Galacturonsäurederivate. I. Galacturonate aus Acetyl‐ und Isopropyliden‐D‐galactopyranosen

Vogel, C.; Boye, Hanna; Kristen, H.

doi:10.1002/prac.19903320104

Cited by 18 publications

(5 citation statements)

References 25 publications

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“…The combined organic layers were washed with H 2 O, brine, dried over NaSO 4 , filtered and solvent removed under reduced pressure. Flash chromatography of the residue (petroleum ether-EtOAc 2:1) provided the title compound 16 (13.5 g, 69% over two steps) as a white solid; NMR data ( 1 H and 13 C) were in good agreement with the reported literature data; 17…”

Section: 234-tetra-o-acetyl-α-d-galactopyranosiduronic Acid Methyl Ester (16)supporting

confidence: 79%

“…As previously described for the deprotection of uronic acid derivatives, the removal of the protecting groups was achieved using hydroperoxide generated in n-propanol from sodium propoxide and hydrogen peroxide. 17 The use of methoxide, which is more basic than peroxide, can lead to the elimination of acetic acid and the formation of the undesired saturated compound. The synthesis of the 1,4-triazole galactose derivative 5 was achieved by a similar sequence from the azide 17.…”

Section: Scheme 3 Synthesis Of α-Azides 6 and 17mentioning

confidence: 99%

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Synthesis of α-galactosyl ceramide analogues with an α-triazole at the anomeric carbon

McDonagh

Murphy

2014

Tetrahedron

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Section: 234-tetra-o-acetyl-α-d-galactopyranosiduronic Acid Methyl Ester (16)supporting

confidence: 79%

Section: Scheme 3 Synthesis Of α-Azides 6 and 17mentioning

confidence: 99%

Synthesis of α-galactosyl ceramide analogues with an α-triazole at the anomeric carbon

McDonagh

Murphy

2014

Tetrahedron

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“…Since the non-reducing residue is a4 -O-benzyl-protected uronic acid, care has to be exercised to avoid elimination in saponification reaction. As described earlier, [25] aone pot procedure of H 2 O 2 with LiOH efficiently reduces elimination side product and gave the deacetylated and demethylated product (H2A) in high yield (93 %). Thefreed hydroxyls were then sulfated using pyridine or triethylamine-sulfur trioxide complex under microwave conditions to give H2B in 72 %yield.…”

Section: Angewandte Chemiementioning

confidence: 70%

A Hexasaccharide Containing Rare 2‐O‐Sulfate‐Glucuronic Acid Residues Selectively Activates Heparin Cofactor II

et al. 2017

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Glycosaminoglycan (GAG) sequences that selectively target heparin cofactor II (HCII), akey serpin present in human plasma, remain unknown. Using ac omputational strategy on alibrary of 46 656 heparan sulfate hexasaccharides we identified ar are sequence consisting of consecutive glucuronic acid 2-O-sulfate residues as selectively targeting HCII. This and four other unique hexasaccharides were chemically synthesized. The designed sequence was found to activate HCII ca. 250-fold, while leaving aside antithrombin, ac losely related serpin, essentially unactivated. This group of rare designed hexasaccharides will help understand HCII function. More importantly,our results show for the first time that rigorous use of computational techniques can lead to discovery of unique GAGsequences that can selectively target GAG-binding protein(s), which may lead to chemical biology or drug discovery tools.Heparin cofactor II (HCII) is as erine protease inhibitor (serpin) that circulates in human plasma at high levels. Although it has been known to selectively inhibit thrombin for several decades, [1][2][3] its true physiologic function remains to be understood. [4] HCII is known to bind to glycosaminoglycans (GAGs) such as dermatan sulfate (DS) and heparan sulfate (HS), which help mediate its inhibition of thrombin. One of the key reasons for the inability to identify HCIIs biologic role is the lack of knowledge on the specificity of HCII-GAGi nteraction.HCII is an interesting serpin. It bears considerable similarity to antithrombin (AT), another plasma serpin that mediates the anticoagulant action of heparin and fondaparinux, [5,6] two clinically used drugs.A Tand HCII are homologous in primary,secondary and tertiary structure ( Figure S1 in the Supporting Information). Yet, whereas AT binds specifically to fondaparinux sequence in heparin, [7] HCII is considered to bind non-specifically to heparin and HS. Further,a lthough both serpins display at wo-step,i nducedfit, allosteric activation mechanism in inhibiting their target enzymes, [8][9][10] no HS oligosaccharide has been discovered to induce robust activation of HCII.Identifying GAGs equences that selectively target proteins is extremely challenging.Akey reason for this is their structural complexity.H S, ah ighly anionic polymer containing variably sulfated, acetylated and epimerized residues, presents enormous structural diversity that makes comprehensive analysis of all possible sequences difficult. Thus, identifying key "needles" in this haystack, especially with synthesis [11,12] or isolation of oligosaccharides from nature nearly impossible. [13] We had earlier developed ad ual-filter computational algorithm, called combinatorial virtual library screening (CVLS) strategy,torapidly sort HS sequences into "specific" and "non-specific" bins. [14,15] We wondered whether this tool could pinpoint HS sequences that preferentially activate HCII for inhibition of thrombin. Further, we posited that such asequence,ifany,would be different from the pentasaccharide seq...

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“…Aldehydes 12 -16, ketones 20 -22, 27, 28 and 30 as well as carboxylic acids 35 -41 are described in the literature or are commercially available. The spectroscopic and physical data of aldehydes 15 [29] and 16, [30] of ketones 27 [31] , 28, [32] and of carboxylic acids 39 [33] 40 [34] and 41 [35] are listed in the literature.…”

Section: Resultsmentioning

confidence: 99%

“…Compound 41: colourless solid; mp 152 8C (ref. [35] : mp 157 8C); [a] 20 D : À 102.98 (CHCl 3 , c 1) {ref. [34] : [a] …”

Section: -Methoxybenzoic Acid (38)mentioning

confidence: 99%

Practical TEMPO-Mediated Oxidation of Alcohols using Different Polymer-Bound Co-Oxidants

Kloth¹,

Brünjes²,

Kunst³

et al. 2005

Advanced Synthesis & Catalysis

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Hypochlorite and chlorite exchange resins are evaluated as co-oxidants or oxidants, respectively, for the oxidation of alcohols to the corresponding aldehydes, ketones or carboxylic acids. Polymer-bound hypochlorite can act as a co-oxidant in TEMPOmediated oxidations of alcohols. The formation of aldehydes only works under weakly acidic conditions. However, the cheap hypochlorite exchange resin is less efficient as co-oxidant compared to the use of ionically immobilised bisacetoxybromate(I) anions. In contrast, the chlorite exchange resin is a highly potent co-oxidant for the preparation of carboxylic acids from the corresponding primary alcohols in the presence of TEMPO. It is demonstrated that in this case also the resin acts as a polymer-bound co-oxidant for both oxidation steps. Yields are commonly excellent as is also demonstrated for examples taken from natural product synthesis which include acid labile glycosides. In most cases, work-up of this heavy metal-free oxidation is kept to a minimum. It often includes filtration followed by removal of the solvent.

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Galacturonsäurederivate. I. Galacturonate aus Acetyl‐ und Isopropyliden‐D‐galactopyranosen

Cited by 18 publications

References 25 publications

Synthesis of α-galactosyl ceramide analogues with an α-triazole at the anomeric carbon

Synthesis of α-galactosyl ceramide analogues with an α-triazole at the anomeric carbon

A Hexasaccharide Containing Rare 2‐O‐Sulfate‐Glucuronic Acid Residues Selectively Activates Heparin Cofactor II

Practical TEMPO-Mediated Oxidation of Alcohols using Different Polymer-Bound Co-Oxidants

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