Biochemical and structural characterisation of the second oxidative crosslinking step during the biosynthesis of the glycopeptide antibiotic A47934

• Veronika Ulrich,
• Clara Brieke and
• Max J. Cryle

Beilstein J. Org. Chem. 2016, 12, 2849–2864, doi:10.3762/bjoc.12.284

• , which is generated by the actions of cytochrome P450 (Oxy) enzymes that affect the crosslinking of aromatic side chains of amino acid residues contained within the GPA heptapeptide precursor. Given the crucial role peptide cyclisation plays in GPA activity, the characterisation of this process is of

• NRPS machineries, known as the X-domain [16]. Characterisation of this domain has shown that it is a modified, catalytically inactive condensation-type domain and that this domain is capable of forming 1:1 complexes with the Oxy enzymes from GPA biosynthesis [16]. More importantly, with the exception

• of OxyBvan, the activity of Oxy enzymes in vitro has also been shown to be highly dependent on the presence of the X-domain fused to the peptidyl carrier protein domain [16]. This in turn has, for the first time, allowed the characterisation of the second cyclisation step, catalysed by OxyA, from the

Organofluorine chemistry: Difluoromethylene motifs spaced 1,3 to each other imparts facial polarity to a cyclohexane ring

• Mathew J. Jones,
• Ricardo Callejo,
• Alexandra M. Z. Slawin,
• Michael Bühl and
• David O'Hagan

Beilstein J. Org. Chem. 2016, 12, 2823–2827, doi:10.3762/bjoc.12.281

• paper, we now report the design, synthesis and characterisation of a novel tetrafluorocyclohexane structure 4, rendered polar by placing two CF2 groups located 1,3 from each other (Scheme 1). This forces two C–F bonds to lie 1,3-diaxial to each other while the cyclohexane adopts the classic chair

New syntheses of (±)-tashiromine and (±)-epitashiromine via enaminone intermediates

• Darren L. Riley,
• Joseph P. Michael and
• Charles B. de Koning

Beilstein J. Org. Chem. 2016, 12, 2609–2613, doi:10.3762/bjoc.12.256

• :15. The NMR spectroscopic data for the two diastereomers (8R*,8aR*)-12b' and (8R*,8aS*)-12b", pure samples of which could be obtained for characterisation by careful chromatography, agreed with those reported for the same isomers by Kiss et al. [9]. The reduction of the alkene unit in the bicyclic

• (±)-tashiromine (1) and its epimer (±)-epitashiromine (2) in an overall yield of 87% and in a 13:87 ratio, which matches the diastereoisomeric ratio in the precursor (Scheme 3). Pure samples for characterisation could be obtained by flash column chromatography on silica gel using a 95:4.75:0.25 mixture of

Synthesis of three-dimensional porous hyper-crosslinked polymers via thiol–yne reaction

• Mathias Lang,
• Alexandra Schade and
• Stefan Bräse

Beilstein J. Org. Chem. 2016, 12, 2570–2576, doi:10.3762/bjoc.12.252

• crosslinking reaction conditions. The obtained HCPs showed BET surface areas up to 650 m²/g and are insoluble in common organic solvents. The characterisation of the networks was performed using IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), powder X

A direct method for the N-tetraalkylation of azamacrocycles

• Andrew J. Counsell,
• Angus T. Jones,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2016, 12, 2457–2461, doi:10.3762/bjoc.12.239

• Information File 469: Experimental procedures and characterisation data for all compounds, crystallographic information and copies of 1H and 13C NMR spectra for novel compounds. Supporting Information File 470: CIF file of [3(H2)](ClO4)2, CCDC 1503283. Acknowledgements We thank the Australian Research

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• those for BTR, except for a significant drop in Voc to 0.88 V from 0.92 V. One can only speculate on the cause of the Voc drop until further structural characterisation of the thin films is completed. The poor Jsc and FF for the BT8R devices indicates a poor development of morphology and indicates that

Mechanistic investigations on six bacterial terpene cyclases

• Patrick Rabe,
• Thomas Schmitz and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2016, 12, 1839–1850, doi:10.3762/bjoc.12.173

• ][28][29][30][31]. Due to the rapidly increasing number of sequenced bacterial genomes also the number of uncharacterised bacterial terpene cyclases grows fast. Therefore, we have recently developed a screening approach for the characterisation of bacterial terpene cyclases that is based on gene

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• formation of up to two new stereocentres. Its appearance in several polyketide biosynthetic pathways was proposed for a decade based on gene cluster analysis. An in vitro characterisation of responsible catalytic units has however only recently been achieved. Two pyran-forming cyclase domains were

• tetrahydrofuran formation during biosynthesis. As the enzyme must act on biosynthetic intermediates of strongly varying size, this attributes a remarkably broad substrate tolerance to PamS. No detailed characterisation of PamS has been carried out yet. Oocydin. Homologs of trans-AT-PKS-characteristic pyran

• the mutagenic DNA binding, is then set up stereospecifically by the versiconal cyclase, which accepts both enantiomers (2’R and 2’S) of versiconal (105) [96][108]. Heterologous expression and characterisation by Townsend and co-workers revealed that the versicolorin B synthase (VBS) does not require

Copper-catalyzed [3 + 2] cycloaddition of (phenylethynyl)di-p-tolylstibane with organic azides

• Mizuki Yamada,
• Mio Matsumura,
• Yuki Uchida,
• Masatoshi Kawahata,
• Yuki Murata,
• Naoki Kakusawa,
• Kentaro Yamaguchi and
• Shuji Yasuike

Beilstein J. Org. Chem. 2016, 12, 1309–1313, doi:10.3762/bjoc.12.123

• NOBF4. Cu-catalyzed reaction of ethynylstibane 1 with benzylazide 2aa. Supporting Information Supporting Information File 160: Experimental procedures, full compound characterisation data and X-ray crystallographic data. Acknowledgements This research was supported by a research grant from Institute

Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides

• Andrew W. Truman

Beilstein J. Org. Chem. 2016, 12, 1250–1268, doi:10.3762/bjoc.12.120

• heterocyclisation to form thiazolines or oxazolines, and radical-mediated reactions between unactivated carbons. Future prospects for RiPP pathway discovery and characterisation will also be highlighted. Keywords: biosynthesis; cyclisation; enzymes; peptides; RiPPs; Introduction Nature employs a number of routes

• oxidise the cysteine. A mechanistic proposal based on structural data involves the oxidation of the thiol to a thioaldehyde, which then functions as an electron sink to facilitate decarboxylation to generate the double bond between Cα and Cβ [66] (Figure 5A). The functional characterisation of EpiD led to

• inform the characterisation of primary metabolism. Surprisingly, the gene cluster for the AviCys-containing RiPP cypemycin indicates that this pathway features an alternative way to produce dehydrated amino acids [65]. Firstly, the cluster does not encode any Lan-like dehydratases, and secondly, the Dha

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

• Daniel Wiegmann,
• Stefan Koppermann,
• Marius Wirth,
• Giuliana Niro,
• Kristin Leyerer and
• Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

• characterisation of this enzyme, the sphJ gene was employed as a probe to clone the entire genetic locus consisting of 34 putative ORFs. The expression of three selected genes (including sphJ) was monitored under different growth conditions. Under the thereby identified optimal conditions, the actinomycete

Scope and limitations of the dual-gold-catalysed hydrophenoxylation of alkynes

• Adrián Gómez-Suárez,
• Yoshihiro Oonishi,
• Anthony R. Martin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2016, 12, 172–178, doi:10.3762/bjoc.12.19

• ] (0.5 mol %), 1o (2 equiv.) Supporting Information Supporting Information File 12: Experimental procedures and characterisation data for all the compounds. Acknowledgements The ERC (Advanced Investigator Award-FUNCAT) and Syngenta are gratefully acknowledged for support. Umicore AG is acknowledged for

A convergent, umpoled synthesis of 2-(1-amidoalkyl)pyridines

• Tarn C. Johnson and
• Stephen P. Marsden

Beilstein J. Org. Chem. 2016, 12, 1–4, doi:10.3762/bjoc.12.1

• arylation/decarboxylative hydrolysis approach to 2-(1-amidoalkyl)pyridines. Substrate scope of the direct amidoalkylation of pyridine N-oxides. Supporting Information Supporting Information File 7: Experimental procedures and full compound characterisation data for products 8a–j. Supporting Information

Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

• A. John Blacker and
• Katherine E. Jolley

Beilstein J. Org. Chem. 2015, 11, 2408–2417, doi:10.3762/bjoc.11.262

• product from the water soluble NaOH (Scheme 1). Such separation of biphasic mixtures is known in continuous systems, for example membrane-based separators [26][27]. Mixing is a key parameter for reactions in multiphasic systems and characterisation of material flows within different continuous reactors is

Biocatalysis for the application of CO₂ as a chemical feedstock

• Apostolos Alissandratos and
• Christopher J. Easton

Beilstein J. Org. Chem. 2015, 11, 2370–2387, doi:10.3762/bjoc.11.259

• the ability of autotrophic organisms to convert CO2 into other materials, and these are therefore a valuable source of the required biocatalysts. The development of methodologies for expression, characterisation, engineering and optimisation of CO2-transforming enzymes will form the basis of any

Synthesis of constrained analogues of tryptophan

• Elisabetta Rossi,
• Valentina Pirovano,
• Marco Negrato,
• Giorgio Abbiati and
• Monica Dell’Acqua

Beilstein J. Org. Chem. 2015, 11, 1997–2006, doi:10.3762/bjoc.11.216

• free amino acid function at C-3, Scheme 2. The deprotection of indole nitrogen, giving rise to compounds 5a–d, was achieved in high yields in the presence of 1 equiv of potassium carbonate, in methanol at reflux for 2 h. After characterisation, the obtained compounds 5a–d and 3i were treated first with

Total synthesis of panicein A₂

• Lili Yeung,
• Lisa I. Pilkington,
• Melissa M. Cadelis,
• Brent R. Copp and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 1991–1996, doi:10.3762/bjoc.11.215

• propargyl ether 8 through formation of trifluoroacetate intermediate 17. Synthesis of propargyl ether 8 through carbonate 18. Synthesis of panicein A2 (5). Supporting Information Supporting Information File 549: Experimental procedures, characterisation data of new compounds, NMR comparison tables of

Influence of bulky yet flexible N-heterocyclic carbene ligands in gold catalysis

• Alba Collado,
• Scott R. Patrick,
• Danila Gasperini,
• Sebastien Meiries and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 1809–1814, doi:10.3762/bjoc.11.196

• hydration.a Influence of the ITent ligands in the gold-catalysed synthesis of homoallylic ketones.a Supporting Information Supporting Information File 342: Experimental information and full characterisation of the complexes including a copy of the NMR spectra. Acknowledgements The ERC (Advanced Investigator

The simple production of nonsymmetric quaterpyridines through Kröhnke pyridine synthesis

• Isabelle Sasaki,
• Jean-Claude Daran and
• Gérard Commenges

Beilstein J. Org. Chem. 2015, 11, 1781–1785, doi:10.3762/bjoc.11.193

• drawn at the 50% probability level. H atoms are represented as small circle of arbitrary radii. Synthesis of the quaterpyridines 6–8 and of the platinum complex 9. Supporting Information Supporting Information File 350: Experimental procedures, characterisation data for all new compounds and X-ray

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

• Alexander L. Kanibolotsky,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

• ]. Polymers with fused TTF units The electronic characterisation for monomer units 14a–c and 28a is shown in Table 1. Electropolymerisation of monomer compounds 14a, 14c and 28a [73] was attempted. Due to the high oxidation potential (see Table 1) of the thiophene unit in the fused system 14a (2.18 V vs Ag

• ) revealed by GPC analysis (Table 2) corresponds to about 7 thienoTTF monomer units per polymer chain for 35 and 37, and about 6 units for 39. MALDI–TOF MS characterisation was only successful for polymer 39 and showed a series of peaks with a mass difference of 516 Da, corresponding to the mass of the 2

• . Characterisation of the polymers 34, 35, 37, and 39. Performance of BHJSCs fabricated from the thiophene-TTF hybrid systems. The properties of monodisperse oligothiophene-TTF systems in dichloromethane solution. Acknowledgements PJS thanks the Royal Society for a Wolfson Research Merit Award and ALK thanks the

Thiazole-induced rigidification in substituted dithieno-tetrathiafulvalene: the effect of planarisation on charge transport properties

• Rupert G. D. Taylor,
• Joseph Cameron,
• Iain A. Wright,
• Neil Thomson,
• Olena Avramchenko,
• Alexander L. Kanibolotsky,
• Anto R. Inigo,
• Tell Tuttle and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1148–1154, doi:10.3762/bjoc.11.129

• : Full experimental and characterisation for compounds 1, 2 and 4–6, as well as OFET fabrication methods and AFM images of OFETs containing 2. Acknowledgements PJS thanks the Royal Society for a Wolfson Research Merit Award, ALK thanks the EPSRC for funding (EP/I029141), and RGDT thanks the EPSCR for

Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes

• Luke J. O’Driscoll,
• Sissel S. Andersen,
• Marta V. Solano,
• Dan Bendixen,
• Morten Jensen,
• Troels Duedal,
• Jess Lycoops,
• Cornelia van der Pol,
• Rebecca E. Sørensen,
• Karina R. Larsen,
• Kenneth Myntman,
• Christian Henriksen,
• Stinne W. Hansen and
• Jan O. Jeppesen

Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125

• of BPTTFs with promising initial results (Scheme 7 and Table 4). Difficulties were encountered with the isolation, purification and characterisation of the targeted species, which appeared to relate to their extremely poor solubility. Nonetheless, it proved possible to synthesise 5c–f (see Scheme 7

• and Table 4), and accomplish some characterisation. The parent deprotected BPTTFs 5a’ and 5b’ were first prepared in near-quantitative yield, comparably to MPTTFs 4c’, 4d’, 4f’ and 4g’ (similarly, bulkier 5b’ required a much longer reaction time than 5a’). In some cases 5a’ was observed to decompose

Hydrogenation of unactivated enamines to tertiary amines: rhodium complexes of fluorinated phosphines give marked improvements in catalytic activity

• Sergey Tin,
• Tamara Fanjul and
• Matthew L. Clarke

Beilstein J. Org. Chem. 2015, 11, 622–627, doi:10.3762/bjoc.11.70

• solvent. Supporting Information Supporting Information File 198: Full details of substrate syntheses, product isolation and characterisation, along with NMR spectra of substrates and products. Acknowledgements We thank all the technical staff in the School of Chemistry for their assistance. We thank Dr

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

• this compound prevents its characterisation but it is tentatively ascribed to a mixture (12, Scheme 4) of hydroquinone and its monomethylether on the basis of partial 1H NMR spectrum and ESI mass spectra. The poorly performing runs of Table 1 also show a broad isolable red band (Rf ca. 0.18, 4:1

• extensive decomposition prevented other characterisation. Based on this model system, it is proposed that intermolecular [2 + 2] reactions of bis-allenes, similar to results in other reported allenic rearrangements to rubrene [27][28], 2c,d result in the formation of numereous stereoisomeric oligomers

• –j. Supporting Information Supporting Information File 44: Experimental procedures, characterisation data, X-ray structures, data for the DFT calculations, and NMR spectra. Acknowledgements This project has received funding from the European Union’s Seventh Programme for research, technological

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• the diastereoisomers 7a and 7b was achieved using column chromatography and allowed characterisation of the individual isomers. Comparison of the 1H and 13C NMR data of isomers 7a and 7b showed strong similarities between 7a and the reported data [1] for hyperaspidinols A (1) and B (2) whilst isomer

• procedures, characterisation data of new compounds and NMR tables of 7a and 7b. Supporting Information File 132: 1H/13C NMR spectra. Acknowledgements We would like to acknowledge the University of Auckland for funding this project.