Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles

• Zong Guan,
• Jan C. Namyslo,
• Martin H. H. Drafz,
• Martin Nieger and
• Andreas Schmidt

Beilstein J. Org. Chem. 2014, 10, 832–840, doi:10.3762/bjoc.10.79

• reference. Multiplicities are described by using the following abbreviations: s = singlet, d = doublet, t = triplet, q = quartet, and m = multiplet. FTIR spectra were obtained on a Bruker Vector 22 in the range of 400 to 4000 cm−1. The mass spectra were measured with a Varian 320 MS Triple Quad GC–MS/MS

Structure elucidation of female-specific volatiles released by the parasitoid wasp Trichogramma turkestanica (Hymenoptera: Trichogrammatidae)

• Armin Tröger,
• Teris A. van Beek,
• Martinus E. Huigens,
• Isabel M. M. S. Silva,
• Maarten A. Posthumus and
• Wittko Francke

Beilstein J. Org. Chem. 2014, 10, 767–773, doi:10.3762/bjoc.10.72

• -diene and (2E,4E,6S,8S,10S)-4,6,8,10-tetramethyltrideca-2,4-dien-1-ol or their enantiomers as sex specific volatiles. The structures were assigned on the basis of GC–MS investigations using synthetic reference compounds. Keywords: natural products; structure elucidation; sex specific; Trichogramma

• of 8 showed an E/Z-ratio of ca. 2:1 and was highly dominated by the anti-isomers (see Supporting Information File 1, Figure S1). The E/Z-isomers of the two pairs of diastereomers could be separated by gas chromatography. Analysis by coupled gas chromatography/mass spectrometry (GC–MS) showed the 70

• stereoisomers of the target diene 14 was obtained via 2,4,6-trimethylnonanal (13) [15]. GC–MS-analysis of this mixture revealed a 3:1 dominance of the E-configurated racemates over the earlier eluting Z-series. The chromatogram showed seven well-separated peaks, indicating that only two isomers co-eluted (see

Asymmetric total synthesis of a putative sex pheromone component from the parasitoid wasp Trichogramma turkestanica

• Danny Geerdink,
• Jeffrey Buter,
• Teris A. van Beek and
• Adriaan J. Minnaard

Beilstein J. Org. Chem. 2014, 10, 761–766, doi:10.3762/bjoc.10.71

• , not even with freshly prepared 14. Moreover, in none of the successive steps the impurity could be separated and therefore also this approach was abandoned. Although NMR and GC–MS analysis of the mixture gave no conclusive evidence for the nature of the impurity, double bond isomers of 15 could

Rapid pseudo five-component synthesis of intensively blue luminescent 2,5-di(hetero)arylfurans via a Sonogashira–Glaser cyclization sequence

• Fabian Klukas,
• Alexander Grunwald,
• Franziska Menschel and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 672–679, doi:10.3762/bjoc.10.60

• ]). 1H NMR (DMSO-d6, 600 MHz) δ 7.08 (s, 2H), 7.31 (t, 3J = 7.4 Hz, 2H), 7.46 (t, 3J = 7.8 Hz, 4H), 7.82 (d, 3J = 7.3 Hz, 4H); 13C NMR (DMSO, 150 MHz) δ 108.2 (CH), 123.4 (CH), 127.5 (CH), 128.9 (CH), 130.0 (Cquat), 152.6 (Cquat). GC–MS (m/z (%)): 220 (M+, 100), 191 (13), 115 ((M-C7H5O)+, 41), 105

Zirconoarylation of alkynes through p-chloranil-promoted reductive elimination of arylzirconates

• Xiaoyu Yan,
• Chao Chen and
• Chanjuan Xi

Beilstein J. Org. Chem. 2014, 10, 528–534, doi:10.3762/bjoc.10.48

• standard. GC–MS spectra were recorded on a Hewlett Packard GC–MS system. Typical procedure for TCQ-promoted arylzirconation of alkynes To a solution of Cp2ZrCl2 (1.2 mmol, 351 mg) in 5 mL THF, n-BuLi (2.4 mmol, 1.5 mL, 1.6 M in hexane) was added at −78 °C and the mixture was stirred for 1 h at the same

• , Me4Si) δ 6.93 (s, 1H), 6.99–7.30 (m, 15H); 13C NMR (75 MHz, CDCl3, Me4Si) δ 126.6, 126.8, 127.5, 127.6, 127.7, 128.1, 128.3, 128.7, 129.7, 130.5, 137.5, 140.5, 142.7, 143.5; GC–MS m/z: 256. 2-Deuterium-1,1,2-triphenylethene (3a-D) [59]: The reaction mixture containing 4a was quenched with DCl, and 3a-D

• was isolated in 60% yield. 1H NMR (300 MHz, CDCl3, Me4Si) δ 7.00–7.51 (m, 15H); 13C NMR (75 MHz, CDCl3, Me4Si) δ 127.0, 127.6, 127.7, 127.7 (t, JDC = 7.2 Hz), 127.8, 128.2, 128.4, 128.8, 129.7, 130.6, 137.5, 140.5, 142.7, 143.6; GC–MS m/z: 257. 1,2-Diphenyl-1-(p-tolyl)ethene (3b) [58]: The reaction

Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions

• Andrea Caporale,
• Stefano Tartaggia,
• Andrea Castellin and
• Ottorino De Lucchi

Beilstein J. Org. Chem. 2014, 10, 384–393, doi:10.3762/bjoc.10.36

• °C, heating rate 25 °C/min, 3 min at 250 °C). Column chromatography was performed with 230–400 mesh silica-gel. NMR spectra were obtained on a Bruker AVANCE 300 spectrometer (300 MHz) using CDCl3 as solvent, 300 MHz and 75 MHz, respectively. Mass spectral data were acquired on a Trace GC–MS 2000

The regioselective synthesis of spirooxindolo pyrrolidines and pyrrolizidines via three-component reactions of acrylamides and aroylacrylic acids with isatins and α-amino acids

• Tatyana L. Pavlovskaya,
• Fedor G. Yaremenko,
• Victoria V. Lipson,
• Svetlana V. Shishkina,
• Oleg V. Shishkin,
• Vladimir I. Musatov and
• Alexander S. Karpenko

Beilstein J. Org. Chem. 2014, 10, 117–126, doi:10.3762/bjoc.10.8

• . The COSY, NOESY, HSQC, and HMBC spectra were recorded using the standard procedure with gradient separation of the signal. The mass spectra were recorded on a Varian 1200L GC–MS instrument, ionization by EI at 70 eV. Elemental analysis was carried out on an EA 3000 Eurovector elemental analyzer

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• catalyst, 2% palladium on silica was purchased from Johnson Matthey. Gas chromatography–mass spectra GC–MS analyses (EI and CI modes) were performed using a PerkinElmer GC–MS with a 30 m × 0.25 mm × 0.25 μm Phenomenex-ZB5 column by Jane Stanbra and Simon Thorpe in the Department of Chemistry, The

• containing the mixture of products. The samples were then analysed by gas chromatography (GC) and GC-mass spectrometry (GC–MS) against known calibration standards of the starting material and products. At the end of reaction, the system tubing and reactor were flushed with CO2 and the organic solvent mixture

• layer of the extraction mixture was withdrawn using a Pasteur pipette and added into the GC vial. The solution was thoroughly mixed and analysed by GC and/or GC–MS. Schematic diagram of the stirred autoclave reactor. Pickel’s pump NWA PM101 was used to achieve supercritical pressure. Schematic diagram

[²H₂₆]-1-epi-Cubenol, a completely deuterated natural product from Streptomyces griseus

• Christian A. Citron and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2013, 9, 2841–2845, doi:10.3762/bjoc.9.319

• shifts [10], stereospecific conversions along multistep biosynthetic pathways [11], hydride abstractions in oxidation steps [12], or deprotonations [13] are to be followed. Its incorporation is best observed by GC–MS, and if fragmentation mechanisms are known [14], the site of incorporation can be

• ], followed by extraction with dichloromethane and GC–MS analysis of headspace extracts. While 2-MIB (1), caryolan-1-ol (2) and 1-epi-cubenol (3) were all produced during growth on full medium (65.GYM), consistent with previous results using other full media [26], only for 3 similar levels of production were

• –24 h. The absorbed volatiles were eluted with analytically pure dichloromethane (40–50 μL) and the extract (1 μL) was immediately analyzed by GC–MS. The rest was stored at −80 °C for future reference. GC–MS. GC–MS analyses were carried out on an Agilent 7890A connected with an Agilent 5975C inert

Halogenated volatiles from the fungus Geniculosporium and the actinomycete Streptomyces chartreusis

• Tao Wang,
• Patrick Rabe,
• Christian A. Citron and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2013, 9, 2767–2777, doi:10.3762/bjoc.9.311

• brominated or even iodinated volatiles are even more rare. Surprisingly, headspace extracts from Streptomyces chartreusis contained methyl 2-iodobenzoate, a new natural product that adds to the small family of iodinated natural products. Keywords: constitutional isomerism; GC-MS; natural products

• Geniculosporium sp. 9910 were trapped on charcoal filters by using a closed-loop stripping apparatus (CLSA) [20]. After one day of collection a solvent extract of the trapped material was analysed by GC–MS. The analytical process was performed three times to demonstrate reproducibility of the results, and a

• benzyltrimethylammonium tetrachloroiodate in moderate yield (34%) [22]. All six compounds were subjected to GC–MS analysis using the same type of GC column as for the headspace extract from Geniculosporium (HP5-MS) and their retention indices together with the NMR spectroscopic data are summarised in Table 2. Mass

Reaction of 2,2,4,4-tetrakis(trifluoromethyl)-1,3-dithiethane with N-vinyl compounds

• Viacheslav A. Petrov and
• Will Marshall

Beilstein J. Org. Chem. 2013, 9, 2615–2619, doi:10.3762/bjoc.9.295

• internal standard. CDCl3 was used as a lock solvent. GC and GC–MS analyses were carried out on a HP-6890 instrument by using an HP FFAP capillary column and either TCD (GC) or mass-selective (GC–MS) detectors, respectively. Dry DMF (water <100 ppm), vinylamines 2a–e and 4 (Aldrich), sulfur (Alfa Aesar

One-pot sequential synthesis of isocyanates and urea derivatives via a microwave-assisted Staudinger–aza-Wittig reaction

• Diego Carnaroglio,
• Katia Martina,
• Giovanni Palmisano,
• Andrea Penoni,
• Claudia Domini and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2013, 9, 2378–2386, doi:10.3762/bjoc.9.274

• , respectively) at 25 °C; chemical shifts were calibrated to the residual proton and carbon resonances of the solvents: CDCl3 (δH = 7.26, δC = 77.16) or CD3OD (δH = 3.31, δC = 49.00). GC–MS analyses were performed in a GC Agilent 6890 (Agilent Technologies, USA) that was fitted with a mass detector Agilent

Crystal design using multipolar electrostatic interactions: A concept study for organic electronics

• Peer Kirsch,
• Qiong Tong and
• Harald Untenecker

Beilstein J. Org. Chem. 2013, 9, 2367–2373, doi:10.3762/bjoc.9.272

• processability. Experimental General remarks: Reagents and solvents were obtained commercially and used as supplied. 1H and 19F NMR spectra were collected using a Bruker Avance 400 spectrometer. 1H NMR chemical shifts were referenced to the solvent signal. GC–MS experiments were performed on an Agilent 7890A

Elucidation of the regio- and chemoselectivity of enzymatic allylic oxidations with Pleurotus sapidus – conversion of selected spirocyclic terpenoids and computational analysis

• Verena Weidmann,
• Mathias Schaffrath,
• Holger Zorn,
• Julia Rehbein and
• Wolfgang Maison

Beilstein J. Org. Chem. 2013, 9, 2233–2241, doi:10.3762/bjoc.9.262

• hydrogen abstraction in position 2, spiroether 7 was selectively converted to the spirolactone 14. The alternative oxidation product 15 was not found by GC–MS. The regioisomeric spiroether 8 offers only one plausible path for allylic oxidation in position 3. However, this spiroether was not converted at

A concise enantioselective synthesis of the guaiane sesquiterpene (−)-oxyphyllol

• Martin Zahel and
• Peter Metz

Beilstein J. Org. Chem. 2013, 9, 2028–2032, doi:10.3762/bjoc.9.239

• (triplet), q quartet), br (broad). Coupling constants (J) are quoted to the nearest 0.1 Hz. Mass spectra were recorded with an Agilent 5973N detector coupled with an Agilent 6890N GC (GC–MS, 70 eV). HRMS spectra were recorded on a Finnigan MAT 95 (EI, 70 eV). Optical rotations were measured on a Perkin

• , 977 cm−1; GC–MS: m/z = 296 [M]+; anal. calcd for C15H20O4S: C 60.79, H 6.80; found: C 60.88, H 6.92. Alcohol 3: Epoxide 4 (100.0 mg, 454 μmol) and cobalt(II) acetylacetonate (23.3 mg, 91 μmol) were dissolved in THF (5 mL), and the solution was cooled to 0 °C. Oxygen was bubbled through the solution

• : 3446, 2957, 2930, 2874, 1708, 1130, 852 cm−1; GC–MS: m/z = 238 [M]+; HRMS (EI) m/z: [M]+ calcd for C14H22O3, 238.1569; found, 238.1564. Allyl ether 11: Methyltriphenylphosphonium bromide (131.5 mg, 368 μmol) was suspended in THF (1.5 mL), and a solution of sodium hexamethyldisilazide in THF (2.0 M, 172

Damage of polyesters by the atmospheric free radical oxidant NO₃^•: a product study involving model systems

• Catrin Goeschen and
• Uta Wille

Beilstein J. Org. Chem. 2013, 9, 1907–1916, doi:10.3762/bjoc.9.225

• )] in deuterated DMSO. If necessary the assignment of the chemical shifts was confirmed by utilising 2D NMR techniques. GC–MS (EI, 70 eV) analysis was run on an Agilent 7890A GC/5975C MSD, column from SUPELCO 30 m, 0.32 mm ID, 0.25 μm film thickness fused silica capillary column, using the temperature

Integrating reaction and analysis: investigation of higher-order reactions by cryogenic trapping

• Skrollan Stockinger and
• Oliver Trapp

Beilstein J. Org. Chem. 2013, 9, 1837–1842, doi:10.3762/bjoc.9.214

• evaporation the reaction mixture was dissolved in pentane and washed with water. The diluted pentane solution was analyzed by GC–MS. For the ocRGC analysis separate DCM solutions of anthracene or anthracene derivative and benzenediazonium-2-carboxylate were prepared, both containing 1 mg per mL. The injection

• -order reactions. Experimental Benzenediazonium-2-carboxylate was synthesized according to a procedure described in [33][34]. Anthracene, 9-bromoanthracene, 9-anthracenecarboxaldehyde and 9-anthracenemethanol were purchased from Aldrich Chemical, Acros or ABCR and used without further purification. As GC

• –MS a Trace GC Ultra combined with an ISQ Single Quadrupole mass spectrometer, both from Thermo Scientific, were used. For cryofocusing a Cryogenic CO2 Cold Trap System by SGE Analytical Science was installed, according to the experimental setup outlined in Figure 2. For cryofocusing CO2 was used as a

Activation of cryptic metabolite production through gene disruption: Dimethyl furan-2,4-dicarboxylate produced by Streptomyces sahachiroi

• Dinesh Simkhada,
• Huitu Zhang,
• Shogo Mori,
• Howard Williams and
• Coran M. H. Watanabe

Beilstein J. Org. Chem. 2013, 9, 1768–1773, doi:10.3762/bjoc.9.205

• characterization of the major metabolite was carried out using LC–MS analysis and 1D and 2D cryoprobe NMR spectroscopy (data provided in Supporting Information File 1). The molecular formula was established as C8H8O5 based upon a molecular ion peak observed by LC–APCIMS at m/z 185.0453 [M + H]+ and GC–MS. The GC

• –MS fragmentation of the compound matched that provided in the Ultra GC–DSQ (ThermoElectron, Waltham, MA) GC–MS database. The structure of the compound was determined by NMR analysis in CDCl3 (Table 1). The presence of two O-CH3 groups at C-2’ (δc 51.99, δH 3.94) and C-2” (δc 52.31, δH 3.88) and

• flow rate of 0.75 mL/min in 254 nm UV. The same program was used for LC–APCI analysis. For GC–MS analysis, the sample was diluted 1:10 in DCM and was performed on an Ultra GC/DSQ (ThermoElectron, Waltham, MA). A Rxi-5ms gas chromatographic column was utilized with dimensions of 60 m length, 0.25 mm i.d

Gold-catalyzed intermolecular coupling of sulfonylacetylene with allyl ethers: [3,3]- and [1,3]-rearrangements

• Jungho Jun,
• Hyu-Suk Yeom,
• Jun-Hyun An and
• Seunghoon Shin

Beilstein J. Org. Chem. 2013, 9, 1724–1729, doi:10.3762/bjoc.9.198

• the presence of the Au-catalyst, no cross-over product was observed by GC–MS and NMR spectrometry, indicating the [3,3]- and [1,3]-rearrangement occurred intramolecularly (Scheme 2, reaction 2). This was further confirmed by the cross-over experiment employing 2i and 2m, two α-substituted allyl ethers

The preparation of several 1,2,3,4,5-functionalized cyclopentane derivatives

• André S. Kelch,
• Peter G. Jones,
• Ina Dix and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 1705–1712, doi:10.3762/bjoc.9.195

• derivatives of 16, it should also be mentioned that attempts to prepare the corresponding pentachloride (by treatment with either SOCl2 or PCl3) and pentaiodide (red P/iodine) also failed. In all these experiments complex product mixtures resulted, the GC–MS analysis of which demonstrated that only partially

•  5). Finally, the hydrogenation of 28 over Pd/C in methanol furnished a mixture of the saturated pentaesters 26 and 27 (ratio 4:1, capillary GC–MS-analysis) in practically quantitative yield (98%). Although we were unable to separate the two components quantitatively by column chromatography on

Bromination of hydrocarbons with CBr₄, initiated by light-emitting diode irradiation

• Yuta Nishina,
• Bunsho Ohtani and
• Kotaro Kikushima

Beilstein J. Org. Chem. 2013, 9, 1663–1667, doi:10.3762/bjoc.9.190

• species for the bromination. The generation of CHBr3 was confirmed by NMR spectroscopy and GC–MS spectrometry analysis, indicating that the present bromination involves the homolytic cleavage of a C–Br bond in CBr4 followed by radical abstraction of a hydrogen atom from a hydrocarbon. Keywords

• (0.50 mmol) dissolved in cyclohexane (0.10 mL) and CDCl3 (0.40 mL) (Figure 2b). Additionally, the generation of CHBr3 in the present bromination was confirmed by 1H NMR spectroscopy and GC–MS spectrometry. These results support the reaction pathway described above, although the chemical species after

Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

• Brian M. Casey,
• Dhandapani V. Sadasivam and
• Robert A. Flowers II

Beilstein J. Org. Chem. 2013, 9, 1472–1479, doi:10.3762/bjoc.9.167

• system from Teledyne Isco, Inc. All new compounds were characterized by 1H NMR, 13C NMR, GC–MS, IR, and LC–HRMS. Known compounds were characterized by 1H NMR, 13C NMR and GC–MS. 1H NMR and 13C NMR spectra were recorded on a Bruker 500 MHz spectrometer. Mass spectra were obtained by using a HP 5890 series

• GC–MS instrument. A Satellite FTIR from Thermo-Mattson was used to obtain IR spectra. LC–HRMS data were recorded at the Mass Spectrometry Facility at Notre Dame University. General procedure for the synthesis of δ-aryl-β-dicarbonyl compounds 1a–j. Sodium hydride (11 mmol) was suspended in 25 mL of

Isolation and X-ray characterization of palladium–N complexes in the guanylation of aromatic amines. Mechanistic implications

• Abdessamad Grirrane,
• Hermenegildo Garcia and
• Eleuterio Álvarez

Beilstein J. Org. Chem. 2013, 9, 1455–1462, doi:10.3762/bjoc.9.165

• S21 and S22 for 5a, Figures S24 and S25 for 5b, our recent published work for 5c [20] and experimental section in Supporting Information File 1). ESIMS and GC–MS of solutions obtained respectively after dissolving guanidines 5a and 5b in CH2Cl2/MeOH (1:1) and CH2Cl2 shows a single positive MS peak at

• and GC–MS spectra for new compounds. Supporting Information File 380: X-Ray structure analysis data for 4a (CCDC-931786, 4b (CCDC-931787), 4c (CCDC-931788) and 5a (CCDC-931789) are given. These data can also be obtained free of charge from The Cambridge Crystallographic Data Centre via http

Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts

• Stefan Riedmüller and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2013, 9, 1202–1209, doi:10.3762/bjoc.9.136

• equal or better in efficiency and yield. Changing Pd2(dba)3 to Pd(OAc)2 had no significant impact on product yields (Table 1, entry 12). Further increase of the catalyst ratio from 5 to 10 mol % had little effect (Table 1, entry 15). Next, we decided to analyze the byproducts of this reaction by GC–MS

• GC–MS analysis, we could detect 2-iodobiphenyl, 2,2'-diiodobiphenyl, 2-(2,5-dimethylphenyl)-2'-iodobiphenyl, and 2'-iodo-N-phenylbiphenyl-2-amine in the absence of any produced 3a. Contrary to that observation, when we conducted an analogous experiment without aniline, we observed no decomposition or

Interplay of ortho- with spiro-cyclisation during iminyl radical closures onto arenes and heteroarenes

• Roy T. McBurney and
• John C. Walton

Beilstein J. Org. Chem. 2013, 9, 1083–1092, doi:10.3762/bjoc.9.120

• communicated previously, 3-substituted phenanthridines 10a–f were isolated in good to quantitative yields (52–99%, Scheme 1) irrespective of the nature of the 4-substituent [26]. No spiro-products were detected even by GC–MS analyses of reaction mixtures. Byproducts included traces of imines ArC(R2)=NH (ImH