- C-3 epimers of sugar amino acids as foldameric building blocks: improved synthesis, useful derivatives, coupling strategies
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To obtain key sugar derivatives for making homooligomeric foldamers or α/β-chimera peptides, economic and multigram scale synthetic methods were to be developed. Though described in the literature, the cost-effective making of both 3-amino-3-deoxy-ribofuranuronic acid (H–tX–OH) and its C-3 epimeric stereoisomer, the 3-amino-3-deoxy-xylofuranuronic acid (H–cX–OH) from d-glucose is described here. The present synthetic route elaborated is (1) appropriate for large-scale synthesis; (2) reagent costs reduced (e.g. by a factor of 400); (3) yields optimized are ~80% or higher for all six consecutive steps concluding –tX– or –cX– and (4) reaction times shortened. Thus, a new synthetic route step-by-step optimized for yield, cost, time and purification is given both for d-xylo and d-ribo-amino-furanuronic acids using sustainable chemistry (e.g. less chromatography with organic solvents; using continuous-flow reactor). Our study encompasses necessary building blocks (e.g. –X–OMe, –X–OiPr, –X–NHMe, Fmoc–X–OH) and key coupling reactions making –Aaa–tX–Aaa– or –Aaa–tX–tX–Aaa– type “inserts”. Completed for both stereoisomers of X, including the newly synthesized Fmoc–cX–OH, producing longer oligomers for drug design and discovery is more of a reality than a wish.
- Nagy, Adrienn,Csordás, Barbara,Zsoldos-Mády, Virág,Pintér, István,Farkas, Viktor,Perczel, András
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p. 223 - 240
(2017/02/05)
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- Synthesis of oligosaccharide mimetics with glycoaminoxy acids
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From readily available di-O-isopropylidene-D-glucose, a Dribofuranoid glycoaminoxy acid and its τBu ester have been efficiently prepared as a new family of sugar building blocks by introducing the phthallmido aminoxy group by a Mitsunobu reaction. We found that the τBu ester can be selectively deprotected with 13.7% TFA in CH2Cl2 at 0°C in the pres-ence of the 1,2-O-isopropylldene acetal. This selective deprotection has made possible the synthesis of homo-oligomers of glycoaminoxy acids (up to six sugar units) as a novel type of oligosaccharide mimetics,
- Gong, Yanchun,Sun, Hongbin,Xie, Juan
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scheme or table
p. 6027 - 6033
(2010/03/25)
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- Synthesis of solid-phase bound sulfonate esters
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p-Pivaloyloxybenzenesulfonyl and methylsulfonyl residues were used as linkers to attach secondary alcohols to Wang resin and to Merrifield resin, respectively. p-Pivaloyloxybenzenesulfonates of alcohols were deprotected at the phenolic group and coupled with Wang resin by Mitsunobu reaction whereas mesylates were lithiated at the methyl group and subsequently connected with chloromethyl residues of Merrifield resin.
- Furman,Lysek,Matyjasek,Wojtkielewicz,Chmielewski
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p. 2795 - 2802
(2007/10/03)
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- Study of stereoselectivity in organometallic additions to 1,2-O-isopropylidene-O-R-α-D-xylopentodialdo-1,4-furanose
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Diastereofacial selectivity of the addition of organometallic reagents to 1,2-O-isopropylidene-O-R-α-D-xylopentodialdo-44-furanose (6) was studied.
- Gracza, Tibor,Szolcsanyi, Peter
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p. 1386 - 1398
(2007/10/03)
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- New nucleoside heteroanalogues: Desoxynucleoside selenocyanates
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New nucleoside heteroanalogues, 5' and 3'-desoxynucleoside selenocyanates and primary desoxysugar selenocyanates, were synthesized from activated nucleoside and sugar derivatives and a new convenient seleno nucleophile, tetrabutylammonium selenocyanate. Tresylate-based activation of hydroxy functions turned out to be most successful for formation of theme selenocyanates compared with mesylate- or triflate-based activation.
- Belostotskii,Lexner,Hassner
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p. 1181 - 1184
(2007/10/03)
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- Chemical Synthesis of 13C-labelled Monomers for the Solid-Phase and Template Controlled Enzymatic Synthesis of DNA and RNA Oligomers
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The preparation of 13C-labelled ribonucleosides starting from -glucose 1 and the corresponding nucleobases 5a-e or 6a-e (N6-benzoyl-adenine, N2-acetyl-guanine, N4-benzoyl-cytosine, uracil and thymine) in 47-66percent overall yield is described.Their subsequent transformation into 5'-O-dimethoxytrityl protected DNA-phosphoramidites and 5'-O-dimethoxytrityl-2'-O-trialkylsilyl protected RNA-phosphor-amidites for the solid phase synthesis of DNA- and RNA-oligomers and to 5'-O-ribo- and deoxyribo-nucleosidetriphosphates for template controlled enzymatic synthesis (polymerase- or reverse transcriptase reaction) has been carried out.
- Quant, S.,Wechselberger, R. W.,Wolter, M. A.,Woerner, K.-H.,Schell, P.,et al.
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p. 6649 - 6652
(2007/10/02)
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