Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

• Pramod R. Markad,
• Navanath Kumbhar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2016, 12, 1765–1771, doi:10.3762/bjoc.12.165

• , antiviral, antibacterial and antifungal [2]. Peptidyl nucleosides in which the sugar part is in the furanose form are common, however, the sugar framework in the pyranose form, with a nucleobase and a peptide linker at either ends, are rare in nature. A few examples of this category are amipurimycin and

• including solvent, Lewis acid, and protecting groups on the nucleobase or sugar; we thought of synthesizing the peracylated anhydrosugar to alter its reactivity towards glycosylation [22]. In this regard, anhydrosugar 15 was subjected to 10% Pd/C and Et3SiH (for deprotection of the benzyl functionality and

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• be obtained by spontaneous or enzyme-supported hemiacetalisation followed by dehydration [34]. The tricyclic core unit is oxidised further and heavily decorated by tailoring enzymes, also involving an unusual rearrangement leading to the dioxane unit, whose carbon atoms originally derive from a sugar

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• hydrophilic pocket (Ser251 and Lys215) where the hydroxy groups of the sugar interact and a phosphonate binding site close to the magnesium ion located in the substrate binding site. Thus, as few cytosine-containing analogues were equipotent in terms of cN-II inhibition to their purine counterparts (Figure 1

• synthesis of 1,2,3-triazolonucleotides (1a–o, Figure 1) was envisaged using the Huisgen 1,3-dipolar cycloaddition of the azido-sugar-phosphonate key-intermediate 2 (Scheme 1) and selected commercially available alkynes. Thus, (1-azido-2,5-di-O-acetyl-3-O-benzoyl-6-deoxy-6-diethylphosphono)-β-ribo-(5S

• -protected nucleotides 3a–o (Scheme 2) in moderate to good yields. Removal of the sugar protecting groups (acetyl and benzoyl) in basic conditions resulted in the formation of the nucleotides 4a–q (Scheme 2), which were then treated by trimethylsilyl bromide (TMSBr) to generate the corresponding phosphonic

Mutagenic activity of quaternary ammonium salt derivatives of carbohydrates

• Barbara Dmochowska,
• Karol Sikora,
• Anna Woziwodzka,
• Jacek Piosik and
• Beata Podgórska

Beilstein J. Org. Chem. 2016, 12, 1434–1439, doi:10.3762/bjoc.12.138

• the same recognition pattern is used to fight bacterial infections. Dendritic cells from mammalian immune system express a variety of sugar-binding proteins (lectins) at their surface. They capture, process, and display antigens to native T-cells and trigger the adaptive immune system [3]. Proteins

• and sugar moieties were described before [22][25][26]. It was shown that quaternization of chitosan increases its antimicrobial activity; such polymer is proposed to be used as a wound dressing after surgeries to eliminate infections and to improve the healing process [27][28][29]. Moreover, the

• introduction of a sugar moiety to anticancer drug molecules enhanced their activity and selectivity [30][31]. In this paper, we describe process of synthesis, structural characteristics, and mutagenic activity profile of eight new QAS derivatives of 6-aminohexyl D-glucopyranosides. These compounds correspond

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

• Daniel Wiegmann,
• Stefan Koppermann,
• Marius Wirth,
• Giuliana Niro,
• Kristin Leyerer and
• Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

• glycosylated in its 5'-position with an aminoribose unit and in some cases a lipophilic side chain is attached to the hydroxyleucine residue. The 19 compounds are divided into four different series (A–D) which mainly vary in the leucine residue and the lipophilic side chain or the amino sugar (Figure 1). The

• : Bacterial cell walls consist of peptidoglycan, a heteropolymer with long chains of alternating units of N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) that are cross-linked through peptide chains attached to the muramic acid sugar (Figure 3) [52]. The biosynthesis of peptidoglycan is

• been reported elsewhere [52]. The membrane-associated steps commence with the transfer of UDP-MurNAc-pentapeptide to the lipid carrier undecaprenyl phosphate, catalysed by translocase I (MraY), to give lipid I (Figure 4, product of step B). The glycosyltransferase MurG attaches a GlcNAc sugar to

Synthesis and in vitro cytotoxicity of acetylated 3-fluoro, 4-fluoro and 3,4-difluoro analogs of D-glucosamine and D-galactosamine

• Štěpán Horník,
• Lucie Červenková Šťastná,
• Petra Cuřínová,
• Jan Sýkora,
• Kateřina Káňová,
• Roman Hrstka,
• Ivana Císařová,
• Martin Dračínský and
• Jindřich Karban

Beilstein J. Org. Chem. 2016, 12, 750–759, doi:10.3762/bjoc.12.75

• -2-azido-hexopyranoses have potential as synthons in oligosaccharide assembly. Keywords: amino sugars; cytotoxicity; fluorinated carbohydrates; fluorine; hexosamines; Introduction Derivatives of D-glucosamine (GlcN) and D-galactosamine (GalN) are essential amino sugar components of glycans in

• glycan and glycosaminoglycan biosynthesis [2][3], to inhibit amino sugars processing enzymes [4][5], to probe interactions of amino sugars with their target enzymes and lectins [6][7], or to increase the hydrolytic stability of the glycosidic bond in amino sugar glycosides [8][9]. For example, acetylated

Three new trixane glycosides obtained from the leaves of Jungia sellowii Less. using centrifugal partition chromatography

• Luíse Azevedo,
• Larissa Faqueti,
• Marina Kritsanida,
• Antonia Efstathiou,
• Despina Smirlis,
• Gilberto C. Franchi Jr,
• Grégory Genta-Jouve,
• Sylvie Michel,
• Louis P. Sandjo,
• Raphaël Grougnet and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2016, 12, 674–683, doi:10.3762/bjoc.12.68

• groups, three were oxygenated while the CH groups included one anomeric (δ 4.28/104.7, Table 2 and Table 3), one olefin (δ 6.79/139.7), and four bearing oxygen (δ 3.20/75.0, 3.38/78.0, 3.32/71.8, and 3.30/77.4). A sugar moiety was deduced mainly from HSQC and COSY correlations observed between the

• oxymethine groups, the hemi-acetal and one of the CH2O (δ 3.65, 3.83/63.0) groups. Furthermore, the quaternary carbons included an α,β-unsaturated carbonyl (δ 165.5), an olefinic carbon (δ 137.5) and two sp3 carbons (δ 47.7 and 53.8). Fifteen carbon shifts remained after the sugar deduction suggesting the

• carbons C-2 (δ 43.0), C-10 (δ 65.2), C-11 (δ 47.7), and C-13 (δ 76.4). The sugar moiety was identified as glucopyranosyl by comparing its chemical shift with those formerly reported [35]. It was further attached to the aglycone at C-13 since H-13 (δ 3.39, 3.82) correlated with the anomeric carbon (104.7

Elucidation of a masked repeating structure of the O-specific polysaccharide of the halotolerant soil bacteria Azospirillum halopraeferens Au4

• Elena N. Sigida,
• Yuliya P. Fedonenko,
• Alexander S. Shashkov,
• Nikolay P. Arbatsky,
• Evelina L. Zdorovenko,
• Svetlana A. Konnova,
• Vladimir V. Ignatov and
• Yuriy A. Knirel

Beilstein J. Org. Chem. 2016, 12, 636–642, doi:10.3762/bjoc.12.62

• hydrolysis of the lipopolysaccharide isolated by the phenol–water extraction from the halotolerant soil bacteria Azospirillum halopraeferens type strain Au4. The polysaccharide was studied by sugar and methylation analyses, selective cleavages by Smith degradation and solvolysis with trifluoroacetic acid

• -substituted Rha residue is partially 2-O-methylated in the OPS, a finding consistent with identification of Rha2Me in sugar analysis. The 1H and 13C NMR spectra of the OPS (Supporting Information File 1) showed signals of different intensities and thus indicating a structural irregularity. Further studies

• degradation was used, which included periodate oxidation of the vicinal hydroxy groups in the monosaccharides, mild acidic hydrolysis at the linkages of the destroyed sugar residues, and borohydride reduction of aldehyde groups before and after hydrolysis [17]. Based on the methylation analysis data (see

A selective and mild glycosylation method of natural phenolic alcohols

• Mária Mastihubová and
• Monika Poláková

Beilstein J. Org. Chem. 2016, 12, 524–530, doi:10.3762/bjoc.12.51

• Acetyl-protecting groups are the simplest choice also for the protection of the glycone part since the deprotection of both, sugar and aromatic moieties, can be accomplished in one step. Naturally occurring O-glycosides possess mostly 1,2-trans-glycosidic linkages. Therefore, neighbouring group

Effective in silico prediction of new oxazolidinone antibiotics: force field simulations of the antibiotic–ribosome complex supervised by experiment and electronic structure methods

• Jörg Grunenberg and
• Giuseppe Licari

Beilstein J. Org. Chem. 2016, 12, 415–428, doi:10.3762/bjoc.12.45

• . Particularly, two H-bonds between the sugar backbone of residues A2451 and U2584 (EC numbering) may be the main responsible for the increased potency. Due to this earlier study, the hydroxy functionality in 7 is donating the hydrogen bond superseding linezolid’s acetamide hydrogen donor. Indeed our stochastic

• hydroxy group is stabilized by a hydrogen bond with the phosphate of G2540 (relaxed force constant: 0.20 N/cm). Furthermore, the pyridine group establishes a second hydrogen bond with the sugar of G2541 (relaxed force constant: 0.21 N/cm), confirming the capability of this substructure to interact with

Self and directed assembly: people and molecules

• Tony D. James

Beilstein J. Org. Chem. 2016, 12, 391–405, doi:10.3762/bjoc.12.42

• formed very strongly complexes with tartaric acid [60]. This paper made us realise that our chiral binol boronic acid 8 should be able to discriminate the enantiomers of tartaric acid and also bind strongly with other sugar acids. Therefore, with Jianzhang Zhao an outstanding Postdoctoral Research Fellow

• in my group and currently a Professor at Dalian University of Technology, we decided to investigate the properties of the enantiomerically pure forms of the receptor with chiral tartaric acid and other sugar acids. It turned out that the chiral system 8 (R or S) was very good at differentiating the

• enantiomers of tartaric acid and also bound bind strongly with other sugar acids [61] (Figure 9). While, we were very happy with these results, we realised that the system could be improved by changing the fluorophore from binol, to a much better fluorophore such as anthracene. Therefore, we combined the

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• sugar sensors [43][44][45], and Anthony Czarnik had published his landmark treatise “Desperately Seeking Sensors” [72]. These three individuals are the true fathers of “Supramolecular Analytical Chemistry”, even if our group later introduced this terminology [73]. Sensing a paradigm shift Whereas

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• environment only. The secondary carbon substitution results in inversion in the reaction centre which changes the sugar moiety from glucoside to mannoside, altroside or alloside making those derivatives CD-based cyclic oligosaccharides and not CDs. The design of green synthetic methods for the bulk

Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time ¹³C CP-MAS solid-state NMR characterization

• Isabelle Mallard,
• Davy Baudelet,
• Franca Castiglione,
• Monica Ferro,
• Walter Panzeri,
• Enzio Ragg and
• Andrea Mele

Beilstein J. Org. Chem. 2015, 11, 2785–2794, doi:10.3762/bjoc.11.299

• good line-shape fitting was obtained for all carbons of the sugar ring (C1–C5) and C6 for CRYSMEB, while for the three polymers the C6 signal is strongly overlapped with the epichlorohydrin resonances, consequently this line was not analyzed. The TCH values extracted from fitting the exponential rise

• carbon atoms show similar TCH values (Table 2, column 3). Similar results are observed for the three polymers, as shown by the values of columns 5, 7 and 9 in the order. For polymers D1 and D3, the TCH values of the β-CD sugar moiety are decreased with respect to that observed for native CRYSMEB, while

• for polymer D2 the opposite trend is observed. The emerging overall picture is that the polymerization can significantly change the response of the cyclodextrin macro-ring C atoms to the cross-polarization with respect to the pristine CRYSMEB. In detail, the sugar ring C atoms show TCH values

Recent advances in copper-catalyzed asymmetric coupling reactions

• Fengtao Zhou and
• Qian Cai

Beilstein J. Org. Chem. 2015, 11, 2600–2615, doi:10.3762/bjoc.11.280

• advantage of a chiral (R)-BINOL-bridge to link the two aromatic acids and obtained the coupling product with excellent stereocontrol (up to 100% de) (Scheme 1) [16][17][18][19]. In 1998, Martin et al. [20] applied this strategy to the asymmetric intramolecular biaryl coupling of sugar derivatives carrying 2

Versatile synthesis and biological evaluation of novel 3’-fluorinated purine nucleosides

• Hang Ren,
• Haoyun An,
• Paul J. Hatala,
• William C. Stevens Jr,
• Jingchao Tao and
• Baicheng He

Beilstein J. Org. Chem. 2015, 11, 2509–2520, doi:10.3762/bjoc.11.272

• formation and ring opening as well as reversion of the hydroxy group on the sugar ring. Jeong and co-workers [38][39][40] synthesized fluorine-substituted ribofuranose but isolation required a challenging separation. Therefore, the synthetic challenges for preparing 3’-fluorine modified sugars and

• ). 6-Methylpurine (28) was synthesized from 6-chloropurine according to the reported protocol [44]. Compound 28 was silylated with BSA and glycosylated with the 3’-fluoro-sugar 25 to provide the desired compound 29 in 78% yield. Subsequent deprotection furnished the targeted novel fluorine modified 6

Two strategies for the synthesis of the biologically important ATP analogue ApppI, at a multi-milligram scale

• Janne Weisell,
• Jouko Vepsäläinen and
• Petri A. Turhanen

Beilstein J. Org. Chem. 2015, 11, 2189–2193, doi:10.3762/bjoc.11.237

• , 1H), 4.34–4.23 (m, 2H), 4.08–4.00 (m, 2H), 3.24 (q, J = 7.0, 16H, from triethylammonium salt), 2.30 (t, J = 6.5, 2H), 1.69 (s, 3H), 1.31 (t, J = 7.5, 24H, from triethylammonium salt). C=CH2 signals and one “sugar” proton signal under HDO-line at 4.8. 13C NMR (D2O) δ 158.5, 155.7, 152.1, 146.2, 142.8

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• western countries, of people with obesity and type-II diabetes has pushed the food industry to develop new low calorie sweeteners, better known as sugar substituents. Among all artificial sweeteners so far developed: aspartame, saccharin, acesulfame K and sucralose are undoubtedly the most popular

• . However, questions regarding the safety of these sweeteners are still largely argued from the scientific community [1]. Thus, the discovery of new sugar substituents has become a target of food industry, to this regard new sweet-tasting natural products might offer a valid alternative to the artificial

• , in honor of the Spanish scientist, this natural product was called hernandulcin [6]. Hernandulcin is the first strongly sweet sesquiterpene, making it a breakthrough discovery in the field of natural sugar substitutes. It turned out that 1, which belongs to the family of bisabolanes, is more than

Cholesterol lowering effects of mono-lactose-appended β-cyclodextrin in Niemann–Pick type C disease-like HepG2 cells

• Keiichi Motoyama,
• Yumi Hirai,
• Rena Nishiyama,
• Yuki Maeda,
• Taishi Higashi,
• Yoichi Ishitsuka,
• Yuki Kondo,
• Tetsumi Irie,
• Takumi Era and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2015, 11, 2079–2086, doi:10.3762/bjoc.11.224

• , Japan), and lyophilized to obtain Lac-β-CyD. The reaction was monitored by TLC (silica gel F254, Merck, Whitehouse Station, NJ). Eluent: methanol/water 9:1 (v/v), indicator: p-anisaldehyde for sugar and ninhydrin for amino groups. The Lac-β-CyD gave 1H NMR spectra consisting of protons of both β-CyD and

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• synthesis of fused medium-sized rings has been reported by Ghosh and co-workers [41] via a sequential diastereoselective DA reaction and a RRM protocol. A variety of sugar-based norbornene derivatives provide an entry to various functionalized bicyclic sugar derivatives containing 7–9 membered rings. To

• protocol for the synthesis of bicyclic sugar derivatives. ROM–RCM sequence of the norbornene derivatives 186 and 187. RRM approach toward highly functionalized bridge tricyclic system. RRM approach toward highly functionalized tricyclic systems. Synthesis of hexacyclic compound 203 by RRM approach. RRM

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• give the carboxyl derivative 12b (reaction performed in acetonitrile containing 1% H2O v/v) or to link it to a sugar, like glucose to give the hybrid compound 12c (reaction performed in dry acetonitrile containing glucose). Both derivatives were significantly more soluble in aqueous solutions than the

Towards inhibitors of glycosyltransferases: A novel approach to the synthesis of 3-acetamido-3-deoxy-D-psicofuranose derivatives

• Maroš Bella,
• Miroslav Koóš and
• Chun-Hung Lin

Beilstein J. Org. Chem. 2015, 11, 1547–1552, doi:10.3762/bjoc.11.170

• unknown [7]. In general, GTs transfer sugar nucleotide donors onto suitable acceptors during the biosynthesis of glycans and glycoconjugates [8]. Both donor and acceptor substrates are recognized by GTs binding pockets. For instance, in the course of biosynthesis of complex and hybrid oligosaccharides

• complexity of the GnTs catalytic mechanism. The main reasons originating from the complex character of the catalytic mechanism which complicate the search for GnTs inhibitors are a) participation of four components in the transition state (sugar donor, acceptor, nucleotide and metal co-factor), b) weak

Qualitative evaluation of regioselectivity in the formation of di- and tri-6-O-tritylates of α-cyclodextrin

• Keisuke Yoshikiyo,
• Yoshihisa Matsui and
• Tatsuyuki Yamamoto

Beilstein J. Org. Chem. 2015, 11, 1530–1540, doi:10.3762/bjoc.11.168

• the C(6)-OH on the adjacent glucopyranose in a counter-clockwise direction and sterically retards the additional tritylation of the C(6)-OH. Experimental Materials The α-CD was supplied by Ensuiko Sugar Refining Co., Ltd., and dried overnight in vacuo at 110 °C before use. TrCl (Tokyo Chemical

Structure and conformational analysis of spiroketals from 6-O-methyl-9(E)-hydroxyiminoerythronolide A

• Ana Čikoš,
• Irena Ćaleta,
• Dinko Žiher,
• Mark B. Vine,
• Ivaylo J. Elenkov,
• Marko Dukši,
• Dubravka Gembarovski,
• Marina Ilijaš,
• Snježana Dragojević,
• Ivica Malnar and
• Sulejman Alihodžić

Beilstein J. Org. Chem. 2015, 11, 1447–1457, doi:10.3762/bjoc.11.157

• 1) in acid medium does not degrade to the spiroketal but instead loses the cladinose sugar [48][49]. The degradation process terminates with decladinosyl clarithromycin in equilibrium with the 9,12-hemiacetal decladinosyl clarithromycin [50]. Unlike the acid degradation product anhydroerythromycin A

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• ] have reported the synthesis of a glycotriazolophane 309 (carbohydrate–triazole–cyclophane hybrid) from a sugar amino acid via a copper-catalyzed azide-alkyne cycloaddition sequence. An aminosugar acid was identified as a useful building block to generate cyclophanes. Thus, the treatment of 304 with