Breaking paracyclophane: the unexpected formation of non-symmetric disubstituted nitro[2.2]metaparacyclophanes

• Suraj Patel,
• Tyson N. Dais,
• Paul G. Plieger and
• Gareth J. Rowlands

Beilstein J. Org. Chem. 2021, 17, 1518–1526, doi:10.3762/bjoc.17.109

• % probability level [63]. Crystal structure of 15. Ellipsoids are drawn at a 50% probability level [63]. Possible origin of stereoselectivity. Nitration of [2.2]paracyclophane (1) and the synthesis of 4-hydroxy-5-nitro[2.2]metaparacyclophane (5) and the cyclohexadienone cyclophane 6 (average yield from more

Antiviral therapy in shrimp through plant virus VLP containing VP28 dsRNA against WSSV

• Santiago Ramos-Carreño,
• Ivone Giffard-Mena,
• Jose N. Zamudio-Ocadiz,
• Alfredo Nuñez-Rivera,
• Ricardo Valencia-Yañez,
• Jaime Ruiz-Garcia,
• Maria Teresa Viana and
• Ruben D. Cadena-Nava

Beilstein J. Org. Chem. 2021, 17, 1360–1373, doi:10.3762/bjoc.17.95

• -dsRNAvp28 was administered per os. However, we experiment with the same dose of VLP-dsRNAvp28 (6.0 µg/shrimp), equivalent to the same dilution of WSSV to infect them. But the bioassay was finished at 17 dpi. However, one should not rule out possible differences in the shrimp origin line (genetics

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

• , his Introduzione allo Studio degli Alcaloidi con special riguardo agli alcaloidi vegetali ed alle ptomaine (An Introduction to Alkaloid Chemistry, and especially on those of plant origin and on ptomaines), first published in 1892, was translated four years later into German, and the popularity of this

• origin of this is considered the central puzzle of biology [58]. Hydrogen cyanide is a fundamental prebiotic constituent, and glutarimides are easily formed under prebiotic conditions [58]. Could a Guareschi amide precursor have served as a primordial source of reducing power in prebiotic media en route

• could be used to produce oil, a finite resource, or even be involved in the generation of oil. Guareschi maintained an active interest in the origin of oil, with his first publication being the study of a fossil resin, and wrote two monumental monographs on this topic [42]. Despite intense geological

A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry

• Marine Vallet,
• Filip Kaftan,
• Veit Grabe,
• Fatemeh Ghaderiardakani,
• Simona Fenizia,
• Aleš Svatoš,
• Georg Pohnert and
• Thomas Wichard

Beilstein J. Org. Chem. 2021, 17, 1313–1322, doi:10.3762/bjoc.17.91

• high concentrations during saline stress conditions [32]. It has not yet been described in the Ulva–bacteria symbiosis. Not all essential genes for ectoine biosynthesis reported by [33] were found in the U. mutabilis genome [34], providing further support for the bacterial origin of ectoine. Homologs

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

• striving to deliver cheaper and more environmentally friendly processes. All commercially available products comprised of fragrance ingredients on the market can be traced back to the innovation of fragrance companies as their manufactured products (both of natural and synthetic origin) are sold on to

• remains a relatively under-explored area of research. While the majority of reported examples have been of academic origin, there is a high level of interest in the pursuit of aldol reactions in flow by industry. The production of α,β-unsaturated C10-aldehydes [116] as multiphase aldol condensations in

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• atom during the study being DCM [56]. Another study suggests that the chlorinated product may be formed from a Cl radical generated during the reaction, although it was not stated if the origin of the radical was DCM or DDQ [57]. Here, it was shown that the source of Cl to yield the meso-chlorinated

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• models were proposed to rationalize organometallic additions to N-sulfinyl imines. The mechanism for obtaining these two stereoisomers was elucidated in the work published by Andersen and co- workers [36]. The origin of the reversal of the diastereofacial selectivity on the change of reducing agents is

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

• Christopher Liczner,
• Kieran Duke,
• Gabrielle Juneau,
• Martin Egli and
• Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

• group between the sugars in DNA and RNA is at the origin of the vastly expanded fold [29][30][31][32] and functional spaces of RNA [33][34][35][36][37][38][39]. Perhaps less known is the fact that the sugar moiety in the backbone of a nucleic acid determines the base pairing priorities. For example, in

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• ]PCBM; diazo compounds; mechanisms and optimal conditions of cyclopropanation; methanofullerenes C60; Introduction Taking into consideration that all life on Earth is of organic origin. with carbon as its basic element (20% by weight of every living organism, and the fourth most abundant element in the

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• solutions are required to overcome the chemical inertness for, and the thermodynamic limitations of the reversal of each polymer. Indeed, the ease (and outcome) of chain scission does not depend on the origin of the polymer but on its chemical structure [74][75]. For instance, plastics derived from biomass

Metal-free visible-light-enabled vicinal trifluoromethyl dithiolation of unactivated alkenes

• Xiaojuan Li,
• Qiang Zhang,
• Weigang Zhang,
• Jinzhu Ma,
• Yi Wang and
• Yi Pan

Beilstein J. Org. Chem. 2021, 17, 551–557, doi:10.3762/bjoc.17.49

• terminal olefins. Origin of the reaction design. Substrate scope of disulfides. Substrate scope of unactivated alkenes. Control experiments. Proposed mechanism. Optimization of the reaction conditions.a Supporting Information Supporting Information File 84: Full experimental details, compound

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

• reaction medium by centrifugation and washed several times with acetonitrile. Thus, the catalyst could be recovered and reused in three consecutive cycles, showing no loss of activity, but a drop in selectivity after the first cycle (selectivity/conversion for each cycle: 94/99.5; 78/99; 77/99). The origin

The synthesis of chiral β-naphthyl-β-sulfanyl ketones via enantioselective sulfa-Michael reaction in the presence of a bifunctional cinchona/sulfonamide organocatalyst

• Deniz Tözendemir and
• Cihangir Tanyeli

Beilstein J. Org. Chem. 2021, 17, 494–503, doi:10.3762/bjoc.17.43

• transition state model to explain the origin of the stereoinduction was proposed (Scheme 2), according to the Houk’s Brønsted acid hydrogen bonding model. Guo’s computational work in 2017 on the sulfa-Michael addition of thiols to enones in the presence of cinchona alkaloid-type organocatalysts showed that

Biochemistry of fluoroprolines: the prospect of making fluorine a bioelement

• Vladimir Kubyshkin,
• Rebecca Davis and
• Nediljko Budisa

Beilstein J. Org. Chem. 2021, 17, 439–460, doi:10.3762/bjoc.17.40

• reactivity of proline at the P-site to a level comparable to that of other coded amino acids (Figure 11) [57]. The enhancement of the translation velocity was also observed for Dfp. For S-Flp, however, the reaction was substantially slowed down even compared to the native substrate proline. The origin of

• test sequence (formyl-Met-Lys-Lys-Lys-Xaa-Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Lys-OH, Xaa = proline analogue) was expressed in an in vitro system. It was found that the yield of the target peptide increases in the order Pro ≈ R-Flp < S-Flp ≈ Dfp [86]. The origin of the effect is unclear. Nonetheless, these

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

• into dimethyl trisulfide and S-methyl methanethiosulfonate, and revealed the origin of the methylsulfanyl group of 2-(methyldisulfanyl)benzothiazole from methionine or DMSP, while the biosynthetic origin of the benzothiazol-2-ylsulfanyl portion could not be traced. The heterocyclic moiety of this

• compound is likely of anthropogenic origin, because 2-mercaptobenzothiazole is used in the sulfur vulcanization of rubber. Also in none of the feeding experiments incorporation into ethyl (E)-3-(methylsulfanyl)acrylate could be observed, questioning its bacterial origin. Our results demonstrate that the

• that some of the detected sulfur compounds are not or only partly of bacterial origin. Results and Discussion Headspace analysis The volatiles released by six marine Celeribacter type strains, including C. marinus DSM 100036T, C. neptunius DSM 26471T, C. manganoxidans DSM 27541T, C. baekdonensis DSM

Synthesis of legonmycins A and B, C(7a)-hydroxylated bacterial pyrrolizidines

• Wilfred J. M. Lewis,
• David M. Shaw and
• Jeremy Robertson

Beilstein J. Org. Chem. 2021, 17, 334–342, doi:10.3762/bjoc.17.31

• . These species include both Gram-positive and Gram-negative bacteria, indicating that pyrrolizidines are potential secondary metabolites of a variety of bacterial genera. The most recent addition to the bacterial pyrrolizidine literature also concerns their biosynthesis and addresses the origin of the

Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

• Alexander Zika and
• Franziska Gröhn

Beilstein J. Org. Chem. 2021, 17, 166–185, doi:10.3762/bjoc.17.17

• depicted in Figure 11. The highest percentage of reformed Flavy is found for l = 0.9, while the reversibility is less expressed with decreasing loading ratios for both cycles. Since it is independent on the cycle and dependent on the loading ratio the origin likely lies in the fact that with a decreasing

• MicroCal ITC data analysis software for Origin 7.0. Top: pelargonidin cation (Flavy) and network of chemical reactions; bottom: corresponding UV–vis spectra of the different states of Flavy. Characterization of Flavy: a) 1H NMR spectrum at pH 7.0 (form A) before and after irradiation; b) 13C NMR spectrum

Control over size, shape, and photonics of self-assembled organic nanocrystals

• Chen Shahar,
• Yaron Tidhar,
• Yunmin Jung,
• Haim Weissman,
• Sidney R. Cohen,
• Ronit Bitton,
• Iddo Pinkas,
• Gilad Haran and
• Boris Rybtchinski

Beilstein J. Org. Chem. 2021, 17, 42–51, doi:10.3762/bjoc.17.5

• ) and Origin 7.5 (OriginLab) softwares. Chemical structure of compound 1 and UV–vis spectra in an aggregating aqueous medium and in the disaggregating solvent THF. Transmission electron microscopy (TEM) images (left, zoomed-out and zoomed-in; 1 × 10−4 M solutions of 1 deposited on TEM grids) and crystal

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• majority of these alkaloids have an endogenous origin. In a dangerous situation or predator attack, the beetles can emit droplets of hemolymph. This substance comes from the tibiofemoral joints situated in their legs, a mechanism known as reflex bleeding. This situation brings the alkaloids to the surface

• this precursor in (−)-adaline, supporting fatty acid origin for this alkaloid. Reflex bleeding is costly due to energy expended in chemical synthesis and fluid loss. Therefore, it is only deployed when other strategies have failed, and the ladybird is in severe danger [35][36]. A massive discrepancy in

Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of ¹J_C,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites

• Md. Rokon Ul Karim,
• Enjuro Harunari,
• Amit Raj Sharma,
• Naoya Oku,
• Kazuaki Akasaka,
• Daisuke Urabe,
• Mada Triandala Sibero and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 2719–2727, doi:10.3762/bjoc.16.222

• actinomycete origin. For example, salinosporamide A, an antitumor drug candidate in clinical trials, is a proteasome inhibitor with an unusual γ-lactam-β-lactone bicyclic core produced by marine Salinospora tropica [10]. Abyssomicin, another example of uncommon polycyclic frameworks, is an antibacterial

• members, nocarimidazoles C (1) and D (2), were obtained from a marine-derived actinomycete of the genus Kocuria. The exclusive origin of these metabolites from marine bacteria, as well as the distribution among phylogenetically distinct taxa imply their potential function in the adaptation of the

Asymmetric Mannich reactions of (S)-N-tert-butylsulfinyl-3,3,3-trifluoroacetaldimines with yne nucleophiles

• Ziyi Li,
• Li Wang,
• Yunqi Huang,
• Haibo Mei,
• Hiroyuki Konno,
• Hiroki Moriwaki,
• Vadim A. Soloshonok and
• Jianlin Han

Beilstein J. Org. Chem. 2020, 16, 2671–2678, doi:10.3762/bjoc.16.217

• sulfinyl oxygen and the oxygen electron lone pair. The latter presents a lesser steric obstacle rendering the corresponding nucleophilic attack the more probable event. These ever-unexpected results strongly suggest that the origin of the stereocontrol in the reactions of imine 1 is not just the bulk of

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• 1505.9611 (Δ = + 5.2 ppm). The surprising presence of six equivalents of water points to the formation of strong hydrogen bonds between the sugar ester bonds of TBTQ-(OAcG)6 and the water molecules as guests. However, the origin of this intriguing observation associated with the attachment of just two

Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties

• Anka Utama Putra,
• Deniz Çakmaz,
• Nurgül Seferoğlu,
• Alberto Barsella and
• Zeynel Seferoğlu

Beilstein J. Org. Chem. 2020, 16, 2282–2296, doi:10.3762/bjoc.16.189

• Shimadzu 1800 UV–vis spectrophotometer in Britton–Robinson buffer solutions [63] with pH values ranging from 5.5 to 11 at room temperature (25 °C). The pKa values were obtained using the Origin software by recording the curve data. Computational methods The geometries of the dyes in their ground states

Tools for generating and analyzing glycan microarray data

• Akul Y. Mehta,
• Jamie Heimburg-Molinaro and
• Richard D. Cummings

Beilstein J. Org. Chem. 2020, 16, 2260–2271, doi:10.3762/bjoc.16.187

• aglycone (for example, a glycolipid obtained directly by extraction from a natural origin), an appropriate surface needs to be selected which is compatible with the glycoconjugate. Printing methods Once the decision about the surface to which they are to be attached is made, the glycans are dissolved in

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• ). Origin 7.0 software, supplied by the manufacturer, was used for data analysis. During the titration of ct-DNA, d: poly(rA)–poly(rU), poly(dAdT)–poly(dAdT), and poly(dGdC)–poly(dGdC) with the compound 4, one aliquot of 2 μL and 27 aliquots of 10 μL of 4 (c = 1.0 × 10−4 M) were injected from rotating