Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• be produced by feeding prenol and/or isoprenol to the fermentation broth after E. coli being induced by IPTG, and fermented at 18 °C for 72 h. In our hand, feeding a mixture of prenol and isoprenol in a 1:1 ratio would give the best yield of spiroviolene. GC–MS analysis (Figure 2A) of the EtOAc

Genome mining of labdane-related diterpenoids: Discovery of the two-enzyme pathway leading to (−)-sandaracopimaradiene in the fungus Arthrinium sacchari

• Fumito Sato,
• Terutaka Sonohara,
• Shunta Fujiki,
• Akihiro Sugawara,
• Yohei Morishita,
• Taro Ozaki and
• Teigo Asai

Beilstein J. Org. Chem. 2024, 20, 714–720, doi:10.3762/bjoc.20.65

• Information File 1). The constructed plasmid was introduced into A. oryzae to give the transformant AO-AsGGS/AsCPS/AsPS. We then analyzed the metabolite of this transformant by GC–MS. By comparing the metabolites extracted from A. oryzae NSAR1, we identified compound 1 as a product (Figure 3A and Figure S2 in

• File 1, Figure S3). The purified proteins were incubated in the presence of GGPP and Mg2+. GC–MS analysis of the hexane extract revealed the enzyme-dependent formation of compound 1 (Figure 4A and Figure S2 in Supporting Information File 1). The formation of 1 was not observed when either AsPS or AsCPS

• GGPP, followed by hydrolysis by acid phosphatase. GC–MS analysis revealed that AsCPS synthesizes the same product to ObCPS_11g (see Supporting Information File 1, Figure S4A and B). It should be noted that the stereochemistry of CPP needs further verification due to the lack of chiral resolution of our

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• moiety (Figure 1 and Figure S18 in Supporting Information File 1). Subsequently, to determine the acyl chain, the hydrolysate of 3 was treated with 2-amino-2-methyl-1-propanol to yield a 4,4-dimethyloxazoline (DMOX) derivative of the fatty acid, which was then subjected to GC–MS [14][15]. The EIMS of the

• from 4 was subjected to GC–MS analysis. The EIMS spectrum showed two typical prominent ions at m/z 113 and m/z 126, as well as two ions at m/z 222 and m/z 208, corresponding to the loss of methylene groups (14 mass units). More importantly, a gap of 12 mass units between m/z 196 (C8) and 208 (C9) was

• File 1). Subsequent GC–MS analysis of the DMOX derivative allowed us to deduce the fatty acyl chain in 5 as a 7-tetradecenoic acid, confirming 5 as another new variochelin analog, variochelin E. The absolute configurations of the newly isolated congeners (3–5) were determined by Marfey’s analysis [17

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• toluene and bibenzyl, i.e., RH and R2 products, which were identified by the masses observed through GC–MS and through comparison of the GC–MS retention times with authentic samples. Higher concentrations and reaction times (entries 7–9 in Tabe 1) lead to larger extents of conversion (up to 61% at 18 h

• several other benzyl halides (1b–e), an alkyl halide 2, and several aryl halides (3a–f). Again GC–MS was used to identify and quantify the products; the necessary authentic samples were mostly commercially available, but the R2 products from 1b and 1c were not, although well-known in the literature (for

• (or (Cyc-DMBI)2) and light. Moreover, in the cases of 1d and 1e there are significant mismatches between conversion and the yields of the corresponding RH and R2 species, indicating that additional products must be formed. Indeed, in the case of 4-methylbenzyl chloride GC–MS shows a product with a

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• –7.79 (m, 2H), 7.63–7.50 (m, 2H); GC–MS: 442 [M]+. 2,6-Bis(3,6-di-tert-butylcarbazol-9-yl)-4-(4-bromophenyl)pyridine-3,5-dicarbonitrile (4). Sodium hydride (60% oil dispersion, 180 mg, 5.36 mmol, 3.2 equiv) was added to THF (15 mL) under Ar atmosphere. Then, 3,6-di-tert-butyl-9H-carbazole (1.40 g, 5.3

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs

• Binbin Gu,
• Lin-Fu Liang and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1452–1459, doi:10.3762/bjoc.19.104

• products that have been identified by GC–MS analysis and the synthesis of reference compounds [30][31]. Notably, 2MIBS also shows some substrate flexibility and can convert GPP into monoterpenes in vitro, albeit with less efficiency as compared to the conversion of 2-Me-GPP [24]. On the other hand, single

• intestinal phosphatase (CIP), followed by extraction of the reaction mixture with hexane and GC–MS analysis. Several combinations of DMAPP and IPP analogs resulted in a good production of the corresponding GPP analogs (indicated by three black plus signs in Table 1). Other combinations gave a medium (++) or

Functional characterisation of twelve terpene synthases from actinobacteria

• Anuj K. Chhalodia,
• Houchao Xu,
• Georges B. Tabekoueng,
• Binbin Gu,
• Kizerbo A. Taizoumbe,
• Lukas Lauterbach and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

• identified by GC–MS. The characterised enzymes include a new epi-isozizaene synthase with monoterpene synthase side activity, a 7-epi-α-eudesmol synthase that also produces hedycaryol and germacrene A, and four more sesquiterpene synthases that produce mixtures of hedycaryol and germacrene A. Three

• high yield of α-cadinene (11) (Figure 3C and 3D), and GGPP and GFPP were not accepted as substrate. For verification of the GC–MS-based identification the product was isolated from a preparative scale incubation of FPP (80 mg, 185 μmol) to obtain pure 11 (1.3 mg, 6.4 μmol, 3.5%). Structure elucidation

• that was identified by GC–MS as amorpha-4,11-diene (12, Figure 4). The structure of the product was confirmed through a preparative scale incubation of FPP (80 mg, 185 μmol) yielding pure 12 (1 mg, 4.9 μmol, 2.6%) for NMR spectroscopic analysis (Table S4, Figures S24–S31, Supporting Information File 1

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• ellipsoid contour probability level of 50%; edetected by GC–MS. The acid-catalyzed reversible transformation of tetrahydrofuro[3,2-c]pyridine 4a and 3-(2-oxopropyl)piperidin-4-one 5a. The product yield was determined by GC–MS using an internal standard. Synthesis of tetrahydropyrrolo[3,2-c]pyridine 6a

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• the level of degradation compounds were determined by thermal methods (thermogravimetry-differential thermogravimetry, TG–DTG, and differential scanning calorimetry, DSC) and gas chromatography–mass spectrometry (GC–MS), respectively. The addition of sodium caseinate during the CD complexation of fish

• was demonstrated by both thermal (TG–DTG and DSC) and chromatographic (GC–MS for the degradation compounds, i.e., aldehydes, formylated carboxylic acids, or dicarboxylic acids) methods [16]. Also, vegetable oils containing unsaturated FA moieties were stabilized by CD complexation. Common bean

• contents of 10.5–22.8% and 6.4–11.0%, respectively [31]. The fatty acid profile of hazelnut oil revealed a significantly high content of oleic acid (as methyl ester, determined by GC–MS) of 74.2–82.8%, among linoleic acid and even ALA (9.8–18.7% and ≈0.1%, respectively) [32][33]. The very high content of

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

• Swantje Lerch,
• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20

• amounts of acetic anhydride were used and a time-dependent investigation of the catalytic system was performed. Samples of the reaction mixture were taken after 10, 20, 30, 60 and 120 minutes and analyzed via GC–MS. The results are shown in Figure 1. The results show that full conversion of the starting

• via GC–MS). The products were isolated via flash column chromatography to determine the yield. Anthracene was selectively acylated at the 9-position (14) using acetic anhydride. The use of other anhydrides was also tested: propionic anhydride and benzoic anhydride lead to yields between 41% and 92

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• , but this study did not report on the isolation and structure elucidation [117]. Rather the identification was only based on GC–MS data, without a reference to a previous identification through rigorous structure elucidation. Conclusively, this compound has not been described thoroughly and its

• based on tentative GC–MS assignments, often even without comparison to authentic standards, which results in a lot of information of questionable relevance. The large number of such papers published today makes it more and more difficult to find the relevant information in the literature. With this work

Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones

• Benedikt Kolb,
• Daniela Silva dos Santos,
• Sanja Krause,
• Anna Zens and
• Sabine Laschat

Beilstein J. Org. Chem. 2023, 19, 176–185, doi:10.3762/bjoc.19.17

• and HPLC purification steps. However, GC–MS analysis of the crude product of one exemplary dienone 27ac (with only 17% yield) indicated only decomposition in the reaction sequence. Further, phenylenyne 25a was treated with different conjugated and aliphatic acyl chlorides 26m–p (Table 4, entries 13–16

Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris

• Angelique Ladwig,
• Markus Kroll and
• Stefan Schulz

Beilstein J. Org. Chem. 2023, 19, 167–175, doi:10.3762/bjoc.19.16

• chromatography; enantioselective synthesis; GC/MS; semiochemicals; Introduction Hyperolius cinnamomeoventris (Figure 1) is one of the largest species of reed frogs (Hyperoliidae), which are commonly found in Africa, south of the Sahara. Males of the Hyperoliidae possess a characteristic yellow gular patch on

• A and C (Figure 3). As biological material is scarce and the amount of analytes is low, GC–MS trace analytical methods are performed to investigate extracts from the glands of individual frogs to identify their constituents. The analysis of MS and GC–IR data as well as gas chromatographic retention

Characterization of a new fusicoccane-type diterpene synthase and an associated P450 enzyme

• Jia-Hua Huang,
• Jian-Ming Lv,
• Liang-Yan Xiao,
• Qian Xu,
• Fu-Long Lin,
• Gao-Qian Wang,
• Guo-Dong Chen,
• Sheng-Ying Qin,
• Dan Hu and
• Hao Gao

Beilstein J. Org. Chem. 2022, 18, 1396–1402, doi:10.3762/bjoc.18.144

• ]. The resulted transformant was cultivated in the modified Czapek–Dox medium for four days, and then mycelia were harvested and extracted for analysis. Upon gas chromatography-mass spectrometry (GC–MS) analysis, we observed an additional peak at m/z = 272 [M]+ from the tadA harboring transformant

• with or without addition of deuterated water (D2O). GC–MS analysis showed that when the reaction mixture was supplemented with D2O, the ion peak at m/z 273 was observed, indicating that exogenous deuterium was incorporated into 1 (Supporting Information File 1, Figure S19). This suggests that TadA

• , through careful examination of the GC–MS profile of the transformant expressing tadA, we also observed the appearance of 3, the content of which is rather lower than that in the tadAY91H-containing transformant (Supporting Information File 1, Figure S25). Based on these, we propose that though both MgMS

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• File 250: 1H NMR and 13C NMR spectra, GC–MS, and HRMS; supplementary computational data and coordinates; additional photophysical. Acknowledgements We thank Dr. David Hall for providing help with the calculations and initial samples of some of the intermediates. Funding M. K. would like to thank 2214

From amines to (form)amides: a simple and successful mechanochemical approach

• Federico Casti,
• Rita Mocci and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 1210–1216, doi:10.3762/bjoc.18.126

• intermediate was not detected by NMR or GC–MS analysis, possibly due to its instability [64]. Several studies carried out on our reaction crude at different times did not show the presence of compounds traceable to formylimidazole. The imidazole plays a dual role as promoting reagent and solid grinding

• assistance with the generation of the 1H, 13C NMR, and GC–MS spectroscopic data. Funding This research was funded by MIUR Italy, PRIN 2017 project (grant number: 2017B7MMJ5_001) “MultIFunctional poLymer cOmposites based on groWn matERials (MIFLOWER) and Fondazione di Sardegna (FdS, F72F20000230007).

The stereochemical course of 2-methylisoborneol biosynthesis

• Binbin Gu,
• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

• by GC/MS analysis and synthesis of reference compounds [29], several of which also occur in Escherichia coli or yeast strains that were engineered for the biosynthesis of methylated monoterpenes derived from 2-Me-GPP [30][31]. About one decade ago, the crystal structures of GPPMT and 2MIBS have been

• enriched 2-Me-LPP with 2-MIBS The enantiomerically enriched substrates (R)- and (S)-2-Me-LPP were incubated with purified 2MIBS (Figure S2 in Supporting Information File 1), followed by extraction of the enzyme reactions with hexane and GC/MS analysis of the obtained products (Figure S3, Table S1 in

• enantiomerically pure 2-Me-LPP with 2-MIBS Both pure enantiomers of 2-Me-LPP were incubated with 2-MIBS. GC/MS analysis of the products (Figure 3A and 3B, and Table S1 in Supporting Information File 1) showed with the substrate (R)-2-Me-LPP an efficient conversion into 2-methylisoborneol (1, 75%). Minor compounds

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

• Durbis J. Castillo-Pazos,
• Juan D. Lasso and
• Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

• 2-(perfluorohexyl)-1,1-diphenylethylene (8), and propiophenone through GC–MS analysis. Additionally, the presence of free SO2 gas was confirmed by the reaction of acidic potassium dichromate solution on paper (green coloration of the exposed surface). See Supporting Information File 1 for details

• as N-phenylpyrrole and 2-phenylindole were found to produce large quantities of the desired perfluorohexyl and perfluorooctyl analogues as observed by both 1H NMR and GC–MS analysis. However, these molecules generated large concentrations of fluorinated byproducts which rendered separation of the

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• overview of selected flow protocols for the synthesis of various odorants and highlight their role for perfumery. All quotations of percentages of these raw materials in perfumes are in the concentrate formula, before dilution, and are taken from GC/MS analyses. Review Classification of odorants As there

• heated tube reactor made from stainless steel 316L. In this reactor, the second step, i.e. pyrolysis of triperoxide 55 is achieved at 270 °C with a residence time of 12 min. The reaction mixture is collected and analyzed by GC/MS indicating formation of juniper lactone (56) in a yield of 10% along with

• temperature of 70 °C and a residence time of 30 min, macrocycles 65 and 66 are obtained in excellent yields with a preference for the E-isomers as determined by GC/MS analysis. Although, macrocycles 65 and 66 are, to the best of our knowledge, not used as musks in perfumery, this work demonstrates the value

A trustworthy mechanochemical route to isocyanides

• Francesco Basoccu,
• Federico Cuccu,
• Federico Casti,
• Rita Mocci,
• Claudia Fattuoni and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 732–737, doi:10.3762/bjoc.18.73

• (GC–MS analysis). Unexpectedly, the addition of Lewis acids, namely LiCl and BF3·Et2O, did not improve the enolate generation. The next step was searching the optimal conditions for a better conversion of 1f in 2f. These were found in the 1:2:7 ratios of the three components with the addition of 400

• after 1h (70%, GC–MS analysis). Reducing the amount of sodium carbonate did not provide any advantage. Interestingly, using anhydrous sodium carbonate instead of its hydrated form improved reaction yields, likely due to the hydrolysis of tosyl chloride. With these data in hand, we then opted for

Terpenoids from Glechoma hederacea var. longituba and their biological activities

• Dong Hyun Kim,
• Song Lim Ham,
• Zahra Khan,
• Sun Yeou Kim,
• Sang Un Choi,
• Chung Sub Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2022, 18, 555–566, doi:10.3762/bjoc.18.58

• spectrum of 1S,4S,5R,8S,10R-(1a). Finally, the ᴅ-glucopyranosyl moiety was identified by GC–MS analysis of a chiral derivatization product of the sugar obtained by enzyme hydrolysis of 1 [9][10]. The retention time of glucopyranose (11.3 min) corresponded to that of the standard ᴅ-glucopyranose (11.3 min

• as 3α,12α,16α [15]. Finally, the ᴅ-glucopyranose unit in 4 was confirmed by GC–MS analysis as described above (Supporting Information File 1, Figure S35) [10], and the coupling constant of anomeric protons at δH 4.33 (J = 7.8 Hz) implied β-ᴅ-glucopyranose [16]. Thus, the structure of compound 4 was

• using GC–MS. Monosaccharides (1, 0.4 mg; 2, 0.3 mg; 3, 0.4 mg; 4, 0.4 mg), obtained by hydrolysis, were dissolved in pyridine (0.5 mL), then ʟ-cysteine methyl ester hydrochloride (2 mg) was added. The reaction mixtures were then stirred at 60 °C for 2 h. After adding 1-trimethylsilylimidazole (0.1 mL

Synthesis of piperidine and pyrrolidine derivatives by electroreductive cyclization of imine with terminal dihaloalkanes in a flow microreactor

• Yuki Naito,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2022, 18, 350–359, doi:10.3762/bjoc.18.39

• column (Mightysil RP-18 GP II 250-4.6 (5 µm), Cica) using a mixture of H2O/MeCN/H3PO4 (60/40/0.1%) as a mobile phase. All chromatograms were recorded using an LC workstation (LabSolutions DB, Shimadzu). Helium gas was used as a carrier gas for the gas chromatography/mass spectrometry (GC–MS) analyses. 1H

A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• subsequent water elimination leading to a stable tertiary, bis-benzyl carbocation that evolves forming the corresponding alkene by proton elimination (Scheme 3). The reaction was carried out at 60 °C with 10 mol % of 16 (Table 2, entry 1), monitoring the formation of the products by 1H NMR and GC–MS (see

• spectra were acquired at 298 K with a Bruker AVANCE 300 spectrometer operating at 300.15 MHz and with a Bruker 400 spectrometer operating at 400.15 MHz. The chemical shift values (δ) in ppm refer to SiMe4 (TMS) as standard. For GC–MS analysis a GC Trace GC 2000 apparatus was used equipped with an HP5-MS

• . Subsequently, the substrate (75 mM) was introduced, and the tube was maintained at 60 °C. The progress of the reaction was monitored by 1H NMR and GC–MS by periodic sampling of the solution. Product assignments in the 1H NMR spectra were carried out in accordance with literature data: for citronellal

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