Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• due to atropisomerism (Figure 2), although the TDDFT-ECD curve of (3S,3′S,6R)-1 showed a further small positive Cotton effect around 228 nm. Nevertheless, due to the high similarity of both curves, we believe that the calculated ECD data could not distinguish between (3R,3′R,6R)-1 and (3S,3′S,6R)-1

• and HSQC NMR data revealed a similarity to compound 1 (Table 1). In addition, the presence of resonances δC (in ppm) corresponding to two carbonyl carbon atoms at 172.4 (C-1/C-1′), two methyl carbon atoms at 20.8 (C-11′) and 24.1 (C-13′), respectively, two methoxy carbon atoms at 56.5 (C-7/C-7′), two

Two new aromatic polyketides from a sponge-derived Fusarium

• Mada Triandala Sibero,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Ocky K. Karna Radjasa,
• Agus Sabdono,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2941–2947, doi:10.3762/bjoc.15.289

• . Results and Discussion A fungal strain was isolated from a sponge Xestospongia sp. collected in Karimunjawa National Park, Central Java, and identified as a member of Fusarium on the basis of sequence similarity of the internal transcribed spacer (ITS) domain to Fusarium oxysporum strains in the DNA

• ][30]. Strain KJMT.FP.4.3 was identified as Fusarium on the basis of the gene sequence analytical data of the ITS domain of partial 18S rRNA gene and 28S rRNA gene. Strain KJMT.FP.4.3 showed 99.7% similarity of ITS domain of partial 18S rRNA gene and 28S rRNA gene (555 nucleotides, GeneBank accession

• number MK393925.1) to Fusarium oxysporum strain NZZCDHL (549 nucleotides, GeneBank accession number KU939031.1) and 99.5% similarity of ITS domain of partial 18S rRNA gene and 28S rRNA gene to Fusarium oxysporum isolate DG-2 (548 nucleotides, GeneBank accession number MK429839.1). Fermentation Strain

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

• Eric J. N. Helfrich,
• Geng-Min Lin,
• Christopher A. Voigt and
• Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

• NRPSs), bacterial TCs show only little overall sequence similarity [1]. The lack of conservation in primary sequence has slowed down our understanding of terpene cyclization and, as a result, hampered the development of efficient genome mining platforms for the detection of bacterial terpene BGCs

• . antiSMASH [48] is the only open source web application that annotates bacterial terpene BGCs. As a result of the low conserved sequence similarity between TCs, terpene BGCs are missed more frequently by antiSMASH than other BGC classes [49]. In contrast to the well-characterized biosynthetic rules of

Emission and biosynthesis of volatile terpenoids from the plasmodial slime mold Physarum polycephalum

• Xinlu Chen,
• Tobias G. Köllner,
• Wangdan Xiong,
• Guo Wei and
• Feng Chen

Beilstein J. Org. Chem. 2019, 15, 2872–2880, doi:10.3762/bjoc.15.281

• similarities occurred between PpolyTPS1 and PpolyTPS4 (72%) and between PpolyTPS2 and PpolyTPS3 (64%). PpolyTPS1/4 and PpolyTPS2/3, however, showed only ≈30% sequence similarity to each other. Terpene synthases can be classified into class I and class II, based on the reaction mechanisms they catalyze. These

Palladium-catalyzed synthesis and nucleotide pyrophosphatase inhibition of benzo[4,5]furo[3,2-b]indoles

• Hoang Huy Do,
• Saif Ullah,
• Alexander Villinger,
• Joanna Lecka,
• Jean Sévigny,
• Peter Ehlers,
• Jamshed Iqbal and
• Peter Langer

Beilstein J. Org. Chem. 2019, 15, 2830–2839, doi:10.3762/bjoc.15.276

• 52% in case of ENPP3, amino acids sequence similarity with template, mouse ENPP1. The RMSD for ENPP1 was 0.613 Å and 1.349 Å for ENPP3, over 816 and 811 residues in comparison to the template, respectively. The Ramachandran plot represented promising stereochemical properties as above 98% amino acids

Design, synthesis and investigation of water-soluble hemi-indigo photoswitches for bioapplications

• Daria V. Berdnikova

Beilstein J. Org. Chem. 2019, 15, 2822–2829, doi:10.3762/bjoc.15.275

• (thio)indigo, the energy maximum in the ground state corresponds to the 90° rotation about the central double bond resulting in formation of a state with biradical-like character that is polarized along the molecule’s long axis [22]. The close structural similarity allows to expect a similar character

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• terpene synthase family, showing similarity to haloacid dehalogenase (HAD)-like hydrolases [21]. Thus, we suspected that a related enzyme may be involved in the biosynthesis of the nanangenines, and used the amino acid sequence of AstC to probe the A. nanangensis genome. We also hypothesised that the acyl

1,5-Phosphonium betaines from N-triflylpropiolamides, triphenylphosphane, and active methylene compounds

• Vito A. Fiore,
• Chiara Freisler and
• Gerhard Maas

Beilstein J. Org. Chem. 2019, 15, 2603–2611, doi:10.3762/bjoc.15.253

• an intramolecular P···O coordination in the Z-isomers (vide supra), the chemical shift values by themselves (compare: δP = 18.7 ppm for (E)-Ph3P+–CH=CHMe Br− [31]) and the similarity of the chemical shifts for E/Z pairs indicate a tetracovalent rather than a pentacovalent phosphorus atom [28

Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides

• José Brango-Vanegas,
• Luan A. Martinho,
• Lucinda J. Bessa,
• Andreanne G. Vasconcelos,
• Alexandra Plácido,
• Alex L. Pereira,
• José R. S. A. Leite and
• Angelo H. L. Machado

Beilstein J. Org. Chem. 2019, 15, 2544–2551, doi:10.3762/bjoc.15.247

• , some observations can be made: (1) 9e is the only one among all the analogues derived from the acetaldehyde adduct that, regardless of the configuration of the stereogenic centres, has the same amino acid residue sequence found in solonamides; (2) despite the close similarity on the amino acid residue

Experimental and computational electrochemistry of quinazolinespirohexadienone molecular switches – differential electrochromic vs photochromic behavior

• Eric W. Webb,
• Jonathan P. Moerdyk,
• Kyndra B. Sluiter,
• Benjamin J. Pollock,
• Amy L. Speelman,
• Eugene J. Lynch,
• William F. Polik and
• Jason G. Gillmore

Beilstein J. Org. Chem. 2019, 15, 2473–2485, doi:10.3762/bjoc.15.240

• analysis of quinazolinespirohexadienone (QSHD) 3b (Figure 3) was qualitatively similar to the parent PSHDs 1a,b as expected based on structural similarity and computationally calculated molecular orbital diagrams (Figure 6 and Supporting Information File 1). Surprisingly, the Eored of the electrochemically

Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

• Alessandro Iagatti,
• Baihao Shao,
• Alberto Credi,
• Barbara Ventura,
• Ivan Aprahamian and
• Mariangela Di Donato

Beilstein J. Org. Chem. 2019, 15, 2438–2446, doi:10.3762/bjoc.15.236

• similarity of the successive evolution and of the transient spectra detected in the two cases indicates that a similar reactivity is induced upon one-photon and two-photon excitation, further confirming the two-photon photoswitching ability of hydrazone 1 already inferred by previous measurements [29]. Using

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