Two new 2-alkylquinolones, inhibitory to the fish skin ulcer pathogen Tenacibaculum maritimum, produced by a rhizobacterium of the genus Burkholderia sp.

• Dandan Li,
• Naoya Oku,
• Atsumi Hasada,
• Masafumi Shimizu and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2018, 14, 1446–1451, doi:10.3762/bjoc.14.122

• seed-cultured in 500 mL K-1 flasks each containing 100 mL of medium V-22 (soluble starch 1%, glucose 0.5%, NZ-case 0.3%, yeast extract 0.2%, tryptone 0.5%, K2HPO4 0.1%, MgSO4·7H2O 0.05%, and CaCO3 0.3%, pH 7.0) by rotary shaking at 200 rpm at 30 °C for two days. A three-mL aliquot of the resulting

• culture was inoculated into 100 mL of the IMM-HS production medium (glucose 1%, K2HPO4 0.36%, KH2PO4 0.41%, MgSO4·7H2O 0.02%, CaCl2·2H2O 0.01%, FeSO4·7H2O 0.002%, NH4Cl 0.1%, biotin 0.0001%, and L-histidine 0.4%), and shaken at 200 rpm at 30 °C for 4 days. For the extraction of secondary metabolites, 100

Synthetic avenues towards a tetrasaccharide related to Streptococcus pneumonia of serotype 6A

• Aritra Chaudhury,
• Mana Mohan Mukherjee and
• Rina Ghosh

Beilstein J. Org. Chem. 2018, 14, 1095–1102, doi:10.3762/bjoc.14.95

• bears a repeating unit, α-D-Galp(1->3)-α-D-Glcp(1->3)-α-L-Rhap(1->3)-D-Rib (SPn 6A). A closer look at the structure reveals the presence of α-linked galactose and glucose residues. The synthesis of these 1,2-cis glycosidic linkages are considered challenging particularly in the context of a one-pot

• conditions [41], followed by hydrogenation with H2/Pd-C in EtOH/EtOAc/AcOH solvent to give the deprotected tetrasaccharide 23 in 85% yield over two steps. 1H NMR in D2O of the target tetrasaccharide 23 showed the anomeric protons of the galactose, glucose, and rhamnose residues from the non-reducing end

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• conjugates in the minor groove by marinating a stable hairpin structure [96]. The authors tethered various monosaccharides such as β-xylose, α-xylose, β-galactose, β-glucose and β-L-fucose to a minor groove binding residue, Py-γ-Py-Ind, structurally analogous to distamycin and netropsin. A new set of novel

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

• increased glucose uptake by cancer cells [12]. Nowadays, it has been demonstrated that malignant cells differ markedly in many metabolic aspects compared to normal cells [13], thus offering the opportunity to target them in various ways. Most cancer tissues exhibit the following characteristics that can be

Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin–GnRH-III conjugates developed for targeted drug delivery

• Sabine Schuster,
• Beáta Biri-Kovács,
• Bálint Szeder,
• Viktor Farkas,
• László Buday,
• Zsuzsanna Szabó,
• Gábor Halmos and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 756–771, doi:10.3762/bjoc.14.64

• times with serum-free medium and one time with HPMI medium (containing 100 mM NaCl, 5.4 mM KCl, 0.4 mM MgCl2, 0.04 mM CaCl2, 10 mM Hepes, 20 mM glucose, 24 mM NaHCO3 and 5 mM Na2HPO4 at pH 7.4) and trypsinized for 10 min at 37 °C. Trypsinization was stopped by HPMI medium supplemented with 10% FBS

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• conversion of glucose in a tandem reaction [82]. The hydrophilic block of their polymersomes was PEG, and the hydrophobic block contained both poly[2-(diethylamino)ethyl methacrylate] (PDEAEM) which is pH responsive, and poly[4-(3,4-dimethylmaleimido)butyl methacrylate] (PDMIBM) as cross-linker. The activity

• of glucose oxidase (GOx) to convert glucose into D-glucono-δ-lactone and hydrogen peroxide was the first step of the reaction (Scheme 3A); subsequently, myoglobin (Myo) employed the hydrogen peroxide produced to oxidize guaiacol to quinone and water (Scheme 3B). When the pH was below 7, the

AuBr₃-catalyzed azidation of per-O-acetylated and per-O-benzoylated sugars

• Jayashree Rajput,
• Srinivas Hotha and
• Madhuri Vangala

Beilstein J. Org. Chem. 2018, 14, 682–687, doi:10.3762/bjoc.14.56

• good to excellent yields. Results and Discussion We began our studies by treating per-O-acetylated glucose with 3 equiv trimethylsilyl azide in the presence of 10 mol % AuBr3 in dichloromethane at room temperature. The reaction proceeded smoothly giving 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl azide

• , but the starting materials remained unaffected. Finally, the potential of the gold(III)-catalyzed azidation for large scale applications was demonstrated by performing a gram-scale synthesis on glucose peracetate giving product 2 in 90% yield. Conclusion In summary, a facile methodology demonstrating

• -acetylated glucose. Scope of AuBr3-catalyzed azido glycosylation of peracetates. Scope of AuBr3-catalyzed azido glycosylation of perbenzoylated sugars. Supporting Information Supporting Information File 70: Plausible catalytic cycle, experimental data and copies of 1H and 13C NMR spectra of glycosyl azides

Synthesis of a sucrose-based macrocycle with unsymmetrical monosaccharides "arms"

• Karolina Tiara,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2018, 14, 634–641, doi:10.3762/bjoc.14.50

• functionalized sucrose amines of type 9 (Figure 2) which will be obtained by a selective introduction of different fragments 8 (obtained from, e.g., glucose, mannose, etc.). At this stage we were focused on the elaboration of a methodology allowing to introduce different fragments at the sucrose terminals. We

• of alcohol 13 (derived from D-glucose) with a rigid fragment and we decided to introduce the phenyl ring. Treatment of alcohol 13 with para-nitrophenol under Mitsunobu conditions afforded the nitro compound 14 in 63% yield. Stereoisomeric alditol 15, obtained from D-mannose, was converted analogously

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

• Fabio Tonin and
• Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

• an immobilized NAD+-dependent 7α-HSHS (first reactor column); afterwards, 7-oxo-LCA is reduced to UDCA by an immobilized NADP+-dependent 7β-HSDH (second reactor column). The cofactors are individually regenerated in each column by the co-immobilized enzymes, lactate dehydrogenase (LDH) and glucose

• most used enzymes for the cofactor regeneration are glucose dehydrogenase (glucose to glucuronic acid), lactate dehydrogenase (pyruvate to lactate), glutamate dehydrogenase (α-ketoglutarate to glutamate) and formate dehydrogenase (formate to CO2). In particular, the last enzyme is interesting because

• (88.5 g L−1 d−1) for the epimerization of CDCA to UDCA. However, the employed enzymes have different cofactor specificities, leading to the consumption of stoichiometric amounts of sacrificial substrates (pyruvate and glucose). In addition, substrate loadings in the latter process are still modest (10

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 416–429, doi:10.3762/bjoc.14.30

• was used by Wang for the more extended synthesis of a dodecasaccharide oxazoline (Scheme 6) [78]. In this case selective removal of the PMB protecting group at OH-3 was followed by glycosylation with a pentasaccharide glycosyl fluoride donor, comprising one galactose, one glucose, and three mannose

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• to prepare these products. For example, this methodology was employed in 2014 by Kawanishi and Yamakoshi to develop the first total synthesis of naturally occurring prunustatin A, a novel inhibitor of glucose-regulated protein 78 expression [17]. As shown in Scheme 2, the key step of the synthesis

• under mild and neutral conditions. Among them, many syntheses of naturally occurring products have been described for the first time, such as those of the glucose-regulated protein 78 expression inhibitor agent prunustatin A, the antiproliferative agent apratoxin E and its C30 epimer, prebiscibactin

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

• elegant solution consisted in the application of glucose attached at position 6’ via a glutaryl group as a long-chain hydrophilic linker in combination with biotin or the hydrophilic fluorescent label AlexaFluor. The appropriately protected tetraacylated disaccharide 19 was subjected to treatment with Zn

• -catalysed phosphitylation of the 4’-OH group with N,N-diethylaminophosphepane followed by oxidation of the intermediate phosphite with m-CPBA to furnish the corresponding phosphate, and subsequent deprotection of the 6’-O-TBDMS ether gave the hexaacylated phosphotriester 21. The glutaryl-glucose linker

• (prepared from O-benzyl-protected glucose and glutaric anhydride) was introduced at the free 6’-OH group using DCC and DMAP to give 22. The anomeric allyl group was cleaved by standard procedure, the phosphorylation of the 1-OH group was performed by 1-O-lithiation and subsequent treatment with tetrabenzyl

Synthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of γ-cyclodextrin

• Markéta Bláhová,
• Sergey K. Filippov,
• Lubomír Kováčik,
• Jiří Horský,
• Simona Hybelbauerová,
• Zdenka Syrová,
• Tomáš Křížek and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2017, 13, 2509–2520, doi:10.3762/bjoc.13.248

• 6, 7 or 8 glucose units, respectively. Both chemically modified and native CDs are used in numerous applications, e.g., in separation methods [2][3] or in the pharmaceutical industry [4][5]. CDs are well-known as host molecules for various guest substances in aqueous solutions [4]. Derivatives of

• of 6-O-isomers, (ii) the spacer of the 6-O-isomer is elongated by a CH2 group of glucose unit. The details of differences in behavior in water could not be fully assessed due to the low solubility of the 6-O-regioisomer. In fact, the low solubility of the 6-O-regioisomer is the most striking

Herpetopanone, a diterpene from Herpetosiphon aurantiacus discovered by isotope labeling

• Xinli Pan,
• Nicole Domin,
• Sebastian Schieferdecker,
• Hirokazu Kage,
• Martin Roth and
• Markus Nett

Beilstein J. Org. Chem. 2017, 13, 2458–2465, doi:10.3762/bjoc.13.242

• . aurantiacus 114-95T, we fed the strain with 13C-labeled glucose and, subsequently, searched for characteristic mass shifts in its metabolome. This approach led to the discovery of a new natural product, of which the isotope pattern is indicative for a diterpene originating from the methylerythritol phosphate

• terpenoids in their natural bacterial hosts, which is based on the feeding of isotopically labeled glucose. The linear oligoprenyl units, which constitute the carbon backbones of terpenoids, arise from the condensation of activated isoprene units, namely isopentenyl diphosphate (IPP) and dimethylallyl

• diphosphate (DMAPP). The latter two precursors are synthesized by either the mevalonate (MEV) or methylerythritol phosphate (MEP) pathway [7]. Both the MEV and MEP pathway branch from glycolysis. Depending on the respective route, the metabolism of singly labeled glucose gives rise to a characteristic carbon

Diosgenyl 2-amino-2-deoxy-β-D-galactopyranoside: synthesis, derivatives and antimicrobial activity

• Henryk Myszka,
• Patrycja Sokołowska,
• Agnieszka Cieślińska,
• Andrzej Nowacki,
• Maciej Jaśkiewicz,
• Wojciech Kamysz and
• Beata Liberek

Beilstein J. Org. Chem. 2017, 13, 2310–2315, doi:10.3762/bjoc.13.227

• , particularly antifungal [3][4][5][6] and antitumor [7][8][9]. The aglycone part of a saponin is termed sapogenin. Diosgenin, yamogenin, tigogenin, smilagenin and sarsapogenin are the most abundant sapogenins in nature [10]. They are linked via a glycosidic bond to a sugar unit, mainly D-glucose. Diosgenyl

Curcuminoid–BF₂ complexes: Synthesis, fluorescence and optimization of BF₂ group cleavage

• Henning Weiss,
• Jeannine Reichel,
• Helmar Görls,
• Kilian Rolf Anton Schneider,
• Mathias Micheel,
• Michael Pröhl,
• Michael Gottschaldt,
• Benjamin Dietzek and
• Wolfgang Weigand

Beilstein J. Org. Chem. 2017, 13, 2264–2272, doi:10.3762/bjoc.13.223

• ongoing research to increase the selectivity of antitumor active metal complexes [17][18][19][20][21][22], our focus was on the synthesis of curcuminoids that could serve as building blocks to attach sugars like D-fructose or D-glucose [23]. Due to the easy accessibility to azido sugars [24][25] we

Superstructures with cyclodextrins: Chemistry and applications IV

• Gerhard Wenz

Beilstein J. Org. Chem. 2017, 13, 2157–2159, doi:10.3762/bjoc.13.215

• repulsive. The first examples of superstructures formed by attractive intermolecular forces were complexes of crown ethers [1], cryptands [2] and spherands [3], which were recognized by the 1987 Nobel Prize in Chemistry. In addition, inclusion compounds of cyclodextrins (CDs), cyclic oligomers of glucose

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• are liposome derivatives) [20], and cyclodextrin inclusion complexes [21][22][23]. Cyclodextrins (CDs) are naturally occurring cyclic oligosaccharides produced by bacterial degradation of starch. Native CDs have six to eight α-D-glucose units linked by α-1,4 bonds, being called α-, β- and γ-CDs

• include them. Having one glucose unit less, the cavity of β-CD is narrower and therefore the tilted structure of a flavonoid does not fit and one of the rings of the guest is positioned outside the cavity. This geometry was recently demonstrated for epigallocatechin, which has the same molecular backbone

Enzymatic separation of epimeric 4-C-hydroxymethylated furanosugars: Synthesis of bicyclic nucleosides

• Neha Rana,
• Manish Kumar,
• Vinod Khatri,
• Jyotirmoy Maity and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2017, 13, 2078–2086, doi:10.3762/bjoc.13.205

• Neha Rana Manish Kumar Vinod Khatri Jyotirmoy Maity Ashok K. Prasad Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India; Phone: 00-91-11-27662486 10.3762/bjoc.13.205 Abstract Conversion of D-glucose to 4-C-hydroxymethyl-1,2-O-isopropylidene-α-D-ribofuranose

• ribo-trihydroxy sugar derivative starting from diacetone-D-glucose led to the formation of an inseparable 1:1 mixture of the required compound and its C-3 epimer, i.e., 4-C-hydroxymethyl-1,2-O-isopropylidene-α-D-xylofuranose [10]. Lipases have been used extensively for the selective manipulation of

• -isopropylidene-α-D-ribofuranose (3a) can be obtained from D-glucose via diacetonylation followed by selective deprotection of 5,6-isopropylidene protection, sodium periodate oxidation of the vicinal diol and mixed aldol–Cannizaro reaction on the resulted aldehyde 2. However, this methodology always leads to the

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• was glycosylated in the presence of NIS/TfOH to afford tetrasaccharide 32 in 78% as a pure β-diastereomer [70]. Schmidt demonstrated the usefulness of xylylene tethers in application to the iterative synthesis of maltotriose [70]. In this application, the xylylene tether was used to link two glucose

1,3-Dibromo-5,5-dimethylhydantoin as promoter for glycosylations using thioglycosides

• Fei-Fei Xu,
• Claney L. Pereira and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2017, 13, 1994–1998, doi:10.3762/bjoc.13.195

• thioglycosides. Results and Discussion Initially, the capability of DBDMH to activate thioglycoside 1 [32] in order to glycosylate the primary hydroxy group present in D-glucose acceptor 2 [33] was explored without any additives (Table 1, entry 1). This initial experiment furnished disaccharide 3, albeit in

• investigated by using a variety of glycosyl donors 4–10 [34][35][36][37][38] containing C-2 participating groups to ensure 1,2-trans-glycoside formation (Table 2). Each glycosylating agent was reacted with D-glucose acceptors 2 (Table 2, entries 1–8) and 11 [39] (Table 2, entries 9–16) with a free hydroxy

Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides

• Jihen Ati,
• Pierre Lafite and
• Richard Daniellou

Beilstein J. Org. Chem. 2017, 13, 1857–1865, doi:10.3762/bjoc.13.180

• aggression. Their biosynthetic pathway requires the action of a S-GT (UGT74B1) that catalyses the reaction between a thiohydroximate acceptor and UDP-α-D-glucose as sugar donor to yield the corresponding desulfoglucosinolate (Figure 2) [20][21]. UGT74B1 from A. thaliana is a versatile enzyme in terms of

• ][25], and thurandacin [26] revealed S-glycosylation of cysteines. Carbohydrates bound to these bacteriocins are glucose or N-acetylglucosamine. For two of these glycopeptides, the corresponding S-GTs have been characterized and their versatility for a wide range of sugar donors has been tested [26][27

• reported O-GT to catalyse S-glycosylation on thiol acceptors [30]. Genetic engineering of this enzyme has also led to S-GT activities on several thiols. UGT73AE1 from Carthamus tinctorius was able to transfer glucose on a wide range of acceptors, including a S-containing compound, dichlorothiophenol [31

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E

• Marcel Reimann,
• Louis P. Sandjo,
• Luis Antelo,
• Eckhard Thines,
• Isabella Siepe and
• Till Opatz

Beilstein J. Org. Chem. 2017, 13, 1430–1438, doi:10.3762/bjoc.13.140

• agar plates containing GYM medium (10 g/L glucose, 4 g/L yeast extract, 10 g/L malt extract; pH 5.5, adjusted before autoclaving) and 20 g/L agar. The submerged cultivation was carried out for 10 to 20 days at room temperature. For maintenance, agar slants containing the same medium were used and

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• aldehyde or ketone) making this center more electrophilic (Scheme 1) [3]. Secondly, the pKa value of the anomeric OH group (glucose pKa ≈ 12.5 [9] or 14 [10]) is several orders of magnitude lower than for the other hydroxy groups (pKa ≈ 16–18) [9][10] so a careful selection of the base should allow for the

• -glucose in the presence of HCl to provide the methyl glycoside (pathway a, Scheme 6). The reaction proceeds chemoselective at the anomeric position. More recent examples typically use Lewis acids [29][30][31][32][33][34] or microwave irradiation [35][36] to accelerate the reaction. However, shortcomings

• from β-D-glucose pentaacetate, α-fluoro-D-glucose can be obtained with the key fluorination effected by using Olah’s reagent. The appeal of this procedure is obvious. It is an operationally simple and stereo- and regioselective method to obtain tri- and oligosaccharides containing a sucrose moiety