- An Improved, Versatile, and Easily Scalable Synthesis of Sphingomyelins: Application to Stable Isotope Labeling
-
With a view to make conveniently labeled mass spectrometry standards available, a set of deuterated sphingomyelins were prepared by a new expedient, flexible, robust, scalable, and high-yielding synthetic scheme starting from 2-azido-3- O -benzoylsphingos
- Blankenstein, J?rg,Le Strat, Franck,Pérard, Serge,Philippe, Nicolas,Roy, Sébastien
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supporting information
p. 2106 - 2110
(2020/08/17)
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- Synthesis of photolabile group protected anomeric acetals and its application in carbohydrate synthesis with the assistance of continuous flow photo-reactor
-
Selective deprotection of photolabile anomeric 2-nitrobenzyl acetals was achieved using continuous flow photo-reactor (UV radiation at 355 nm) in methanol-water. Various protecting groups such as acetyl, benzyl, benzoyl, benzylidine, TBS, etc. were found to be highly stable during the photolysis.
- Tiwari, Varsha,Badavath, Vishnu Nayak,Singh, Adesh Kumar,Kandasamy, Jeyakumar
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p. 227 - 236
(2020/03/18)
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- NATURAL AND SYNTHETIC DITERPENE GLYCOSIDES, COMPOSITIONS AND METHODS
-
Novel diterpene glycosides isolated from Stevia extract as well as diterpene glycosides that are synthetically prepared are provided herein. Compositions and consumables comprising the novel diterpene glycosides are also provided herein. Methods of enhancing the sweetness and/or flavor of consumables using the novel diterpene glycosides, methods of preparing compositions and consumables comprising the novel diterpene glycosides, methods of purifying the novel diterpene glycosides and methods of synthesizing the diterpene glycosides are also provided.
- -
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Page/Page column 99; 128
(2019/08/12)
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- 5-FLUORO-C-(ARYL OR HETEROCYCLYL)-GLYCOSIDE DERIVATIVES USEFUL AS DUAL SGLT1 / SGLT2 MODULATORS
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The present invention is directed to 5-fluoro-C-(aryl or hetercyclyl)-glycoside derivatives, pharmaceutical compositions containing them and their use in the treatment of disorders and conditions modulated by SGLT activity, more particularly dual SGLT1/2 activity.
- -
-
Paragraph 0387
(2019/02/28)
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- METHOD OF PRODUCING GALACTOOLIGOSACCHARIDE, AND INTERMEDIATE THEREOF
-
PROBLEM TO BE SOLVED: To provide a method of producing a galactooligosaccharide that may cause the onset of allergic reaction, and an intermediate thereof. SOLUTION: A method of producing a galactooligosaccharide represented by the general formula (1) comprises addition of the 1-position of protected galactobiose to the 6-position hydroxy group of protected lactose of formula (5), and subsequent deprotection of a hydroxy group protecting group. SELECTED DRAWING: Figure 5 COPYRIGHT: (C)2018,JPOandINPIT
- -
-
Paragraph 0051-0052
(2018/04/21)
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- Oligosaccharide compound and its manufacture and its intermediate
-
The purpose of the present invention is to provide an oligosaccharide with high versatility that can produce a protected sulfate oligosaccharide that can become a manufacturing intermediate of polysulfated hyaluronic acid, and to provide a manufacturing method therefor and an intermediate thereof. Position 2 amino groups in glucosamine, galactosamine, and the like can react with saccharide receptors having an electron attracting group such as glucuronic acid and protected sulfate groups, by using a saccharide donor protected by a specific protective group.
- -
-
Paragraph 0237; 0238; 0239
(2018/04/14)
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- Α - galactose ceramide new isomer and its synthetic method
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The invention provides an alpha-galactosyl ceramide new isomer and its synthetic method. Configuration of sphingosine chain is changed to 4,5-cis double bond sphingosine chain. According to the invention, reaction steps are shortened, yield is raised, and aftertreatment and purification steps are omitted. The synthetic method can be used for total synthesis of similar glycosyl ceramide and satisfies wide range of development, research and application of different glycosyl ceramide.
- -
-
Paragraph 0026; 0027
(2017/10/31)
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- Synthesis of an allergy inducing tetrasaccharide “4P-X”
-
4P-X (β-D-galactopyranosyl-(1?→?4)-β-D-galactopyranosyl-(1?→?6)-[β-D-galactopyranosyl-(1?→?4)]-β-D-glucopyranose) is included in galacto-oligosaccharides (GOSs) produced by β-galactosidase derived from Bacillus circulans. 4P-X has been known to induce particularly strong allergies. High purity 4P-X is essential for use as a standard to quantify the amount of 4P-X in GOSs; however, the isolation of high purity 4P-X has never been reported. In this study, we achieved the synthesis of 4P-X by a combination of organic and enzymatic chemical syntheses in a short time. This is the first report of isolated, high purity 4P-X.
- Moriya, Takashi,Nagahata, Naoki,Odaka, Rei,Nakamura, Hirohide,Yoshikawa, Jun,Kurashima, Katsumi,Saito, Tadao
-
supporting information
p. 44 - 49
(2017/01/22)
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- 4,5-Cis Unsaturated α-GalCer Analogues Distinctly Lead to CD1d-Mediated Th1-Biased NKT Cell Responses
-
The total synthesis of 4,5-cis unsaturated α-GalCer analogues was achieved, and their immune-response altering activity was assessed in vitro as well as in vivo in mice. Using glycosyl iodide as a glycosyl donor, construction of the sphingosine unit was shortened by four steps and single α-stereoselectivity was achieved in good yield (67%). With regard to the therapeutic use of α-GalCer, the novel analogues (1b and 1c) distinctly induced a Th1-biased cytokine response, avoiding induction of a contradictory response and overstimulation.
- Cui, Yanli,Li, Zhiyuan,Cheng, Zhaodong,Xia, Chengfeng,Zhang, Yongmin
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p. 1209 - 1215
(2015/06/25)
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- Tertiary Amine Promoted Asymmetric Aldol Reaction of Aldehydes
-
The direct asymmetric self-aldol reactions of various α-oxyaldehydes catalyzed by tertiary amines have been demonstrated. By using 10 mol-% of quinine catalyst, dimerization products have been prepared in high yields, with good anti-diastereocontrol, and up to 80% ee. The presented enolate-mediated synthesis of protected tetrose sugars has never been accomplished before by chiral tertiary amine organocatalysts.
- Gut, Bartosz,Mlynarski, Jacek
-
supporting information
p. 5075 - 5078
(2015/08/18)
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- Regioselective Monoesterification Study of the Diol in 1-C-(4,6-O-Benzylidene-β-D-glucopyranosyl) Acetone
-
1-C-(4,6-O-Benzylidene-β-D-glucopyranosyl) acetone has been studied in a catalytic system consisting of triethylamine-p-dimethylaminopyridine (TEA-DMAP) in the presence of a number of esterification reagents in dichloromethane. It was found that all-protected and monoprotected products form simultaneously. However, the regioselectivity tends to favor the 3-substituted derivative. Structural parameters have been determined by 1H NMR, 13C NMR, 1H-1H correlation spectroscopy, and elemental analysis. Furthermore, a possible mechanism for the formation of intramolecular hydrogen-bond networks between the carbonyl group and 2-OH was described. The energy changes of the transition state in this reaction, as determined by a molecular modelling study, provided further evidence to assign the relative reactivities of each individual hydroxyl group.
- Zhang, Tao,Wang, Tianyi,Fang, Zhijie
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p. 2567 - 2575
(2015/11/28)
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- α-Galactobiosyl units: Thermodynamics and kinetics of their formation by transglycosylations catalysed by the GH36 α-galactosidase from Thermotoga maritima
-
Broad regioselectivity of α-galactosidase from Thermotoga maritima (TmGal36A) is a limiting factor for application of the enzyme in the directed synthesis of oligogalactosides. However, this property can be used as a convenient tool in studies of thermodynamics of a glycosidic bond. Here, a novel approach to energy difference estimation is suggested. Both transglycosylation and hydrolysis of three types of galactosidic linkages were investigated using total kinetics of formation and hydrolysis of pNP-galactobiosides catalysed by monomeric glycoside hydrolase family 36 α-galactosidase from T. maritima, a retaining exo-acting glycoside hydrolase. We have estimated transition state free energy differences between the 1,2- and 1,3-linkage (ΔΔG?0 values were equal 5.34 ± 0.85 kJ/mol) and between 1,6-linkage and 1,3-linkage (ΔΔG?0 = 1.46 ± 0.23 kJ/mol) in pNP-galactobiosides over the course of the reaction catalysed by TmGal36A. Using the free energy difference for formation and hydrolysis of glycosidic linkages (ΔΔG?F - ΔΔG?H), we found that the 1,2-linkage was 2.93 ± 0.47 kJ/mol higher in free energy than the 1,3-linkage, and the 1,6-linkage 4.44 ± 0.71 kJ/mol lower.
- Borisova, Anna S.,Ivanen, Dina R.,Bobrov, Kirill S.,Eneyskaya, Elena V.,Rychkov, Georgy N.,Sandgren, Mats,Kulminskaya, Anna A.,Sinnott, Michael L.,Shabalin, Konstantin A.
-
supporting information
p. 115 - 121
(2015/02/19)
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- Organocatalysis for the acid-free O-arylidenation of carbohydrates
-
Methyl glycopyranosides of glucose, galactose, and mannose, their 2,3-di-O-benzyl-protected derivatives, as well as the unprotected sugars react with p-methoxybenzaldehyde dimethyl acetal (3) and with benzaldehyde dimethyl acetal (7) as reagents in the presence of thiourea 1 or squaramide 2 as the organocatalyst to afford regioselectively 4,6-O-arylidenated derivatives 5 and 8. With an excess amount of 3 or 7, diarylidenated derivatives are also obtained. In situ formation of acetals of type 3 and 7 from corresponding aldehydes 10 and 13 in the presence of an orthoester and organocatalyst 1 or 2 can be used to generate 5 and 8 directly from the aldehydes. Some substrates also lead to mixed orthoesters with this procedure. The reaction courses are discussed. A squaramide catalyzes the 4,6-O-arylidenation of glucose, mannose, and galactose with the use of arenecarbaldehyde dimethyl acetals or arenecarbaldehydes and orthoesters as the reagents. Glycoside derivatives also undergo this reaction. Copyright
- Geng, Yiqun,Faidallah, Hassan M.,Albar, Hassan A.,Mhkalid, Ibrahim A.,Schmidt, Richard R.
-
supporting information
p. 7035 - 7040
(2013/11/06)
-
- A new method for selective deprotection of anomeric N,O -dimethylhydroxylamine promoted by TMSCl
-
TMSCl was shown to be an efficient reagent for selective deprotection of the anomeric position protected as N,O-dimethylhydroxylamine glycoside. This deprotection condition was proved to be compatible with a number of protecting groups, such as the TBDPS, acetyl, benzyl, benzylidene, and benzoyl groups.Copyright Taylor and Francis Group, LLC.
- Huang, Shengjun,Liao, Jun,Zhao, Qingjie,Chai, Xiaoyun,Wang, Baogang,Yu, Shichong,Wu, Qiuye
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p. 158 - 168
(2013/03/29)
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- Synthesis and α-glucosidase inhibitory activity evaluation of N-substituted aminomethyl-β-d-glucopyranosides
-
A series of N-substituted 1-aminomethyl-β-d-glucopyranoside derivatives was prepared. These novel synthetic compounds were assessed in vitro for inhibitory activity against yeast α-glucosidase and both rat intestinal α-glucosidases maltase and sucrase. Mo
- Bian, Xiaoli,Fan, Xiangni,Ke, Changhu,Luan, Yajun,Zhao, Guilan,Zeng, Aiguo
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p. 5442 - 5450
(2013/09/02)
-
- Exciton chirality method in vibrational circular dichroism
-
The interaction of two IR chromophores yields a strong vibrational circular dichroism couplet whose sign reflects the absolute configuration of the molecule. We present a method to determine absolute configuration of a chiral molecule based on this couplet without need of theoretical calculation. Not only can this method analyze various molecules whose absolute configuration is difficult to determine by other spectroscopic methods, but also it can significantly enhance VCD signals.
- Taniguchi, Tohru,Monde, Kenji
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supporting information; scheme or table
p. 3695 - 3698
(2012/04/11)
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- Regioselective removal of the anomeric O-benzyl from differentially protected carbohydrates
-
A mild, regioselective deprotection of the anomeric O-benzyl from multi-functionally protected carbohydrates via catalytic transfer hydrogenation is described. The protocol is tolerant of O-benzyl and O-benzylidene protections at non-anomeric positions, g
- Jalsa, Nigel Kevin
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supporting information; scheme or table
p. 6587 - 6590
(2012/02/03)
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- Glycosylation catalyzed by a chiral bronsted acid
-
"Chemical equation presented" The use of a chiral Bronsted acid catalyst for the activation of trichloroacetimidate glycosyl donors has been demonstrated for the first time. In toluene the chirality of the acid catalyst is seen to influence the stereochem
- Cox, Daniel J.,Smith, Martin D.,Fairbanks, Antony J.
-
supporting information; experimental part
p. 1452 - 1455
(2010/06/20)
-
- Synthesis of a 1α-C-methyl analogue of 25-hydroxyvitamin D3: interaction with a mutant vitamin D receptor Arg274Leu
-
Vitamin D3 analogues have been developed for a mutant vitamin D receptor (VDR), Arg274Leu. The mutant VDR has a mutation at Arg274, which forms an important hydrogen bond with 1α-OH of 1α,25-dihydroxyvitamin D3 to anchor the ligand t
- Honzawa, Shinobu,Takahashi, Naoyuki,Yamashita, Atsushi,Sugiura, Takayuki,Kurihara, Masaaki,Arai, Midori A.,Kato, Shigeaki,Kittaka, Atsushi
-
experimental part
p. 7135 - 7145
(2009/12/06)
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- Involvement of the S-aglycon in the conformational preferences of thioglucosides
-
The conformational preferences of two series of alkyl β-d-thioglucopyranosides in solution were investigated by NMR and CD. The rotamer populations of the hydroxymethyl group were found to depend on the structural nature of the S-aglycon. The population of the gt rotamer increased and that of the gg rotamer decreased as the alkyl group attached to the S atom increased in size. These rotamer populations have a linear correlation with the Taft' steric parameters, the nS s(-) σC s(-) O* exo-anomeric interaction may express these rotational preferences. Comparative analysis of the hydroxymethyl populations between alkyl O- and S-glucosides revealed identical or slightly higher gt and smaller gg populations for the latter compounds.
- Sanhueza, Carlos A.,Dorta, Rosa L.,Vazquez, Jesus T.
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p. 258 - 264
(2008/09/19)
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- A practical and enantiospecific conversion of d-galactose to a substituted α,β-unsaturated δ-lactone synthon
-
A multi-gram synthesis of a substituted α,β-unsaturated δ-lactone synthon, 1, was developed from commercially available d-galactose. The use of a Horner-Wadsworth-Emmons reaction was able to furnish, with Z selectivity, the enone ester that spontaneously
- Stephens, Benjamin E.,Liu, Fei
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p. 9116 - 9119
(2008/09/17)
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- Biological evaluation of de-O-sulfonated analogs of salacinol, the role of sulfate anion in the side chain on the α-glucosidase inhibitory activity
-
De-O-sulfonated analogs (10a, Y- = CH3OSO3 and 10b, Y- = Cl) of salacinol, a naturally occurring glycosidase inhibitor, and its diastereomer (12a, Y- = CH3OSO3) with l-thiosugar moiety (1,4-dideoxy-1,4-epithio-l-arabinitol) were prepared. Their inhibitory activities against intestinal maltase and sucrase were examined and compared with those of the parent α-glycosidase inhibitor, salacinol (1a). Compounds 10a and 10b showed a potent inhibitory activity equal to that of 1a against both enzymes, although 12a was a weak inhibitor against sucrase and maltase. These results indicated that the O-sulfonate anion moiety of 1a is not essential for the inhibitory activity.
- Tanabe, Genzoh,Yoshikai, Kazuya,Hatanaka, Takanori,Yamamoto, Mizuho,Shao, Ying,Minematsu, Toshie,Muraoka, Osamu,Wang, Tao,Matsuda, Hisashi,Yoshikawa, Masayuki
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p. 3926 - 3937
(2008/02/13)
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- Synthesis of benzylidenated hexopyranosides in ionic liquids
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The synthesis of 4,6-O-benzylidenated monosaccharides and disaccharides has been studied using ionic liquids as a unique solvent alternative. An examination of several imidazolium ionic liquids indicates that the benzylidenation of hexopyranosides in 3-bu
- Zhang, Jianguo,Ragauskas, Arthur J.
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p. 2812 - 2815
(2007/10/03)
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- Conformational study of the hydroxymethyl group in α-D-mannose derivatives
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A study of the dependence of the hydroxymethyl group in α-D-mannose derivatives on the aglycon and its absolute configuration was performed by means of circular dichroism (CD) and NMR data. Depending mainly on the aglycon present, the gg or the gt rotamer was the most populated, the tg rotamer having a small population. In addition, the study showed a correlation between the rotational populations and the aglycon, the population of the gt rotamer increasing as the pKa of the bonded alcohol (aglycon) increased. Furthermore, the results revealed a strong dependence on the absolute configuration of the aglycon and point to the stereoelectronic exo-anomeric effect being responsible for these rotational dependencies besides nonbonding interactions.
- Nobrega, Chaxiraxi,Vazquez, Jesus T.
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p. 2793 - 2801
(2007/10/03)
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- A new reaction manifold for the Barton radical intermediates: Synthesis of N-heterocyclic furanosides and pyranosides via the formation of the C1-C2 bond
-
The first radical intermediate in the thiourethane-mediated deoxygenation of an alcohol (Barton-McCombie reaction) can participate in an exo-hex-5-enyl- or exo-hept-6-enyl-type radical cyclization when a suitable radical acceptor (e.g., α,β-unsaturated es
- Rhee, Jong Uk,Bliss, Brian I.,RajanBabu
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p. 1492 - 1493
(2007/10/03)
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- Inhibitory effects of Ellagi- and gallotannins on rat intestinal α-glucosidase complexes
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The clove ellagitannins and their related polygalloylglucoses inhibited maltase activity of rat intestinal α-glucosidases. The structure-activity relationship study of those galloylglucoses, varying the extent of galloylation on the glucose core, with the
- Toda, Miou,Kawabata, Jun,Kasai, Takanori
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p. 542 - 547
(2007/10/03)
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- Synthesis of a nitrogen analogue of salacinol and its α-glucosidase inhibitory activity
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A nitrogen analogue 4 of the naturally occurring sulfoniumion salacinol (1), a potent α-glucosidase inhibitor isolated from the Ayruvedic medicine Salacia reticulata, was synthesized and its inhibitory activity against α-glucosidase tested. Substitution o
- Muraoka,Ying,Yoshikai,Matsuura,Yamada,Minematsu,Tanabe,Matsuda,Yoshikawa
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p. 1503 - 1505
(2007/10/03)
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- Stereochemical models for the enantiocontrolled construction of fully functionalized C rings via intramolecular aldolization in advanced precursors to paclitaxel
-
Six transition-state models for intramolecular aldol C-ring annulation in suitably substituted bicyclo-[6.2.1]undecanones have been defined. The first consideration is the inherent conformational flexibility of the nine- membered ketonic ring which does not limit effective deprotonation to a single C-8 epimer. When the oxygen substituents at C-4 and C-5 are not covalently linked, the configuration at C-5 defines the stereochemical course of the ring closure, with only the β series being amenable to the proper elaboration of paclitaxel. When C-4 and C-5 are incorporated into a 1,3- dioxane ring instead, the principal stereocontrol element is translocated into the aryl-substituted carbon of the cyclic acetal. To the extent that the Ar group remains equatorially disposed, then proper aldolization will materialize in only one of the four possible diastereomers. Experimental tests that are provided for three of the models are shown to conform to expectations. This analysis of the origin of stereoselectivity has, for the first time, defined the scope and limitations associated with C-ring closure by means of the aldol protocol.
- Paquette, Leo A.,Zeng, Qingbei,Tsui, Hon-Chung,Johnston, Jeffrey N.
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p. 8491 - 8509
(2007/10/03)
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- A versatile strategy for the synthesis of complex type N-glycans: Synthesis of diantennary and bisected diantennary oligosaccharides1
-
Based on readily available glucose, 2-azido-glucose, mannose, and N- phthaloyllactosamine building blocks 5, 6, 8, and 13 a highly versatile strategy for the synthesis of complex type and bisected complex type N- glycan residues is established; this is demonstrated for the synthesis of nonasaccharide 1 and decasaccharide 2, respectively. The glucose residue g finally provides regioselective access to the 3-, 4-, and/or 6-hydroxy groups for antenna attachment, introduction of the bisecting N-acetylglucosamine residue, and epimerisation at C-2 in order to generate the required β- linked mannosyl residue c.
- Weiler, Sven,Schmidt, Richard R.
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p. 2299 - 2302
(2007/10/03)
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- Stereochemical study of the CD spectral differences between anomers of alkyl glucopyranosides
-
Slightly different chair conformation geometries were demonstrated to be the origin of the C-D spectral differences observed in anomers of alkyl glucopyranosides. The study, using methyl glucopyranoside derivatives as model compounds, showed excellent agreement between CD data, 1H NMR data, and semiempirical calculations, and the geometries found explained satisfactorily the higher amplitudes observed for the β-anomers of tetrachromophorically substituted alkyl glucopyranosides. The pairwise interactions involving the chromophore at C2, the 2/3, 2/4 and 2/6, were the most dependent on the anomeric configuration, the 2/4 interaction even showing opposite CD signs for the anomers. In addition, the 2/3 pairwise interaction was revealed to be independent of the structural nature of the aglycon.
- Padron, Juan I.,Vazquez, Jesus T.
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p. 613 - 627
(2007/10/03)
-
- Alkyl galactopyranosides: Rotational population dependence of the hydroxymethyl group on the aglycon and its absolute configuration and on the anomeric configuration
-
The rotational populations of the hydroxymethyl group in chiral and nonchiral alkyl α- and β-galactopyranosides proved, on the basis of circular dichroism (CD) and 1H NMR data, to be dependent on the structure of the aglycon: the population of the gt and tg rotamers increased and decreased, respectively, as the pK(a) of the bonded alcohol (aglycon) increased, while the population of the gg rotamer remained practically constant. Furthermore, low-temperature CD measurements proved that the most stable rotamer is the gt, and not the tg. In addition, a clear correlation between the rotational populations and the absolute configuration of the chiral aglycon was observed; namely, higher and smaller gt and tg populations were observed for the (S)-alkyl β-D-galactopyranosides than for their (R)- alkyl β-D-galactopyranoside counterparts, the opposite behavior being observed for the α-anomers. The results point to the exo anomeric effect as being responsible for these rotational dependencies, as well as to nonbonding interactions between the aglycon and the chromophore at C6 for those stereoisomers having in their aglycon a bulky substituent syn to the endocyclic oxygen (O5). In addition, the chemical shift differences (Δδ) of the aglyconic protons of galactosylated chiral alcohols proved to be characteristic of the absolute configuration of the bonded chiral alcohol.
- Padron, Juan I.,Morales, Ezequiel Q.,Vazquez, Jesus T.
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p. 8247 - 8258
(2007/10/03)
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- The reaction of partially protected aldoses with stabilized arsonium ylides: Synthesis of E acyclic unsaturated derivatives and C-glycosyl derivatives
-
The reaction of partially protected aldoses with (carbomethoxymethyl)triphenylarsonium bromide and zinc in toluene gave E α,β-unsaturated acyclic esters. When intramolecular transesterification occurred, bicyclic 1,4-lactone derivatives were formed concurrently. Otherwise, using these non alcaline conditions, olefination did not favour the formation of C-glycosyl derivatives. On the other hand, when the reaction was performed with (carbomethoxymethylene)triphenylarsorane in toluene, followed by the addition of n-butyllithium, bicyclic derivatives were obtained rapidly in good yields. Moreover, when cyanomethyltriphenylarsonium bromide was used in place of (carbomethoxymethyl)triphenylarsonium bromide, the corresponding E aldooctenonitriles were produced in satisfactory yields.
- Lievre, Catherine,Frechou, Catherine,Demailly, Gilles
-
-
- A new approach to some 1,6-dideoxy 1,6-epithio sugars
-
The treatment of hexopyranosyl bromides, also activated at C6 (Br, OTs, OMs), with H2S/HCONMe2 under basic conditions gives rise to 1,6-dideoxy 1,6-epithio sugars. One such sugar has been further transformed into the synthetically useful 3,4-anhydro-1,6-dideoxy-1,6-epithio-β-D-galactose. The treatment of this epoxide with sodium azide and with cyclohexylamine is described. An analogous treatment of one doubly activated hexopyranosyl bromide with sodium hydrogen selenide has led to a novel 1,6-dideoxy 1,6-episeleno sugar which displayed interesting n.m.r. spectra. Finally, in an attempt to prepare 1,6-dideoxy 1,6-epidithio sugars, a tetraalkylammonium tetrathiomolybdate reagent was found to be the reagent of choice for converting doubly activated hexopyranosyl bromides into 1,6-dideoxy 1,6-epithio sugars.
- Driguez, Hugues,McAuliffe, Joseph C.,Stick, Robert V.,Tilbrook, Matthew G.,Williams, Spencer J.
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p. 343 - 348
(2007/10/03)
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- CD and 1H NMR Study of the Rotational Population Dependence of the Hydroxymethyl Group in β Glucopyranosides on the Aglycon and Its Absolute Configuration
-
The rotamer population around the C5-C6 bond of chiral and nonchiral alkyl β-glucopyranoside derivatives proved to be dependent on the structure of the aglycon; the population of the gg and gt rotamers decreased and increased, respectively, as the pK
- Morales, Ezequiel Q.,Padron, Juan I.,Trujillo, Mar,Vazquez, Jesus T.
-
p. 2537 - 2548
(2007/10/02)
-
- Dimethylformamide-dimethyl sulfate adduct as an effective reagent for the preparation of benzylideneacetals of mono- and disaccharides
-
A simple and effective method for the preparation of cyclic 4,6-benzylideneacetals of mono and disaccharides has been developed.It involves treatment of the sugar with benzaldehyde in dimethyl sulfate and dry DMF under nitrogen atmosphere at room temperature.
- Mani, N. S.
-
p. 602 - 603
(2007/10/02)
-
- The Selective Monobenzylidenation of Some Monosaccharides and Their Derivatives with α,α-Dimethoxytoluene
-
The treatment of some monosaccharides and their derivatives with α,α-dimethoxytoluene and an acid catalyst in dimethylformamide at about 80 deg C can lead to selective benzylidenation, e.g. methyl α-D-mannopyranoside gives mainly methyl 4,6-O-benzylidene-α-D-mannoside, together with two other minor monobenzylidene derivatives (2,3-) and two minor dibenzylidene derivatives (2,3:4,6-).The treatment of various other pyranoses and pyranosides is also described.As well, a 1H n.m.r. study of the acid transformation of some of the above α-D-mannosides is reported, together with a single-crystal X-ray diffraction structure determination of a novel monobenzylidene derivative, namely methyl (S)-2,3-O-benzylidene-α-D-mannopyranoside.
- Patroni, Joseph J.,Stick, Robert V.,Skelton, Brian W.,White, Allan H.
-
-
- HYDROGENOLYSIS OF THE ISOMERIC 1,2:4,6-DI-O-BENZYLIDENE-α-D-GLUCOPYRANOSE DERIVATIVES WITH THE LiAlH4-AlCl3 REAGENT
-
Both isomers of 1,2:4,6-di-O-benzylidene-α-D-glucopyranose (and their 3-O-acetyl and 3-O-benzyl derivatives) have been prepared and their 1H- and C13-n.m.r.spectra assigned.The mode of hydrogenolysis of the dioxolane ring in these isomers by the LiAlH4-Al
- Liptak, Andras,Imre, Janos,Harangi, Janos,Nanasi, Pal
-
p. 217 - 226
(2007/10/02)
-
- (13)C-N.M.R. STUDIES OF D-GLUCOSE AND D-GALACTOSE MONOSULPHATES
-
D-Galactose and D-glucose 2-, 3-, 4-, and 6-sulphates, 2,3,4,6-tetra-O-acetyl-β-D-glucose 1-sulphate, and 2-acetamido-2-deoxy-D-glucose 6-sulphate have been definitively synthesised, and the positions of the sulphate groups verified by (13)C-n.m.r. spectroscopy.New syntheses are given for D-galactose 3- and 4-sulphates and for D-glucose 4-sulphate.The (13)C-n.m.r. spectra showed downfield displacements, with respect to the parent sugar, of the shifts of carbon atoms carrying a sulphate group and smaller upfield shifts for adjacent carbon atoms.The technique of deuterium-induced, differential isotope shift (d.i.s.), (13)C-n.m.r. spectroscopy is shown to be valuable for the assignment of chemical shifts.
- Archbald, P. Jane,Fenn, M. David,Roy, Alexander B.
-
p. 177 - 190
(2007/10/02)
-