AgNTf₂-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives

• Ziping Cao,
• Jiekun Zhu,
• Li Liu,
• Yuanling Pang,
• Laijin Tian,
• Xuejun Sun and
• Xin Meng

Beilstein J. Org. Chem. 2019, 15, 2623–2630, doi:10.3762/bjoc.15.255

• , then dried in a vacuum drying oven at 50 °C for 24 h to give the pure pyrrole product 10aa, 75.8 mg, 99% yield. For products 10ab–ae, 10ka–la, the purification method was as follows: evaporation of volatiles under reduced pressure to give the residue, which was suffered from column chromatography on

Analysis of sesquiterpene hydrocarbons in grape berry exocarp (Vitis vinifera L.) using in vivo-labeling and comprehensive two-dimensional gas chromatography–mass spectrometry (GC×GC–MS)

• Philipp P. Könen and
• Matthias Wüst

Beilstein J. Org. Chem. 2019, 15, 1945–1961, doi:10.3762/bjoc.15.190

• available for most of the analytes. For this reason, feeding experiments (in vivo labeling) were carried out using the stable isotope-labeled precursors [5,5-2H2]-1-deoxy-ᴅ-xylulose (d2-DOX) and [6,6,6-2H3]-(±)-mevalonolactone (d3-MVL) to clearly identify the volatiles. Based on the recorded mass spectra of

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• the reaction mixture was stirred at room temperature for 24 h. The volatiles were removed under reduced pressure and the resulting crude product was dissolved in 100 mL of CH2Cl2. The organic phase was washed sequentially with an aqueous saturated solution of citric acid (50 mL), aqueous 10% NaHCO3

Phylogenomic analyses and distribution of terpene synthases among Streptomyces

• Lara Martín-Sánchez,
• Kumar Saurabh Singh,
• Mariana Avalos,
• Gilles P. van Wezel,
• Jeroen S. Dickschat and
• Paolina Garbeva

Beilstein J. Org. Chem. 2019, 15, 1181–1193, doi:10.3762/bjoc.15.115

• volatiles, the number and amounts of geosmin synthase side products associated with it can vary [33][34], possibly as a result of an evolution of enzyme function. Phylogenetic analysis of 2-MIB synthases To gain insights into the evolution of the 2-MIB synthases a phylogenetic analysis of all the enzymes

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

• Shahien Shahsavari,
• Dhananjani N. A. M. Eriyagama,
• Bhaskar Halami,
• Vagarshak Begoyan,
• Marina Tanasova,
• Jinsen Chen and
• Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

• ODN]. Fractions of the major ODN peak at ≈39 min were collected, concentrated to ≈100 μL, and injected into HPLC to give the profile of purified trityl-tagged ODN. To the dried trityl-tagged ODN was added 1 mL of 80% AcOH, and the mixture was shaken gently at rt for 3 h. Volatiles were evaporated. The

Design, synthesis and spectroscopic properties of crown ether-capped dibenzotetraaza[14]annulenes

• Krzysztof M. Zwoliński and
• Julita Eilmes

Beilstein J. Org. Chem. 2019, 15, 617–622, doi:10.3762/bjoc.15.57

• chloroform and methanol (1:1, v/v). The third, main band, was eluted isocratically with a mixture of CHCl3/MeOH/NH3aq (10:10:1, v/v/v), evaporated to dryness under reduced pressure, and kept in a vacuum overnight at ambient temperature to remove all volatiles. Crown ether-capped DBTAA macrocycle 3a: [7,16

Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum

• Jan Rinkel,
• Alexander Babczyk,
• Tao Wang,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 2974–2990, doi:10.3762/bjoc.14.277

• 10.3762/bjoc.14.277 Abstract The volatiles emitted by the ascomycetes Hypoxylon griseobrunneum and Hypoxylon macrocarpum (Hypoxylaceae, Xylariales) were collected by use of a closed-loop stripping apparatus (CLSA) and analysed by GC–MS. The main compound class of both species were polysubstituted benzene

• that was supported by a feeding experiment with (methyl-2H3)methionine. Keywords: constitutional isomerism; gas chromatography; mass spectrometry; natural products; volatiles; Introduction Fungi release a large number of different volatiles that belong to all kinds of natural product classes [1

• producing and non-producing Penicillium roqueforti isolates [6]. On the other hand, fungal volatiles are interesting, because they contribute with their aroma to the flavour of many edible mushrooms. One of the first identified and certainly most widespread compounds is matsutake alcohol, (R)-oct-1-en-3-ol

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• were found to be relatively stable under anhydrous conditions and could be readily prepared via Michaelis–Arbusov (M–A) chemistry (Scheme 15) [23][56]. Transfer of crude M–A reaction mixtures to a zirconia ball mill vessel and removal of volatiles enabled the concomitant partial hydrolytic desilylation

Development of novel cyclic NGR peptide–daunomycin conjugates with dual targeting property

• Andrea Angelo Pierluigi Tripodi,
• Szilárd Tóth,
• Kata Nóra Enyedi,
• Gitta Schlosser,
• Gergely Szakács and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 911–918, doi:10.3762/bjoc.14.78

• . The lyophilized compound was then purified by RP-HPLC prior to the cyclization. Cyclization Prior to the head-to-side chain cyclization a salt exchange needs to be performed using 10 equiv of pyridinium hydrochloride in 5 mL MeOH. After 20 min volatiles were removed under reduced pressure, the

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

• encoded terpene synthases for each strain. Besides terpenes, a series of aromatic compounds and volatiles derived from fatty acid and branched amino acid metabolism were identified. Some of these compounds have not been described as fungal metabolites before. For the compound ethyl (E)-hept-4-enoate known

• 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

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

• with different ring substitution patterns. For the set of identified compounds a plausible biosynthetic scheme was suggested that gives further support for the assigned structures. Keywords: constitutional isomerism; gas chromatography; mass spectrometry; natural products; volatiles; Introduction The

• , Agaricus bisporus, and other delicacies from the fungal world such as the oyster mushroom, the penny bun, and shiitake [2][3]. The ecological function of most fungal volatiles is unknown, but for the alcohol 1 (Figure 1) a germination inhibitory function has been reported [4]. For 6-pentyl-2H-pyran-2-one

Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands

• Rebecca Pittkowski and
• Thomas Strassner

Beilstein J. Org. Chem. 2018, 14, 664–671, doi:10.3762/bjoc.14.54

• )propane-1,3-dione (495 mg, 1.4 mmol) were added, and the mixture was stirred for 24 hours at room temperature and then for six hours at 110 °C; all volatiles were removed in vacuo, the crude product was washed with water and purified by flash chromatography (silica gel, DCM/isohexanes 3:1). Afterwards, it

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

• natural product is 6-nonyl-2H-pyran-2-one. The antimicrobial and cytotoxic effects of the synthetic volatiles are also reported. Keywords: enantioselective synthesis; gas chromatography; mass spectrometry; natural products; volatiles; Introduction A large variety of volatile organic compounds from

• biocontrol agents [6]. On the contrary, fungi can also produce mycotoxins, which must be excluded for their safe usage in agricultural biocontrol. Some volatiles, especially terpenes, point to the production of certain toxins in fungi, e.g., aristolochene (3) is the precursor of PR toxin in Penicillium

Hydrolysis, polarity, and conformational impact of C-terminal partially fluorinated ethyl esters in peptide models

• Vladimir Kubyshkin and
• Nediljko Budisa

Beilstein J. Org. Chem. 2017, 13, 2442–2457, doi:10.3762/bjoc.13.241

• the next 12 hours. Volatiles were removed under reduced pressure; the crude material was purified on a short (21 g) silica gel column using ethyl acetate/methanol 39:1 mixture as the eluent. 132 mg of 4 was obtained as a clear oil (yield 94%), Rf = 0.69 (ethyl acetate/methanol 39:1). The procedure in

• temperature for 10 min. It was then added to the peptide (25 μmol; in this example 18.4 mg of Ac(εBocLys)3OH) soaked in chloroform (100 μL). The resulting mixture was shaken at room temperature for approximately 10 hours. Volatiles were removed with nitrogen gas, and the residue was freeze-dried from an

• as follows. Ac(Pro)6OH (8a, 5.6 mg) was dissolved in methanol (0.5 mL), and trimethylsilyl chloride (0.08 mL) was added. The mixture was shaken at room temperature for 24 hours. Volatiles were removed with nitrogen gas, and the residue was freeze-dried from water. No HPLC purification has been

Comparative profiling of well-defined copper reagents and precursors for the trifluoromethylation of aryl iodides

• Peter T. Kaplan,
• Jessica A. Lloyd,
• Mason T. Chin and
• David A. Vicic

Beilstein J. Org. Chem. 2017, 13, 2297–2303, doi:10.3762/bjoc.13.225

• the volatiles were evaporated on a high vacuum line. The white residue was filtered and washed twice with 5 mL toluene and then twice with 5 mL of pentane. The yield of [(SIMes)2Cu][Cu(CF3)2] was 81%. The spectroscopic data matched literature values [10]. 1H NMR (25 °C, CD2Cl2) δ 1.84 (s, 12H), 2.39

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• , and placed overnight in a freeze-dryer to remove the volatiles. A voluminous pale yellow solid was obtained with quantitative yield (240 mg). Rehydration of the solid was achieved by placing it in an open glass container inside a vial containing a thin layer of water at the bottom, thus creating a

A speedy route to sterically encumbered, benzene-fused derivatives of privileged, naturally occurring hexahydropyrrolo[1,2-b]isoquinoline

• Olga Bakulina,
• Alexander Ivanov,
• Vitalii Suslonov,
• Dmitry Dar’in and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2017, 13, 1413–1424, doi:10.3762/bjoc.13.138

• temperature. The volatiles were removed in vacuo. The residue was dissolved in DCM, washed with water, brine, dried over Na2SO4 and concentrated to give crude methyl ester 10', which was purified by column chromatography on silica gel. The Castagnoli–Cushman reaction (CCR). Assembly of hexahydropyrrolo[1,2-b

Total synthesis of elansolids B1 and B2

• Liang-Liang Wang and
• Andreas Kirschning

Beilstein J. Org. Chem. 2017, 13, 1280–1287, doi:10.3762/bjoc.13.124

• stirring was continued for 8 h. The volatiles were removed in vacuo and the residue was purified by silica gel chromatography to afford vinyl boronate 13 (8.5 mg, 12.3 µmol, 82%). Rf = 0.40 (PE/EtOAc 10:1, visualized using an anisaldehyde stain or UV), [α]D20 = −34.5 (c 0.8, CH2Cl2); 1H NMR (400 MHz, CDCl3

• , 0.079 mmol, 0.7 equiv) were added and the reaction mixture was stirred for additional 5 h. The volatiles were then removed in vacuo at ambient temperature. The residue was purified by silica gel column chromatography to give vinyl iodide 17 (62.0 mg, 0.092 mmol, 77%). Rf = 0.60 (PE/EtOAc 3:1, visualized

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

• the plant volatiles do not act as repellents on bees. The fact that D. viscosa, called by the natives “akoniza”, has been used by the local beekeepers as a means of controlling varroosis, prompted us to analyze the components of the plant in order to identify the active agent and study its efficacy

Identification, synthesis and mass spectrometry of a macrolide from the African reed frog Hyperolius cinnamomeoventris

• Markus Menke,
• Pardha Saradhi Peram,
• Iris Starnberger,
• Walter Hödl,
• Gregory F.M. Jongsma,
• David C. Blackburn,
• Mark-Oliver Rödel,
• Miguel Vences and
• Stefan Schulz

Beilstein J. Org. Chem. 2016, 12, 2731–2738, doi:10.3762/bjoc.12.269

• , releases a complex blend of volatiles when exposed [5]. A first analysis revealed the presence of mostly unknown terpenes, macrolides and other components in species specific compositions [5]. Detailed exploration of the function of these frog volatiles requires the analysis of the secretion and the

Facile synthesis of a 3-deazaadenosine phosphoramidite for RNA solid-phase synthesis

• Elisabeth Mairhofer,
• Elisabeth Fuchs and
• Ronald Micura

Beilstein J. Org. Chem. 2016, 12, 2556–2562, doi:10.3762/bjoc.12.250

• 1 h at 105 °C, followed by evaporation of all volatiles. The residue was diluted in dichloromethane (20 mL) and washed with saturated sodium bicarbonate solution (3 × 30 mL). The combined organic layers were dried over Na2SO4 and all volatiles were evaporated. The yellow-beige crude product was

• % methylamine in water (10 mL) and stirred for 18 hours at room temperature. All volatiles were evaporated and the residue was dried in high vacuum. The crude product was purified by dissolving the byproduct (N-methylbenzamide) in chloroform and subsequent collection of the precipitate by centrifugation (3000

• volatiles were evaporated, the residue dried in high vacuum and redissolved in dry pyridine (5 mL). 4-(Dimethylamino)pyridine (28.4 mg, 233 µmol) and 4,4’-dimethoxytrityl chloride (686 mg, 2.03 mmol) were added and the reaction was allowed to proceed for 16 hours. The reaction was quenched with methanol (1

Application of heterocyclic aldehydes as components in Ugi–Smiles couplings

• Katelynn M. Mason,
• Michael S. Meyers,
• Abbie M. Fox and
• Sarah B. Luesse

Beilstein J. Org. Chem. 2016, 12, 2032–2037, doi:10.3762/bjoc.12.191

• volatiles gave the crude material, which was purified via flash column chromatography on silica gel. For full details, see Supporting Information File 1. N-Arylepoxyisoindolines via tandem Ugi–Smiles/IMDA reaction. Reaction monitoring by 1H NMR for production of 1b. Use of a thienyl-substituted aldehyde for

Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes

• Michael Nonnenmacher,
• Dominik M. Buck and
• Doris Kunz

Beilstein J. Org. Chem. 2016, 12, 1884–1896, doi:10.3762/bjoc.12.178

• μmol) in 5 mL dichloromethane and pressurized with CO (8 bar) upon which an immediate color change to green was observed. Afterwards the pressure was released and all volatiles removed in vacuo. The light yellow residue was washed two times with pentane (1 mL each) and dried in vacuo to obtain the

• ) (15.0 mg, 30.0 μmol) was dissolved in 2.5 mL dichloromethane and pressurized with CO (8 bar) in a 10 mL-size glass autoclave. After 10 min the pressure was released and all volatiles were removed in vacuo. The residue was washed with pentane (1 mL) and dried in vacuo to obtain about 50% (7.0 mg, 15 μmol

Artificial Diels–Alderase based on the transmembrane protein FhuA

• Hassan Osseili,
• Daniel F. Sauer,
• Klaus Beckerle,
• Marcus Arlt,
• Tomoki Himiyama,
• Tino Polen,
• Akira Onoda,
• Ulrich Schwaneberg,
• Takashi Hayashi and
• Jun Okuda

Beilstein J. Org. Chem. 2016, 12, 1314–1321, doi:10.3762/bjoc.12.124

• solution and the mixture was stirred for 16 h at 23 °C. The solution was filtered and all volatiles evaporated. The residue was dissolved in dichloromethane (50 mL), washed twice with water (50 mL), and once with brine (50 mL). The organic layer was dried over Na2SO4 and the solvent removed under vacuum

Biosynthesis of α-pyrones

• Till F. Schäberle

Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56

• volatile of Trichoderma asperellum IsmT5 [36]. Deeper investigation of the volatiles released by Trichoderma species revealed the complexity of the volatile mixture consisting of many derivatives [37]. Several alkylated and alkenylated α-pyrones with length variations in the side chain and different

• aspects of influencing interacting behavior between individuals. Hence, such volatiles are used in courtship behavior to find mating partners. Also another α-pyrone fulfilling pheromone function in insects is known, i.e., the queen recognition pheromone of the red imported fire ant, 6-(1-pentenyl)-2H