The enzyme mechanism of patchoulol synthase

• Houchao Xu,
• Bernd Goldfuss,
• Gregor Schnakenburg and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 13–24, doi:10.3762/bjoc.18.2

• the target compound (2-2H)FPP with some (2,15-2H2)FPP, seems to be the more likely explanation for the deuteration of 3 at C15 observed by Faraldos et al. [14]. This can also much better explain the deuterium content observed by GC–MS in the PTS products that were proposed to transfer deuterium to 3

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

• Rodolfo H. V. Nishimura,
• Thiago dos Santos,
• Valter E. Murie,
• Luciana C. Furtado,
• Leticia V. Costa-Lotufo and
• Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

• , copies of 1H and 13C spectra and additional information of antiproliferative assay. Acknowledgements The authors acknowledge the assistance of Mrs. Izabel C. C. Turatti, Mr. José C. Tomaz and Mr. Vinicius Palaretti in the GC–MS, HRMS and NMR analysis, respectively. Funding The authors gratefully thank

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

• secondary and tertiary amines, amides/lactams/carbamates, and nitrile. The test reactions were monitored by thin-layer chromatography (TLC) and, where deemed necessary, results were further verified by GC–MS. The reagents employed encompassed tritylium tetrafluoroborate [50], H2O2/HBr [42], ceric ammonium

• /reagent combinations employed. The reaction of the secondary N-methylamine 2b with CBr4 [22] gave fluorenone (3) in 6% yield (determined by GC–MS), while tertiary amines, amides, and the γ-lactam 2e did not yield any. Formation of fluorenone (3) was also confirmed after applying a modified version of one

• fluorenone (3) in 30% yield (determined by GC–MS). TLC analysis further revealed that fluorenone formation does not occur when treating tertiary amides 2h and 2i, γ-lactam derivative 2e, and carbamate 2j with this reagent (Table 1, entries 5, 8, 9, and 10). The reaction does, however, also work with tertiary

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• standard conditions could inhibit the formation of target product. In contrast, the compound TEMPO–N3 was detected by GC–MS analysis. Based on the radical trapping experiment and previous reports, the reaction may undergo a radical process. 2-Carbonylpyrrole is a key subunit of many bioactive natural

Targeting active site residues and structural anchoring positions in terpene synthases

• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 2441–2449, doi:10.3762/bjoc.17.161

• (Supporting Information File 1, Figure S2). Enzyme reactions with GFPP as substrate were performed in triplicates and the relative activities were determined based on the sum of peak integrals for all sesterterpene products monitored by GC–MS (for representative chromatograms cf. Supporting Information File 1

• diterpenes cembrene A (8) and nephthenol (9) that were identified by GC–MS (Figure 5 and Supporting Information File 1, Figure S5). While it is easy to understand that GFPP cannot enter the active site of the A222V variant, these findings raise the question why GGPP is not converted by the wildtype? A

Phenolic constituents from twigs of Aleurites fordii and their biological activities

• Kyoung Jin Park,
• Won Se Suh,
• Da Hye Yoon,
• Chung Sub Kim,
• Sun Yeou Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2021, 17, 2329–2339, doi:10.3762/bjoc.17.151

• demethyldihydrodehydrodiconiferyl alcohol based on the comparison of 1H NMR and MS data [13]. The relatively large coupling constant of the anomeric proton (7.8 Hz) confirmed that the glucose is combined as β-form [14]. ᴅ-Glucose was identified by co-TLC with a standard sample [CHCl3/MeOH/H2O 2:1:0.1, Rf = 0.3)] and GC–MS analysis

• analyzed by GC–MS. The identification of ᴅ-glucose and ʟ-rhamnose was carried out by coinjection of the hydrolysate with standard silylated samples, giving a single peak at 9.730 and 9.712 min, respectively. Authentic samples (Sigma-Aldrich, St. Louis, MO, USA) that were treated in the same way showed a

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

• Tülay Yıldız,
• İrem Baştaş and
• Hatice Başpınar Küçük

Beilstein J. Org. Chem. 2021, 17, 2203–2208, doi:10.3762/bjoc.17.142

• and were characterized by IR and GC–MS. All novel pruducts were characterized by IR, 1H NMR, 13C NMR, elemental analysis and GC–MS. The reactions were monitored by TLC using silica gel plates and the products were purified by flash column chromatography on silica gel (Merck; 230–400 mesh), eluting

• with hexane/ethyl acetate (v/v 9:1). NMR spectra were recorded at 500 MHz for 1H and 125 MHz for 13C using Me4Si as the internal standard in CDCl3. GC–MS were recorded on a Shimadzu/ QP2010 Plus spectrometer. IR spectra were recorded on a Mattson 1000 spectrometer. Melting points were determined with a

Volatile emission and biosynthesis in endophytic fungi colonizing black poplar leaves

• Christin Walther,
• Pamela Baumann,
• Katrin Luck,
• Beate Rothe,
• Peter H. W. Biedermann,
• Jonathan Gershenzon,
• Tobias G. Köllner and
• Sybille B. Unsicker

Beilstein J. Org. Chem. 2021, 17, 1698–1711, doi:10.3762/bjoc.17.118

• collection PDMS tubes were immediately removed from the wire and stored in glass vials at −20 °C until further analysis. Volatiles trapped on PDMS tubes were analyzed by GC–MS (GCMS-QP2010 Ultra, Shimadzu, Duisburg, Germany) coupled to a thermal desorption unit (TD-20, Shimadzu, Duisburg, Germany). A single

• )-GGPP) and 20 mM MgCl2. Assays were overlaid with 100 µL hexane and incubated for 60 minutes at 30 °C. One microliter of the hexane phase was injected into the GC–MS machine and the analysis was conducted using an Agilent 6890 Series gas chromatograph coupled to an Agilent 5973 quadrupole mass selective

Icilio Guareschi and his amazing “1897 reaction”

• Gian Cesare Tron,
• Alberto Minassi,
• Giovanni Sorba,
• Mara Fausone and
• Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

• before the introduction of GC–MS, and the elemental analysis of gases required special attention [55]. Guareschi also made the observation that air was necessary for the development of the gas, proposing a general scheme for the transformation that provides, however, no clue for a possible mechanism. In

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Synthesis of bis(aryloxy)fluoromethanes using a heterodihalocarbene strategy

• Carl Recsei and
• Yaniv Barda

Beilstein J. Org. Chem. 2021, 17, 813–818, doi:10.3762/bjoc.17.70

• the corresponding mass was observed by GC–MS, we were unable to isolate 13 in pure form. The base-mediated method we have reported herein is complementary to that of Scheeren, since it is apparently more practical for electron-poor arenes, while the bis(aryloxy)chloromethanes required as intermediates

A chromatography-free and aqueous waste-free process for thioamide preparation with Lawesson’s reagent

• Ke Wu,
• Yichen Ling,
• An Ding,
• Liqun Jin,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2021, 17, 805–812, doi:10.3762/bjoc.17.69

• compound obtained by EtOH treatment was assigned as diethyl (p-methoxyphenyl)thiophosphonate (C1) via GC–MS and confirmed by GC–TOF [42]. The change in the polarity of the byproduct after MeOH or EtOH treatment indicated that the separation by column chromatography could be simplified in a small-scale

Breakdown of 3-(allylsulfonio)propanoates in bacteria from the Roseobacter group yields garlic oil constituents

• Anuj Kumar Chhalodia and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 569–580, doi:10.3762/bjoc.17.51

• stripping apparatus (CLSA) [33], followed by the extraction of the filters with CH2Cl2 and analysis by gas chromatography–mass spectrometry (GC–MS) of the resulting extracts. Most of the compounds were readily identified by the comparison of their mass spectra and retention indices to published data. Every

• extraction to a CLSA [33] for 24 h. The released volatiles were collected on charcoal filters (Chromtech, Idstein, Germany), followed by the extraction of the filters with dichloromethane (50 μL), and analysis of the extracts by GC–MS. For comparison, blank experiments with MB medium alone and with MB agar

• plates spiked with DAllSP or AlMSP were performed in the same way. All the volatiles mentioned in Table 1 and Table 2 were not observed in the blank experiments. GC–MS The GC–MS analyses were carried out on a HP7890A GC system connected to a HP5975C mass selective detector fitted with a HP-5MS fused

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

• Lucía Rossi-Fernández,
• Viviana Dorn and
• Gabriel Radivoy

Beilstein J. Org. Chem. 2021, 17, 519–526, doi:10.3762/bjoc.17.46

• optimized conditions the epoxidation of styrene (1a) was stopped at 20% conversion (20 min), the catalyst filtered off and the resulting filtrate was allowed to react for 6 additional hours. Analysis by GC–MS of the crude reaction mixture revealed a conversion of only 33% into styrene oxide (2a), thus

• internal reference. Mass spectra (EI) were obtained at 70 eV on a Agilent HP-7890B GC/MS instrument equipped with a Agilent 5977A selective mass detector. Infrared (FTIR) spectra were obtained on a Nicolet-Nexus spectrophotometer. The purity of volatile compounds and the chromatographic analyses (GC) were

Identification of volatiles from six marine Celeribacter strains

• Anuj Kumar Chhalodia,
• Jan Rinkel,
• Dorota Konvalinkova,
• Jörn Petersen and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 420–430, doi:10.3762/bjoc.17.38

• , Inhoffenstraße 7b, 38124 Braunschweig, Germany 10.3762/bjoc.17.38 Abstract The volatiles emitted from six marine Rhodobacteraceae species of the genus Celeribacter were investigated by GC–MS. Besides several known compounds including dimethyl trisulfide and S-methyl methanethiosulfonate, the sulfur-containing

• Celeribacter strains are capable of methionine and DMSP degradation to widespread sulfur volatiles, but the analysis of trace compounds in natural samples must be taken with care. Keywords: GC–MS; isotopes; Roseobacter; sulfur metabolism; volatiles; Introduction Bacteria from the roseobacter group belong to

• 27375T, C. halophilus DSM 26270T and C. indicus DSM 27257T, were collected through a closed-loop stripping apparatus (CLSA) on charcoal [37]. After extraction with dichloromethane the obtained extracts were analyzed by GC–MS (Figure 1). The compounds were identified by the comparison of the recorded EI

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

• accessible; however, it is possible that important biotransformation products may not to be detected using these techniques. For example, the fluorometabolites detected upon fungal degradation of cyhalothrin were not observed by GC–MS of culture supernatants. When the nature of the degradation products is

• . [110] investigated the bacterial degradation of pentafluorosulfanyl (SF5)-substituted aminophenols and via 19F NMR analysis of culture extracts was able to determine the production of new fluorinated metabolites (Figure 16). Subsequent analysis by GC–MS was required to further characterize the products

Selective synthesis of α-organylthio esters and α-organylthio ketones from β-keto esters and sodium S-organyl sulfurothioates under basic conditions

• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Thiago Barcellos,
• Claudio C. Silveira and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2021, 17, 234–244, doi:10.3762/bjoc.17.24

• results by Bolm et al. [45] and Wang et al. [47], we turned to conduct the reaction under an oxygen atmosphere (Table 1, entry 22). To our delight, the product 3a was obtained selectively in 86% yield. In this case, even GC–MS analysis of the crude sample did not show the presence of 4a. With the best

One-pot multicomponent green Hantzsch synthesis of 1,2-dihydropyridine derivatives with antiproliferative activity

• Giovanna Bosica,
• Kaylie Demanuele,
• José M. Padrón and
• Adrián Puerta

Beilstein J. Org. Chem. 2020, 16, 2862–2869, doi:10.3762/bjoc.16.235

• ® SMP11 melting point apparatus. Reactions were monitored by TLC and GC. Mass spectra were measured via a Thermo Scientific GC/MS DSQ II device, which contained a column: EC-5 30 m × 0.25 mm i.d. × 0.25 µm or using the direct-infusion method using a Waters® ACQUITY® TQD system with a tandem quadrupole

On the mass spectrometric fragmentations of the bacterial sesterterpenes sestermobaraenes A–C

• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2020, 16, 2807–2819, doi:10.3762/bjoc.16.231

• enzymatic conversion of the correspondingly 13C-labelled isoprenyl diphosphate precursors with the sestermobaraene synthase from Streptomyces mobaraensis. The main compounds sestermobaraenes A, B, and C were analysed by gas chromatography–mass spectrometry (GC–MS), allowing for a deep mechanistic

• water, simple alcohols. These volatile compounds can efficiently be trapped by specialised methods including the closed-loop stripping apparatus (CLSA) [4] technique or solid-phase microextraction (SPME) [5][6], and then analysed by gas chromatography–mass spectrometry (GC–MS) [7]. Through these and

• allows to identify interesting candidate genes coding for terpene synthases for further studies by genome mining. A major difficulty in the GC–MS-based identification of terpenes is associated with the high similarity of the mass spectra of structurally related terpenes. For this reason, the unambiguous

3-Acetoxy-fatty acid isoprenyl esters from androconia of the ithomiine butterfly Ithomia salapia

• Florian Mann,
• Daiane Szczerbowski,
• Lisa de Silva,
• Melanie McClure,
• Marianne Elias and
• Stefan Schulz

Beilstein J. Org. Chem. 2020, 16, 2776–2787, doi:10.3762/bjoc.16.228

• esters identified in two subspecies, Ithomia salapia aquinia and I. s. derasa. The major components were identified as isoprenyl (3-methyl-3-butenyl) (Z)-3-acetoxy-11-octadecenoate, isoprenyl (Z)-3-acetoxy-13-octadecenoate (12) and isoprenyl 3-acetoxyoctadecanoate (11) by GC/MS and GC/IR analyses

• the wing androconia of I. s. derasa and I. s. aquinia were analyzed by GC/MS. The extracts consisted predominately of fatty acid esters with few other compounds (Table 1). While most ithomiines possess PA-derivatives in the androconia [10][11][12][18][19], only two of the five samples of I. s. aquinia

• formed from hedycaryol (7) during GC/MS analysis by a Cope-rearrangement [20][21], indicating that 7 might be originally present in the hairpencils. That said, we cannot disprove that this rearrangement could also occur in the androconia. Hedycaryol is an early product of sesquiterpene biosynthesis

Synthesis of purines and adenines containing the hexafluoroisopropyl group

• Viacheslav Petrov,
• Rebecca J. Dooley,
• Alexander A. Marchione,
• Elizabeth L. Diaz,
• Brittany S. Clem and
• William Marshall

Beilstein J. Org. Chem. 2020, 16, 2739–2748, doi:10.3762/bjoc.16.224

• (with minimal contribution from such forces as hydrogen bonding or solvent interactions), and the relative enthalpy of activation for each compound (major to minor vs minor to major) are roughly similar to the difference in total enthalpy for the two rotamers for each compound. Experimental GC and GC–MS

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• are reported in parts per million (δ); CDCl3, (CD3)2CO and (CD3)2SO were used as solvents. GC–MS analyses were performed on a HP 6890 gas chromatograph, Series II by using a HP1 column (methyl siloxane; 30 m × 0.32 mm × 0.25 μm film thickness) equipped with a mass-selective detector operating at 70 eV

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

• Dalel El-Marrouki,
• Sabrina Touchet,
• Abderrahmen Abdelli,
• Hédi M’Rabet,
• Mohamed Lotfi Efrit and
• Philippe C. Gros

Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144

• 7053 – L2CM) for the HRMS and GC–MS experiments and related discussions. They thank also the Université de Lorraine and the CNRS for their support. Funding The University of Tunis El Manar and the Tunisian Ministry of Higher Education and Scientific Research are acknowledged for a grant to D. M.

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• GC–MS, after being washed with pentane at 0 °C and dried under vacuum, showed no evidence of organic compounds. It seemed that TMPMgCl⋅LiCl coordinated less LiCl than the corresponding iPrMgCl⋅LiCl and triggered LiCl crystallization. To solve this issue, the packed-bed column temperature was decrease

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• fluorescence quenching studies, UV–vis spectroscopy experiments, calculation of the quantum yield, a cutoff experiment below 400 nm, GC–MS analysis, and NMR spectroscopic mechanistic experiments. They also concluded that an energy transfer mechanism could not be possible since the solvent employed affected the