Secondary metabolome and its defensive role in the aeolidoidean Phyllodesmium longicirrum, (Gastropoda, Heterobranchia, Nudibranchia)

• Alexander Bogdanov,
• Cora Hertzer,
• Stefan Kehraus,
• Samuel Nietzer,
• Sven Rohde,
• Peter J. Schupp,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2017, 13, 502–519, doi:10.3762/bjoc.13.50

• correlations from H3-28 to C-23 and from H3-29 to C-22, C-23, C-24 and C-30 (see Figure 3). The NMR data (Supporting Information File 1, Table S1) of compound 1 resembled most closely those of epoxy-secosterols isolated from the gorgonian Pseudopterogorgia americana [22] and from the soft coral Pachyclavularia

• violacea (now Briareum violaceum [23]) by Anta et al. ([24], Figure 4). However, the 13C NMR chemical shifts of C-5 and C-6 in compound 1 (δC 80.7 and δC 75.7, respectively) differ from shifts for the equivalent carbons in epoxy-secogorgosterol reported by Naz et al. (δC 61.0 and δC 60.4, respectively; [22

• ]) and from those of the epoxy-secosterol reported by Anta et al. (δC 65.5 and δC 58.1, respectively; [24]). The downfield shift, observed for these carbons in 1, results from the cleavage of the epoxide ring, and 13C values around δC 70–80 as observed for 1 are characteristic for hydroxylated carbons

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• in 98% yield for both THP and MOM ethers (Scheme 62). Irradiation of aromatic γ,δ-epoxy ketones 226 with a medium-pressure UV mercury lamp (450 W) led to the formation of 1-indanones 227 via a photochemical epoxy rearrangement and 1,5-biradical cyclization tandem reaction (Scheme 63) [92]. The best

cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

• Dimpee Gogoi,
• Runjun Devi,
• Pallab Pahari,
• Bipul Sarma and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2016, 12, 2816–2822, doi:10.3762/bjoc.12.280

• Abstract We have synthesized a series of cis-6a,7,8,12b-tetrahydro-6H-naphtho[2,1-c]chromen-6a-ols as B-ring-modified analogues of (±)-brazilin. A completely regio- and cis-diastereoselective intramolecular Friedel–Crafts epoxy–arene cyclization of 1-tetralone-derived glycidyl ethers catalyzed by Brønsted

• been reductively removed by a diastereoselective method which should be useful in future for preparing libraries of chroman-fused tetralins with trans-stereochemistry at the ring junction. Keywords: brazilin; chroman; epoxy-arene cyclization; natural-product-like molecules; tetralin; Findings The

• studied during the past 15 years [19]. Moreover, on many occasions natural product-like molecules exhibit more potent biological activities than the parent natural products [20]. Meanwhile, the intramolecular Friedel–Crafts epoxy–arene (IFCEA) cyclization has been well-established as a powerful tool for

Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

• Pramod R. Markad,
• Navanath Kumbhar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2016, 12, 1765–1771, doi:10.3762/bjoc.12.165

• Sharpless asymmetric epoxidation (SAE) [16][17]. Thus, allyl alcohol 7 was subjected for SAE first using (+)-DET that afforded a diastereomeric mixture of epoxy alcohols 8 and 9 in the ratio of 88:12 (based on the 1H NMR analysis) in 85% yield. Similarly, use of (–)-DET in SAE afforded epoxide 8 and 9 in

• the ratio of 18:82 in 83% yield. With the understanding of SAE mnemonic, we assigned the absolute configuration in epoxide 8 as 7S,8S and in epoxide 9 as 7R,8R. Subsequently, major isomers of epoxy alcohols 8 and 9 were individually subjected to regioselective epoxide ring opening using trimethyl

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• (Scheme 6). The acid-catalyzed Baeyer–Villiger oxidation of cyclic epoxy ketones 22 produces lactones of type 23, which convert into carbenium ions 24 in the presence of the acid. Subsequently, these ions can be transformed with participation of H2O2 through three different pathways into dihydroperoxides

• synthesis of various heterocyclic systems, such as furan, thiophene, and pyrrole derivatives. The reaction of unsymmetrical epoxy dioxanes 290a–d with triethylamine is accompanied by the 1,2-dioxane-ring opening to form 4-hydroxy-2,3-epoxy ketones 291a–d in high yields. The base catalysis involves the

• abstraction of the most acidic α-proton in the vicinity of the O–O bond followed by the rearrangement accompanied by the O–O-bond cleavage to form 4-hydroxy-2,3-epoxy ketones (Scheme 86) [364]. The Kornblum–DeLaMare rearrangement is of special synthetic value in view of the synthesis of biologically active

Marine-derived myxobacteria of the suborder Nannocystineae: An underexplored source of structurally intriguing and biologically active metabolites

• Antonio Dávila-Céspedes,
• Peter Hufendiek,
• Max Crüsemann,
• Till F. Schäberle and
• Gabriele M. König

Beilstein J. Org. Chem. 2016, 12, 969–984, doi:10.3762/bjoc.12.96

• haliangicin stereoisomers, which differed in the configuration of the three terminal double bonds in the tetraene moiety. Each of the isomers haliangicin, haliangicin B, haliangicin C and haliangicin D happened to be present with two different configurations around the epoxy group. The NOESY spectra showed

Highly stable and reusable immobilized formate dehydrogenases: Promising biocatalysts for in situ regeneration of NADH

• Barış Binay,
• Dilek Alagöz,
• Deniz Yildirim,
• Ayhan Çelik and
• S. Seyhan Tükel

Beilstein J. Org. Chem. 2016, 12, 271–277, doi:10.3762/bjoc.12.29

• boidinii as cross-linked enzyme aggregate (CLEA) and demonstrated that the residual activity and thermal stability of CLEA were strictly dependent on the type of cross-linker. Epoxy group containing supports are widely used in enzyme immobilization studies to obtain highly stable enzyme preparations by

• conditions. Hence, the use of a proper immobilization technique and support could stabilize its dimeric form. In this study, NAD+-dependent FDH from Candida methylica was covalently immobilized onto Immobead 150, an epoxy group containing commercial support, and Immobead 150 support modified with

• immobilized enzyme is the type of binding groups on the support which provides higher loading of enzyme and higher retention of activity [28]. Epoxy group containing supports are widely used in the immobilization of many enzymes through multi-point covalent attachments since epoxy groups can easily react with

Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

• Helmut Ritter,
• Monir Tabatabai and
• Markus Herrmann

Beilstein J. Org. Chem. 2016, 12, 245–252, doi:10.3762/bjoc.12.26

• polymerization; (meth)acryl polymers; neighboring group effects; solvent polarity; Introduction Amino groups are important functionalities in polymer chemistry, e.g., for hardening various epoxy resins [1]. However, they easily react in an undesired side reaction with electron-poor double bonds of (meth

Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions

• Shawna L. Balof,
• K. Owen Nix,
• Matthew S. Olliff,
• Sarah E. Roessler,
• Arpita Saha,
• Kevin B. Müller,
• Ulrich Behrens,
• Edward J. Valente and
• Hans-Jörg Schanz

Beilstein J. Org. Chem. 2015, 11, 1960–1972, doi:10.3762/bjoc.11.212

• was truncated to isolate the sample, sealed with epoxy, and mounted on a pin; the pin was placed on a goniometer head. The crystallographic properties and data were collected using Mo Kα radiation and the charge-coupled area detector (CCD) detector on an Oxford Diffraction Systems Gemini S

Cross metathesis of unsaturated epoxides for the synthesis of polyfunctional building blocks

• Meriem K. Abderrezak,
• Kristýna Šichová,
• Nancy Dominguez-Boblett,
• Antoine Dupé,
• Zahia Kabouche,
• Christian Bruneau and
• Cédric Fischmeister

Beilstein J. Org. Chem. 2015, 11, 1876–1880, doi:10.3762/bjoc.11.201

• Chemistry, Hlavova 2030, CZ-128 40 Prague, Czech Republic Faculty of Chemistry, University of Seville, E-41012 Seville, Spain 10.3762/bjoc.11.201 Abstract The cross metathesis of 1,2-epoxy-5-hexene (1) with methyl acrylate and acrylonitrile was investigated as an entry to the synthesis of polyfunctional

• are much more demanding transformations [13][14][24]. We have investigated the reactivity of 1,2-epoxy-5-hexene (1) with methyl acrylate and acrylonitrile and further exploited the versatility of the epoxide ring to prepare trifunctional molecules by ring opening of the epoxide. To date, 1 has been

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• . Polyesters containing epoxy moieties. Biocatalyzed synthesis of polyesters containing glycerol. Iataconic (34) and malic (35) acid. Oxidized poly(hexanediol-2-mercaptosuccinate) polymer. C-5-substituted isophthalates. Curcumin-based polyesters. Silylated polyesters. Polyesters containing reactive ether

Design and synthesis of polycyclic sulfones via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Rama Gunta

Beilstein J. Org. Chem. 2015, 11, 1373–1378, doi:10.3762/bjoc.11.148

• , commercially available as Oxone®) in aqueous methanol. Equipped with this information, oxidation of compound 5 was attempted under similar reaction conditions to get the desired sulfone 6 [33] (Scheme 1, Table 1). Initially, when the reaction was carried out at 0 °C, the epoxy sulfone 7 was the major product

• (Table 1, entry 1). However, after a considerable amount of experimentation (Table 1), the desired sulfone 6 has been produced in 89% yield (Table 1, entry 2) but it was not possible to eliminate the formation of the epoxy sulfone 7. Next, our efforts were directed towards the synthesis of various

Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

• Stephan Schmidt,
• Hanqing Wang,
• Daniel Pussak,
• Simone Mosca and
• Laura Hartmann

Beilstein J. Org. Chem. 2015, 11, 720–729, doi:10.3762/bjoc.11.82

• Equation 1). AFM force spectroscopy with a NanoWizard 3 system (JPK instruments AG, Berlin, Germany) was performed to determine the elastic modulus of the microparticles. As AFM probe a glass bead with a diameter of 5.1 µm was glued with an epoxy glue onto a tipless, non-coated cantilever (spring constant

Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS

• Lars W. Städe,
• Thorbjørn T. Nielsen,
• Laurent Duroux,
• Reinhard Wimmer,
• Kyoko Shimizu and
• Kim L. Larsen

Beilstein J. Org. Chem. 2015, 11, 514–523, doi:10.3762/bjoc.11.58

• interactions with the silane linker. The change in chemical composition after silanization with GPTMS and grafting of the β-CD dimer by CuAAC was verified by X-ray photoelectron spectroscopy (XPS). Table 1 displays the chemical surface composition of an unmodified, an epoxy-activated, and a β-CD-dimer-grafted

• unmodified, epoxy-activated and β-CD-dimer-grafted quartz.a Supporting Information Supporting Information File 138: 1H NMR and 13C HSQC spectra of β-CD dimer, 13C HSQC spectra of β-CD dimer in complex with 2,6-ANS and TIRF 2,6-ANS titration on bare quartz. Acknowledgements FeF Chemicals, Køge, Denmark and

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

• the previously discussed strained epoxy-derivatives could be detected. Transformation of 1,4-dienols via electro-generated iodonium cations In a similar approach we investigated the cyclisation of the 1,4-dienols 2 with in situ electrochemically generated iodonium ions for the desired synthesis of

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

• highest degradation temperature) and for an unidentified sesquiterpene oxide (with an increase of 244%, from 0.1% to 0.3%, Table 2). Other epoxy derivatives appear upon degradation, such as ionone oxide (20). This compound was found increasingly concentrated in degraded samples (and not identified in the

Regio- and stereoselective synthesis of new diaminocyclopentanols

• Evgeni A. Larin,
• Valeri S. Kochubei and
• Yuri M. Atroshchenko

Beilstein J. Org. Chem. 2014, 10, 2513–2520, doi:10.3762/bjoc.10.262

• .10.262 Abstract The optimal conditions for regio- and stereoselective epoxide ring opening of N,N-disubstituted 1,2-epoxy-3-aminocyclopentanes by different nucleophilic reagents have been developed. The substituents on the nitrogen atom in the epoxide precursor and the orientation of the oxirane ring are

• crucial for the reaction outcome. Thus, treatment of (1RS,2SR,3SR)-1,2-epoxy-3-(N,N-dibenzylamino)cyclopentane (3b) with amines gave a mixture of C1 and C2 regioadducts, while the use of (1RS,2SR,3SR)-1,2-epoxy-3-(N-benzyl-N-methylamino)cyclopentane (3a) led ultimately to C1 adducts. Base-catalyzed

• outcome, epoxides 3c and 3d were additionally synthesized, and the results are summarized in Table 3. It has been proposed earlier that the coordination of the Lewis acid to both oxygen atoms in 2,3-epoxy alcohols and acids leads to the formation of the intermediate complex, for which nucleophiles attack

Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin

• Melanie Rauschenberg,
• Eva-Corrina Fritz,
• Christian Schulz,
• Tobias Kaufmann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 1354–1364, doi:10.3762/bjoc.10.138

• silicon oxide surfaces can be obtained in only one step from an epoxy-terminated trimethoxysilane. The most common approaches to fabricate epoxide SAMs is by dip-coating or vapor condensation. However, this leads to the formation of thick films of aggregated molecular layers with undefined surface

Heronapyrrole D: A case of co-inspiration of natural product biosynthesis, total synthesis and biodiscovery

• Jens Schmidt,
• Zeinab Khalil,
• Robert J. Capon and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2014, 10, 1228–1232, doi:10.3762/bjoc.10.121

• the farnesyl residue (for atom numbering see Scheme 1), followed by regio- and stereoselective nucleophilic addition of water (and methylation) would deliver heronapyrroles A and B. Similarly, regio- and stereoselective nucleophilic addition of water to a tris-epoxy farnesyl intermediate 4 could

• produce an alternative bis-epoxy intermediate 3 that can deliver a hitherto undetected mono-tetrahydrofuran heronapyrrole (e.g., heronapyrrole D, Scheme 1). To test this hypothesis we completed an asymmetric synthesis of the putative natural product heronapyrrole D, and used this material to probe

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

Metal and metal-free photocatalysts: mechanistic approach and application as photoinitiators of photopolymerization

• Jacques Lalevée,
• Sofia Telitel,
• Pu Xiao,
• Marc Lepeltier,
• Frédéric Dumur,
• Fabrice Morlet-Savary,
• Didier Gigmes and
• Jean-Pierre Fouassier

Beilstein J. Org. Chem. 2014, 10, 863–876, doi:10.3762/bjoc.10.83

• , respectively, is quite easy; polymerization of sustainable monomers can also be achieved (e.g., epoxidized soybean oil). A possible dual behavior (simultaneous generation of radicals and cations that ensure the formation of, e.g., an epoxy/acrylate interpenetrated network IPN) is achieved. Examples of PICs

• (JASCO FTIR 4100) at about 1630 cm−1 as in [15]. iv) The ring opening polymerization of epoxides: The photosensitive formulations were deposited (25 µm thick) on a BaF2 pellet under air. The evolution of the epoxy group content was continuously followed by real time FTIR spectroscopy (JASCO FTIR 4100) at

Plakilactones G and H from a marine sponge. Stereochemical determination of highly flexible systems by quantitative NMR-derived interproton distances combined with quantum mechanical calculations of ¹³C chemical shifts

• Simone Di Micco,
• Angela Zampella,
• Maria Valeria D’Auria,
• Carmen Festa,
• Simona De Marino,
• Raffaele Riccio,
• Craig P. Butts and
• Giuseppe Bifulco

Beilstein J. Org. Chem. 2013, 9, 2940–2949, doi:10.3762/bjoc.9.331

• = 2.0 and 8.0 Hz) and 2.69 (ddd, J = 2.0, 5.6, 7.5 Hz), observed in the 1H NMR spectrum, were found to correlate in the HSQC spectrum with two oxygenated carbons at δC 63.3 and 61.6, respectively, and were assigned to an epoxy ring. The localization of the epoxy functionality at C-7 and the structure

N,N'-(Hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide): Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation

• Julian Fischer,
• Simon Millan and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2834–2840, doi:10.3762/bjoc.9.318

• adequate phase transfer catalysts and the cyclodextrin–guest complexes were characterized by 1H NMR and 2D NMR ROESY spectroscopy. Finally, the curing properties of the diepoxide with lysine-based α-amino-ε-caprolactam were analyzed by rheological measurements. Keywords: alkylation; cyclodextrins; epoxy

• Hz, 2H, O–CH2, trans), 2.40 (s, 6H, Ar-CH3), 1.55 (m, 4H, -CH2-), 1.27 (m, 4H, -CH2-); 13C NMR (75 MHz, CDCl3, δ) 143.6 (2C, Ar(C)-CH3), 136.8 (2C, RO2S-(C)Ar), 130.0 (4C, Ar(C)), 127.3 (4C, Ar(C)), 51.2 (2C, epoxy), 51.0 (2C, N-CH2-CH2R), 49.4 (2C, N-CH2-epoxy), 45.4 (2C, epoxy), 28.5 (2C, -CH2

Oligomeric epoxide–amine adducts based on 2-amino-N-isopropylacetamide and α-amino-ε-caprolactam: Solubility in presence of cyclodextrin and curing properties

• Julian Fischer and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2803–2811, doi:10.3762/bjoc.9.315

• with hydrophobic guest molecules is widely used in drug, food, cosmetics, textile, adhesives, plastics and more industries [11][12][13]. Interestingly, recently it was confirmed that α- and β-CD cannot interact with PNIPAM. Only γ-CD has a tendency to include the PNIPAM main chain [14]. Normally, epoxy

• resins exhibit poor solubility in water [15][16][17]. Accordingly, epoxide–amine polymers are not yet deeply investigated in respect to LCST behavior [18][19]. At present, most available bio-based and water soluble epoxy resins are expensive and use petroleum-based curing agents [20]. Thus, in the

• present paper we wish to describe our results about preparation and solubility of novel bio-based amine–epoxy oligoadducts. Also, we present some effects of CD on the solubility of these oligomers. Results and Discussion Generally, primary amins are bifunctional towards diepoxides and are thus monomers

Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

• Sudipta Pathak,
• Kamalesh Debnath and
• Animesh Pramanik

Beilstein J. Org. Chem. 2013, 9, 2344–2353, doi:10.3762/bjoc.9.269

• sulfonic group of SSA generates dehydrated cationic intermediate 9. This reactive intermediate 9 provokes a nucleophilic attack of primary amines to form bicyclo[3.3.0]octanamino compound 10. Then the α-hydroxy group of 10 attacks the adjacent carbonyl carbon to generate epoxy intermediate 11. This

• unstable epoxy intermediate 11 produces a six-membered lactone intermediate 12 through the breaking of a C–C bond. Subsequently, intermediate 12 tautomerizes to 13 under formation of the isocoumarin skeleton. The dihydropyrrole-fused isocoumarin intermediate 14 is formed through the intramolecular

• nucleophilic attack of the secondary amine group to the carbonyl carbon of 13. Finally, intermediate 14 loses water to furnish pyrrole-fused isocoumarins 5 or 8. It is worth mentioning that in the previous method instead of the formation of epoxy intermediate like 11 a transannular rearrangement was proposed