenesulfonyl (2) or methanesulfonyl chloride (2') under phase transfer conditions.
- Szeja, W.
-
p. 983 - 985
(2007/10/02)
-
- A Contribution to the Structural Assignment of Positional Isomers of Bis-galacto and Bis-manno Crown Ethers
-
A structural assignment to the positional isomers of bis-galacto 3/4 and bis-manno crown ethers 6/7 is not possible using spectroscopic data only.Crown ethers 3 and 6 with a 3/3' and 2/2'conjunction of the two sugar moieties are available rationally via the "half crowns" 11 and 13 and are thus identifiable.
- Hain, Wolfgang,Lehnert, Rudolf,Walz, Bernhard,Schroeder, Gerhard
-
p. 1046 - 1051
(2007/10/02)
-
- STEREOSELECTIVE SYNTHESIS OF(-)-α-MULTISTRIATIN FROM D-GLUCOSE
-
D-glucose was converted into (-)-α-multistriatin, the aggregation pheromone of the Europian elm bark beetle, via a highly stereoselective eighteen-step route
- Sum, Phaik-Eng,Weiler, Larry
-
p. 327 - 334
(2007/10/02)
-
- Epoxidation with Triphenylphosphine and Diethyl Azodicarboxylate. II Methyl 4,6-O-Benzylidene-D-aldohexopyranosides
-
Epoxidation of the conformationally rigid diaxial diol methyl 4,6-O-benzylidene-α-D-altropyranoside with triphenylphosphine and diethyl azodicarboxylate proceeds in high yield under very mild conditions to give the corresponding 2,3-anhydro-D-mannoside.By contrast, the corresponding diequatorial diol, methyl 4,6-O-benzylidene-α-D-glucopyranoside, undergoes epoxidation only under forcing conditions and gives the D-allo isomer.Evidence is presented for the formation of a cyclic phosphorane intermediate in the latter case.
- Guthrie, R. D. (Gus),Jenkins, Ian D.
-
p. 1997 - 2000
(2007/10/02)
-
- SELECTIVE ESTERIFICATION OF METHYL 4,6-O-BENZYLIDENE-α-D- AND β-D-GALACTOPYRANOSIDE IN A CATALYTIC TWO-PHASE SYSTEM
-
Selective tosylation of methyl 4,6-O-benzylidene-α-D- (1) and β-D-galactopyranoside (8) in a catalytic two-phase system (CTP system) yields preferentially 2-O-p-toluenesulfonate and 3-O-p-toluenesulfonate, respectively.In the course of unimolar benzoylation of 1 and 8, under similar conditions, a migration of the acyl group takes place and an equilibrium mixture is obtained.Esterification of 1 and 8 with benzoyl chloride under CTP conditions, in presence of an aqueous sodium hydroxide solution, saturated with sodium perchlorate, afforded in preponderant yields 2-O-benzoate and 3-O-benzoate, respectively.
- Szeja, Wieslaw
-
p. 1803 - 1808
(2007/10/02)
-