Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• ); lit. data [43], UV (50 mM phosphate buffer (pH 7.0)/ethanol 9:1, v/v) λmax, nm (ε): 247.5 (9,100), 279.0 (9,300); for 1H and 13C NMR data see [42] and Supporting Information File 1. Synthesis of nelarabine employing crude Ara-1Pi without isolation from the reaction mixture of Ara-U phosphorolysis. Ara

• earlier [29]. Synthesis of kinetin riboside (KR) employing the crude Rib-1Pi (Ba2+) without isolation from the reaction mixture of uridine phosphorolysis. The E. coli UP (95 IU; 580 units per 1 mmol of uridine) was added to the heterogeneous mixture containing uridine (40 mg, 0.164 mmol), Dowex-nPi (3 mL

• ; after attaining more that 90% uridine phosphorolysis by E. coli UP at rt and isolation from the reaction mixture) and N6-benzylaminopurine (BAP) catalyzed by E. coli PNP under standard reaction conditions.a Condensation of 2ClAde with dRib-1Pi (Ba2+) and with dRib-1Pi ionically bound by QAE Sephadex A

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• Oxone™ (Wegner et al. [19][20][21], Scheme 1). Isolation of 3 was achieved, however, a one pot approach including a subsequent Baeyer–Mills reaction to yield 10 is preferred. 1-Iodo-3-nitrosobenzene (6) cannot be prepared by oxidation of the corresponding aniline because hypervalent iodine is formed [22

Synthesis of novel fluorinated building blocks via halofluorination and related reactions

• Attila Márió Remete,
• Tamás T. Novák,
• Melinda Nonn,
• Matti Haukka,
• Ferenc Fülöp and
• Loránd Kiss

Beilstein J. Org. Chem. 2020, 16, 2562–2575, doi:10.3762/bjoc.16.208

• reagent addition and a prolonged reaction time, 46% of the unreacted starting material could be retrieved, together with 11% of the iodofluorinated product (rac)-20b. Another halofluorinated product was also formed, but the isolation of the compound in a pure form failed. Attempts to perform this

• )-10 and the bicyclic lactam (rac)-14, the formation of fluoroselenated products in low amounts could be detected, but the isolation in a pure form failed. The treatment of the diester 16 with PhSeBr caused lactonization regardless of the presence or absence of Deoxo-Fluor®. The yield was better when

Synthesis of 6,13-difluoropentacene

• Matthias W. Tripp and
• Ulrich Koert

Beilstein J. Org. Chem. 2020, 16, 2136–2140, doi:10.3762/bjoc.16.181

• corresponding pentacenequinone by chloride. This side reaction could be avoided using polyphosphoric acid as Friedel–Crafts reagent. The pentacenequinone showed very low solubility, which complicated a chromatographic isolation. However, the crude 1H NMR showed sufficiently clean conversion, hence the

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

• Ken-ichi Nakashima,
• Junko Tomida,
• Tomoe Tsuboi,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 2100–2107, doi:10.3762/bjoc.16.177

• fungal metabolites produced by Muyocopron spp. Thus, as part of our research into the natural products produced by plant-associated fungi [13][14][15], we isolated two new azaphilones from the cultures of an endophytic fungus, namely Muyocopron laterale ECN279. Herein, the isolation, structural

• few such compounds have been previously reported. Conclusion In summary, we successfully performed the isolation and structural determination of muyocopronones A (1) and B (2) from the cultures of an endophytic fungus Muyocopron laterale ECN279. Muyocopronones A (1) and B (2) are both azaphilones

• isolated from a healthy leaf of Canavalia lineata (Thunb.) DC collected at Tanegashima, Kagoshima, Japan. Strain isolation was performed using a previously described method [13]. Based on the DNA sequencing of the rDNA ITS and the D1/D2 domain of the 26S rDNA, the isolate was identified as Muyocopron

Convenient access to pyrrolidin-3-ylphosphonic acids and tetrahydro-2H-pyran-3-ylphosphonates with multiple contiguous stereocenters from nonracemic adducts of a Ni(II)-catalyzed Michael reaction

• Alexander N. Reznikov,
• Dmitry S. Nikerov,
• Anastasiya E. Sibiryakova,
• Victor B. Rybakov,
• Evgeniy V. Golovin and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2020, 16, 2073–2079, doi:10.3762/bjoc.16.174

• presence of Pd/C. However, phosphonate 7 was unstable: already during its isolation, it was partially transformed into compounds 8 and 9. It can be assumed that N-alkylation by the phosphoryl group occurs [47][48][49]. To avoid this undesirable process, the product 7 was formylated before its isolation

Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes

• Thomas Schneider,
• Michael Keim,
• Bianca Seitz and
• Gerhard Maas

Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173

• -disubstituted cyclobutene 15d and subsequent conrotatory electrocyclic ring-opening, from which Z(1,2),E(3,4)-configured butadiene intermediate 17d results. The intermediacy of a cyclobutene 15 in the mechanistic scenario of Scheme 5 is corroborated by the isolation of cyclobutene 18 from the reaction of 1a

Isolation and structure determination of a tetrameric sulfonyl dilithio methandiide in solution based on crystal structure analysis and ⁶Li/¹³C NMR spectroscopic data

• Jürgen Vollhardt,
• Hans Jörg Lindner and
• Hans-Joachim Gais

Beilstein J. Org. Chem. 2020, 16, 2057–2063, doi:10.3762/bjoc.16.172

• up to now. Herein, we describe the isolation and determination of the structure of tetrameric dilithio (trimethylsilyl)(phenylsulfonyl) methandiide in solution and in the crystal. The elucidation of the structure of the tetramer is based on crystal structure analysis and 13C/6Li NMR spectroscopic

• substructure of which could be disclosed [15]. We describe in this paper the isolation of a tetramer of 2a and the determination of its structure in solution based on crystal structure analysis and previously described NMR spectroscopic data. Results and Discussion Crystal structure Treatment of sulfone 4 in a

The biomimetic synthesis of balsaminone A and ellagic acid via oxidative dimerization

• Sharna-kay Daley and
• Nadale Downer-Riley

Beilstein J. Org. Chem. 2020, 16, 2026–2031, doi:10.3762/bjoc.16.169

• reduction using dithionite proved too harsh for the substrate, and like the photolysis of the binaphthyl 16, degradation occurred. However, the use of triethylamine instead of aqueous sodium hydroxide resulted in the isolation of balsaminone A (4) in 13% yield, an overall 7–8% yield over 3 steps, completing

A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates

• Olusesan K. Koleoso,
• Matthew Turner,
• Felix Plasser and
• Marc C. Kimber

Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165

• conditions, using diethyl bromomalonate (18), 4-anisidine (16) as the amine nucleophile, and allenamide 15 we were able to isolate N-acyl-N’-aryl-N,N’-allylaminal 19 as the sole identifiable product in 54% yield. All of the starting allenamide 15 was consumed in the reaction, but the isolation of 19 proved

• reports of the isolation of analogous N-acyl-N’-aryl-N,N’-allylaminal substrates in the literature, consequently, these specific conditions were not optimized [51]. The evidence for the formation of 19 was the appearance of the methylene protons in 1H NMR at δ 5.46 (d, J = 1.6 Hz, 1H) and δ 5.45 (d, J

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

• -(1H)-imidazoles when a solution in ChCl/Gly (1:2) is heated to 80 °C for 4–16 h in the presence of NaN3 (1.5 equiv). In most cases, their isolation can be performed by a very gentle procedure: decantation/centrifugation as soon as they form from the above eutectic mixture. The reaction proceeds in

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• under ultrasound irradiation. Notable advantages of this methodology include the clean reaction profile, broad substrate scope, simplicity of the process and handling, low catalyst loading, and the easy and quick isolation of the products in good to excellent yield. Besides, the products obtained were

Three new O-isocrotonyl-3-hydroxybutyric acid congeners produced by a sea anemone-derived marine bacterium of the genus Vibrio

• Dandan Li,
• Enjuro Harunari,
• Tao Zhou,
• Naoya Oku and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1869–1874, doi:10.3762/bjoc.16.154

• describe the isolation, structure elucidation, including the absolute configuration, and bioactivity of 1–4. Results and Discussion The producing strain was cultured in a sea water-based medium and then extracted with n-BuOH. The extract was successively fractionated by silica gel chromatography using a

• number LHPJ01000025). Fermentation and isolation of 1–4 Colonies of the strain SI9, recovered on a Marine Agar plate, were transferred into a 500 mL K-1 flask containing 100 mL 1/3 strength of simplified Marine Broth, which was prepared from 0.5% peptone, 0.1% yeast extract, and 3 L seawater, with the pH

On the hydrolysis of diethyl 2-(perfluorophenyl)malonate

• Ilya V. Taydakov and
• Mikhail A. Kiskin

Beilstein J. Org. Chem. 2020, 16, 1863–1868, doi:10.3762/bjoc.16.153

• starting ester remained intact, while under drastic conditions (high concentration of alkali, homogeneous solutions, elevated temperatures), decomposition and/or decarboxylation occurred. However, it is possible that decarboxylation took place during the isolation of the free acid. In all cases, no desired

Et₃N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

• Dharmender Singh,
• Vipin Kumar and
• Virender Singh

Beilstein J. Org. Chem. 2020, 16, 1740–1753, doi:10.3762/bjoc.16.146

• found to be slow reacting and produced 2aA in a lower yield (42%). From the perspective of green chemistry, one-pot reactions are preferred as less waste is generated due to the avoidance of work-up, isolation, and purification of intermediates [66]. Accordingly, the feasibility of a one-pot synthesis

• 70 °C smoothly afforded the corresponding β-carboline-linked benzothiophenone derivative 2bA in less than 30 min. More importantly, a clean reaction was observed during the one-pot strategy which surely avoided the isolation of the intermediate (2-nitrochalcone derivative 1bA), and a significant

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• moiety for photocrosslinking to MPD-recognizing proteins. The presence of an additional propargyl group provides a way to further derivatize the probe with biotin azide via click-type chemistry [16] for the isolation of protein–lipid adducts using streptavidin resins [10]. To synthesize such molecular

Synthesis of the tetrasaccharide repeating unit of the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71^T using linear and one-pot iterative glycosylations

• Arin Gucchait,
• Pradip Shit and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2020, 16, 1700–1705, doi:10.3762/bjoc.16.141

• ]. However, detailed biological studies to understand the biochemical role of cell-wall polysaccharides require significant quantities of the polysaccharides with adequate purity, which are difficult to achieve through isolation from the natural sources. Therefore, the development of chemical synthetic

• without the isolation and purification of the intermediate glycosylation products. Finally, compound 7 was subjected to a set of reactions involving (a) transformation of the azido group to an acetamido group by the treatment with thioacetic acid [33]; (b) removal of the benzylidene acetal by the

Synthesis of Streptococcus pneumoniae serotype 9V oligosaccharide antigens

• Sharavathi G. Parameswarappa,
• Claney L. Pereira and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2020, 16, 1693–1699, doi:10.3762/bjoc.16.140

• polysaccharides are O-acetylated [9][10]. Especially SP serotypes, such as 9 (A, V) and 18C differ in O-acetylation. Two O-acetylated serotypes (9V and 18C) are part of the commercial vaccine Prevnar® 13. The traditional CPS isolation approach produces varying length CPS with different degrees of acetylation. An

• acetate loss during isolation, purification, or protein conjugation leads to structurally altered CPS. Vaccines based on synthetic carbohydrate antigens [11][12][13][14][15] such as the first commercially available semisynthetic glycoconjugate vaccine Quimi Hib® against H. influenzae [16] and Shigella

Clickable azide-functionalized bromoarylaldehydes – synthesis and photophysical characterization

• Dominik Göbel,
• Marius Friedrich,
• Enno Lork and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2020, 16, 1683–1692, doi:10.3762/bjoc.16.139

• fluorene showed such a high reactivity that rapid decomposition occurred. However, bromination was conducted by various substitution methods delivering benzyl bromide 24, which upon isolation cyclized to iminium bromide 25 in high yield. To suppress this unexpected cyclization, careful fine-adjustment of

Pauson–Khand reaction of fluorinated compounds

• Jorge Escorihuela,
• Daniel M. Sedgwick,
• Alberto Llobat,
• Mercedes Medio-Simón,
• Pablo Barrio and
• Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

• isolation of 41 (Scheme 20) [59]. Under the optimized conditions, using stoichiometric Co2(CO)8 and DMSO as the promoter, the process worked well and moderate to good yields were obtained for derivatives 42 bearing aryl substituents at the propargyl moiety, regardless of their electronic nature (Scheme 21

• and co-workers [73] allowed the efficient preparation of a small library of substrates bearing aryl, alkyl, and alkenyl substitutents. These were isolated after complexation to Co2(CO)8 as the corresponding adducts 64, due to difficulties in their isolation. Subsequent heating with norbornadiene

Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)

• Cora Hertzer,
• Stefan Kehraus,
• Nils Böhringer,
• Fontje Kaligis,
• Robert Bara,
• Dirk Erpenbeck,
• Gert Wörheide,
• Till F. Schäberle,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132

• (Chromodorididae, Doridoidea) nudibranchs, their egg ribbons, and the associated dietary sponge Spongia cf. agaricina (Demospongiae, Porifera) led to the isolation of the structurally new scalarane-type sesterterpene 12-deacetoxy-4-demethyl-11,24-diacetoxy-3,4-methylenedeoxoscalarin, with an unprecedented position

• Doriprismatica (former Glossodoris or Casella) atromarginata [38][41][44][45][50], reported the isolation of scalaranes, homoscalaranes, norscalaranes, spongian diterpenoids and furanoditerpenoids. A dietary origin of these molecules was inferred and attributed to dictyoceratid sponges of the genera Hyrtios and

• isolation Six Doriprismatica stellata nudibranchs (3.7 g wet weight), their egg ribbons (0.7 g wet weight) and pieces of the associated sponge (3.5 g wet weight) were separately frozen, crushed and ultrasonicated for a total of 3 minutes (30 s intervals) on ice, while submerged in a minimum of first acetone

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

• could potentially be hydrolysed post-clipping to allow isolation of the macrocycle. The diamide/bisamide thread had flexible stoppers, which may enable dethreading by slippage in a polar solvent as previously observed [5][16]. When the reaction was performed with the double ester template 4c, it was not

Photoredox-catalyzed silyldifluoromethylation of silyl enol ethers

• Vyacheslav I. Supranovich,
• Vitalij V. Levin and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 1550–1553, doi:10.3762/bjoc.16.126

• borohydride, and the decreased reactivity of this ketone allowed its isolation. A proposed mechanism for the photoredox fluoroalkylation reaction is shown in Scheme 3. The photoexcited catalyst converts silane 1 into difluoromethylsilyl-based radical. The efficiency of [AuCl(μ-dppm)]2 compared to other

4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity

• Dandan Li,
• Naoya Oku,
• Yukiko Shinozaki,
• Yoichi Kurokawa and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124

• secondary metabolism [15]. In the course of our continuing studies on bioactive metabolites of less studied bacterial taxa [16], Burkholderia sp. 3Y-MMP, isolated from soil by an exhaustive enrichment culture under Zn2+-load, was selected for a detailed chemical study, which resulted in the isolation of 4

• -hydroxy-3-methyl-2(1H)-quinolone (1, Figure 1). This compound was recently reported from the root of woad (Isatis tinctoria, family Brassicaceae) with no details of structure characterization [17]. Herein we describe the isolation, unequivocal structure characterization, and antioxidant activity of

• ). This strain will be deposited in NBRC once it resumes services, which is currently suspended due to a nation-wide State of Emergency regarding COVID-19 declared on April 16 by the Government of Japan. Fermentation and isolation A cell mass of Burkholderia sp. 3Y-MMP, scraped off from an agar plate, was

One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol

• Aleksandar Pashev,
• Nikola Burdzhiev and
• Elena Stanoeva

Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121

• enhances the treatment by sensitizing cancer cells to anticancer drugs [5]. The presence of such structural pattern has driven the development of various approaches for its obtaining – based either on isolation from naturally occurring sources or through multistep synthetic routes [6]. The pyrrolo[2,1-a