Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• on the prototypical arylazopyrazole 1 [35] (Scheme 1) and a previously reported [48] metal–organic cage 2 (see Figure 1). We have recently demonstrated that various azobenzenes formed 2:1 inclusion complexes with 2 [49] and hypothesized, based on the structural similarity between azobenzenes and

Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical complex

• Yoichi Kobayashi,
• Yukie Mamiya,
• Katsuya Mutoh,
• Hikaru Sotome,
• Masafumi Koga,
• Hiroshi Miyasaka and
• Jiro Abe

Beilstein J. Org. Chem. 2019, 15, 2369–2379, doi:10.3762/bjoc.15.229

• constant at the early stage of the transient absorption spectra. The EAS with time constants of 2.5 ns and 2.0 μs are safely assigned to the absorption spectra of the S1 and the T1 states, respectively, because of the similarity of the spectra to those reported previously [39][40]. In the Benzil-PIC system

• ≈2 ps [45]. The similarity of the time constant of the bond breaking to that of EAS1 supports that the C–N bond is cleaved by the direct excitation of the PIC unit. The spectral evolution from EAS2 (1.4 ps) to EAS3 (38 ps, green in Figure 3d) shows the continuous spectral shift due to the benzil unit

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• dilution was spread onto marine agar 2216 (Difco). The plates were kept at 23 °C, and a single colony was repeatedly transferred onto the same agar medium to obtain the pure isolate of strain C4-6. The strain was identified as a member of the genus Microbulbifer on the basis of 99.0% similarity in the 16S

Small anion-assisted electrochemical potential splitting in a new series of bistriarylamine derivatives: organic mixed valency across a urea bridge and zwitterionization

• Keishiro Tahara,
• Tetsufumi Nakakita,
• Alyona A. Starikova,
• Takashi Ikeda,
• Masaaki Abe and
• Jun-ichi Kikuchi

Beilstein J. Org. Chem. 2019, 15, 2277–2286, doi:10.3762/bjoc.15.220

• E1/21, two new absorption bands were observed in this solution (Figure 4a). Based on its similarity to the reported NAr3•+ derivatives [56], the first band at 760 nm derives from the π–π* transition of the NAr3•+ moiety of 1b+ [56]. However, the second band in the NIR region significantly differs in

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• photoswitchable, compounds 4a and 4b were synthesized to test the influence of a rigid conformation around the C=C double bond on sirtuin inhibition. Interestingly, this increased rigidity provokes a complete loss of activity against Sirt1. Despite the fact, that all mammalian sirtuins possess profound similarity

• the LC–HRMS, clearly confirming the experimentally found blue shift of 0.75 eV and 0.54 eV compared to compounds (E)-2b and (Z)-2b, respectively. Also here, we conclude that the calculations clearly support the formation of compounds 8a and/or 8b. However, due to the similarity of the spectra of 8a

• and 8b, calculations do not allow to predict which of the two isomers was present in the respective fraction analysed. Regarding the high similarity between 8a/8b and selisistat, it was likely that these cyclized compounds could possess biological activity against sirtuins, too. On the other hand they

Archangelolide: A sesquiterpene lactone with immunobiological potential from Laserpitium archangelica

• Silvie Rimpelová,
• Michal Jurášek,
• Lucie Peterková,
• Jiří Bejček,
• Vojtěch Spiwok,
• Miloš Majdl,
• Michal Jirásko,
• Miloš Buděšínský,
• Juraj Harmatha,
• Eva Kmoníčková,
• Pavel Drašar and
• Tomáš Ruml

Beilstein J. Org. Chem. 2019, 15, 1933–1944, doi:10.3762/bjoc.15.189

• of action are unknown. Therefore, based on the structural similarity between compound 1 and 2, we suspected that new interesting and relevant information on this biologically largely undescribed SL could be identified. In order to study the action of these commercially unavailable compounds

• trilobolide (2), from the seeds of Laserpitium archangelica Wulfen, we extended the knowledge on the first one, so far almost undescribed. We revealed that despite a high degree of structural similarity with two cytotoxic SLs, compound 2 and thapsigargin, compound 1 exhibited cytotoxicity neither in the

Halide metathesis in overdrive: mechanochemical synthesis of a heterometallic group 1 allyl complex

• Ross F. Koby,
• Nicholas R. Rightmire,
• Nathan D. Schley,
• Timothy P. Hanusa and
• William W. Brennessel

Beilstein J. Org. Chem. 2019, 15, 1856–1863, doi:10.3762/bjoc.15.181

• that both [KA']∞ and [CsKA'2] display three such angles, two of which are relatively similar at ca. 135–140°, and a third that is substantially more bent (<120°) (see the Supporting Information File 1, Figure S2, for a visualization of the similarity). The significance of this is that [KA'] can be

The cyclopropylcarbinyl route to γ-silyl carbocations

• Xavier Creary

Beilstein J. Org. Chem. 2019, 15, 1769–1780, doi:10.3762/bjoc.15.170

• ]. The similarity of products formed from acetolysis of 32 and 42 implies that the same cation rearrangement manifold is involved. Scheme 9 gives a mechanistic rationale for these products. Capture of an unrearranged discrete cyclopropylcarbinyl cation 43 gives the major product 38, while migration of

Fluorine-containing substituents: metabolism of the α,α-difluoroethyl thioether motif

• Andrea Rodil,
• Alexandra M. Z. Slawin,
• Nawaf Al-Maharik,
• Ren Tomita and
• David O’Hagan

Beilstein J. Org. Chem. 2019, 15, 1441–1447, doi:10.3762/bjoc.15.144

• other areas of bioactives discovery research, to complement the widely used ROCF3 and RSCF3 groups and there is a clear similarity to the ‘polar lipophilic’ groups ROCF2H, and RSCF2H [26]. Experimental Microorganism growth Cunninghamella elegans DSM1908 was grown on Saboraud dextrose agar gel plates for

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• waves in the cyclic voltammograms, the LUMO energy levels were calculated from Egopt and the HOMO energy and decrease with increasing amount of selenium atoms in the heterotriacenes. Because of the structural similarity of heterotriacenes 1–4 to 2,2’-bithiophene and 2,2’-biselenophene, which can be

Catalytic asymmetric oxo-Diels–Alder reactions with chiral atropisomeric biphenyl diols

• Chi-Tung Yeung,
• Wesley Ting Kwok Chan,
• Wai-Sum Lo,
• Ga-Lai Law and
• Wing-Tak Wong

Beilstein J. Org. Chem. 2019, 15, 955–962, doi:10.3762/bjoc.15.92

• supramolecular helices or dimers through intermolecular hydrogen bonding of two axially chiral biphenyl hybrid diols (1 and 2 in Scheme 1) which contain point chirality at the side arms and axial chirality at the biphenyl backbone [37]. We envisage the structural similarity and the ability of our scaffold to

An efficient synthesis of the guaiane sesquiterpene (−)-isoguaiene by domino metathesis

• Yuzhou Wang,
• Ahmed F. Darweesh,
• Patrick Zimdars and
• Peter Metz

Beilstein J. Org. Chem. 2019, 15, 858–862, doi:10.3762/bjoc.15.83

• roots of Parthenium hysterophorus [5]. A recent enantioselective synthesis of (−)-isoguaiene (1) from (+)-dihydrocarvone [6] enabled an unambiguous assignment of its absolute configuration as depicted in Figure 1. Due to the structural similarity of 1 and the trisnorsesquiterpene clavukerin A (2), we

Selective benzylic C–H monooxygenation mediated by iodine oxides

• Kelsey B. LaMartina,
• Haley K. Kuck,
• Linda S. Oglesbee,
• Asma Al-Odaini and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55

• the use of a catalytic system using HNO3, dioxygen, iodine and NHPI in the acetoxylation of C–H bonds [47]. Given this similarity, we believe that the two systems are operating by similar mechanisms. In the Minisci system, a phthalimide N-oxyl (PINO) radical, which is formed by the oxidation of NHPI

Computational characterization of enzyme-bound thiamin diphosphate reveals a surprisingly stable tricyclic state: implications for catalysis

• Ferran Planas,
• Michael J. McLeish and
• Fahmi Himo

Beilstein J. Org. Chem. 2019, 15, 145–159, doi:10.3762/bjoc.15.15

• , albeit more indirect, comes from an inhibition study using omeprazole, which was predicted to possibly interact with ThDP-dependent enzymes. The prediction was based on the similarity of omeprazole to the tricyclic form of thiamin. This was confirmed experimentally when omeprazole was subsequently shown

Synthesis, biophysical properties, and RNase H activity of 6’-difluoro[4.3.0]bicyclo-DNA

• Sibylle Frei,
• Adam K. Katolik and
• Christian J. Leumann

Beilstein J. Org. Chem. 2019, 15, 79–88, doi:10.3762/bjoc.15.9

• opposite the modified part and 2’-O-methyl RNA flanks. The same construct was previously applied for the evaluation of 2’F-tc-ANA [35] and a similar one for CeNA [52]. For the assay E. coli RNase H was used due to its commercial availability and its similarity to the human enzyme [22]. The cleavage pattern

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• products of Rv1753 and Rv2082 were reported to have 27% and 25% amino acid sequence similarity to the ALS1 gene from Candida albicans, which encodes the candida adhesin [78]. This lectin is cell surface-localized and mediates adherence of the fungus to endothelial and epithelial cells [86][87]. Fucose

• Rv2082, and an associated ALS-like lectin function is only speculation. Mannose-sensitive hemagglutinin Two Mtb gene products, encoded by Rv2813 and Rv3659, were classified as MSHA-like proteins, with the highest amino acid similarity directed to MshM (41%) and MshE (26%), respectively, of the marine

• homodimers, homotrimers, and higher-ordered oligomers, which increases their avidity for multivalent ligands. C-Type lectins play key roles in cell–cell interactions, such as host–pathogen interactions, and phagocytosis [92]. The Mtb gene product of Rv2075c shows partial amino acid sequence similarity to

N-Acylated amino acid methyl esters from marine Roseobacter group bacteria

• Hilke Bruns,
• Lisa Ziesche,
• Nargis Khakin Taniwal,
• Laura Wolter,
• Thorsten Brinkhoff,
• Jennifer Herrmann,
• Rolf Müller and
• Stefan Schulz

Beilstein J. Org. Chem. 2018, 14, 2964–2973, doi:10.3762/bjoc.14.276

• and ESI mass spectra revealed fragmentation patterns helpful for the detection of similar compounds derived from other amino acids. Some of these compounds showed antimicrobial activity. The structural similarity of N-acylated amino acid methyl esters and similar lipophilicity to AHLs might indicate a

• retention index for iso-C15:0 and anteiso-C15:0-NAME are Ic = 2352 and Ic = 2365, respectively, while all other methyl branch locations had a lower value. The close similarity of Inat = 2354 and Ic = 2352 suggested the methyl branch to be located in the iso-position. Consequently, iso-C15:0-NAME (6) was

• against E. coli TolC, and it was the only compound that showed moderate cytotoxicity on a human cancer cell line. The close similarity of NAMEs, NAVMEs, and NAGMEs to AHLs might indicate a function as signalling compounds, although experiments with NAMEs and AHL reporter assays did not reveal any activity

The activity of indenylidene derivatives in olefin metathesis catalysts

• Maria Voccia,
• Steven P. Nolan,
• Luigi Cavallo and
• Albert Poater

Beilstein J. Org. Chem. 2018, 14, 2956–2963, doi:10.3762/bjoc.14.275

• 29.6% for SIMes-based catalysts 1, 3 and 5, respectively (see Figure 1). The same trend applies to the IMes-based catalysts 2, 4 and 6, with %VBur values of 30.0%, 29.7% and 29.6%, respectively. On the other hand, as expected since there is similarity in the part bonded to the metal [49], no

Protein–protein interactions in bacteria: a promising and challenging avenue towards the discovery of new antibiotics

• Laura Carro

Beilstein J. Org. Chem. 2018, 14, 2881–2896, doi:10.3762/bjoc.14.267

• was screened by X-ray crystallography leading to the identification of four fragment hits. In an attempt to improve their binding affinities, another library was searched for compounds displaying similarity to these initial hits. After a docking-based screening followed by a fluorescence polarization

Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid

• Jacqueline Pollini,
• Valentina Bragoni and
• Lukas J. Gooßen

Beilstein J. Org. Chem. 2018, 14, 2737–2744, doi:10.3762/bjoc.14.252

• are certainly drawbacks for larger scale production (Scheme 2) [27]. Due to the structural similarity of ginkgolic and anacardic acids, we believed that a particularly desirable synthesis of 2-hydroxy-6-tridecylbenzoic acid (3) would involve CNSL as the substrate basis. However, the functionalization

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