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

• Abstract The volatiles emitted by agar plate cultures of three genome sequenced fungal strains from the genus Aspergillus were analysed by GC–MS. All three strains produced terpenes for which a biosynthetic relationship is discussed. The obtained data were also correlated to genetic information about the

• from cantaloupe a structural revision to the Z stereoisomer is proposed. Ethyl (Z)-hept-4-enoate also occurs in Aspergillus clavatus and was identified by synthesis of an authentic standard. Keywords: Aspergillus; GC–MS; genomics; terpenes; volatiles; Introduction Ascomycete fungi are a highly

• grown on medium 129 were collected on charcoal filters with a closed loop stripping apparatus (CLSA) [23]. After solvent extraction (CH2Cl2) of the filters the extracts were analysed by GC–MS and compounds were identified by comparison of the recorded EI mass spectra to mass spectral libraries and of

Volatiles from the xylarialean fungus Hypoxylon invadens

• Jeroen S. Dickschat,
• Tao Wang and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 734–746, doi:10.3762/bjoc.14.62

• The volatiles emitted by agar plate cultures of the xylarialean fungus Hypoxylon invadens were investigated by use of a closed loop stripping apparatus in combination with GC–MS. Several aromatic compounds were found that could only be identified by comparison to all possible constitutional isomers

• α-cadinene (5). The same problem applies to the unambiguous identification of regioisomers of aromatic compounds. We have recently reported on the GC–MS-based identification of the fungal volatiles 1-chloro-3,4-dimethoxybenzene (6) and 1,3-dichloro-4,5-dimethoxybenzene (7) from an endophytic

• unambiguous GC–MS-based structural assignment was only possible by comparison to all regioisomers with different substitution patterns at the benzene ring. Results and Discussion The volatiles released by agar plate cultures of Hypoxylon invadens MUCL 54175 were collected through the CLSA headspace method and

Stepwise radical cation Diels–Alder reaction via multiple pathways

• Ryo Shimizu,
• Yohei Okada and
• Kazuhiro Chiba

Beilstein J. Org. Chem. 2018, 14, 704–708, doi:10.3762/bjoc.14.59

• the reaction was indeed stepwise. When the reaction was carefully monitored by gas chromatography–mass spectrometry (GC–MS), we found that an adduct was generated in the early stage that was not the Diels–Alder product 3. Therefore, we intentionally stopped the reaction after 0.1 F/mol of electricity

• development in our laboratory. GC–MS Monitoring of the oxidative SET-triggered reaction of aryl vinyl ether 1c. Radical cation Diels–Alder reaction of trans-anethole [17]. Radical cation Diels–Alder reactions of aryl vinyl ether and sulfides [17][25]. Radical cation Diels–Alder reaction of aryl vinyl ether (1

Investigating radical cation chain processes in the electrocatalytic Diels–Alder reaction

• Yasushi Imada,
• Yohei Okada and
• Kazuhiro Chiba

Beilstein J. Org. Chem. 2018, 14, 642–647, doi:10.3762/bjoc.14.51

• spectrometry (GC–MS, Figure 2). Surprisingly, we found that only 0.015 F/mol was sufficient to complete the reaction and the Diels–Alder adduct 3 was obtained in 98% yield, suggesting that the current efficiency was up to 6533%. To the best of our knowledge, this is one of the highest current efficiencies in

• electrochemical synthesis in that one electron can run the radical cation chain process up to 65 times. GC–MS monitoring showed a sigmoidal curve with an induction period. The monitoring was carried out in the presence of a large excess (10 equivalents) of isoprene (2), which might follow pseudo-first order

• [33]. The reaction was monitored by GC–MS and also showed a sigmoidal curve (Figure 4). Conclusion In conclusion, we have optimized the reaction conditions for the electrocatalytic Diels–Alder reaction in order to improve the turnover number of the radical cation chain process, which resulted in a

Diastereoselective auxiliary- and catalyst-controlled intramolecular aza-Michael reaction for the elaboration of enantioenriched 3-substituted isoindolinones. Application to the synthesis of a new pazinaclone analogue

• Romain Sallio,
• Stéphane Lebrun,
• Frédéric Capet,
• Francine Agbossou-Niedercorn,
• Christophe Michon and
• Eric Deniau

Beilstein J. Org. Chem. 2018, 14, 593–602, doi:10.3762/bjoc.14.46

• Ministère de l’Enseignement Supérieur et de la Recherche, the Région Hauts-de-France and the FEDER are acknowledged for supporting and funding partially this work. Mrs Céline Delabre (UCCS) is thanked for GC–MS and HPLC analyses. Dr M. Kouach and Ms A. Descat (Univ. Lille) are thanked for HRMS analyses. Ms

High-yielding continuous-flow synthesis of antimalarial drug hydroxychloroquine

• Eric Yu,
• Hari P. R. Mangunuru,
• Nakul S. Telang,
• Caleb J. Kong,
• Jenson Verghese,
• Stanley E. Gilliland III,
• Saeed Ahmad,
• Raymond N. Dominey and
• B. Frank Gupton

Beilstein J. Org. Chem. 2018, 14, 583–592, doi:10.3762/bjoc.14.45

• found to give near quantitative conversion. The reaction profile was monitored using GC–MS and 1H NMR – no intermediates were observed under these conditions. Optimization of the flow rate with 55% hydroiodic acid (Table 1, entries 6–8) revealed that a flow rate of 1.0 mL min−1 (tR = 5 min) gave an

• (residence time, tR = 5 min) at 80 °C. The completion of the reaction was monitored using GC–MS. Complete consumption of starting material was observed. The reaction mixture was cooled to room temperature and sodium hydrogencarbonate was added until neutralized at pH 7. The crude mixture was extracted with

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu₄NI

• Mi-Hai Luo,
• Yang-Ye Jiang,
• Kun Xu,
• Yong-Guo Liu,
• Bao-Guo Sun and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

• gives imine intermediate product 5, which was detected by TLC and GC–MS. Moreover, when separated synthesized 5 was subjected to react with 2a, the corresponding product 3aa was isolated in 89% yield. These control experiments indicate that 5 is a possible reaction intermediate. Based on these control

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

• /bjoc.14.9 Abstract The volatiles from the fungus Daldinia clavata were collected by use of a closed-loop stripping apparatus and analysed by GC–MS. A few compounds were readily identified by comparison of measured to library mass spectra and of retention indices to published data, while for other

• included in the Xylariaceae, but have recently been reassigned to the Hypoxylaceae [16]. Since many of the compounds observed during GC–MS analyses in the volatile profiles of these fungi could not be identified with confidence in the latter study, we have selected some of these strains for intensified

• unambiguous verification of the suggested structures. Volatiles from Daldinia clavata identified by GC–MS A representative total ion chromatogram of a CLSA headspace extract from D. clavata is shown in Figure 1. Several of the emitted volatiles were readily identified from their mass spectra and retention

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

• and the fluorescence spectra on a Cary Eclipse fluorescence spectrophotometer (Varian, Australia). The GC–MS analysis was performed on a gas chromatograph HP 6890 GC System Plus coupled to a mass selective detector HP 5973 MSD. The mass selective detector operated in electron impact ionization mode at

• , 880, 765, 725, 625 cm−1; GC–MS m/z: 324 (100%, [M+] − CH3); elemental analysis (%) for C19H16ClIN2S Mw = 466.77, calcd for N, 6.00; found: 5.57. Procedures B1 and B2: 2a (1 mmol) and 4a (1 mmol) were finely ground together and the mixture was transferred to a 50 mL reaction flask. Distilled water (15

• , 1450, 1370, 1315, 1110, 974, 780, 750, 725 cm−1; GC–MS (m/z): 324 (100%, [M+] − CH2Ph); elemental analysis (%) for C25H20ClIN2S Mw = 542.86, calcd for N 5.16; found: 5.53. 2-((1-Benzyl-7-(trifluoromethyl)quinolin-4(1H)-ylidene)methyl)-3-methylbenzo[d]thiazol-3-ium iodide (5b): Yield 68%; mp 284–285 °C

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• -unsaturated ketones 58 (Scheme 31b). Benzophenone (BP) or anthracene-9,10-dione (AQ) were used as sensitizers under irradiation using a UV lamp at 280 nm. A radical pathway that involves CF3• was established after a negative reaction in the presence of TEMPO (TEMPO–CF3 was detected by GC–MS). An example of

Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• experiment, 1-octyne and complex 1 (2 mol %) were heated at 50 °C in aqueous acetone. In situ analysis of the reaction mixture after 20 hours by GC–MS failed to reveal any new product next to unchanged 1-octyne. We have recently developed standardized screening procedures for detecting alkyne hydration

Mechanically induced oxidation of alcohols to aldehydes and ketones in ambient air: Revisiting TEMPO-assisted oxidations

• Andrea Porcheddu,
• Evelina Colacino,
• Giancarlo Cravotto,
• Francesco Delogu and
• Lidia De Luca

Beilstein J. Org. Chem. 2017, 13, 2049–2055, doi:10.3762/bjoc.13.202

• selectively that it was complete within just a few minutes. The progress of the reaction was monitored by TLC and GC–MS analysis until the completion of the reaction. The experimental protocol involved two stages, namely the preparation of the catalytic system and the final oxidation reaction. During the

• smoothly reached completion in only 14 minutes (two cycles of 7 minutes each). GC–MS analysis of the crude reaction mixture only showed the presence of the desired aromatic aldehyde, indicating that over-oxidation did not occur (Scheme 2, right side). Prolonged milling did not result in the formation of

• further purified via filtering on a short pad of silica gel to give final aldehyde 2a with a higher degree of purity (>95% as determined by GC–MS analysis). Since most common alcohols are, unfortunately, liquids at room temperature, their mechanical activation requires using a versatile dispersant

Pd(OAc)₂/Ph₃P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

• Dominik Kellner,
• Maximilian Weger,
• Andrea Gini and
• Olga García Mancheño

Beilstein J. Org. Chem. 2017, 13, 1807–1815, doi:10.3762/bjoc.13.175

• ” and a GC–MS “QP-2010 SE”. Exact masses (HRMS) were recorded on an Agilent Q-TOF 6540 UHD spectrometer. Commercially available reagents were used without further purification. Pd-catalyzed dimerization of isoprene The reaction was performed under nitrogen in a screw-cap vial. Pd(OAc)2 (11.2 mg, 0.05

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

• based on the identification of this compound and its Cope rearrangement product β-elemene (2) formed by the thermal impact during GC–MS analysis [19] in E. coli headspace extracts under heterologous expression of the terpene synthase gene (Scheme 1). Here we present the diterpene synthase activity of

• -, sesqui- and diterpene activity by incubation with geranyl (GPP), farnesyl (FPP) and geranylgeranyl diphosphate (GGPP) as substrates, which yielded a single product 3 only from GGPP, but no products from FPP and GPP as demonstrated by GC–MS analysis (Figure 1). The mass spectrum of 3 showed a molecular

• in all treatments to suppress endogenous silencing of N. benthamiana upon agroinfiltration. No difference was found by GC–MS in EtOAc extracts of N. benthamiana leaves expressing an empty vector or HdS, while the chromatogram of an extract obtained from HdS-mit expressing leaves revealed an

An efficient Pd–NHC catalyst system in situ generated from Na₂PdCl₄ and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

• Nan Sun,
• Meng Chen,
• Liqun Jin,
• Wei Zhao,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 1735–1744, doi:10.3762/bjoc.13.168

• standard. Mass spectrometry data (MALDI–TOF) of the three imidazolium salts L1–L3 were collected on a Bruker ultrafleXtreme mass spectrometer. Low-resolution mass analyses were performed on a Thermo Trace ISQ GC–MS instrument in EI mode (70 eV) or a Thermo Scientific ITQ 1100TM mass spectrometer in ESI

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• chromatograph with a flame ionization detector, and equipped with the following columns: HP-5 25 m × 0.20 mm × 0.25 μm column. 1H NMR and 13C NMR were conducted on a high resolution spectrometer Bruker Advance 400, in CDCl3 as solvent. Gas chromatographic/mass spectrometer analyses were carried out on a GC–MS

• stilbene products 3–15 were purified by silica gel column chromatography. The products were characterized by 1H NMR, 13C NMR, and GC–MS. All spectroscopic data were in agreement with those previously reported for the following compounds: (E)-1-(4-styrylphenyl)ethanone (3) [64], (E)-phenyl(4-styrylphenyl

• by silica gel column chromatography. The products were characterized by 1H NMR, 13C NMR, and GC–MS. All the spectroscopic data were in agreement with those previously reported for the following compounds: (E)-1,1'-(ethene-1,2-diylbis(4,1-phenylene))diethanone (17) [68] and (E)-1,2-bis(3,5

Photocatalyzed synthesis of isochromanones and isobenzofuranones under batch and flow conditions

• Manuel Anselmo,
• Lisa Moni,
• Hossny Ismail,
• Davide Comoretto,
• Renata Riva and
• Andrea Basso

Beilstein J. Org. Chem. 2017, 13, 1456–1462, doi:10.3762/bjoc.13.143

• carbonyl oxygen. Compound 9 immediately afforded isochromanone 4d (60%) upon exposure to water (Scheme 4). Careful control of the isolation procedures (see Supporting Information File 1) allowed us to isolate 9 and identify it through GC–MS and 1H NMR experiments (the compound, however, partially

Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

• Ana Franco,
• Sudipta De,
• Alina M. Balu,
• Araceli Garcia and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1439–1445, doi:10.3762/bjoc.13.141

• nm × 0.5 μm and a flame ionization detector (FID). The results were finally confirmed by GC–MS. N2 isotherms of (a) RGO, (b) Fe/RGO, and (c) Co/RGO. SEM images of (a and b) RGO, (c) 1% Fe/RGO, and (d) 1% Co/RGO. TEM micrographs at different magnifications of (a and b) RGO, (c and d) 1% Fe/RGO, and (e

Use of costic acid, a natural extract from Dittrichia viscosa, for the control of Varroa destructor, a parasite of the European honey bee

• Kalliopi Sofou,
• Demosthenis Isaakidis,
• Apostolos Spyros,
• Anita Büttner,
• Athanassios Giannis and
• Haralambos E. Katerinopoulos

Beilstein J. Org. Chem. 2017, 13, 952–959, doi:10.3762/bjoc.13.96

• -methylaromadendrin and 7-O-methylaromadendrin-3-acetate (Figure 4) by GC–MS analysis. To the best of our knowledge, these structures are reported for the first time as components of D. viscosa. The conditions of the GC–MS experiment were as follows [51]: The essential oil and extracts were analyzed by GC–MS on a

• Shimadzu GC-17 A gas chromatograph coupled with a Shimadzu GC–MS-QP 5050 mass selective detector. A Supelco SBP-5 fused silica capillary column of 30 m, 0.25 mm i.d. (0.25 μm film thickness) was used for the analysis. The carrier gas was helium (He) at a flow rate of 0.9 mL/min. The injector and the

• mass spectra using the NIST 64 and NIST 120 GC–MS libraries and the comparison of their retention times with those of reference. Screening tests. The experiment was conducted in a completely randomized design under laboratory conditions in five replications. In each replication 20, 60, or 100

Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

• Adrián A. Heredia and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92

• ). However, with 6-bromohex-1-ene the yield of compound 5d dropped to 41% (Table 3, entry 5) and 2-methyltetrahydro-2H-selenopyran was detected by GC–MS. This indicates a possible competitive intramolecular addition reaction between the selenium atom-centered radical and the alkenyl moiety. The reaction with

• -substituted product 5p was only detected in traces by GC–MS suggesting that this product cyclized in the reaction medium to afford indole 9 (Table 4, entry 9). On the other hand, when o-MeO-substituted phenylacetylene 6j was employed the corresponding selenyl-substituted product 5q was isolated in 51% yield

• ]. Therefore, we can explain the formation of indole 9 by oxidation of 5p, generated in situ as described above, to afford the iminium intermediate 12. Hydrolysis of the latter liberates the secondary amine 13 (Scheme 7). This intermediate was detected by GC–MS in traces. Finally, the presence of base in

Substitution of fluorine in M[C₆F₅BF₃] with organolithium compounds: distinctions between O- and N-nucleophiles

• Anton Yu. Shabalin,
• Nicolay Yu. Adonin and
• Vadim V. Bardin

Beilstein J. Org. Chem. 2017, 13, 703–713, doi:10.3762/bjoc.13.69

• polyfluoroaryltrifluoroborates by hydrogen in alcohol at elevated temperature and obtaining the corresponding polyfluoroarenes in high yields. The latter are more simple substances and available for analysis by NMR spectroscopy, GC–MS and HRMS methods [33]. Heating a mixture of 6-K, 7-K, 8-K and 9-K in MeOH leads to conversion

• ]. The structures of 18 and 19 are consistent with 19F NMR, GC–MS and HRMS data. For characterization of the products derived from 1-K and PhLi we performed the hydrodeboration of a mixture of 1-K, 10-K and 11-K by stirring it in 2-methoxyethanol under reflux. After evaporation of the alcohol and C6F5H

• , the known 2,3,5,6-tetrafluorobiphenyl (14) [35][36] and 2,3,4,5-tetrafluorobiphenyl (15) [35][36] were obtained (Scheme 6). Then a mixture of borates 10-K, 11-K, 12-K, and 13-K was converted to biphenyls 14, 15, and terphenyls 20, 21, respectively, and characterized by 19F NMR spectroscopy, GC–MS and

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

• Gabriel P. Costa,
• Natália Seus,
• Juliano A. Roehrs,
• Raquel G. Jacob,
• Ricardo F. Schumacher,
• Thiago Barcellos,
• Rafael Luque and
• Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

• spectra (13C NMR) were obtained at 100 MHz on Bruker DPX 400 spectrometer. Chemical shifts are reported in ppm, referenced to the solvent peak of CDCl3. Low-resolution mass spectra were obtained with a Shimadzu GC-MS-QP2010 mass spectrometer. High resolution mass spectra (HRMS) were recorded on a Bruker

Unpredictable cycloisomerization of 1,11-dien-6-ynes by a common cobalt catalyst

• Abdusalom A. Suleymanov,
• Dmitry V. Vasilyev,
• Valentin V. Novikov,
• Yulia V. Nelyubina and
• Dmitry S. Perekalin

Beilstein J. Org. Chem. 2017, 13, 639–643, doi:10.3762/bjoc.13.62

• protons. On the basis of 1H–1H and 1H–13C correlation NMR spectra as well as GC–MS analysis we had assigned the structures of these products as the cyclopropane derivatives with internal 4 and exocyclic 5 double bonds (Scheme 2). Our spectral data correlate well with that of similar compounds, which were

Polyketide stereocontrol: a study in chemical biology

• Kira J. Weissman

Beilstein J. Org. Chem. 2017, 13, 348–371, doi:10.3762/bjoc.13.39

• product structures by gas-chromatography/mass spectrometry (GC–MS) and liquid chromatography (LC)–MS. Review Biosynthesis of complex polyketides by modular PKSs and stereochemical considerations The reduced or complex class of polyketides is assembled in bacteria by gigantic multienzymes called polyketide

• )- and (4S)-[4-2H]NADPH) with modules 1, 2, 5 and 6 from the DEBS PKS and analysis of the resulting products by GC-MS, showed that all of the KRs are specific for the 4′-pro-S hydride of the nicotinamide cofactor [52][53], as found for fatty acid biosynthesis [54][55]. Given the high sequence similarity

• group because it mimics the terminal portion of the phosphopantetheine cofactor to which the chain extension intermediates are normally tethered. The stereochemistry of the reduction products was typically established by GC–MS and comparison to authentic synthetic standards, or alternatively by LC–MS

Continuous N-alkylation reactions of amino alcohols using γ-Al₂O₃ and supercritical CO₂: unexpected formation of cyclic ureas and urethanes by reaction with CO₂

• Emilia S. Streng,
• Darren S. Lee,
• Michael W. George and
• Martyn Poliakoff

Beilstein J. Org. Chem. 2017, 13, 329–337, doi:10.3762/bjoc.13.36

• Gases (99.8%). The γ-alumina (PURALOX NWa155) was supplied by SASOL. It was sieved before use, to obtain the desired particle size (125–170 μm), which was used as the catalyst. Reaction mixtures were analysed using GC, GC–MS, 1H and 13C NMR. Compounds 1a–c, 4, 9, 10, 13, 14, 16 were obtained from