Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids

• Herman O. Sintim,
• Hamad H. Al Mamari,
• Hasanain A. A. Almohseni,
• Younes Fegheh-Hassanpour and
• David M. Hodgson

Beilstein J. Org. Chem. 2019, 15, 1194–1202, doi:10.3762/bjoc.15.116

• observations. Tartrate alkylation chemistry with more complex alkyl iodides [12][13]. Epimerisation of monoalkylated tartrates. Supporting Information Supporting Information File 146: Experimental procedures, characterisation data and 1H and 13C NMR spectra for all new compounds. Acknowledgements We thank

Phylogenomic analyses and distribution of terpene synthases among Streptomyces

• Lara Martín-Sánchez,
• Kumar Saurabh Singh,
• Mariana Avalos,
• Gilles P. van Wezel,
• Jeroen S. Dickschat and
• Paolina Garbeva

Beilstein J. Org. Chem. 2019, 15, 1181–1193, doi:10.3762/bjoc.15.115

• structure was the first of a diterpene cyclase of bacterial origin reported [41]. Isoafricanol synthases were first noticed in S. violaceusniger and S. rapamycinicus based on the presence of 8 in culture headspace extracts as a major sesquiterpene [34][42], followed by the biochemical characterisation of

Mechanistic investigations on multiproduct β-himachalene synthase from Cryptosporangium arvum

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2019, 15, 1008–1019, doi:10.3762/bjoc.15.99

• TSs is largely unknown [12]. In this study, we present the characterisation of a bacterial TS with a reduced selectivity both for substrates and for products together with the challenging investigation of its cyclisation mechanism by labelling experiments. Results and Discussion A bacterial β

• functional characterisation (Table S1, Supporting Information File 1). The purified recombinant protein (Figure S3, Supporting Information File 1) was incubated with the common TS substrates geranyl- (GPP, C10), farnesyl- (FPP, C15), geranylgeranyl- (GGPP, C20) and geranylfarnesyl (GFPP, C25) diphosphate

New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita

• Frank Surup,
• Florian Hennicke,
• Nadine Sella,
• Maria Stroot,
• Steffen Bernecker,
• Sebastian Pfütze,
• Marc Stadler and
• Martin Rühl

Beilstein J. Org. Chem. 2019, 15, 1000–1007, doi:10.3762/bjoc.15.98

• strains, targeting both volatile and non-volatile compounds. The present paper will describe the discovery of one known and three new non-volatile terpenoids (Figure 1) that were isolated from liquid cultures of C. aegerita and their physicochemical and preliminary biological characterisation. Results and

Stereochemical investigations on the biosynthesis of achiral (Z)-γ-bisabolene in Cryptosporangium arvum

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2019, 15, 789–794, doi:10.3762/bjoc.15.75

• in the biosynthesis of the achiral sesquiterpene (Z)-γ-bisabolene (5) by a TS from a soil bacterium. Results and Discussion Functional characterisation of a bacterial (Z)-γ-bisabolene synthase Within our efforts to characterise bacterial TSs with new functions and mechanisms, a TS (WP_035857999) from

• currently largely underinvestigated in the characterisation of TSs, even for cascades requiring its involvement. Structures of achiral terpenes: (E)-β-farnesene (1), α-humulene (2), 1,8-cineol (3) and sodorifen (4). A) Total ion chromatogram of a hexane extract from the incubation of FPP with BbS and B) EI

Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation

• Łukasz Gułajski,
• Andrzej Tracz,
• Katarzyna Urbaniak,
• Stefan J. Czarnocki,
• Michał Bieniek and
• Tomasz K. Olszewski

Beilstein J. Org. Chem. 2019, 15, 160–166, doi:10.3762/bjoc.15.16

• microwave (μW) and ultrasound irradiation (US) irradiation on the RCM of lipophilic substrates in water.a Supporting Information Supporting Information File 60: Experimental procedures and characterisation data for all previously unreported compounds. Acknowledgements Ł. G. and M. B. acknowledge the

Systematic synthetic study of four diastereomerically distinct limonene-1,2-diols and their corresponding cyclic carbonates

• Hiroshi Morikawa,
• Jun-ichi Yamaguchi,
• Shun-ichi Sugimura,
• Masato Minamoto,
• Yuuta Gorou,
• Hisatoyo Morinaga and
• Suguru Motokucho

Beilstein J. Org. Chem. 2019, 15, 130–136, doi:10.3762/bjoc.15.13

• [25], no further reports on the systematic synthesis and comparison of the four LMdiols have been published. The stereochemical structures of LMdiols are not depicted in several reports [26] presumably due to a lack of reliable characterisation data for the four LMdiols. Therefore, reliable

• characterisation data of LMdiols and LM5CCs are required, particularly if the confusion surrounding LMdiols should be resolved. Herein, we focus on two compounds, LMdiol and LM5CC, as versatile and functional LM derivatives, and report the systematic synthesis of each of their four diastereomers and their

• characterisation using spectroscopic methods, mainly NMR. Comparing the data, unambiguous distinction of the four diastereomers is achieved in both cases. Results and Discussion Syntheses of LM5CC 1a and 1d and LMdiol 2a and 2d Facile syntheses of two LM5CCs 1a and 1d and one LMdiol 2d have been preliminarily

Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum

• Jan Rinkel,
• Alexander Babczyk,
• Tao Wang,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 2974–2990, doi:10.3762/bjoc.14.277

• DFG (DI1536/9-1). We thank Andreas Schneider (Bonn) for compound purification by preparative HPLC and Jacques Fournier (Rimont, France) and Eric Kuhnert (Leibniz University Hannover) for their previous support in the characterisation of the H. griseobrunneum strain.

The design and synthesis of an antibacterial phenothiazine–siderophore conjugate

• Abed Tarapdar,
• James K. S. Norris,
• Oliver Sampson,
• Galina Mukamolova and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2018, 14, 2646–2650, doi:10.3762/bjoc.14.242

• Supporting Information File 328: Full experiential protocols, characterisation of compounds including 1H and 13C NMR spectra, and biological evaluation of compound 4. Acknowledgements We thank the Royal Society for funding this research. We would also like to acknowledge Mick Lee for HRMS data of final

A challenging redox neutral Cp*Co(III)-catalysed alkylation of acetanilides with 3-buten-2-one: synthesis and key insights into the mechanism through DFT calculations

• Andrew Kenny,
• Alba Pisarello,
• Arron Bird,
• Paula G. Chirila,
• Alex Hamilton and
• Christopher J. Whiteoak

Beilstein J. Org. Chem. 2018, 14, 2366–2374, doi:10.3762/bjoc.14.212

• reaction mixture heated to 80 °C with stirring for 24 hours. After this period, the solvent was removed under reduced pressure and the crude product purified by column chromatography (ethyl acetate/petroleum ether; 80:20 in most cases). For full characterisation data of all products obtained, see

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• the reaction is not dependent on the catalytic cycle characterisation – either reductive or oxidative quenching. Net oxidative reactions require the presence of an oxidising agent. The advantage of photoredox net oxidative reactions, compared to conventional oxidation reactions, is that much milder

Volatiles from three genome sequenced fungi from the genus Aspergillus

• Jeroen S. Dickschat,
• Ersin Celik and
• Nelson L. Brock

Beilstein J. Org. Chem. 2018, 14, 900–910, doi:10.3762/bjoc.14.77

• analyses demonstrate that a reasonable correlation of data from chemical analyses to genomic data allows for a tentative assignment of functions to biosynthetic enzymes, this work cannot replace their necessary biochemical characterisation, but the approach presented here can help to identify interesting

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

• Morten M. C. H. van Schie,
• Tiago Pedroso de Almeida,
• Gabriele Laudadio,
• Florian Tieves,
• Elena Fernández-Fueyo,
• Timothy Noël,
• Isabel W. C. E. Arends and
• Frank Hollmann

Beilstein J. Org. Chem. 2018, 14, 697–703, doi:10.3762/bjoc.14.58

• high O2-transfer rates thereby enabling efficient and robust oxidase-catalysed oxidation reactions. Results and Discussion Selection and characterisation of the biocatalyst As biocatalyst for this study we focussed on the recombinant aryl alcohol oxidase from Pleurotus eryngii (PeAAOx) [28][29][30][31

• rates while avoiding enzyme robustness issues frequently observed with ‘traditional’ aeration methods. Future developments in our laboratories will concentrate on the characterisation, extension and preparative demonstration of this powerful combination of oxidase catalysis and flow chemistry

Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

• Katharina Hiebler,
• Georg J. Lichtenegger,
• Manuel C. Maier,
• Eun Sung Park,
• Renie Gonzales-Groom,
• Bernard P. Binks and
• Heidrun Gruber-Woelfler

Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52

• mixed oxides with the molecular formula Ce0.99−xSnxPd0.01O2−δ (x = 0, 0.20, 0.495, 0.79 and 0.99) were synthesised and attained in quantitative amounts (>99%). The obtained solids can be used directly for characterisation as well as for the activity tests. Characterisation The Ce–Sn–Pd catalysts were

• analysed using different state-of-the-art methods. Details of the characterisation were published recently [37]. Here, only the most important characteristics are summarised. The obtained X-ray diffraction (XRD) profiles proved the nanocrystallinity of the catalyst particles, which either show single phase

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• percentage content. Thus, the above experimental wt % value of Pd is in agreement with the theoretical one of 30 wt % as described in the experimental section. Once the Pd/C electrocatalyst characterisation was performed, Pd/C based cathodes either with 0.2 or 0.02 mg Pd per cm2 were prepared and

• ., carbon). Apart from the SEM characterisation, the determination of the electrochemically active surface area (ESA) of the cathodic electrocatalytic layer is also crucial for the characterisation of both electrodes. In this regard, Figure 3 depicts the electrochemical behaviour of a Pd0.20/C/T electrode

• the Pd nanoparticles. Thermogravimetric analysis (TGA) was performed using a Mettler Toledo model TGA/SDTA851 and /SF/1100 using a heating slope of 10 K min−1 from 298 K to 1023 K under a N2:O2 (4:1) atmosphere. For the characterisation of the Pdx/C/T scanning electron microscopy (SEM) micrographs

Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

• Tao Wang,
• Kathrin I. Mohr,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9

• that the natural product was identical to (4R,5R,6S)-11a (Figure 3). For the chemical characterisation of all eight stereoisomers of 11 the mixture obtained by the reaction shown in Scheme 4 was separated by extensive chromatographic purification. Compound 11c was readily separated from the mixture of

• products so far. Biological characterisation of compounds Three of the volatile metabolites identified from D. clavata (compounds 9, 14 and 17) were evaluated for antimicrobial and cytotoxic activities using a standard panel of fungi and bacteria, as well as the murine cell line L929 (Table 3). The 2

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• 88: Synthetic protocols and spectral and TEM characterisation for ATT 33 (Scheme 11), ATT-AuNPs (Scheme 11), GlcNAc azide 34, and click reaction of ATT-AuNPs.

Halogen-containing thiazole orange analogues – new fluorogenic DNA stains

• Aleksey A. Vasilev,
• Meglena I. Kandinska,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• David Sucunza,
• Juan J. Vaquero,
• Obis D. Castaño,
• Stanislav Baluschev and
• Silvia E. Angelova

Beilstein J. Org. Chem. 2017, 13, 2902–2914, doi:10.3762/bjoc.13.283

• ) in methanol for compounds 5a–d, TO and TO-7Cl in methanol. Supporting Information Supporting Information File 486: Characterisation data for the compounds: NMR and GS–MS spectra; validation of the theoretical computations; photostabilities at 532 nm. Acknowledgements The theoretical calculations

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

• antibiotics primycin and desertomycin [10] but not in the reported cluster for mediomycin in S. blastmyceticus [8], so the enzyme hypothesised to be responsible for this step in mediomycin biosynthesis has not been identified until now. We present here the characterisation of the med biosynthetic gene cluster

Homologated amino acids with three vicinal fluorines positioned along the backbone: development of a stereoselective synthesis

• Raju Cheerlavancha,
• Ahmed Ahmed,
• Yun Cheuk Leung,
• Aggie Lawer,
• Qing-Quan Liu,
• Marina Cagnes,
• Hee-Chan Jang,
• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228

• Et3N·3HF according to O’Hagan’s method [34] (Scheme 3). This did effect epoxide-opening to some extent, but the reaction was rather unsatisfactory because it was low-yielding and non-regioselective, which made full characterisation of the product mixture (32/33) impossible. Nevertheless, an analytical

• compounds. Model studies that informed the final steps of the synthesis. Supporting Information Supporting Information File 300: Synthetic procedures and characterisation data of intermediated, NMR spectra and NMR simulations for 6a,b. Acknowledgements L.H. thanks the Australian Research Council for

18-Hydroxydolabella-3,7-diene synthase – a diterpene synthase from Chitinophaga pinensis

• Jeroen S. Dickschat,
• Jan Rinkel,
• Patrick Rabe,
• Arman Beyraghdar Kashkooli and
• Harro J. Bouwmeester

Beilstein J. Org. Chem. 2017, 13, 1770–1780, doi:10.3762/bjoc.13.171

• this enzyme in in vitro experiments and the first heterologous expression of a bacterial terpene synthase gene in a plant, Nicotiana benthamiana. Results and Discussion Characterisation of a diterpene synthase from Chitinophaga pinensis in vitro The terpene synthase from C. pinensis was heterologously

• was indicated by conversion of (12-13C)FPP and (13-13C)FPP [25] with IPP by GGPPS and HdS that resulted in the specific incorporation of labelling into the carbon atoms absorbing at 30.8 ppm and 30.7 ppm, respectively (Figure 5). Functional characterisation of bacterial diterpene synthase in planta To

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

• . Supporting Information Supporting Information File 124: Procedures for the synthesis and characterisation data of the compounds. Acknowledgements This work was supported by the Rhineland Palatinate Center for Natural Products Research as well as by BASF SE. We thank Dr. J. C. Liermann (Mainz) for NMR

Switchable highly regioselective synthesis of 3,4-dihydroquinoxalin-2(1H)ones from o-phenylenediamines and aroylpyruvates

• Juraj Dobiaš,
• Marek Ondruš,
• Gabriela Addová and
• Andrej Boháč

Beilstein J. Org. Chem. 2017, 13, 1350–1360, doi:10.3762/bjoc.13.132

• , which can expand the synthetic impact of our study. Experimental Syntheses and characterisation of compounds 16d (SYN) and 17d (ANTI) are described below. The synthesis of all prepared compounds 12a,b, 16a–f (SYN) and 17a–f (ANTI) together with their characterisation, spectral diagrams and spectra can

• . The guide for reaction conditions for obtaining the desired regioisomer of 3,4-dihydroquinoxaline-2(1H)one 16 (SYN) or 17 (ANTI) with the best selectivity. Supporting Information Supporting Information File 156: Additional experimental and characterisation data. Acknowledgements This research was

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• carbonyl-containing functional groups such as carboxylic acids and amides, which coated a graphitic-type core. The nanoparticles exhibit excitation-dependent emission and were blue-emissive under UV excitation, but green when excited at 496 nm. Although no NMR characterisation was carried out on the

How and why kinetics, thermodynamics, and chemistry induce the logic of biological evolution

• Addy Pross and
• Robert Pascal

Beilstein J. Org. Chem. 2017, 13, 665–674, doi:10.3762/bjoc.13.66

• that could induce the selective formation of limited sets of building blocks potentially favourable toward that transition [8][9]. Much work has previously been devoted to the physicochemical characterisation of life. These attempts can be divided into two major approaches. Authors favouring a