Synthesis and characterization of benzodithiophene and benzotriazole-based polymers for photovoltaic applications

• Desta Gedefaw,
• Marta Tessarolo,
• Margherita Bolognesi,
• Mario Prosa,
• Renee Kroon,
• Wenliu Zhuang,
• Patrik Henriksson,
• Kim Bini,
• Ergang Wang,
• Michele Muccini,
• Mirko Seri and
• Mats R. Andersson

Beilstein J. Org. Chem. 2016, 12, 1629–1637, doi:10.3762/bjoc.12.160

• ring) in comparison to PTzBDT-1, not only allows a higher donor content in the blend (enhanced light absorption) but also seems to be crucial in terms of precipitation/segregation kinetics during the deposition/drying process of the active blend, strongly influencing the self-organization, the quality

Catalytic Chan–Lam coupling using a ‘tube-in-tube’ reactor to deliver molecular oxygen as an oxidant

• Carl J. Mallia,
• Paul M. Burton,
• Alexander M. R. Smith,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1598–1607, doi:10.3762/bjoc.12.156

• (Figure 7). In the case of substrate 40 precipitation occurred as soon as the two solutions came into contact at the T-piece mixer, which was probably due to strong coordination to the copper acetate by the imidazole ring. This made running this reaction problematic in flow due to the occurrence of

One-pot synthesis of tetracyclic fused imidazo[1,2-a]pyridines via a three-component reaction

• Bo Yang,
• Chuanye Tao,
• Taofeng Shao,
• Jianxian Gong and
• Chao Che

Beilstein J. Org. Chem. 2016, 12, 1487–1492, doi:10.3762/bjoc.12.145

• precipitation from the reaction mixture and n-BuOH proved to be the most suitable solvent in the reaction. Performing the reaction in refluxing n-BuOH in the presence of one equivalent of HClO4 for 8 h, compound 1a was obtained in 30% isolated yield. Other acids including p-toluenesulfonic acid (PTSA), HCl, and

Synthesis of ferrocenyl-substituted 1,3-dithiolanes via [3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl S-methanides

• Grzegorz Mlostoń,
• Róża Hamera-Fałdyga,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 1421–1427, doi:10.3762/bjoc.12.136

• mixture was heated at 45 °C until the evolution of N2 ceased. Then, the solvent was evaporated and the crude products were purified by CC (SiO2, hexane/ethyl acetate 95:5). The major product was isolated using diethyl ether (precipitation). 4-Ferrocenyl-5,5-diphenyl-4-(selenophen-2-yl)-1,3-dithiolane (5c

Artificial Diels–Alderase based on the transmembrane protein FhuA

• Hassan Osseili,
• Daniel F. Sauer,
• Klaus Beckerle,
• Marcus Arlt,
• Tomoki Himiyama,
• Tino Polen,
• Akira Onoda,
• Ulrich Schwaneberg,
• Takashi Hayashi and
• Jun Okuda

Beilstein J. Org. Chem. 2016, 12, 1314–1321, doi:10.3762/bjoc.12.124

• oxidized to Cu(II) by contamination with air. Cu(II) led to protein aggregation and precipitation. This was shown in an independent experiment. When one equiv of Cu(NO3)2·3H2O was added to a solution of FhuA ΔCVFtev, the protein precipitated rapidly and quantitatively. MALDI–TOF–MS analysis for the whole

Synthesis, fluorescence properties and the promising cytotoxicity of pyrene–derived aminophosphonates

• Jarosław Lewkowski,
• Maria Rodriguez Moya,
• Anna Wrona-Piotrowicz,
• Janusz Zakrzewski,
• Renata Kontek and
• Gabriela Gajek

Beilstein J. Org. Chem. 2016, 12, 1229–1235, doi:10.3762/bjoc.12.117

• dichloromethane solutions with a saturated aqueous sodium bicarbonate solution, which allowed to remove dimethyl phosphite. This procedure was followed by column chromatography, and, in a case of N-benzyl derivative 3Aa, triturating the product with diethyl ether until the precipitation of a solid was

Unusual traits of cis and trans-2,3-dibromo-1,1-dimethylindane on the way from 1,1-dimethylindene to 2-bromo-, 3-bromo-, and 2,3-dibromo-1,1-dimethylindene

• Rudolf Knorr,
• David S. Stephenson,
• Ernst Lattke,
• Petra Böhrer and
• Jakob Ruhdorfer

Beilstein J. Org. Chem. 2016, 12, 1178–1184, doi:10.3762/bjoc.12.113

• ensuing, regiospecific HBr elimination afforded 3-bromo-1,1-dimethylindene. The addition of elemental bromine to the latter compound, followed by thermal HBr elimination, furnished 2,3-dibromo-1,1-dimethylindene, whose Br/Li interchange reaction, precipitation, and subsequent protolysis yielded only 2

Scope and mechanism of the highly stereoselective metal-mediated domino aldol reactions of enolates with aldehydes

• M. Emin Cinar,
• Bernward Engelen,
• Martin Panthöfer,
• Hans-Jörg Deiseroth,
• Jens Schlirf and
• Michael Schmittel

Beilstein J. Org. Chem. 2016, 12, 813–824, doi:10.3762/bjoc.12.80

• following results were obtained, which are well in agreement with the outcome of the batch experiments. Since a slow flow rate of 1 mL min−1 caused precipitation of the compounds and consequently blocking the reactor, flow rates from 2 mL min−1 onwards were used to run the reaction (Table 8). The breakdown

New synthetic strategies for xanthene-dye-appended cyclodextrins

• Milo Malanga,
• Andras Darcsi,
• Mihaly Balint,
• Gabor Benkovics,
• Tamas Sohajda and
• Szabolcs Beni

Beilstein J. Org. Chem. 2016, 12, 537–548, doi:10.3762/bjoc.12.53

• ), during the reaction, an additional base such as N-methylmorpholine (NMM) or NaOH is required. If amine-bearing CDs are used as free bases, the additional base can be omitted. The synthesis of the reactions simply consists of the selective precipitation of the target compound with acetone and removal of

• the unreacted dye by filtration. The purity of the starting dye is a crucial parameter for the outcome of the reaction, since it will greatly affect the crude composition and consequently the purification process. If the purity of the starting dye is satisfactory, selective precipitation/filtration

• development stages, and in particular, immediately after the removal from the developing chamber (1), after heating (2), under UV excitation at 254 nm (3), under UV excitation at 366 nm (4), and finally, after charring (5). The right panels in Figure 3 show the effectiveness of the selective precipitation

Optimized methods for preparation of 6^I-(ω-sulfanyl-alkylene-sulfanyl)-β-cyclodextrin derivatives

• Eva Bednářová,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2016, 12, 349–352, doi:10.3762/bjoc.12.38

• reducing agent. The separation of the thiol product consists just of its precipitation with acetone from the reaction mixture. This separation method is very efficient and is used very often for separation of monosubstituted CD derivatives. The same reaction conditions, as for compound 6e, were used for

• simple synthetic step and isolated by precipitation. Synthesis of oligoethylene glycol dithiols. Synthesis of β-cyclodextrinthiols and -disulfides. Supporting Information Supporting Information File 258: General experimental procedures, instruments, materials. Detailed experimental procedures and

Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

• Miriana Kfoury,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2016, 12, 29–42, doi:10.3762/bjoc.12.5

• leading to their precipitation [38]. The slopes of AL-type and the linear segment of B-type profiles were less than one indicating the formation of 1:1 inclusion complexes in accordance with UV–visible results. Kf values were consequently calculated and were in good agreement with those obtained by the

Effective immobilisation of a metathesis catalyst bearing an ammonium-tagged NHC ligand on various solid supports

• Krzysztof Skowerski,
• Jacek Białecki,
• Stefan J. Czarnocki,
• Karolina Żukowska and
• Karol Grela

Beilstein J. Org. Chem. 2016, 12, 5–15, doi:10.3762/bjoc.12.2

• industrial potential [50]. Preparation of high-surface 8 by precipitation and by immobilisation on charcoal, silica, alumina, cotton and paper and the application of such materials in catalysis Microcrystalline 8 showed only marginal activity in olefin metathesis when applied as a suspension in toluene. This

• aluminium oxide, cotton-viscose wool (cosmetic) and even filter paper. In each case 5 wt % of catalyst was deposited on the selected support (see Supporting Information File 1 for details). During this part of the study we also discovered that the protocol involving fast precipitation of 8 from diluted

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• . Imidazolinium salt 14 was obtained by treatment of 13 with trimethyl orthoformate in 73% yield. It is worth noting that ethylenediamine 13 and imidazolinium salt 14 were sufficiently pure after precipitation, thus chromatographic purification was not necessary. Some specific effects are observed in the NMR

• (35 mg, 0.65 mmol) was added in a similar manner as described in [40]. The reaction mixture was refluxed for 2 h. Solids were filtered off and the filtrate was evaporated to dryness. The resulting oil was stirred overnight with diethyl ether causing precipitation of a white solid (160 mg, 73% yield

Assembly of synthetic Aβ miniamyloids on polyol templates

• Sebastian Nils Fischer and
• Armin Geyer

Beilstein J. Org. Chem. 2015, 11, 2646–2653, doi:10.3762/bjoc.11.284

• are known to form fibrils and there is no way to stop the process until complete precipitation. Intermediate soluble oligomers were identified as neurotoxic agents, but they are difficult to study because of their heterogeneous composition and transient character due to the onset of amyloid formation

• , such as those forming amyloids. The solubility of the assembly should be maintained throughout the experiment and precipitation strictly avoided to reach the thermodynamic equilibrium with the formation of the most stable miniamyloid in solution. Not all functional groups listed above for the

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

• Mino R. Caira,
• Susan A. Bourne,
• Halima Samsodien and
• Vincent J. Smith

Beilstein J. Org. Chem. 2015, 11, 2616–2630, doi:10.3762/bjoc.11.281

• approximate unit cell dimensions (a ≈ 19.2, b ≈ 24.4, c ≈ 32.8 Å), results which were subsequently confirmed by a single crystal X-ray diffraction study of the same phase obtained via the co-precipitation method. (Relevant PXRD traces and single crystal data are provided in Supporting Information File 1

• employed for preliminary investigation of single crystals of a putative inclusion complex between 2ME and DIMEB, prepared using the co-precipitation method. (Details of the thermal analysis of the DIMEB complex of 2ME are provided in the Supporting Information File 1). The crystals, immersed in silicone

• complex between 2ME and the fully methylated host TRIMEB was prepared by the co-precipitation method and initially examined by HSM. (Details of the thermal analysis of the TRIMEB complex of 2ME are provided in Supporting Information File 1). Upon heating the crystals under silicone oil, no dehydration was

Size-controlled and redox-responsive supramolecular nanoparticles

• Raquel Mejia-Ariza,
• Gavin A. Kronig and
• Jurriaan Huskens

Beilstein J. Org. Chem. 2015, 11, 2388–2399, doi:10.3762/bjoc.11.260

• avoid precipitation. Wintgens et al. showed the formation of SNPs by controlling the host–guest ratio and the total concentration of components with a neutral polymer backbone [13]. Recently, our group [2][14][15] formed SNPs by varying the ratio of neutral monovalent stoppers and multivalent

• synthesized by a reaction of 1-(chlorocarbonyl)ferrocene with the terminal amino group of methoxypoly(ethylene glycol)amine (Mw = 5000 g/mol) in dichloromethane, using an excess of triethylamine as a base, followed by precipitation from diethyl ether. To evaluate the association constant of the Fc moiety with

• over paper, the solvent was removed by evaporation and the remaining precipitate was redissolved in 2 mL chloroform. The chloroform solution was added dropwise to 40 mL of diethyl ether, giving immediate precipitation of a yellow solid, which was filtrated and dried in a vacuum oven at 40 °C overnight

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

• Nicolas Desbois,
• Sandrine Pacquelet,
• Adrien Dubois,
• Clément Michelin and
• Claude P. Gros

Beilstein J. Org. Chem. 2015, 11, 2202–2208, doi:10.3762/bjoc.11.239

• obtained by precipitation from a concentrated methanolic solution by slow addition of diethyl ether. Compound 3 was reacted with Ga(NO3)3 to lead to 10b in 94% yield after flash chromatography. The IR spectrum of 10b exhibits the characteristic band of the carbonyl stretching vibration from 1722 cm−1 to

• propargyl NOTA was performed by precipitation in diethyl ether in 94% yield. To prepare the gallium complex 12b, propargyl NOTA 4 and Ga(NO3)3 were dissolved, at pH 3, in water and then refluxed for 30 min. The pH of the reaction was adjusted (AcONa 0.5 M), in each case, to optimize the complexation kinetic

Olefin metathesis in air

• Lorenzo Piola,
• Fady Nahra and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 2038–2056, doi:10.3762/bjoc.11.221

• exctraction with water or precipitation with ether. With a catalyst loading of 10 mol % in refluxing nondegassed dichloromethane, very high conversions were achieved in less than 1 hour for di- and trisubstituted olefins. Towards the end of 2009, the Meier group reported the use of Grubbs (15), Hoveyda–Grubbs

New aryloxybenzylidene ruthenium chelates – synthesis, reactivity and catalytic performance in ROMP

• Patrycja Żak,
• Szymon Rogalski,
• Mariusz Majchrzak,
• Maciej Kubicki and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2015, 11, 1910–1916, doi:10.3762/bjoc.11.206

• corresponding phosphine in order to bind the HCl liberated during the reaction, which resulted in a significant increase in the reaction yield. Complexes 8–10 were easily isolated by precipitation with methanol or hexane from concentrated solution in methylene chloride (isolated yields = 86–90%). 1H NMR spectra

• chloride anion into the coordination sphere of ruthenium. Exposition of complex 8 to one equivalent of HCl brought a change in the solution colour from green to light-green. The fine-crystalline light-green precipitate was isolated from the post-reaction mixture by precipitation with hexane with 95

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• volatiles were evaporated under reduced pressure. The residue was washed with water and dried in vacuo. The yellow residue was dissolved in MeCN and concentrated to about 2 mL. The addition of Et2O induced precipitation of the product as a yellow solid. Yield: 190 mg, 53%. Anal. calcd for C16H20F12N8P2Ru: C

A facile synthetic route to benzimidazolium salts bearing bulky aromatic N-substituents

• Gabriele Grieco,
• Olivier Blacque and
• Heinz Berke

Beilstein J. Org. Chem. 2015, 11, 1656–1666, doi:10.3762/bjoc.11.182

• triethyl orthoformate at almost reflux temperature (145 °C) for reaction times between 10 and 20 min. Then TMSCl was added in large excess all at once leading to precipitation of greyish products, which indicated the formation of the benzimidazolium chlorides. In this way not only the known compound 1-Cl

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

• obtaining high molecular weight polyesters by lipase catalysis. This problem can be circumvented by the synthesis of telechelics, oligomers with functional ends. The synthesis of oligomers avoids the precipitation of polymers during the synthesis. The functional ends of the telechelics can be used in a

Preparation of a disulfide-linked precipitative soluble support for solution-phase synthesis of trimeric oligodeoxyribonucleotide 3´-(2-chlorophenylphosphate) building blocks

• Amit M. Jabgunde,
• Alejandro Gimenez Molina,
• Pasi Virta and
• Harri Lönnberg

Beilstein J. Org. Chem. 2015, 11, 1553–1560, doi:10.3762/bjoc.11.171

• phosphorylated with bis(benzotriazol-1-yl) 2-chlorophenyl phosphate. The “outdated” phosphotriester strategy, based on coupling of PV building blocks in conjunction with quantitative precipitation of the oligodeoxyribonucleotide with MeOH is applied. Subsequent release of the resulting phosphate and base

• -protected oligodeoxyribonucleotide trimer 3’-pTpdCBzpdGibu-5’ as its 3’-(2-chlorophenyl phosphate) was achieved by reductive cleavage of the disulfide bond. Keywords: disulfide linker; oligodeoxyribonucleotides; phosphotriester chemistry; precipitation; soluble support; Introduction Synthetic nucleic

• -hydroxybenzotriazole promoted phosphotriester coupling [11][22][23] and efficient purification of the support bound product by precipitation from MeOH after each deprotection and coupling step. Results and Discussion The synthesis of the disulfide tethered tetrakis-O-({4-[(2-hydroxyethyldisulfanyl)methyl]-1H-1,2,3

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• excess of KI) [14]. The side-product in the iodination of 3 was bis(pyridine)iodonium tetrafluoroborate, which can be easily isolated from the reaction mixture by precipitation upon addition of diethyl ether. This iodonium salt was first synthetized by Barluenga [85] and later used for mild iodination of

Synthesis and evaluation of the biostability and cell compatibility of novel conjugates of nucleobase, peptidic epitope, and saccharide

• Dan Yuan,
• Xuewen Du,
• Junfeng Shi,
• Ning Zhou,
• Abdulgader Ahmed Baoum,
• Khalid Omar Al Footy,
• Khadija Omar Badahdah and
• Bing Xu

Beilstein J. Org. Chem. 2015, 11, 1352–1359, doi:10.3762/bjoc.11.145

• conjugates exhibit excellent solubility in water without resulting in hydrogelation or precipitation. We observed that only the mixture of a proper pair of TTPV-containing (e.g., 5) and LGFNI-containing (8) conjugates self-assembles to form nanofibers and results in a supramolecular hydrogel. Moreover, the