Synthesis and biological evaluation of 1,2-disubstituted 4-quinolone analogues of Pseudonocardia sp. natural products

• Stephen M. Geddis,
• Teodora Coroama,
• Suzanne Forrest,
• James T. Hodgkinson,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2018, 14, 2680–2688, doi:10.3762/bjoc.14.245

• analogues was observed to inhibit production of the virulence factor pyocyanin in the human pathogen Pseudomonas aeruginosa, which may be a result of their similarity to the Pseudomonas quinolone signal (PQS) quorum sensing autoinducer. This provided new insights regarding the effect of N-substitution in

• was noted for the compounds possessing a linear octanyl side chain. We speculate that this is due to the similarity to the heptanyl chain present in the native PQS ligand. This observation is highly intriguing, as HHQ (Figure 1), which differs from these analogues only by the lack of an N-substituent

Non-native autoinducer analogs capable of modulating the SdiA quorum sensing receptor in Salmonella enterica serovar Typhimurium

• Matthew J. Styles and
• Helen E. Blackwell

Beilstein J. Org. Chem. 2018, 14, 2651–2664, doi:10.3762/bjoc.14.243

• correlation is interesting because sdiA is the descendent of a horizontal gene transfer of rhlR [63]. Indeed, the sequence of SdiA from Salmonella is 45% identical to RhlR, more than it is to LasR (27%), QscR (33%), TraR (23%), LuxR (27%), or CviR (32%) [21]. In further support of a possible similarity

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• similarity to the signal molecule synthase were investigated. Here, substrates of chalcone synthase CHS2 from Medicago sativa were tested for their ability to block PqsD function. Indeed, caffeic acid analogues, such as 15, were identified as hits and further characterized as channel blockers as described

• before [59]. Further interesting starting points for the discovery of PqsD inhibitors have been provided by a dedicated screening campaign involving fragment-based hit discovery, in silico screening and a similarity-guided approach starting from FabH inhibitors [60]. The most potent hit 16 of this study

Synthesis of 3-aminocoumarin-N-benzylpyridinium conjugates with nanomolar inhibitory activity against acetylcholinesterase

• Nisachon Khunnawutmanotham,
• Cherdchai Laongthipparos,
• Patchreenart Saparpakorn,
• Nitirat Chimnoi and
• Supanna Techasakul

Beilstein J. Org. Chem. 2018, 14, 2545–2552, doi:10.3762/bjoc.14.231

• acetylcholinesterase complexed with donepezil (PDB code 4ey7) [18] retrieved from the Protein Data Bank was used in the study because of its high similarity (approximately 88% similarity), good resolution (at 2.35 Å) and ligand state with donepezil of Human AChE structure. Molecular docking of AChE via the GOLD v5.2.2

The enzymes of microbial nicotine metabolism

• Paul F. Fitzpatrick

Beilstein J. Org. Chem. 2018, 14, 2295–2307, doi:10.3762/bjoc.14.204

• predicted sequences of Kdha and Kdhb show significant similarity to the small and medium subunits of nicotine dehydrogenase, while that of Kdhc shows the highest similarity to chicken xanthine dehydrogenase. The spectral properties of the partially purified protein are consistent with 6

• in (S)-nicotine to form N-methylmyosmine. The recent evidence that the product of the oxidation of 6-hydroxynicotine by LHNO and DHNO arises from oxidation of a carbon–nitrogen bond [18][24] and the similarity of the active sites of LHNO and NicA2 to that of MAO makes it much more likely that the

Lanyamycin, a macrolide antibiotic from Sorangium cellulosum, strain Soce 481 (Myxobacteria)

• Lucky S. Mulwa,
• Rolf Jansen,
• Dimas F. Praditya,
• Kathrin I. Mohr,
• Patrick W. Okanya,
• Joachim Wink,
• Eike Steinmann and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 1554–1562, doi:10.3762/bjoc.14.132

• ]+ with high congruency of measured and calculated ion intensities while the [M + H]+ ion cluster was completely absent. In spite of their similarity, the lanyamycin epimers 1 and 2 could be separated by repeated RP-HPLC on Nucleodur Phenyl-Hexyl with an isocratic water/acetonitrile solvent system (52:48

• other bafilomycin type antibiotics, show very little similarity in their structures. The typical α-methyl-β-hydroxy part of the bafilomycin side chain is absent in 1/2, which features a unique α-methylene group. However, both share a carbonyl function in δ-position to the macrolide, which often is

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• structural similarity of the possible oxidation products makes the assignment of occurring IR bands to certain species challenging. Glycerol oxidation was studied over different catalytically active metals, such as Au [15], AuAg/C [16], Pt [17][18], Au/C [19][20], Pt/C [20][21], Pd/C [20], PdAu/C [22], PdNi

Oligonucleotide analogues with cationic backbone linkages

• Melissa Meng and
• Christian Ducho

Beilstein J. Org. Chem. 2018, 14, 1293–1308, doi:10.3762/bjoc.14.111

• oligonucleotide was observed. Other types of oligonucleotides with aminoalkyl moieties as part of artificial internucleotide linkages have also been reported. With respect to their structural similarity to Letsinger's aminoalkyl phosphoramidate linkages, these variants are categorized as 'related systems' in this

• retained base-pairing fidelity and improved cellular uptake have been reported for some oligonucleotides with structural similarity to Letsinger's first-generation aminoalkylated phosphoramidates. Bruice's guanidinium- and S-methylthiourea-linked systems have a pronounced tendency to form triple-helical

A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols

• Anna Czarnecka,
• Emilia Kowalska,
• Agnieszka Bodzioch,
• Joanna Skalik,
• Marek Koprowski,
• Krzysztof Owsianik and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2018, 14, 1229–1237, doi:10.3762/bjoc.14.105

• are to be expected. This task is additionally difficult to accomplish due to a chemical similarity of oxygen and sulfur, two neighboring heteroatoms from the main group VI of the periodic table. A longer atomic radius of sulfur than oxygen should make the C–S bond weaker and more reactive than the C–O

Synthesis of pyrazolopyrimidinones using a “one-pot” approach under microwave irradiation

• Mark Kelada,
• John M. D. Walsh,
• Robert W. Devine,
• Patrick McArdle and
• John C. Stephens

Beilstein J. Org. Chem. 2018, 14, 1222–1228, doi:10.3762/bjoc.14.104

• compounds, as well as its structural similarity to purine [1][2][3][4]. Pyrazolo[1,5-a]pyrimidinone derivatives have found use in the battle against several illnesses including cancer [5], viral infections [6][7][8], obesity [9], and cystic fibrosis [10] (Figure 1). It is these pharmacological properties

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

An uracil-linked hydroxyflavone probe for the recognition of ATP

• Márton Bojtár,
• Péter Zoltán Janzsó-Berend,
• Dávid Mester,
• Dóra Hessz,
• Mihály Kállay,
• Miklós Kubinyi and
• István Bitter

Beilstein J. Org. Chem. 2018, 14, 747–755, doi:10.3762/bjoc.14.63

• made to selectively recognize and detect these analytes, especially ATP using small-molecule fluorescent chemosensors. Despite the various solutions, the selective detection of ATP is still challenging due to the structural similarity of various nucleotides. In this paper, we report the conjugation of

• ], metal-complexes [21][22][23][24][25][26][27] and other direct sensing systems [28][29][30] have significant advantages over the classical, separation-based methods. The primary difficulties in the design of an ATP chemosensor are the structural similarity of ATP to other nucleotides (i.e., to guanosine

Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications

• Mattias Bood,
• Sangamesh Sarangamath,
• Moa S. Wranne,
• Morten Grøtli and
• L. Marcus Wilhelmsson

Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7

• nucleoside in 65% yield. Subsequent phosphitylation followed by salt-formation finally furnished compound 35 in 52% over two steps. Since the quadracyclic adenine presented an overall structural similarity with adenine and keeping a very rigid heterocyclic system suggesting few options for the molecule to

• °, respectively, that are in good agreement with the experimentally determined one for the cytosine analogue FRET pair (58°) and the TDDFT-estimated one for the adenine analogue FRET pair (41°) [14][25]. Also the spectral overlap integrals show high similarity to the values resulting from the best fit. Taken

A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway

• Dmitry Yu. Vandyshev,
• Khidmet S. Shikhaliev,
• Andrey Yu. Potapov,
• Michael Yu. Krysin,
• Fedor I. Zubkov and
• Lyudmila V. Sapronova

Beilstein J. Org. Chem. 2017, 13, 2561–2568, doi:10.3762/bjoc.13.252

• . Allowing for the formal structural similarity of intermediates 5–8d, we assume that one of the chromatographic peaks with the retention time of 3.6 or 3.8 min corresponds to the intermediate diaminoimidazole 5d, and the second one corresponds to one of succinimides 6–8d. The accumulation of the compound

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

• vicinal couplings (3JH2-N8 and 3JH6-N8) made this strategy not applicable for compound 24-15N2. In this case, the supposed assignment of the N3 resonance was indirectly confirmed by the similarity of its chemical shifts in compounds 21a-15N2 and 24-15N2. NMR and Х-ray diffraction data revealing several

Sulfation and amidinohydrolysis in the biosynthesis of giant linear polyenes

• Hui Hong,
• Markiyan Samborskyy,
• Katsiaryna Usachova,
• Katharina Schnatz and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2017, 13, 2408–2415, doi:10.3762/bjoc.13.238

• analysis returned two strong matches, Medi4948 (80% identity, 93% similarity) and Medi2865 (82% identity, 92% similarity), both provisionally annotated as agmatinases (the numbers quoted refer to the position of the respective orf in the genome sequence). The next best match was a further agmatinase

• Medi0234 (41% identity, 57% similarity). Each of these three genes was cloned and expressed in Escherichia coli as an N-terminally histidine-tagged protein as described in the Experimental section, and purified by chromatography on a Ni-NTA column. The putative amidinohydrolases Medi2865 and Medi0234 were

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• sterically more biased carbonyl group (Scheme 7). In addition to NMR spectroscopic and mass spectrometric characterization the crystal structures of the imine condensation products 5 and 6 were determined (Figure 2 and Figure 3) [50]. In similarity to 4b the twist angles of the phenyl substituents (rings A

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

• traces of crystallites of either γ-CD heptahydrate or pure fisetin (Figure 1). It should be highlighted that the absence of peaks indicating recrystallization of the isolated components is a clear evidence of the formation of a stable and pure inclusion compound [30]. Note also the good similarity

β-Cyclodextrin- and adamantyl-substituted poly(acrylate) self-assembling aqueous networks designed for controlled complexation and release of small molecules

• Liang Yan,
• Duc-Truc Pham,
• Philip Clements,
• Stephen F. Lincoln,
• Jie Wang,
• Xuhong Guo and
• Christopher J. Easton

Beilstein J. Org. Chem. 2017, 13, 1879–1892, doi:10.3762/bjoc.13.183

• region where those assigned to β-CDen/ADen substituent dipolar interactions arise (Figure 5) indicating that β-CDen substituent proton dipolar interactions with PAAβ-CDen backbone protons are insignificant.) The similarity of the spectra in Figure 5 and Figure S2 (Supporting Information File 1) and the K

Solvent-free sonochemistry: Sonochemical organic synthesis in the absence of a liquid medium

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 1850–1856, doi:10.3762/bjoc.13.179

• recently been recognised for its similarity to mechanochemistry and is now included under the umbrella term of mechanochemistry. Typically, due to the hypothesised cavitation mechanism, a liquid medium is considered as a necessity for a process to take place as a result of ultrasonic irradiation. In view

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

• course of mycolactone-mediated apoptosis. Silencing Bim and Fas by RNA interference proved that Bim is the key driver of mycolactone-mediated apoptosis while Fas upregulation may represent a passive bystander effect. Based on these results and considering the remote similarity of mycolactones with

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

• most likely shows similarity to the fatty acid synthesis pathway [2]. All fusaricidins have three amino acids (L-Thr, D-allo-Thr, and D-Ala) in common and are mostly isolated in pairs which differ in a single amino acid (asparagine vs glutamine). There are several known members of the fusaricidin

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• and ring enlargement, with structural similarity to the simple product from the Ti(IV) reaction with 4a. The reducing agent is Pt(II), which is oxidised to Pt(III) during the reaction (Scheme 3d) [34]. Scheme 3 also depicts paclitaxel (taxol, 11), an important anticancer drug, as there are some

• similarities (shown in red in Scheme 3) but also differences to our compounds obtained by Pt(II) catalysis from, e.g., 4a. The eye-catching dimethylmethylene bridge over the largest carbocyclic ring is of course the most striking similarity, although this ring is in our compounds one-carbon unit smaller (9 vs

• analogous to the one observed previously with the bis-phenylalkynyl compound [27] as a starting material. Cyclisation of the alkynes and a three-carbon ring enlargement lead in a single step to a rare bicyclic carbon framework that bears some similarity to that of the anticancer drug paclitaxel. Remarkably

Characterization of non-heme iron aliphatic halogenase WelO5* from Hapalosiphon welwitschii IC-52-3: Identification of a minimal protein sequence motif that confers enzymatic chlorination specificity in the biosynthesis of welwitindolelinones

• Qin Zhu and
• Xinyu Liu

Beilstein J. Org. Chem. 2017, 13, 1168–1173, doi:10.3762/bjoc.13.115

• basis for the altered structural diversity of hapalindole-type alkaloids between the two welwitindolinone producers. The extreme sequence similarity (95% identical) between WelO5* and WelO5 allowed us to trace the origin of this observed specificity difference to 11 amino acid residues at a C-terminal

• two welwitindolinione producers. Furthermore, the close sequence similarity between WelO5* and WelO5 allowed us to reveal a C-terminal sequence motif (residues 215–232) that harbors 11 varied amino acids between the two proteins plays the most critical role on the observed enhanced activity of WelO5

Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience

• Serge Pérez and
• Daniele de Sanctis

Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114

• is a fucose-binding lectin having similarity with tumour necrosis factor. The structure of the other domain (C-terminal part) which belongs to the superfamily of calcium-dependent lectins displays specificity for mannose and L-glycero-D-manno-heptose monosaccharides. The two domains are linked by a