Total synthesis of decarboxyaltenusin

• Lucas Warmuth,
• Aaron Weiß,
• Marco Reinhardt,
• Anna Meschkov,
• Ute Schepers and
• Joachim Podlech

Beilstein J. Org. Chem. 2021, 17, 224–228, doi:10.3762/bjoc.17.22

• pressure (Scheme 4). The product 1 could now be purified by a simple chromatography on silica gel and was obtained in 88% yield. NMR spectroscopic data of the natural product had been published by Wang et al. [2] and by Xiao et al. [7] (Table 1). A comparison of the 13C NMR data of the now synthesized

1,2,3-Triazoles as leaving groups in S_NAr–Arbuzov reactions: synthesis of C6-phosphonated purine derivatives

• Kārlis-Ēriks Kriķis,
• Irina Novosjolova,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 193–202, doi:10.3762/bjoc.17.19

• conversion of starting material 6d was monitored by HPLC, and after completion, product 4d was precipitated from the reaction mixture by hexane. For entries 1 and 3 in Table 2, an extra purification step by silica gel column chromatography was required. For compound 4d, the optimal reaction conditions were 2

• at −20 °C within 10 hours and were then filtered and washed with cold hexane. The product purity, if necessary, was further improved by column chromatography. Some phosphonates, for example, 4b, 4c, and 4f, were reductant to precipitate from hexane and were purified solely by silica gel column

• compounds were monitored by HPLC and TLC analysis using silica gel 60 F254 aluminum plates (Merck). Visualization was accomplished by UV light. Column chromatography was performed on silica gel (60 Å, 40−63 μm, ROCC). The yield of the products refers to chromatographically and spectroscopically homogeneous

Facile preparation and conversion of 4,4,4-trifluorobut-2-yn-1-ones to aromatic and heteroaromatic compounds

• Takashi Yamazaki,
• Yoh Nakajima,
• Minato Iida and
• Tomoko Kawasaki-Takasuka

Beilstein J. Org. Chem. 2021, 17, 132–138, doi:10.3762/bjoc.17.14

• oxidation of the other substrates 1 was performed under similar reaction condition, the results of which are summarized in Table 1. We reported the yield as determined by 19F NMR spectroscopy rather than after purification because of the inherent instability of 2 on silica gel, causing partial decomposition

Circularly polarized luminescent systems fabricated by Tröger's base derivatives through two different strategies

• Cheng Qian,
• Yuan Chen,
• Qian Zhao,
• Ming Cheng,
• Chen Lin,
• Juli Jiang and
• Leyong Wang

Beilstein J. Org. Chem. 2021, 17, 52–57, doi:10.3762/bjoc.17.6

• luminescence with glum values of +0.0021, and −0.0025, respectively. The second way to fabricate the rac-TBPP-based CPL-active material is to co-gel the fluorescent rac-TBPP with a chiral ᴅ-glutamic acid gelator DGG by co-assembly strategy. At the molar ratio of rac-TBPP/DGG = 1:80, the glum value of the co

• -gel was about three times higher than the glum values of R2N-TBPP and S2N-TBPP enantiomers. Interestingly, the CPL handedness of the rac-TBPP/DGG co-gel could be adjusted effectively by changing their stoichiometric ratios. Keywords: circularly polarized luminescence; chiral resolution; co-gelation

• -active enantiomers R2N-TBPP and S2N-TBPP, respectively. The other stratgy is to co-assemble the fluorescent rac-TBPP with the chiral ᴅ-glutamic acid gelator DGG to form the CPL-active co-gel. Interestingly, adjusting the stoichiometric ratios of rac-TBPP/DGG of the co-assembling system, the handedness of

Molecular basis for protein–protein interactions

• Brandon Charles Seychell and
• Tobias Beck

Beilstein J. Org. Chem. 2021, 17, 1–10, doi:10.3762/bjoc.17.1

• resonance (SPR) spectroscopy [27][28], gel filtration [29], isothermal titration calorimetry (ITC) [30][31], fluorescence resonance energy transfer [32], and microscale thermophoresis [33]. In SPR spectroscopy, one of the protein molecules that make up the complex is first immobilised on a metal surface

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• flow rate of 2 mL/min. Low pressure liquid chromatography (LPLC) was performed with a LiChroprep Lobar-A Si 60 column (Merck, Darmstadt, Germany) and an FMI QSY-0 pump. Open columns packed with silica gel 60 (70–230 and 230–400 mesh; Merck), RP-18 silica gel (230–400 mesh; Merck, Darmstadt, Germany

• ), or Diaion® HP-20 resin (Sigma, St. Louis, MO) were implemented for crude fractionation and separation. Precoated silica gel F254 plates and RP-18 F254s plates (Merck, Darmstadt, Germany) were utilized for thin-layer chromatography (TLC) and the spots were detected under UV light or by heating after

• , Sungkyunkwan University, Suwon, Republic of Korea. Extraction and isolation. Extraction and solvent partitions were performed in the same manner as described in [13]. The hexanes-soluble fraction (3 g) was separated over a silica gel column (hexanes/EtOAc 3:1) to yield seven fractions (H1–H7). Fraction H3 (0.4

Deoxyfluorination of acyl fluorides to trifluoromethyl compounds by FLUOLEAD^®/Olah’s reagent under solvent-free conditions

• Yumeng Liang,
• Akihito Taya,
• Zhengyu Zhao,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2020, 16, 3052–3058, doi:10.3762/bjoc.16.254

• mL), and the combined organic layer was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The yield was determined by 19F NMR analysis of the crude mixture by using C6H5OCF3 (40.0 μL, 0.3 mmol, 1.0 equiv) as an internal standard. The residue was purified by silica gel

Secondary metabolites of Bacillus subtilis impact the assembly of soil-derived semisynthetic bacterial communities

• Heiko T. Kiesewalter,
• Carlos N. Lozano-Andrade,
• Mikael L. Strube and
• Ákos T. Kovács

Beilstein J. Org. Chem. 2020, 16, 2983–2998, doi:10.3762/bjoc.16.248

• for 30 s, 62 °C for 30 s, 72 °C for 30 s, and finally, 72 °C for 5 min. All V3-V4 amplicons were purified using the NucleoSpin gel and PCR cleanup kit (Macherey-Nagel) and pooled in equimolar ratios. The amplicon pool was submitted to Novogene Europe Company Limited (United Kingdom) for high

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• -(amino)cyanocyclopropane derivatives not contaminated by intermediates or ring-opening byproducts [21], whereas the asymmetric Strecker synthesis induced by chiral amines was successfully conducted by sonication in the presence of silica gel [22]. Pursuing our interest in developing environmentally

Synthesis of imidazo[1,5-a]pyridines via cyclocondensation of 2-(aminomethyl)pyridines with electrophilically activated nitroalkanes

• Dmitrii A. Aksenov,
• Nikolai A. Arutiunov,
• Vladimir V. Maliuga,
• Alexander V. Aksenov and
• Michael Rubin

Beilstein J. Org. Chem. 2020, 16, 2903–2910, doi:10.3762/bjoc.16.239

• hydrazide was filtered off and rinsed several times with cold ethanol. The combined filtrates were concentrated under reduced pressure to provide the crude amine, which was purified by flash column chromatography on silica gel, eluting with a mixture of dichloromethane/ethanol/triethylamine, gradient 80:10

• mL). The combined organic extracts were concentrated, the residue dried in vacuum, and then purified by preparative column chromatography on silica gel, eluting with a mixture of petroleum ether and ethyl acetate. The titled compound was obtained as yellow solid (lit. [53] yellow crystals), yield 77

Fluorine effect in nucleophilic fluorination at C4 of 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-D-hexopyranose

• Danny Lainé,
• Vincent Denavit,
• Olivier Lessard,
• Laurie Carrier,
• Charles-Émile Fecteau,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2020, 16, 2880–2887, doi:10.3762/bjoc.16.237

• hardly reproducible because a thick gel was formed after neutralisation with an acidic resin, thus resulting in yield loss after a difficult filtration. Next, we evaluated sodium borohydride (NaBH4) as reducing reagent. Difluoroglucose 21 was subjected to 5 equivalents of NaBH4 in EtOH at rt and compound

Incorporation of a metal-mediated base pair into an ATP aptamer – using silver(I) ions to modulate aptamer function

• Marius H. Heddinga and
• Jens Müller

Beilstein J. Org. Chem. 2020, 16, 2870–2879, doi:10.3762/bjoc.16.236

• finally evaluate whether the incorporation of Im:Im pairs into the aptamer allows for its target affinity to be manipulated, a binding assay using ATP-agarose gel was performed [44]. Towards this end, the aptamer derivatives 1af–1df were loaded onto an agarose gel containing immobilized ATP, followed by

• , and Merck. Dry pyridine was purchased from Acros Organics. Dichloromethane was distilled and dried over molecular sieves. Milli-Q water was used to prepare solutions and buffers. The silica gel used for product purification (Geduran® Si60, 40–63 µm) was purchased from Merck. The DMT- and

• ) at 65 °C for 15 min. They were purified using denaturing polyacrylamide gel electrophoresis (gel solution: 7 M urea, 1 TBE buffer, 14 or 18% (depending on the length of the oligonucleotide) polyacrylamide/bisacrylamide (29:1); loading buffer: 11.8 M urea, 42 mM Tris·HCl (pH 7.5), 0.83 mM EDTA (pH 8.0

Changed reactivity of secondary hydroxy groups in C8-modified adenosine – lessons learned from silylation

• Jennifer Frommer and
• Sabine Müller

Beilstein J. Org. Chem. 2020, 16, 2854–2861, doi:10.3762/bjoc.16.234

• , Universität Greifswald, Germany, 2019. We kindly thank Robert Hieronymus for carrying out MALDI–TOF measurements and PAA Gel Electrophoreses.

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• We report new dirhamnolipid ester forming reverse wormlike micelles in nonpolar solvents without the addition of any primer. Therefore, these compounds represent a rare case of a binary system showing this gel-like behavior. In this study, the influence of the concentration of the rhamnolipid ester

• polarity. An unusual behavior was observed when the dirhamnolipid esters were added to toluene. The more polar short chain length dirhamnolipid esters and 7 form a gel-like texture in toluene, indicating the formation of a network structure of the surfactant molecules. With increasing chain length of the

• dirhamnolipid esters, the ability to gel toluene vanishes. Rheological data Temperature sweep With this interesting observation we went on and performed rheological measurements to determine the viscoelastic properties of the dirhamnolipid ester/toluene gels. First, we performed temperature sweep measurements

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

• silica gel column using a mixture solvent of CHCl3/MeOH (1:0, 20:1, 10:1, 4:1, 2:1, 1:1, and 0:1, v/v). Fraction 3 (10:1) was concentrated to yield 0.38 g of a brown oil, which was further fractionated by ODS column chromatography with a stepwise gradient of a MeCN/0.1% HCO2H aqueous solution (2:8, 3:7

Enzyme-instructed morphological transition of the supramolecular assemblies of branched peptides

• Dongsik Yang,
• Hongjian He and
• Bing Xu

Beilstein J. Org. Chem. 2020, 16, 2709–2718, doi:10.3762/bjoc.16.221

• (5 mM) results in a weak gel, while the addition of proteinase K (5 U/mL) to a solution of 2 (5 mM) only produces a viscous solution. The addition of an increased amount of proteinase K (10 U/mL) to a solution of 1 (10 mM) or 2 (10 mM) results in a stable hydrogel. These results indicate that

Activation of pentafluoropropane isomers at a nanoscopic aluminum chlorofluoride: hydrodefluorination versus dehydrofluorination

• Maëva-Charlotte Kervarec,
• Thomas Braun,
• Mike Ahrens and
• Erhard Kemnitz

Beilstein J. Org. Chem. 2020, 16, 2623–2635, doi:10.3762/bjoc.16.213

• -tetrafluoropropene (HFO-1234ze) using mesoporous nanoscopic aluminum fluoride-based catalysts [19]. The catalysts were prepared via a sol–gel process in the presence of polyols, allowing for the evolution of a large surface area and improved acidic properties when compared to fluorinated Cr2O3 or traditional β-AlF3

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

• silica gel column chromatography the desired nucleoside was obtained in 52% yield. The rather long reaction time of the phosphorolysis and the Ara-1P-base coupling is mainly connected with the low quantity of the employed UP and PNP in both transformations. Indeed, it is noteworthy that in the work of

• evaporated, and the residue treated with EtOH (20 mL). The non-dissolved fine powder was filtered off and the filtrate evaporated and co-evaporated with EtOH (2 × 20 mL). The obtained residue was dissolved in MeOH (10 mL), mixed with silica gel (2 mL), evaporated and the residue was put on the top of a

• silica gel column (1.5 × 23 cm) prepared in EtOAc. The fractions containing the nucleoside were combined, evaporated and dried to afford the powdered product (25 mg; 66%) of 95.5% purity (HPLC), that was crystallized from MeCN to give nelarabine (19 mg; 53%; 99.0% purity by HPLC). For NMR data, see

Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• every 3 cycles to limit agglomeration of the powder. The resulting powder was purified by flash chromatography on silica gel using acetonitrile/water 9:1 to 8:2 (v/v) as mobile phase. Isolated yield 21% (364 mg). All runs were performed at least twice in order to ensure reproducibility. X-ray powder

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

• pressure and water (25 mL) was added to the mixture, which was extracted with ethyl acetate (3 × 15 mL). The combined organic layers were dried over anhydrous magnesium sulfate and concentrated to dryness. The crude residue obtained was purified by silica gel column chromatography (petroleum ether/ethyl

A new method for the synthesis of diamantane by hydroisomerization of binor-S on treatment with sulfuric acid

• Rishat I. Aminov and
• Ravil I. Khusnutdinov

Beilstein J. Org. Chem. 2020, 16, 2534–2539, doi:10.3762/bjoc.16.205

• the whole amount of H2SO4 has been added, the reaction mixture was stirred at 20 °С for 15 h. After completion of the reaction, 10% NaOH was added to the reaction mixture, the organic phase was separated, and filtered through a silica gel layer (with petroleum ether as the eluent). The solvent was

• reaction mixture was stirred at 20 °С for 7 h. After completion of the reaction, 10% NaOH was added to the reaction mixture, the organic part was separated, and filtered through a silica gel layer (with petroleum ether as the eluent). The solvent was distilled off and the residue was recrystallized from a

• stirred at 40 °С for 8 h. Then the reactor was cooled to room temperature, the reaction mixture extracted with petroleum ether, and filtered through a silica gel layer (with petroleum ether as the eluent). Hexacyclo[8.4.0.02,7.03,14.04,8.09,13]tetradec-5-ene (4а) and hexacyclo

Access to highly substituted oxazoles by the reaction of α-azidochalcone with potassium thiocyanate

• Mysore Bhyrappa Harisha,
• Pandi Dhanalakshmi,
• Rajendran Suresh,
• Raju Ranjith Kumar and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2020, 16, 2108–2118, doi:10.3762/bjoc.16.178

• 2 (3 mmol) and ferric nitrate (0.5 mmol). The reaction mixture was stirred magnetically at reflux for 6 h. After completion of the reaction (monitored by TLC), the product was diluted with water, extracted with ethyl acetate (15 mL) and purified by column chromatography (100–200 mesh silica gel

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

• Technologies). DNA sequencing was performed using an Applied Biosystems 3130 genetic analyzer. Silica gel AP-300 (Toyota Kako) was employed for column chromatography (CC). Silica gel 60 F254 and RP-18 F254S (both Merck) were used for TLC. Fungal material and identification Muyocopron laterale ECN279 was

• fraction was then separated by silica gel CC using CHCl3/acetone (stepwise gradient, 1:0, 25:1, 10:1, and 0:1 v/v) as the eluent. The fractions were combined according to TLC analysis to yield five fractions. Fraction 2 was recrystallized in MeOH to yield 3 (96.9 mg), while fraction 3 was subjected to

• silica gel CC with n-hexane/ethyl acetate (stepwise gradient, 3:1, 2:1, and 1:1 v/v) to obtain compound 4 (37.3 mg). Fraction 5 was also subjected to silica gel CC with n-hexane/ethyl acetate (stepwise gradient, 4:1, 3:1, 2:1, and 1:1 v/v) to obtain compounds 2 (263.2 mg) and 1 (241.6 mg) eluted at

Clustering and curation of electropherograms: an efficient method for analyzing large cohorts of capillary electrophoresis glycomic profiles for bioprocessing operations

• Ian Walsh,
• Matthew S. F. Choo,
• Sim Lyn Chiin,
• Amelia Mak,
• Shi Jie Tay,
• Pauline M. Rudd,
• Yang Yuansheng,
• Andre Choo,
• Ho Ying Swan and
• Terry Nguyen-Khuong

Beilstein J. Org. Chem. 2020, 16, 2087–2099, doi:10.3762/bjoc.16.176

• µm i.d. uncoated bare fused capillary, HR-NCHO separation gel buffer (Sciex). The applied electric field strength was 1500 V/cm with the cathode at the injection side and the anode at the detection side (reversed polarity). Samples were electrokinetically injected using 1kV for 5 s. For migration

Efficient [(NHC)Au(NTf₂)]-catalyzed hydrohydrazidation of terminal and internal alkynes

• Maximillian Heidrich and
• Herbert Plenio

Beilstein J. Org. Chem. 2020, 16, 2080–2086, doi:10.3762/bjoc.16.175

• using silica gel 60 F254 (0.2 mm) on alumina plates. For preparative chromatography silica gel 60 (70–200 µm) was used. Measurements of the high resolution mass spectra (HRMS) were performed on a Bruker Daltonics Autoflex Speed TOF. Gas chromatographic data was obtained on a Clarus 500 gas