cas 7432-72-6, Methyl 2,3,4-triacetate-alpha-D-glucopyranoside

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Discriminating non-ylidic carbon-sulfur bond cleavages of sulfonium ylides for alkylation and arylation reactions
A sulfonium ylide participated alkylation and arylation under transition-metal free conditions is described. The disparate reaction pattern allowed the separate activation of non-ylidic S-alkyl and S-aryl bond. Under acidic conditions, sulfonium ylides serve as alkyl cation precursors which facilitate the alkylations. While under alkaline conditions, cleavage of non-ylidic S-aryl bond produces O-arylated compounds efficiently. The robustness of the protocols were established by the excellent compatibility of wide variety of substrates including carbohydrates.
Fang, Jing,Li, Ting,Ma, Xiang,Sun, Jiuchang,Cai, Lei,Chen, Qi,Liao, Zhiwen,Meng, Lingkui,Zeng, Jing,Wan, Qian
p. 288 - 292
(2021/07/25)

Zirconium-Catalyzed Hydroalumination of C=O Bonds: Site-Selective De- O-acetylation of Peracetylated Compounds and Mechanistic Insights
An unprecedented hydroalumination of C = O bonds catalyzed by zirconocene dichloride is reported herein and applied to the site-selective deprotection of peracetylated functional substrates. A mixed metal hydride, with 1:1 zirconium/aluminum stoichiometry
Courant, Thibaut,Gavel, Marine,Renard, Romain M. Q.,Gandon, Vincent,Joosten, Antoine Y. P.,Lecourt, Thomas
p. 9280 - 9288
(2021/06/30)

Visible-Light-Mediated, Chemo- and Stereoselective Radical Process for the Synthesis of C-Glycoamino Acids
An approach for efficient synthesis of C-glycosyl amino acids is described. Different from typical photoredox-catalyzed reactions of imines, the new process follows a pathway in which α-imino esters serve as electrophiles in chemoselective addition reactions with nucleophilic glycosyl radicals. The process is highlighted by the mild nature of the reaction conditions, the highly stereoselectivity attending C-C bond formation, and its applicability to C-glycosylations using both armed and disarmed pentose and hexose derivatives.
Ji, Peng,Zhang, Yueteng,Wei, Yongyi,Huang, He,Hu, Wenbo,Mariano, Patrick A.,Wang, Wei
p. 3086 - 3092
(2019/05/01)

Regio- A nd chemoselective deprotection of primary acetates by zirconium hydrides
A combination of DIBAL-H and Cp2ZrCl2 is shown to promote the regioselective cleavage of primary acetates on a broad scope of substrates, ranging from carbohydrates to terpene derivatives, with a high tolerance toward protecting groups and numerous functionalities found in natural products and bioactive compounds. Apart from providing highly valuable building blocks in only two steps from biosourced raw materials, this selective de-O-acetylation should also be strongly helpful to solve selectivity issues in organic synthesis.
Gavel, Marine,Courant, Thibaut,Joosten, Antoine Yvan Philippe,Lecourt, Thomas
supporting information
p. 1948 - 1952
(2019/04/10)

MACROCYCLIC MCL-1 INHIBITORS AND METHODS OF USE
The present disclosure provides for compounds of Formula (I) wherein A2, A3, A4, A6, A7, A8, A15, RA, R5, R9, R10A, R10B, R11, R12, R13, R14, R16, W, X, and Y have any of the values defined in the specification, and pharmaceutically acceptable salts thereof, that are useful as agents in the treatment of diseases and conditions, including cancer. Also provided are pharmaceutical compositions comprising compounds of Formula (I).
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Paragraph 00244

(2019/03/05)

NEW HYDROXYACID DERIVATIVES, A PROCESS FOR THEIR PREPARATION AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM
Compounds of formula (I): wherein R1, R2, R3, R4, R5, R6, R7, R8, R14, A and n are as defined in the description. Medicaments.
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Page/Page column 44; 45

(2017/01/09)

Synthesis of multi-galactose-conjugated 2′-O-methyl oligoribonucleotides and their in vivo imaging with positron emission tomography
68Ga labelled 2′-O-methyl oligoribonucleotides (anti-miR-15b) bearing one, three or seven d-galactopyranoside residues have been prepared and their distribution in healthy rats has been studied by positron emission tomography (PET). To obtain t
M?kil?, Jussi,Jadhav, Satish,Kiviniemi, Anu,K?kel?, Meeri,Liljenb?ck, Heidi,Poij?rvi-Virta, P?ivi,Laitala-Leinonen, Tiina,L?nnberg, Harri,Roivainen, Anne,Virta, Pasi
p. 6806 - 6813
(2015/02/05)

Chemoenzymatic synthesis of neoglycoproteins driven by the assessment of protein surface reactivity
In this paper a series of 2-iminomethoxyethyl mannose-based mono- and disaccharides have been synthesized by a chemoenzymatic approach and used in coupling reactions with ε-amino groups of lysine residues in a model protein (ribonuclease A, RNase A) to give semisynthetic neoglycoconjugates. In order to study the influence of structure of the glycans on the conjugation outcomes, an accurate characterization of the prepared neoglycoproteins was performed by a combination of ESI-MS and LC-MS analytical methods. The analyses of the chymotryptic digests of the all neoglycoconjugates revealed six Lys-glycosylation sites with a the following order of lysine reactivity: Lys 1 Lys 91 ? Lys 31 > Lys 61 ? Lys 66. A computational analysis of the reactivity of each lysine residue has been also carried out considering several parameters (amino acids surface exposure and pKa, protein flexibility). The in silico evaluation seems to confirm the order in lysine reactivity resulting from proteomic analysis.
Bavaro,Filice,Temporini,Tengattini,Serra,Morelli,Massolini,Terreni
p. 56455 - 56465
(2015/02/02)

In(III) triflate-catalyzed detritylation and glycosylation by solvent-free ball milling
A highly efficient In(III) triflate-assisted method for the detritylation of O-trityl derivatives of carbohydrates, phenols, and alcohols using solvent-free mechanochemical method is described. In the case of carbohydrates, further reaction in the presence of an acceptor sugar leads to highly efficient glycosylation in the same pot resulting in the formation of the desired glycoside-product in very high yields. The method was applied successfully to the synthesis of a combinatorial library of galactose-based (1,6)-linked cyclohexa-, hepta-, and octasaccharides on gram scale.
Kumar, Vajinder,Yadav, Narender,Kartha, K.P. Ravindranathan
p. 18 - 26
(2014/10/16)

Lipases in the regioselective preparation of glyceric acid esters of methyl glycosides
The lipase-catalyzed regioselective acylation of methyl α-D-galacto-, -gluco- and -mannopyranosides with isopropylidene-protected (R)- and (S)-glyceric acid methyl esters in organic solvents is presented. Factors affecting the formation of the 6-O-mono- and 2,6-O-diacylated products are examined and preparative-scale reactions are detailed. In addition, studies on partially protected methyl α-D-galactopyranosides are presented, with the 3,4-O-isopropylidene protected compound leading exclusively to the formation of the 6-O-monoacylated product even at high substrate concentrations. Application of acidic resin in methanol allows removal of the isopropylidene protection groups without disturbing the ester bond at C-6. Copyright
Sundell, Riku,Kanerva, Liisa T.
p. 4971 - 4978
(2013/08/23)

One-pot oxidation-hydrocyanation sequence coupled to lipase-catalyzed diastereoresolution in the chemoenzymatic synthesis of sugar cyanohydrin esters
A three-step, one-pot synthesis and diastereoresolution sequence is described in anhydrous toluene starting from methyl α-D-2,3,4-tri-O- acetylgalacto- (1a), -manno- (1b) and -glucopyranosides (1c). The reaction sequence, including consecutive transformations through the aldehyde [PhI(OAc)2, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)] and cyanohydrin [basic resin or (R)-oxynitrilase] into the (6R)-cyanohydrin ester (lipase) is shown to proceed in a one-pot cascade, except that the basic resin (when used) should be removed before the addition of the enzymatic acylation reagents. We have shown that the effective transformation of 1a (75 % reaction yield) through labile intermediates gives the stable (6R)-cyanohydrin butanoate (85 % de). Further diastereomeric purification by chromatography is possible, although the product is already of high diastereopurity. (6R)-Cyanohydrin esters are obtained through acylation with Burkholderia cepacia lipase. The (6S)-ester (de 99 %) is produced by Candida rugosa lipase when the sequence is started from 1c whereas the other sugar derivatives are less suited to the reaction with lipase. Copyright
Hietanen, Ari,Kanerva, Liisa T.
p. 2729 - 2737
(2012/07/13)

Design, synthesis and antifibrotic activities of carbohydrate-modified 1-(substituted aryl)-5-trifluoromethyl-2(1H) pyridones
Pirfenidone, a pyridone compound, is an effective and novel antifibrotic agent. In this article, we describe the design, synthesis and activity evaluation of novel antifibrotic agents, 1-(substituted aryl)-5-trifluoromethyl- 2(1H) pyridones modified with
Lou, Qinghua,Meng, Xiangbao,Lao, Zhiqi,Xuan, Lingling,Bai, Jinye,Hou, Qi,Hu, Gaoyun,Luo, Renna,Tao, Lijian,Li, Zhongjun
p. 884 - 896
(2012/03/09)

Synthesis of a Candida albicans tetrasaccharide spanning the β1,2-mannan phosphodiester α-mannan junction
The cell wall phosphomannan of Candida species is a complex N-linked glycoprotein with a glycan chain containing predominantly an α-linked mannose backbone with α-mannose branches. A minor β-mannan component is attached to the branches either via a glycos
Dang, Anh-Thu,Johnson, Margaret A.,Bundle, David R.
p. 8348 - 8360
(2012/11/07)

NOVEL MANNOPYRANOSIDE DERIVATIVES WITH ANTICANCER ACTIVITY
The present invention relates to mannopyranoside-derived compounds and to the use thereof as medicaments, in particular in the treatment of cancer diseases, and also to the method for preparing same and to pharmaceutical compositions comprising such compo
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Page/Page column 14

(2012/11/07)

2-(Prenyloxymethyl)benzoyl (POMB) group: a new temporary protecting group removable by intramolecular cyclization
2-(Prenyloxymethyl)benzoates can be prepared from alcohols and readily available 2-(prenyloxymethyl)benzoic acid by standard acylation techniques or by Mitsunobu reaction with inversion of configuration. The POMB group can be cleaved first by oxidative removal of the prenyl group with DDQ followed by lactonization with expulsion of the alcohol catalyzed by Yb(OTf)3. These reaction conditions are compatible with the presence of a large number of common protecting groups.
Vatèle, Jean-Michel
p. 10921 - 10929
(2008/02/12)

Removal of acid-labile protecting groups on carbohydrates using water-tolerant and recoverable vanadyl triflate catalyst
Acetal, trityl, and TBDMS protecting groups on saccharides were subjected to alcoholysis using a catalytic amount of vanadyl triflate in an MeOH-CH 2Cl2 solvent system. The configuration at the anomeric positions of saccharides was retained, and no glycosidic bond cleavage and oxidation of sulfides were observed. The presented method was easily implemented, compatible with diverse functional groups, and regioselective in some cases.
Yan, Ming-Chung,Chen, Yeng-Nan,Wu, Huan-Ting,Lin, Chang-Ching,Chen, Chien-Tien,Lin, Chun-Cheng
p. 299 - 302
(2007/10/03)

2-(Prenyloxymethyl)benzoyl (POMB) as a new temporary protecting group for alcohols
The 2-(prenyloxymethyl)benzoyl (POMB) group was introduced in high yields to hydroxyl functions using the crystalline reagent, 2-(prenyloxymethyl)benzoic acid, in the presence of dicyclohexylcarbodiimide (DCC) and 4- dimethylaminopyridine (DMAP). 2-(Prenyloxymethyl)benzoic acid is readily available, in two steps, from phthalide in 65% overall yield. The POMB group can be cleaved, in two steps, by treatment with 2,3-dichloro-5,6-dicyanoquinone (DDQ) followed by intramolecular lactonisation of the resulting hydroxy ester induced by a catalytic amount of Yb(OTf)3·H2O. The reaction conditions are compatible with the presence of a number of protecting groups such as isopropylidene, benzyl, acetyl, chloroacetyl, benzoyl, levulinoyl, Fmoc and Boc groups.
Vatèle, Jean-Michel
p. 2299 - 2301
(2007/10/03)

(2-Azidomethyl)phenylacetyl as a new, reductively cleavable protecting group for hydroxyl groups in carbohydrate synthesis
The (2-azidomethyl)phenylacetyl group (AMPA) is described as a new protecting group for carbohydrates. AMPA was introduced to carbohydrate hydroxyl groups in the presence of DCC, while its removal was conveniently achieved via Lindlar catalyst-catalyzed hydrogenation that had no influence on other protecting groups including benzyl, acyl, acetal and ketal.
Xu, Jinghua,Guo, Zhongwu
p. 87 - 91
(2007/10/03)

Carboproteins: A 4-α-helix bundle protein model assembled on a D-galactopyranoside template
We have recently introduced the concept of monosaccharides as templates for de novo design of protein models and described the synthesis of a model 'carbopeptide'. Here, we report the synthesis of a 64 amino acid (AA) 'carboprotein' by chemoselective ligation of a C-terminal hexadecapeptide aldehyde to a tetra-aminooxy functionalized methyl α-D-galactopyranoside (D-Galp) template. Biophysical characterizations by CD spectroscopy and NMR amide H-D exchange experiments indicated that the four-stranded carboprotein forms a 4-α-helix bundle structure.
Brask, Jesper,Jensen, Knud J
p. 697 - 700
(2007/10/03)

Highly efficient deacetylation by use of the neutral organotin catalyst [tBu2SnOH(Cl)]2
Deprotection of acetyl esters is effected cleanly by the neutral organotin catalyst, [tBu2SnOH(Cl)]2. The mildness of the reaction gives rise to great synthetic versatility and in the process a variety of functional groups are tolerated. Differentiations between primary, secondary, and tertiary alcohols and between acetyl ester and other esters are feasible. No racemization occurs with chiral acetyl esters. Exclusive deprotection of primary acetyl esters in carbohydrates and nucleosides is observed. The crude product thus obtained can be used for further reactions without purification.
Orita, Akihiro,Hamada, Yuuki,Nakano, Takehiko,Toyoshima, Shinji,Otera, Junzo
p. 3321 - 3327
(2007/10/03)

Homologation of ?-acetylated methyl hexopyranosides with a Grignard C1 reagent
Three methyl 2,3,4-tri-?-acetyl-α-D-hexopyranosides of the manno, gluco, and galacto configuration were oxidized to the corresponding methyl hexodialdo-1,5-pyranosides and then reacted with allyloxymethylmagnesium chloride. Methyl heptopyranosides of the D-and L-glycero-α-D-manno-, -α-D-gluco, and -α-D-galacto configuration were obtained in moderate yields. Migration of the 4-?-acetyl group in the products was observed. An interpretation of the results was proposed.
Grzeszczyk, Barbara,Zamojski, Aleksander
p. 610 - 620
(2007/10/03)

Esterase-catalysed regioselective 6-deacylation of hexopyranose per-acetates, acid-catalysed rearrangement to the 4-deprotected products and conversions of these into hexose 4- and 6-sulfates
The esterase from Rhodosporidium toruloides has been used to catalyse the hydrolysis of a series of per-acetylated α-D-hexopyranoses and α-D-hexopyranosides. Per-acetylated glucose 4, mannose 6, N-acetylgalactosamine 8, galactose 10, methyl α-D-glucoside 12, methyl α-D-mannoside 14 and methyl α-D-galactoside 16 have been selectively cleaved at the C-6 position by the esterase to give the 6-OH derivatives 5, 7, 9, 11, 13, 15 and 17. Acid-catalysed rearrangement of acetates 5, 7, 13, 15, 11, 17 and 9 with 4→6 acetyl migration gives the corresponding 4-deprotected derivatives 22-28, respectively. Hydrolyses of β-D-glucose pentaacetate 20 and α-D-lactose octaacetate 21 have been attempted, but no hydrolyses have been observed. 1,2,3,6-TetraacyIated α-D-hexopyranoses 3 and 22, derivatives of N-acetylglucosamine and glucose respectively, and 2,3,6-triacetylated α-D-hexopyranosides 24 and 25, derivatives of glucose and mannose, respectively, have been hydrolysed by the esterase to the corresponding 4,6-dihydroxy acetates 29, 18, 30 and 31. Acylation of methyl α-D-glucopyranoside 32 catalysed by the esterase provides the C-6 monoacetate 33 and the C-3 monoacetate 34 in 4 and 5% yield, respectively. The sodium salts of N-acetylglucosamine, glucose, N-acetylgalactosamine, galactose and mannose 6-sulfates 38-42, respectively, are prepared in two steps from the 6-deacetylated hexopyranoses 2, 5, 9, 11 and 7, respectively. The sodium salts of N-acetylglucosamine, glucose and mannose 4-sulfates 43-45, respectively, are prepared in two steps from the 4-deacetylated precursors 3, 22 and 26 which are obtained via acid catalysed 4→6 acyl migration of compounds 2, 5 and 7.
Horrobin, Tina,Tran, Chuong Hao,Crout, David
p. 1069 - 1080
(2007/10/03)

Detritylation of mono- and di-saccharide derivatives using ferric chloride hydrate
Quantitative detritylation of mono- and di-saccharide derivatives of diverse structure was achieved with FeCl3 · 6H2O in CH2Cl2 at room temperature. Benzyl, isopropylidene, isopropylthio, allyl, acetyl, and benzoyl O-protecting groups were not effected under the designated conditions.
Ding, Xianglan,Wang, Wei,Kong, Fanzuo
p. 445 - 448
(2007/10/03)

A new method of orthoesterification, under kinetic control, at non-anomeric positions. Application to the D-glucose and D-mannose series and selective hydrolysis of the corresponding orthoesters
The reaction of ketene acetals with D-glucose, D-mannose, and their methyl glycosides is described as a new route to unusual cyclic orthoesters (at non anomeric positions). The reaction proceeds by preferential attack of the reagent on the primary hydroxyl group. The synthesis of strained rings (2,3-diequatorial orthoester) is possible. The resulting methoxyethylidene derivatives are very sensitive to hydrolysis, and mild conditions lead to hydroxyacetates that are potentially useful intermediates for carbohydrates synthesis.
Bouchra,Calinaud,Gelas
p. 227 - 237
(2007/10/02)

Total synthesis of bleomycin A2 and related agents. 4. Synthesis of the disaccharide subunit: 2-O-( 3-O-Carbamoyl-α-D-mannopyranosyl)-L-gulopyranose and completion of the total synthesis of bleomycin A2
The chemical synthesis of 2-O-(3-O-carbamoyl-α-D-mannopyranosyl)-L-gulopyranose and its incorporation into a total synthesis of bleomycin A2 (1) readily adaptable to the preparation of structural analogs are detailed. Key strategic elements of
Boger, Dale L.,Honda, Takeshi
p. 5647 - 5656
(2007/10/02)

Use of diphenylacetyl chloride as protective reagent for sugars
Diphenylacetyl chloride is used as a protective reagent for methyl α-D-glucopyranoside, methyl α-D-mannopyranoside, and α,α-trehalose showing a good regioselectivity. The obtained diphenylacetyl esters were readily removed under neutral and mild conditions with N-bromosuccinimide followed by thiourea, in a one-pot reaction, in the presence of acetyl or benzoyl groups.
Santoyo-Gonzalez,Garcia-Calvo-Flores,Isac-Garcia,Robles-Diaz,Vargas-Berenguel
p. 97 - 101
(2007/10/02)

Evidence of acetyl migration during the methylation of methyl 2,3,4-tri-O-acetyl-D-mannose with diazomethane-boron trifluoride etherate
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Manna, Sukumar,AcAnalley, Bill H.
p. 261 - 266
(2007/10/02)

Novel synthesis of monosulphated methyl α-D-galactopyranosides
The syntheses of the methyl α-D-galactopyranoside 2-,3-,4-, and 6-sulphates (11, 12, 16, and 21 respectively) have been achieved using trimethylamine - sulphur trioxide as a sulphating agent.The procedure used is high yielding and requires shorter reactio
Rashid, Abdul,Mackie, William,Colquhoun, Ian J.,Lamba, Doriano
p. 1122 - 1127
(2007/10/02)

FORMATION OF 6-DEOXY-6-IODOHEXOPYRANOSIDES AS SUBSTRATES FOR THE HEX-5-ENOSE DEGRADATION
The synthesis of 6-deoxy-6-iodohexopyranosides as potential substrates for the hex-5-enose degradation has been examined for a range of mono-, di-, and poly-saccharide derivatives.It is shown that (1) unsubstituted D-glucopyranosides undergo selective, primary iodination without unwanted side-reactions; (2) primary iodination of D-galactopyranosides is accompanied by 3,6-anhydride formation, so that the desired reaction is only possible with protection of secondary hydroxyl groups; and (3) the extent of iodination in substrates of higher molecular weight is conveniently determined by reaction of acetylated (or methylated) derivatives with tributylstannane, followed by analysis of the resulting 6-deoxyhexopyranosides.The formation of 6-deoxy-6-iodohexopyranosyl residues in otherwise methylated plant galactomannans proceeds satisfactorily for (terminal) α-D-galactopyranosyl groups but incompletely for unbranched β-D-mannopyranosyl residues.
Aspinall, Gerald O.,Carpenter, Roshan C.,Khondo, Lev
p. 281 - 298
(2007/10/02)

The structure of a novel nucleoside antibiotic, dapiramicin A
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Seto,Otake,Koyama,et al.
p. 495 - 498
(2007/10/02)

A New Method for Cleaving Carbohydrate Triphenylmethyl and Benzyl Ethers
Carbohydrate triphenylmethyl and benzyl ethers are converted into their trimethylsilyl ethers by iodotrimethylsilane.The silyl ethers are hydrolysed to give partially free sugars.From multiple benzylated glycosides it is possible to remove selectively the primary benzyl group, under more vigorous conditions total debenzylation occurs.
Klemer, Almuth,Bieber, Michael,Wilbers, Hubert
p. 1416 - 1421
(2007/10/02)

DIPHENYLMETHYLATION OF CARBOHYDRATE HYDROXYL GROUPS BY THE REACTION WITH DIAZO(DIPHENYL)METHANE
Diphenylmetylation of carbohydrate hydroxyl groups may be effected by the thermal reaction with diazo(diphenyl)methane in absence of catalysts.Migration of the labile ester groups of methyl 2,3,4-tri-O-acetyl-α-D-glucopyranoside and 3-O-benzoyl-1,2-O-isopropylidene-α-D-glucofuranose does not occur during diphenylmethylation by this procedure.The diphenylmethyl group may be readily removed by catalytic hydrogenolysis, and is sufficiently acid-stable to enable the selective hydrolysis of acetal groups.Its use as an O-4 protecting-group and as a non-participating O-2 protecting-group in α-glucoside synthesis has been demonstrated in syntheses of methyl 2,3,6-tri-O-methyl-α-D-glucopyranoside and kojibiose octa-acetate, respectively.
Jackson, Graham,Jones, Haydn F.,Petursson, Sigthor,Webber, John M.
p. 147 - 158
(2007/10/02)