Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp²)–H bond arylations

• Fatiha Abdelmalek,
• Fazia Derridj,
• Safia Djebbar,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2015, 11, 2012–2020, doi:10.3762/bjoc.11.218

• fluorine atom might be arylated under this reaction conditions. Using 4-bromobenzaldehyde as coupling partner, a mixture of two regioisomers in 82:18 ratio was obtained, and the C5 arylation product 25 (major regioisomer) was isolated after flash chromatography in 53% yield as pure product. It is important

Synthesis of constrained analogues of tryptophan

• Elisabetta Rossi,
• Valentina Pirovano,
• Marco Negrato,
• Giorgio Abbiati and
• Monica Dell’Acqua

Beilstein J. Org. Chem. 2015, 11, 1997–2006, doi:10.3762/bjoc.11.216

• the crude reaction mixture, via 1H NMR, along with a mixture of unidentified compounds. The diastereoisomeric mixtures (3/3') could be easily separated by flash chromatography and pure isomers were characterized by combined one- (1H NMR, 13C NMR-APT) and two-dimensional (COSY, HMBC, NOESY) experiments

• hydrochloric acid (12 N) in a multimode microwave oven at 120 °C for 2 h, then with an excess of propylene oxide in ethanol at reflux for 1 h, and finally purified by flash chromatography. The whole reaction sequence was realized in a one-flask procedure. The obtained compounds 6a–e and the relative reaction

Profluorescent substrates for the screening of olefin metathesis catalysts

• Raphael Reuter and
• Thomas R. Ward

Beilstein J. Org. Chem. 2015, 11, 1886–1892, doi:10.3762/bjoc.11.203

• equiv) and then allylamine (378 µL, 5.05 mmol, 1.10 equiv) was added and the mixture was stirred for 2 h at rt until the TLC showed complete consumption. The solvent was removed under reduced pressure and the residue was purified by flash chromatography (silica gel, cyclohexane/EtOAc 3:1) to obtain 960

Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

• Hanmo Zhang,
• E. Ben Hay,
• Stephen J. Geib and
• Dennis P. Curran

Beilstein J. Org. Chem. 2015, 11, 1649–1655, doi:10.3762/bjoc.11.181

• was isolated in 51% yield by flash chromatography. The probable precursor of monochloride 5b is dichloride 5a, which was also apparent as a minor product in the crude reaction mixture from this experiment but was not isolated in pure form. To simplify the situation with respect to reductive

• dechlorination, we treated 3 with excess tributyltin hydride (6 equiv). This gave a relatively clean crude product mixture from which the fully reduced spiroindoline 5c was isolated in 78% yield by flash chromatography. These results suggest that the α-sulfonamidoyl radical resulting from the 5-exo-trig

• ] = 0.01 M) led to complete conversion after 1 h of heating. Solvent evaporation and flash chromatography provided spiro-3,3'-biindoline 8 in 47% isolated yield. As with the formation of 5a–c in Scheme 1, an imine is presumably formed by aryl radical cyclization and then sulfonyl radical elimination, but

Ruthenium indenylidene “1^st generation” olefin metathesis catalysts containing triisopropyl phosphite

• Stefano Guidone,
• Fady Nahra,
• Alexandra M. Z. Slawin and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2015, 11, 1520–1527, doi:10.3762/bjoc.11.166

• desired temperature and stirred for 14 or 19 hours. The reaction mixture was then analyzed by GC and/or purified by flash chromatography. General procedure for kinetic experiments. A Schlenk flask was charged with the olefin (0.5 mmol), then closed, placed under vacuum and introduced in a glovebox. The

Tandem cross enyne metathesis (CEYM)–intramolecular Diels–Alder reaction (IMDAR). An easy entry to linear bicyclic scaffolds

• Javier Miró,
• María Sánchez-Roselló,
• Álvaro Sanz,
• Fernando Rabasa,
• Carlos del Pozo and
• Santos Fustero

Beilstein J. Org. Chem. 2015, 11, 1486–1493, doi:10.3762/bjoc.11.161

• 90 °C in a sealed tube. The reaction mixture was stirred at this temperature for 48 h. The solvents were then removed under reduced pressure and the crude mixture was purified by flash chromatography in n-hexanes/ethyl acetate. (4aR*,8aS*)-6-Phenyl-3,4,4a,7,8,8a-hexahydro-1H-isochromen-1-one (3a

Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

• Karolina Żukowska,
• Eva Pump,
• Aleksandra E. Pazio,
• Krzysztof Woźniak,
• Luigi Cavallo and
• Christian Slugovc

Beilstein J. Org. Chem. 2015, 11, 1458–1468, doi:10.3762/bjoc.11.158

• toluene (25 mL) and the reaction was heated at 80 °C for about an hour. Then the solvent was evaporated and the mixture was purified by flash chromatography using eluents c-hexane/ethyl acetate 10:1 to 1:1 v/v. The solvent was evaporated. The product was then re-dissolved in dichloromethane and cold n

Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

• Adriana K. Slavova-Kazakova,
• Silvia E. Angelova,
• Timur L. Veprintsev,
• Petko Denev,
• Davide Fabbri,
• Maria Antonietta Dettori,
• Maria Kratchanova,
• Vladimir V. Naumov,
• Aleksei V. Trofimov,
• Rostislav F. Vasil’ev,
• Giovanna Delogu and
• Vessela D. Kancheva

Beilstein J. Org. Chem. 2015, 11, 1398–1411, doi:10.3762/bjoc.11.151

• ) was added dropwise. The reaction mixture was stirred at room temperature for 2 h and then acidified with 10% HCl. The organic phase was extracted with CH2Cl2. The crude, dried over Na2SO4, gave a brown solid that was purified by flash chromatography using CH2Cl2 as eluent, to give 4 as an orange solid

• (0.96 mL, 6.5 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 24 h and then acidified with 10% HCl. The organic phase was extracted with CH2Cl2. The crude, dried over Na2SO4, gave a brown solid that was purified by flash chromatography using a 9:1 mixture of petroleum

Pd(OAc)₂-catalyzed dehydrogenative C–H activation: An expedient synthesis of uracil-annulated β-carbolinones

• Biplab Mondal,
• Somjit Hazra,
• Tarun K. Panda and
• Brindaban Roy

Beilstein J. Org. Chem. 2015, 11, 1360–1366, doi:10.3762/bjoc.11.146

• temperature, diluted with water and 50 mL of EtOAc and passed through a pad of celite. The organic layer was washed with H2O (2 × 10 mL) and saturated NaCl (aq) (1 × 10 mL). The organic part was dried over Na2SO4, evaporated and purified by flash chromatography, using ethyl acetate/petroleum ether (2:8) as

Synthesis of γ-hydroxypropyl P-chirogenic (±)-phosphorus oxide derivatives by regioselective ring-opening of oxaphospholane 2-oxide precursors

• Iris Binyamin,
• Shoval Meidan-Shani and
• Nissan Ashkenazi

Beilstein J. Org. Chem. 2015, 11, 1332–1339, doi:10.3762/bjoc.11.143

• not increase the conversion percentage to the desired products significantly. Under these reaction conditions 58–85% yield of 4a–e were observed and the pure products were isolated in 30–80% yield following flash chromatography. The relative amount of the Grignard reagents used was found to be crucial

• high yields (83–97%), leading after work-up and flash chromatography purification to high to moderate (38–95%) isolated yields (Table 2). In general, the relatively higher yields of the phosphine oxides 5a–5e compared to the phosphinate analogs 4a–e can be attributed to the lack of the exocyclic ester

Intermolecular addition reactions of N-alkyl-N-chlorosulfonamides to unsaturated compounds

• Gerold Heuger and
• Richard Göttlich

Beilstein J. Org. Chem. 2015, 11, 1226–1234, doi:10.3762/bjoc.11.136

• radicals. Addition to non-aromatic alkenes proceeds less readily in lower yield and electron-rich alkenes react via a competing polar reaction pathway. Experimental All solvents were purified by distillation and dried, if necessary, prior to use. Products were purified by flash chromatography on silica gel

• and stirred for 48 h at this temperature. The solvent was removed by bulb-to-bulb distillation and the residue was taken up in dichloromethane. Approx. 10 g of silica gel were added and the solvent was removed in vacuo. Purifying by flash chromatography (pentane/ether 10:1 to 1:1) gave the addition

Cathodic hydrodimerization of nitroolefins

• Michael Weßling and
• Hans J. Schäfer

Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131

• washing the solid with petroleum ether/diethyl ether. The products are obtained after purification by flash chromatography as colourless oils, which are mixtures of diastereomers. They crystallize partially or completely after some time and are in general not sensitive against air and light. An exception

• chromatography. The aliphatic nitroalkene 17 could be hydrodimerized in 68% yield to the hydrodimer 31, which is a mixture of diastereomers. Partial separation by flash chromatography and 1H NMR spectroscopy of the fractions indicates four diastereomers in a ratio of about 38:9:14:1. It is possible to substitute

• differ significantly in their MS and IR spectra the compounds had to be characterized by their 1H NMR data. For that purpose the diastereomers were purified as good as possible by flash chromatography and/or HPLC. Single diastereomers are denoted alphanumerically (e.g., 2a, 2b). The same letter means for

Are D-manno-configured Amadori products ligands of the bacterial lectin FimH?

• Tobias-Elias Gloe,
• Insa Stamer,
• Cornelia Hojnik,
• Tanja M. Wrodnigg and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 1096–1104, doi:10.3762/bjoc.11.123

• performed on precoated silica gel plates on aluminum 60 F254 (E. Merck 5554). Detection was effected by UV and/or charring with 10% sulfuric acid in EtOH and/or with ceric ammonium molybdate (100 g ammonium molybdate/8 g ceric sulfate in 1 L 10% H2SO4) followed by heat treatment at ≈180 °C. Flash

• chromatography was performed on silica gel 60 (0.035–0.070 mm, 60 A, Acros Organics 24036) using distilled solvents. For biological testing, black MaxiSorp™ plates were used from Nunc™ (Thermo Scientific™). Bacterial adhesion studies were performed according to the literature [30], using a Tecan infinite® 200

Tuning of tetrathiafulvalene properties: versatile synthesis of N-arylated monopyrrolotetrathiafulvalenes via Ullmann-type coupling reactions

• Vladimir A. Azov,
• Diana Janott,
• Dirk Schlüter and
• Matthias Zeller

Beilstein J. Org. Chem. 2015, 11, 860–868, doi:10.3762/bjoc.11.96

• aromatic starting material and then purified by flash chromatography on silica gel to afford pure N-arylated MPTTFs. Preparation and characterization of 2-[4,5-bis(propylthio)-1,3-dithiol-2-ylidene]-5-(4-methoxyphenyl)-5H-1,3-dithiolo[4,5-c]pyrrole (4a) and 2-[1,3-dithiol-2-ylidene]-5-(4-methoxyphenyl)-5H

• -dithiolo[4,5-c]pyrrole (4b). Prepared from 7b (0.040 g, 0.119 mmol), CuI (0.023 g, 0.119 mmol), K3PO4 (0.020 g, 0.954 mmol), trans-diaminocyclohexane (22 µL, 0.179 mmol) and 4-bromoanisole (8a, 0.033 g, 0.179 mmol) in 3 mL of dry dioxane. The product was purified by flash chromatography (CH2Cl2/cyclohexane

• 4-bromonitrobenzene (8b, 0.045 g, 0.224 mmol) in 2 mL of dry dioxane. The product was purified by flash chromatography (CH2Cl2) to afford deep red crystals. X-ray quality crystals were grown by slow evaporation of CDCl3/heptane solution. Yield: 59.7 mg (0.116 mmol, 83%). Mp 240–244 °C; Rf = 0.72

Mechanical stability of bivalent transition metal complexes analyzed by single-molecule force spectroscopy

• Manuel Gensler,
• Christian Eidamshaus,
• Maurice Taszarek,
• Hans-Ulrich Reissig and
• Jürgen P. Rabe

Beilstein J. Org. Chem. 2015, 11, 817–827, doi:10.3762/bjoc.11.91

• thin-layer chromatography (TLC). Products were purified by flash chromatography on silica gel (32–63 μm, Macherey & Nagel). Yields refer to chromatographically and spectroscopically (1H NMR) homogeneous materials, unless otherwise stated. NMR spectra were recorded on Bruker (AM 250, AC500, AVIII 700

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

• quantitative nature of the CuAAC. The formation of a β-CD trimer was not anticipated to be of major concern because of the unfavorable steric interactions upon grafting of a third β-CD onto the β-CD dimer. This was confirmed during purification by flash chromatography by observation of a major peak with a

• . General procedures: MALDI–TOF mass spectrometry was performed on a Reflex III (Bruker Daltonics, Bremen, Germany) and automated flash chromatography was performed on a Grace Davidson Discovery Science Revelaris system. NMR spectra were recorded at 298.1 K on a Bruker AVIII-600 MHz instrument equipped with

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• a rotary evaporator under reduced pressure and the crude product was purified by flash chromatography. 3-Chloropropyl (E)-3-(4-nitrophenyl)acrylate (3ba): Yield 90%, 0.90 mmol, pale yellow solid, mp 86 °C; 1H NMR (300 MHz, DMSO-d6) δ 8.23 (d, J = 8.7 Hz, 2H), 8.00 (d, J = 8.7 Hz, 2H), 7.77 (d, J

C-5’-Triazolyl-2’-oxa-3’-aza-4’a-carbanucleosides: Synthesis and biological evaluation

• Roberto Romeo,
• Caterina Carnovale,
• Salvatore V. Giofrè,
• Maria A. Chiacchio,
• Adriana Garozzo,
• Emanuele Amata,
• Giovanni Romeo and
• Ugo Chiacchio

Beilstein J. Org. Chem. 2015, 11, 328–334, doi:10.3762/bjoc.11.38

• azides, 11 and 12, epimeric at C-5, in a relative ratio 2:1 with a global yield of 85%. Two azides were separated by flash chromatography (CH2Cl2/MeOH 98:2 as eluent). Compound 12 originates from 11: its formation can be rationalized by considering that the acidic medium of the reaction, linked to the

Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers

• Thorbjørn Terndrup Nielsen,
• Catherine Amiel,
• Laurent Duroux,
• Kim Lambertsen Larsen,
• Lars Wagner Städe,
• Reinhard Wimmer and
• Véronique Wintgens

Beilstein J. Org. Chem. 2015, 11, 147–154, doi:10.3762/bjoc.11.14

• conversion of the CPT after 24 hours. The N3CPT was purified by automated flash chromatography and obtained in good yields (>80%) and purity (verified by NMR spectroscopy). From the N3CPT two series of novel CPT-dextrans were synthesized by a copper(I)-catalyzed alkyne azide coupling (CuAAC). The dextrans

• -deoxyβ-CD onto 70 kDa dextran modified by 7-heptynoic acid, in a similar way as described in literature [15]. The polymer contained 58.6% β-CD (w/w). TLC analyses were made with ALUGRAM® SIL G/UV254 TLC plates with 0.2 mm silica gel, and visualized using UV light. Automated flash chromatography was made

• subjected to automated flash chromatography on a 40 g silica column using a linear DCM/methanol gradient (0–8%). The appropriate fractions were combined, the solvent was removed in vacuo and 575 mg (82%) yellow powder was isolated. 1H NMR (CDCl3) δ (ppm) 8.41 (s, 1H), 8.22 (d, 1H), 7.95 (d, 1H), 7.85 (t, 1H

Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols

• Bianca Rossi,
• Nadia Pastori,
• Simona Prosperini and
• Carlo Punta

Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10

• solution was extracted with EtOAc (3 × 50 mL), and the combined organic layers were dried over Na2SO4 and concentrated in vacuum. Purification of the crude residue by flash chromatography afforded aminoalkylated ethers as the last eluting products. Yields of isolated products are based on the starting

Synthesis and characterization of pH responsive D-glucosamine based molecular gelators

• Navneet Goyal,
• Hari P. R. Mangunuru,
• Bargav Parikh,
• Sonu Shrestha and
• Guijun Wang

Beilstein J. Org. Chem. 2014, 10, 3111–3121, doi:10.3762/bjoc.10.328

• corresponding acid chloride was added dropwise to the solution. The mixture was left stirring for 6–10 h, after which the mixture was concentrated by using a rotary evaporator. The crude residue was purified by flash chromatography by means of a hexane/DCM/MeOH gradient solvent system. The amide derivatives 7

• the mixture was concentrated by using a rotary evaporator. If needed, the crude products were purified by flash chromatography on silica gel. A DCM/MeOH gradient solvent system was used for the chromatography separation. Compound characterization data Compound 7: Pentylamide, isolated as a white solid

Synthesis of divalent ligands of β-thio- and β-N-galactopyranosides and related lactosides and their evaluation as substrates and inhibitors of Trypanosoma cruzi trans-sialidase

• María Emilia Cano,
• Rosalía Agusti,
• Alejandro J. Cagnoni,
• María Florencia Tesoriero,
• José Kovensky,
• María Laura Uhrig and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 3073–3086, doi:10.3762/bjoc.10.324

• irradiation during 50 min. The mixture was then poured into a 1:1 H2O/NH4Cl solution (20 mL) and extracted with EtOAc (4 × 15 mL). The organic layer was dried (Na2SO4), filtered, and the solvent was removed under reduced pressure. The residue was purified by flash chromatography, using the solvent system

Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

• Florian Hamon,
• Claire Blaszkiewicz,
• Marie Buchotte,
• Estelle Banaszak-Léonard,
• Hervé Bricout,
• Sébastien Tilloy,
• Eric Monflier,
• Christine Cézard,
• Laurent Bouteiller,
• Christophe Len and
• Florence Djedaini-Pilard

Beilstein J. Org. Chem. 2014, 10, 2874–2885, doi:10.3762/bjoc.10.304

• with a yield of 49% (Scheme 1) [30]. Then, the carboxylic groups were activated by N-hydroxysuccinimide (NHS) and condensed with mono-6-amino-6-deoxy-β-cyclodextrin (β-CD-NH2) [31] in anhydrous DMF at room temperature. Flash chromatography (C18 column, H2O/MeOH 90:10 to 10:90 v/v in 20 min) afforded

• addition of acetone, then dried under reduced pressure. The product 1 was obtained as an orange powder (m = 4.44 g) with a quantitative yield and an HPLC purity over 98%. Then, the product was purified by flash chromatography (20 min, H2O/MeOH from 90:10 to 10:90 (v/v), 40 mL·min−1) to afford compound 1

Galactan synthesis in a single step via oligomerization of monosaccharides

• Marius Dräger and
• Amit Basu

Beilstein J. Org. Chem. 2014, 10, 2658–2663, doi:10.3762/bjoc.10.279

• glycosylation methods, and the rapid access to glycans in a single step is a strength of this approach. All of the oligosaccharides reported here have successfully been separated using routine normal-phase silica gel columns on a commercially available flash chromatography system. The oligomerization described

A new approach for the synthesis of bisindoles through AgOTf as catalyst

• Jorge Beltrá,
• M. Concepción Gimeno and
• Raquel P. Herrera

Beilstein J. Org. Chem. 2014, 10, 2206–2214, doi:10.3762/bjoc.10.228

• these interesting and appealing reaction products, for which there is still a continuous demand. Experimental Purification of reaction products was carried out by flash chromatography using silica gel (0.063–0.200 mm). Analytical thin-layer chromatography was performed on 0.25 mm silical gel 60-F plates

• removed under vacuum. Then, adducts 6 were finally isolated by flash chromatography (SiO2; hexane/EtOAc, 8:2). Yield for each final product is reported in Table 2. Final products should be stored under nitrogen atmosphere and in the fridge. 3,3'-(3-phenylpropane-1,1-diyl)bis(1H-indole) (6ac) Following