An unusually stable chlorophosphite: What makes BIFOP–Cl so robust against hydrolysis?

• Roberto Blanco Trillo,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2015, 11, 313–322, doi:10.3762/bjoc.11.36

• atoms). The coupling constants (J) are given in Hz. As an external standard, 85% phosphoric acid was used for the 31P NMR spectra. The infrared spectra were recorded on a Shimadzu, IRAffinity-1 instrument. The wavenumbers (ν) of the recorded IR signals are given in cm−1. The GC–MS spectra were recorded

Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes

• Philipp Röse,
• Steffen Emge,
• Jun-ichi Yoshida and
• Gerhard Hilt

Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18

• conversion was detected by TLC and GC–MS analysis. n-Pentane was added, the mixture was filtered through a short pad of silica and concentrated under reduced pressure. The crude material was dissolved in 5 mL tetrahydrofuran, TBAF (1 M in THF, 1.1 equiv) was added and the mixture was stirred at 0 °C for 3 h

• (1.2–1.5 equiv) were added and stirred at room temperature until complete conversion was detected by TLC and GC–MS analysis. Pentane was added and the mixture was filtered through a short pad of silica. The solvent was evaporated and the crude product was purified by column chromatography to give the

• acetonitrile. Then, the cell was equipped with a platinum plate anode and cathode and electrolysed under a constant current (10 mA, 6.67 mA/cm2) at 20 °C until completion was detected by TLC and GC–MS analysis. Then, 15 mL water were added, the mixture was extracted with diethyl ether (three times 15 mL

Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols

• Bianca Rossi,
• Nadia Pastori,
• Simona Prosperini and
• Carlo Punta

Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10

• source. Tandem mass spectra were obtained by CID with helium collision gas after isolation of the precursor ion. Mass spectra were additionally measured with a GC–MS instrument, using a gas chromatograph equipped with an SBP-1 fused silica column (30 m × 0.2 mm i.d., 0.2 μm film thickness) and helium as

Palladium-catalyzed 2,5-diheteroarylation of 2,5-dibromothiophene derivatives

• Fatma Belkessam,
• Aidene Mohand,
• Jean-François Soulé,
• Abdelhamid Elias and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 2912–2919, doi:10.3762/bjoc.10.309

• -methylfuran-3-carboxylate afforded 9 and 10 in 60% and 63% yield, respectively. The reaction of 1 equiv of 2,5-dibromothiophene with 5 equiv of 1-methylpyrrole gave 11 in 78% yield. No significant formation of other polyheterocycles was observed by GC–MS analysis of the crude mixture. Arylation at C4 of 3,5

• 2-bromothiophene (Scheme 6). The reaction of 1 equiv thiophene with 2 equiv of 2-bromothiophene resulted in a poor yield for 7 due to the formation of a mixture of bithiophene 32, terthiophene 7 and also a quaterthiophene (as was observed by GC–MS analysis of the crude mixture). On the other hand

Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

• Daniel I. Hădărugă,
• Nicoleta G. Hădărugă,
• Corina I. Costescu,
• Ioan David and
• Alexandra T. Gruia

Beilstein J. Org. Chem. 2014, 10, 2809–2820, doi:10.3762/bjoc.10.298

• compounds, as determined by GC–MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the β-CD complex is quite different in comparison with the raw material. An

• . essential oil in comparison with the corresponding β-CD complex. For the first time, the protective capability of natural β-CD for labile basil essential oil compounds has been demonstrated. Keywords: basil; β-cyclodextrin; GC–MS analysis; nanoencapsulation; Ocimum basilicum L. essential oil; thermal and

• conditions using gas chromatography–mass spectrometry (GC–MS). The occurrence of harmful degradation compounds in raw basil essential oil and in the recovered product of the β-CD complex subjected to thermal/oxidative degradation has been comparatively evaluated. Results and Discussion Ocimum basilicum L

Oligomerization of optically active N-(4-hydroxyphenyl)mandelamide in the presence of β-cyclodextrin and the minor role of chirality

• Helmut Ritter,
• Antonia Stöhr and
• Philippe Favresse

Beilstein J. Org. Chem. 2014, 10, 2361–2366, doi:10.3762/bjoc.10.246

• Mettler Toledo DSC 822. The GC–MS analyses were carried out on Thermo Finnigan Trace DSQ GC/MS-System with THF as solvent. HPLC analyses were performed on BioTek Konton 525 equipped with UV detector (at 260 nm, diode array detector HPLC 540) at room temperature (column: Chiralcel OD-H, eluent: methanol

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• reaction. Formation of trimeric boronic acid anhydride was observed via GC–MS, a species less reactive in arylation reactions. When small amounts of water were added on purpose the reaction solution turned black immediately, most likely due to the formation of Pd black which is inactive in the present

• and 6). A carbonyl protective group on the nitrogen of THIQ proved to be crucial, as only traces of the correct m/z for desired product 6i were observed (GC–MS) in case of unprotected THIQ 4d (Table 2, entry 8) and also benzyl-protected 4c showed no reaction (6h, Table 2, entry 7). Pathways to

• investigated further. However, attempts to N-arylate 4d did not give a clean transformation (Table 3, entry 8) but ended up in decomposition products observed by TLC and detected by GC–MS (Scheme 4). Similar results were obtained when replacing the iron catalyst with copper(I) iodide, keeping the other

Pd/C-catalyzed aerobic oxidative esterification of alcohols and aldehydes: a highly efficient microwave-assisted green protocol

• Marina Caporaso,
• Giancarlo Cravotto,
• Spyros Georgakopoulos,
• George Heropoulos,
• Katia Martina and
• Silvia Tagliapietra

Beilstein J. Org. Chem. 2014, 10, 1454–1461, doi:10.3762/bjoc.10.149

• selectivity were achieved in most cases, apart from 3,5-dimethoxybenzaldehyde and 4-chlorobenzaldehyde. Pd-catalyzed dehalogenation reaction of 4-chlorobenzaldehyde (120 °C for 1.5 h) gave methyl benzoate as main product besides traces of the desired product (detected by GC–MS analysis). Aiming to reduce this

• . No.75990) and Pd(OAc)2 and PdCl2(PPh3)2 from Merck. NMR spectra were recorded with a Bruker 300 Avance (300 MHz and 75 MHz for 1H and 13C, respectively) at 25 °C. Chemical shifts were calibrated to the residual proton and carbon resonances of the solvent; CDCl3 (δH = 7.26, δC = 77.16). GC–MS analyses

• . Supporting Information Supporting Information File 430: Copies of GC–MS chromatograms, MS, 1H NMR and 13C NMR spectra. Acknowledgements This work was funded by the University of Turin (fondi ricerca locale ex 60%) and by the European Union's Seventh Framework Programme (FP7-REGPOT-2009-1) under grant

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5

• Ulrike Groenhagen,
• Michael Maczka,
• Jeroen S. Dickschat and
• Stefan Schulz

Beilstein J. Org. Chem. 2014, 10, 1421–1432, doi:10.3762/bjoc.10.146

• aqueous phase. In our study the volatile bouquet of the actinomycete Streptomyces sp. FORM5 was investigated and several new 2-alkylated pyridines were identified using the closed-loop stripping analysis (CLSA) [7] headspace technique followed by GC–MS analysis and synthesis of the target compounds for

• with dichloromethane. The extract was then analyzed using GC–MS. More than 40 different compounds were identified in the headspace extract (Table 1, Figure 2, and Figure S1 in Supporting Information File 1). Nevertheless, the major compounds (compounds 8, 9, 11, and 12 in Figure 2) attracted our

• interest, because they were unknown, thus giving room for the discovery of new volatile secondary metabolites. High resolution GC–MS revealed a molecular composition of C10H11N (found 145.09136, calcd 145.08910) for the major compound 12 and C10H13N (found 147.10428, calcd 147.10475) for the minor

Selective allylic hydroxylation of acyclic terpenoids by CYP154E1 from Thermobifida fusca YX

• Anna M. Bogazkaya,
• Clemens J. von Bühler,
• Sebastian Kriening,
• Alexandrine Busch,
• Alexander Seifert,
• Jürgen Pleiss,
• Sabine Laschat and
• Vlada B. Urlacher

Beilstein J. Org. Chem. 2014, 10, 1347–1353, doi:10.3762/bjoc.10.137

• which is putatively involved in substrate binding and thereby might have an effect on enzyme selectivity. To tune regio- and chemoselectivity of the enzyme three mutants at position 286 were constructed and used for substrate oxidation. All formed products were analysed with GC–MS and identified using

• enzymatic regeneration of this expensive cofactor by glucose dehydrogenase was performed [31]. Reactions run for 4 h. Substrate conversion and product distribution were analysed by GC–MS (see Supporting Information File 1). Products were identified using chemically synthesised authentic samples and known

Hindered aryl bromides for regioselective palladium-catalysed direct arylation at less favourable C5-carbon of 3-substituted thiophenes

• Rongwei Jin,
• Charles Beromeo Bheeter and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 1239–1245, doi:10.3762/bjoc.10.123

• GC–MS analysis of the crude mixture. Moreover a high conversion of 86% of this aryl bromide was observed using only 0.5 mol % Pd(OAc)2 as the catalyst. Then, we studied the scope of the coupling of 2-bromo-1,3-dichlorobenzene, using other 3-substituted thiophene derivatives (Scheme 3, Table 1). Both

• Bruker GPX (400 MHz). GC was performed on a Shimadzu GC-2014 and GC–MS was performed on a Shimadzu QP-2010S. Chemical shifts are reported in ppm relative to CDCl3 (1H: 7.26 and 13C: 77.0). Flash chromatography was performed on silica gel (230–400 mesh). General procedure for direct arylations The aryl

• , 136.6, 136.4, 133.1, 130.8, 129.7, 128.0, 122.1, 15.8; Anal. calcd for C11H8Cl2S (243.15): C, 54.34; H, 3.32; found: C, 54.19; H, 3.17. Traces of 8a and 8c were also detected by GC–MS analysis of the crude mixture. 4-Chloro-2-(2,6-dichlorophenyl)thiophene (9b): From 2-bromo-1,3-dichlorobenzene (0.226 g

Homogeneous and heterogeneous photoredox-catalyzed hydroxymethylation of ketones and keto esters: catalyst screening, chemoselectivity and dilution effects

• Axel G. Griesbeck and
• Melissa Reckenthäler

Beilstein J. Org. Chem. 2014, 10, 1143–1150, doi:10.3762/bjoc.10.114

• changes in conversion and chemoselectivity. The formation of formaldehyde as the final oxidation product was proven qualitatively (colorless precipitation of polyformaldehyde was observed in most experiments) and by a GC–MS online detection of monomeric formaldehyde. From these results, we reasoned that

N-Alkylated dinitrones from isosorbide as cross-linkers for unsaturated bio-based polyesters

• Oliver Goerz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 902–909, doi:10.3762/bjoc.10.88

• and 200 °C with a heating rate of 10 °C·min−1. The glass transition temperature (Tg) values reported are taken from the third heating cycle. EIMS spectra were recorded on a GC–MS integrated system Trace DSG by Thermo Finnigan. The instrument was calibrated in the m/z range of 1050 Da. Synthesis of

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