Linear Synthesis of a Protected H-Type II Pentasaccharide Using Glycosyl Phosphate Building Blocks

Love, Kerry R.; Andrade, Rodrigo; Seeberger, Peter H.

doi:10.1021/jo015987h

Cited by 93 publications

(49 citation statements)

References 61 publications

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“…Reductive opening of the benzylidene acetal groups in compounds 2a-2d with triethylsilane in the presence of trifluoroacetic anhydride [21] afforded the 4-O-unprotected 6-O-benzylated derivatives 3a, 3b, 3c [20] and 3d, which were employed for the generation of three pairs with regioisomeric 3-O,4-O-protection. In previous work, the Fmoc group had turned out to be ideally suited as a temporary protecting group in SPOS, so in 3a this group was complemented by the PA, Lev and Alloc groups at 4-O, thus leading to compounds 4ab, 4ac and 4ad.…”

Section: Resultsmentioning

confidence: 99%

Temporary Carbohydrate Diol Protection with Ester Groups – Orthogonality under Solid‐Phase Oligosaccharide Synthesis Conditions

Markad

Schmidt

2009

Eur J Org Chem

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For regioselective deprotection studies under SPOS conditions the glucosamine derivatives 4ab/4ba, 4ac/4ca and 4ad/ 4da -with Fmoc/PA, Fmoc/Lev or Fmoc/Alloc, respectively, as temporary ester protecting groups at 3-O and 4-O -were prepared. Fmoc cleavage with triethylamine in 4ab or 4ba led to PA migration, so the Fmoc/PA pair does not permit regioselective access to the vicinal hydroxy groups. Under the same reaction conditions no Lev migration in 4ac/4ca or Alloc migration in 4ad/4da was observed. Lev removal with hydrazinium acetate in 4ac/4ca and Alloc removal with Pd 0 and dimedone as nucleophile in 4ad/4da was also not accompanied by Fmoc migration, so the Fmoc/Lev pair and the

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Section: Resultsmentioning

confidence: 99%

Temporary Carbohydrate Diol Protection with Ester Groups – Orthogonality under Solid‐Phase Oligosaccharide Synthesis Conditions

Markad

Schmidt

2009

Eur J Org Chem

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“…Referring to the previous protecting-group strategies for heparin synthesis, 8 we envisioned the fully protected tetrasaccharide Benzyl, acetyl, and benzoyl groups were used as permanent protecting groups for the hydroxyl groups; the carboxylic acid groups were blocked with methyl and/or benzyl groups; p-methoxybenzyl (PMB) and 2-(azidomethyl)benzoyl (AZMB) 9 groups were used for the temporary protection of the hydroxyl groups destined for sulfonation; and an azide was employed as the precursor to the sulfonated 2-amino groups of the D-GlcN residues. Considering the pseudo-symmetry of tetrasaccharide 2, we planned to adopt a convergent 2+2 coupling of the disaccharide donor 3 and acceptor 4.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of a tetrasaccharide substrate of heparanase

Chen

Zhou

Chen

et al. 2008

Carbohydrate Research

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“…Removal of the temporary levulinoate protecting group afforded monosaccharide acceptor 24. Glycosylation with galactose phosphate 25 [38], and removal of the levulinoyl protecting group at C(3) gave disaccharide 27 (Scheme 6). Attempts to install the second galactose unit with 25 failed, and unreacted acceptor 27 was recovered, thereby necessitating a new route to the Gal-b-(1 3 3)-Gal linkage.…”

Section: Synthesis Of Phosphate Building Blocksmentioning

confidence: 99%

Automated Synthesis of Oligosaccharides

Palmacci

Plante

Hewitt

et al. 2003

Helvetica Chimica Acta

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Dedicated to Professor Duilio Arigoni on the occasion of his 75th birthdayThe chemical synthesis of oligosaccharides with an automated solid-phase synthesizer is described. An octenediol linker served to attach the growing oligosaccharide chain to the solid support, and the desired structures were cleaved from the support via olefin metathesis to afford a pentenyl glycoside. The automated syntheses of several important carbohydrates, including a pentarhamnoside, a proteoglycan linkage-region tetrasaccharide, a phytoalexin elicitor dodecasaccharide, and a branched Leishmania lipophosphoglycan tetrasaccharide, were accomplished in higher overall yield and ca. 20 times faster than with solution-phase methods.Introduction. ± Nonspecialists can routinely access peptides and oligonucleotides for biochemical studies with commercially available machines, while only highly specialized laboratories can synthesize complex carbohydrates. Our effort towards the automated synthesis of oligosaccharides was inspired by automated methods for peptide and DNA synthesis, and the impact these techniques have had on proteomics and genomics. Here, we describe the development and use of the first automated oligosaccharide synthesizer.The traditional solution-phase chemistry of complex carbohydrates remains a timeconsuming art. Although a plethora of new methods for the construction of oligosaccharides, such as enzymatic [1] and one-pot procedures, [2] [3] have been described, few are generally applicable. The OptiMer One-Pot approach [4] aims to automate synthesis planning by selecting efficient couplings based on a computer program and has been successfully applied to the construction of several complex oligosaccharides [5]. As an alternative to solution-phase assembly, the solid-phase synthesis of oligosaccharides has received increased attention [6]. The elimination of intermediate purification steps has led to the accelerated synthesis of several complex structures. We sought to exploit the benefits of the solid-phase paradigm, without the need for manual manipulations.Influenced by the peptide-synthesizer platform [7] [8], we envisioned a similar machine that could easily accomplish glycosylation and deprotection reactions in an analogous fashion. In this way, the synthesis of complex carbohydrates could be reduced to the acquisition of suitably protected mono-or disaccharide glycosyl donors. The building blocks and reaction cycles required for automated oligosaccharide

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Linear Synthesis of a Protected H-Type II Pentasaccharide Using Glycosyl Phosphate Building Blocks

Cited by 93 publications

References 61 publications

Temporary Carbohydrate Diol Protection with Ester Groups – Orthogonality under Solid‐Phase Oligosaccharide Synthesis Conditions

Temporary Carbohydrate Diol Protection with Ester Groups – Orthogonality under Solid‐Phase Oligosaccharide Synthesis Conditions

Synthesis of a tetrasaccharide substrate of heparanase

Automated Synthesis of Oligosaccharides

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