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

• Gram-negative rods of strictly terrestrial origin. Although isolation of Burkholderia from marine sediments has been reported, these bacteria may not originate in the marine environment, as enrichment in low salinity media is a prerequisite for isolation [4][5][6]. Most of them live in close

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

• -benzoylated disaccharides needed 2–3 h of heating at 55 °C. Keywords: acylated sugars; azidation; gold(III) bromide; N-glycoside; oxophilicity; Introduction The past few decades had seen the enrichment of transition metal complexes in various glycosylation strategies [1]. In particular, gold complexes with

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

• Sergey L. Deev,
• Alexander S. Paramonov,
• Tatyana S. Shestakova,
• Igor A. Khalymbadzha,
• Oleg N. Chupakhin,
• Julia O. Subbotina,
• Oleg S. Eltsov,
• Pavel A. Slepukhin,
• Vladimir L. Rusinov,
• Alexander S. Arseniev and
• Zakhar O. Shenkarev

Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

• complicated the subsequent NMR analysis. Meanwhile, the application of [2,3-15N2]-5-aminotetrazole 7-15N2 provided the single double-labelled products in the tetrazolo[1,5-a]pyrimidine series [33]. Thus, in the current work, [2,3-15N2]-5-aminotetrazole 7-15N2 (98% enrichment for each of the labelled 15N atoms

• -labelled non-adamantylated precursor 13-15N2 (isotopic enrichment 98%) were refluxed for 2 h in TFA without the addition of 1-adamantanol (14, Scheme 4). NMR analysis of the resulting mixture revealed the compounds 13*-15N2, 15a*-15N2, and 15b*-15N2 in a 5:2:3 ratio. The observed equal 15N-isotopic

• enrichment (≈49%) in compounds 13*-15N2, 15a*-15N2, and 15b*-15N2 indicated that the equilibrium 15a15b was reached in the isomerization process. The obtained ratio between the adamantylated products confirmed the higher thermodynamic stability of compound 15b relative to isomer 15a. NMR spectroscopy and

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• Na2CO3. The efficiency of the addition reaction depends on both electron enrichment of the aromatic ring and the electron-withdrawing character of the substituent in nitrosoalkene NSA14. 1,3-Dimethoxybenzene gave the corresponding substitution products in highest yield, while anisole proved to be

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael–Henry cascade reactions

• Yonglei Du,
• Jian Li,
• Kerong Chen,
• Chenglin Wu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2017, 13, 1342–1349, doi:10.3762/bjoc.13.131

• spirocyclopentaneoxindoles containing multiple contiguous stereocenters remains challenging [23][24][25][26]. The medicinal properties of these frameworks mean that fast enrichment of spirooxindoles bearing diverse functional groups is of considerable importance. Recently, an increasing number of asymmetric catalysis

Towards open-ended evolution in self-replicating molecular systems

• Herman Duim and
• Sijbren Otto

Beilstein J. Org. Chem. 2017, 13, 1189–1203, doi:10.3762/bjoc.13.118

• amplification and selection processes using a technique called systematic evolution of ligands by exponential enrichment, or SELEX. In SELEX, a library of DNA and RNA sequences is exposed to a certain target. In multiple selection rounds the binding species are selected and amplified, while the non-binding DNA

From chemical metabolism to life: the origin of the genetic coding process

• Antoine Danchin

Beilstein J. Org. Chem. 2017, 13, 1119–1135, doi:10.3762/bjoc.13.111

• either on the right or on the left to prevent collisions or traffic jams. Any accidental local enrichment of a particular shape would be symmetry-breaking. This contingent pick is a straightforward explanation of the ubiquitous presence of one family of stereoisomers, L-amino acids, in proteins

Substitution of fluorine in M[C₆F₅BF₃] with organolithium compounds: distinctions between O- and N-nucleophiles

• Anton Yu. Shabalin,
• Nicolay Yu. Adonin and
• Vadim V. Bardin

Beilstein J. Org. Chem. 2017, 13, 703–713, doi:10.3762/bjoc.13.69

• ) (Table 3, entries 2, 3 and 6). Other data from Table 3 are not reliable for comparison because the initial ratio is remarkably corrupted by the further reactions. We believe that the enrichment of the reaction mixture in [2-PhC6F4BF3]− occurs because of an additional stabilization of transition state A

Solid-phase enrichment and analysis of electrophilic natural products

• Frank Wesche,
• Yue He and
• Helge B. Bode

Beilstein J. Org. Chem. 2017, 13, 405–409, doi:10.3762/bjoc.13.43

• extracts via their reactivity against azide as a nucleophile followed by their subsequent enrichment using a cleavable azide-reactive resin (CARR). Using this approach, natural products carrying epoxides and α,β-unsaturated enones as well as several unknown compounds were identified in crude extracts from

• entomopathogenic Photorhabdus bacteria. Keywords: azides; click chemistry; enrichment; electrophilic natural products; epoxides; glidobactin; Photorhabdus; stilbenes; Introduction Microorganisms are a major source for novel natural products and the subsequent development of new drugs for all kinds of

• ), Scheme 1) is such a resin able to react with a broad range of azides [15]. Thus, the metabolic fate of azide-containing biosynthesis intermediates or building blocks can be studied and natural products containing these azides can be identified. Herein we describe the application of the CARR enrichment

Chemical probes for competitive profiling of the quorum sensing signal synthase PqsD of Pseudomonas aeruginosa

• Michaela Prothiwa,
• Dávid Szamosvári,
• Sandra Glasmacher and
• Thomas Böttcher

Beilstein J. Org. Chem. 2016, 12, 2784–2792, doi:10.3762/bjoc.12.277

• selectively targeting the active site of an enzyme and a reporter group that allows in-gel imaging and/or affinity enrichment of target enzymes [22]. We thus synthesized a small library of chemical probes with electrophilic α-chloroacetamide, α,β-unsaturated amide, and α,β-unsaturated ketone moieties as

Computational methods in drug discovery

• Sumudu P. Leelananda and
• Steffen Lindert

Beilstein J. Org. Chem. 2016, 12, 2694–2718, doi:10.3762/bjoc.12.267

• comparative assessment of algorithms have been done [112][143][144][145]. Zhou et al. evaluated the performance of several flexible docking algorithms by calculating enrichment factors for a set of pharmaceutical target–drug complexes and found that Glide XP was superior to other methods tested [144]. The

Effects of solvent additive on “s-shaped” curves in solution-processed small molecule solar cells

• John A. Love,
• Shu-Hua Chou,
• Ye Huang,
• Guilllermo C. Bazan and
• Thuc-Quyen Nguyen

Beilstein J. Org. Chem. 2016, 12, 2543–2555, doi:10.3762/bjoc.12.249

• both devices, for devices processed without additive, the s-shaped kink in the J–V curve near open circuit remains. Thus, a contact problem at the anode is ruled out as the underlying cause of the atypical curve shape. Non-ideal vertical phase separation, that is to say, enrichment of donor material at

• relative to each other as the beam penetrates into the film. Looking first at the BHJ processed without additive, when the signals first turn on, there is initially an enrichment of p-SIDT(FBTThCA8)2 immediately followed by a depletion of donor and an enrichment of the PC61BM-d6 signal. This corresponds to

• suggests that in the device there is an enrichment of PC71BM at the anode surface. Such an arrangement, with donor at the top surface and acceptor at the bottom, is non-ideal for the standard device architecture. Processing with DIO has a significant effect on the vertical phase separation. At the top

Selective bromochlorination of a homoallylic alcohol for the total synthesis of (−)-anverene

• Frederick J. Seidl and
• Noah Z. Burns

Beilstein J. Org. Chem. 2016, 12, 1361–1365, doi:10.3762/bjoc.12.129

• protocol with 10 mol % (S,R)-4, the product tetrahalide 11 was isolated in >20:1 dr favouring the same anti-1,3-dihalide. Interestingly, we observed considerable enrichment in the regioisomeric bromochloride ratio for the left hand side, which had roughly doubled from 8:1 to 18:1, and the recovered

Unusual traits of cis and trans-2,3-dibromo-1,1-dimethylindane on the way from 1,1-dimethylindene to 2-bromo-, 3-bromo-, and 2,3-dibromo-1,1-dimethylindene

• Rudolf Knorr,
• David S. Stephenson,
• Ernst Lattke,
• Petra Böhrer and
• Jakob Ruhdorfer

Beilstein J. Org. Chem. 2016, 12, 1178–1184, doi:10.3762/bjoc.12.113

• observed value of 8.4 Hz that is explained by the predominant 2ax-H,3ax-H conformation. Distillation of the trans/cis product mixture led to some enrichment of the thermally more stable diastereomer trans-1 due to the “base-free” HBr elimination from cis-1 with formation of 2-bromo-1,1-dimethylindene (4 in

Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

• Barry M. Trost,
• Michael C. Ryan and
• Meera Rao

Beilstein J. Org. Chem. 2016, 12, 1136–1152, doi:10.3762/bjoc.12.110

• synthetic sequence of p-anisyl catalyst 1. In situ reduction of 4-methoxysulfonyl chloride by triphenylphosphine and trapping with (−)-menthol affords diastereomerically pure sulfinate ester 2 after enrichment by recrystallization [45]. Grignard addition attaches a TMS-protected alkyne of appropriate tether

Antibiotics from predatory bacteria

• Juliane Korp,
• María S. Vela Gurovic and
• Markus Nett

Beilstein J. Org. Chem. 2016, 12, 594–607, doi:10.3762/bjoc.12.58

• [88][89][90]. These organisms serve as attractants that will allow the enrichment of any predators present in the soil sample. Baiting techniques have proven to be particularly useful for the recovery of bacteriolytic myxobacteria, as swarming and fruiting body formation facilitate the separation from

Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions

• Rajeev S. Menon,
• Akkattu T. Biju and
• Vijay Nair

Beilstein J. Org. Chem. 2016, 12, 444–461, doi:10.3762/bjoc.12.47

• Michael adducts into the benzoin product. The prolinol catalyst 60, on the other hand, mediates the epimerisation of the less reactive diastereomer. This synergy leads to the enrichment of the diastereomeric ratio of the final product 64 (Scheme 38) [55]. Enders developed a closely related iminium-cross

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• established that the hydrogen atom in the product comes exclusively from THF and not from pyridine or MeCN (Table 4). The observed deuterium enrichment using THF-d8 was around 80%. Thermal decomposition of aryldiazonium salts prepared from immobilized triazene precursors and the formation of deuterated

Exploring monovalent and multivalent peptides for the inhibition of FBP21-tWW

• Lisa Maria Henning,
• Sumati Bhatia,
• Miriam Bertazzon,
• Michaela Marczynke,
• Oliver Seitz,
• Rudolf Volkmer,
• Rainer Haag and
• Christian Freund

Beilstein J. Org. Chem. 2015, 11, 701–706, doi:10.3762/bjoc.11.80

• affinity. Results and Discussion Phage display In order to determine an optimal peptide sequence for a FBP21-tWW ligand, we conducted a phage display experiment for each of the two WW domains. Phages used in these experiments carried a randomized X9-peptide fused to phage coat protein VIII [16]. Enrichment

Highly selective generation of vanillin by anodic degradation of lignin: a combined approach of electrochemistry and product isolation by adsorption

• Dominik Schmitt,
• Carolin Regenbrecht,
• Marius Hartmer,
• Florian Stecker and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 473–480, doi:10.3762/bjoc.11.53

• process. This was realized by setting up a column filled with anion exchange resin and the corresponding solutions for adsorption (lignin containing reaction mixture) and desorption (acidic eluent) of 1 were pumped through the column. This set-up allows a continuous enrichment of 1 on the column which

• related phenols from the alkaline electrolyte. An easy to perform enrichment of the desired product by adsorption at strongly basic anion exchange resins was established. The larger lignin particles were not bound to the gel-type resins because the size exclusion effect does not affect them. Only small

Anionic sigmatropic-electrocyclic-Chugaev cascades: accessing 12-aryl-5-(methylthiocarbonylthio)tetracenes and a related anthra[2,3-b]thiophene

• Laurence Burroughs,
• John Ritchie,
• Mkhethwa Ngwenya,
• Dilfaraz Khan,
• William Lewis and
• Simon Woodward

Beilstein J. Org. Chem. 2015, 11, 273–279, doi:10.3762/bjoc.11.31

• of anti enriched 8j. The latter could be prepared directly from o-bromobenzaldehyde as shown (Scheme 3) with ca. 1:7 syn:anti enrichment by recrystallisation from CHCl3. The enantiotopic ArCH signals of rac-8a are split into separate signals upon treatment with Eu(facam)3 confirming it to be the C2

Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction

• Vicky Gheerardijn,
• Jos Van den Begin and
• Annemieke Madder

Beilstein J. Org. Chem. 2014, 10, 2566–2572, doi:10.3762/bjoc.10.268

• catalysts, also called DNAzymes [15][16][17] and RNAzymes [10][16][18][19][20][21], respectively. Most catalytic nucleic acids are generated using the SELEX (Systematic Evolution of Ligands by EXponential enrichment) protocol [22][23][24][25] that generates a library of potential catalysts, which are then

A versatile δ-aminolevulinic acid (ΑLA)-cyclodextrin bimodal conjugate-prodrug for PDT applications with the help of intracellular chemistry

• Chrysie Aggelidou,
• Theodossis A. Theodossiou,
• Antonio Ricardo Gonçalves,
• Mariza Lampropoulou and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 2414–2420, doi:10.3762/bjoc.10.251

• cholesterol in lipid raft and non-raft regions as well as removing and redistributing phospholipids [20]. Thus, the transport of an adamantyl-substituted guest that blocks the β-CD cavity is anticipated to alter the above host–membrane interactions. In this respect, the primary side enrichment of 1-CD with

Synthesis of a bifunctional cytidine derivative and its conjugation to RNA for in vitro selection of a cytidine deaminase ribozyme

• Nico Rublack and
• Sabine Müller

Beilstein J. Org. Chem. 2014, 10, 1906–1913, doi:10.3762/bjoc.10.198

• Enrichment) [12][13]. A typical procedure for the selection of a ribozyme, which enhances the reaction between two substrates, involves the conjunction of either of them with the members of an RNA-library. This is mostly achieved by transcription priming [14], which however, allows attachment of a specific

Synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates

• Michał Górny vel Górniak,
• Anna Czernicka,
• Piotr Młynarz,
• Waldemar Balcerzak and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 741–745, doi:10.3762/bjoc.10.68

• chromatography, a significant enrichment in one of the diastereomers had been observed. For example, compound 7b obtained as a 55:45 molar mixture of stereoisomers after purification by means of chromatography was obtained as 85:15 molar mixture. The approach to obtain mixed esters bearing two aromatic moieties