Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• form hydrogels [84][85]. In particular, hydrogels formed by PEG and cyclodextrins have been investigated intensively because of the biocompatibility of their components. Interestingly, local crystallization of the polyrotaxane threaded cyclodextrins, sometimes called molecular necklaces [86], may form

• studies were also consistent with the localized crystallization of α-CD/PEG pseudo-polyrotaxanes forming interchain cross-links in the hydrogel. Low molecular weight <2 kDa PEG forms crystalline precipitates in aqueous solutions in the presence of α-CD largely because multiple α-CD thread onto the PEG

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

• were washed with brine and water, dried over Na2SO4 and evaporated to dryness. After crystallization from ethanol a white solid was obtained (480 mg, 90%). Mp 182–183 °C; IR (KBr) ν: 3369, 2968, 2925, 2779, 1450, 1420, 1265 cm−1; 1H NMR (400 MHz, CDCl3) δ 3.04 (s, 4H, -NCH2CH2N-), 2.64 (t, J = 6.8 Hz

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• analysis (TGA). All copolymers showed only glass-transitions (Tg) and not any exothermal crystallization peak characteristic of polymers containing 9,9-dioctyl-2,7-fluorene units (PFO) [49], Figure 2. The non-rotaxane copolymer 3 has a Tg at 88 °C. The Tg value increases for 3·TM-γCD and 3·TM-βCD to 96 °C

Bifunctional phase-transfer catalysis in the asymmetric synthesis of biologically active isoindolinones

• Antonia Di Mola,
• Maximilian Tiffner,
• Francesco Scorzelli,
• Laura Palombi,
• Rosanna Filosa,
• Paolo De Caprariis,
• Mario Waser and
• Antonio Massa

Beilstein J. Org. Chem. 2015, 11, 2591–2599, doi:10.3762/bjoc.11.279

• reaction time (72 h) [21][22]. Readily available chiral ammonium salts (e.g., cinchona alkaloid-based or commercially available Maruoka catalysts) were also investigated, but the enantioselectivity was lower, reaching a maximum of 46% ee [23]. Gratifyingly, a very efficient heterochiral crystallization

• successfully scaled up to a practical 2 mmol scale with unchanged efficiency. After crystallization, we were able to obtain reasonable quantities of (S)-7 with 95% ee and an overall yield of 77%. The availability of both the enantiomers of the catalysts is another important advantage because of the possibility

• after crystallization overnight at −20 °C, the solid was filtered off and the solution containing the enantioenriched compound was evaporated and analyzed by chiral HPLC. The resulting enantioenriched product was obtained as a colourless oil in 77% overall yield (400 mg, 1.51 mmol, 95% ee). The

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• ]. Indeed, the treatment of (–)-isopulegol with diisopropyl azodicarboxylate (DIAD) and p-nitrobenzoic acid in the presence of triphenylphosphine gave the corresponding ester in an almost quantitative yield. The latter was easily purified by crystallization from n-hexane, and then transesterificated with

• epoxidation of 5 with tert-butylhydroperoxide (TBHP) in toluene gave 6 ([α]D +34.2° (c 1.3, CHCl3)) in 95% yield [9][22]. Then, the diol 7 was obtained in 85% yield from the reduction of epoxide 6 with LiAlH4 in THF at 0 °C. The diol 7 was easily purified by crystallization (85% yield, n-hexane at −50 °C up

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

• Redouane Beniazza,
• Natalia Bayo,
• Florian Molton,
• Carole Duboc,
• Stéphane Massip,
• Nathan McClenaghan,
• Dominique Lastécouères and
• Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

• vapour into the THF solution led to the crystallization of 1 as blue needles, which were recovered by filtration (71% yield). The proposed dinuclear and mononuclear structures of 4 and 1 were confirmed by single crystal X-ray diffraction (Figure 1). The crystal structure of 4 displays the typical “paddle

Cross-metathesis of polynorbornene with polyoctenamer: a kinetic study

• Yulia I. Denisova,
• Maria L. Gringolts,
• Alexander S. Peregudov,
• Liya B. Krentsel,
• Ekaterina A. Litmanovich,
• Arkadiy D. Litmanovich,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2015, 11, 1796–1808, doi:10.3762/bjoc.11.195

• measurements with PCOE are impossible since the solution is not filterable through a 220 nm porosity membrane. Taking into account that the melting temperature of PCOE is about 45 °C, we can relate aggregation in the PCOE solutions at 25 °C to the onset of crystallization. In any case, it makes no sense to

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

• -phenanthroline in heat acetonitrile solution afforded 4 and 5, respectively. Even excess triphenylphosphine and 1,10-phenanthroline were used, only one and two coordinated acetonitrile ligands were substituted in complexes 4 and 5. Crystallization by slow diffusion of diethyl ether into their acetonitrile

• crystallization by slow diffusion of Et2O into the CH3CN solution gave 4 as yellow solid. Yield: 75 mg, 40%. Anal. calcd for C32H32F12N7P3Ru: C, 41.04; H, 3.44; N, 10.47; found: C, 41.10; H, 3.40; N, 10.58; 1H NMR (DMSO-d6) δ 8.99 (s, 1H), 8.46 (s, 1H), 8.38 (s, 1H), 7.87 (s, 1H), 7.57(s, 13H), 7.42 (s, 2H), 7.25

• ). A mixture of 2 (142 mg, 0.2 mmol) and 1,10-phenanthroline·1H2O (198 mg, 1.0 mmol) in 5 mL CH3CN was stirred at 80 °C for 6 h. Then the mixture was filtered through Celite to afford a yellow solution. Crystallization by slow diffusion of Et2O into the CH3CN solution gave 5 as an orange yellow solid

Towards inhibitors of glycosyltransferases: A novel approach to the synthesis of 3-acetamido-3-deoxy-D-psicofuranose derivatives

• Maroš Bella,
• Miroslav Koóš and
• Chun-Hung Lin

Beilstein J. Org. Chem. 2015, 11, 1547–1552, doi:10.3762/bjoc.11.170

• single-crystal X-ray analysis. However, removal of the pivaloyl group from derivative 10 afforded 3-acetamido-3-deoxy-1,2-O-isopropylidene-α-D-psicofuranose (12) which, after crystallization (EtOAc/hexane 1:2), afforded crystals suitable for X-ray analysis. This unambiguously confirmed the α

• -psicofuranoside derivative 15. X-ray analysis Single crystals (stable at ambient temperature) that were suitable for X-ray diffraction measurements were obtained by slow crystallization of 12 from EtOAc/hexane 1:2 with cooling in a refrigerator. The preliminary orientation matrices and final cell parameters were

The enantioselective synthesis of (S)-(+)-mianserin and (S)-(+)-epinastine

• Piotr Roszkowski,
• Jan. K. Maurin and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2015, 11, 1509–1513, doi:10.3762/bjoc.11.164

• recrystallization was applied. The values of specific rotation were [α]D23 +68.1 (c 1, CHCl3) and [α]D23 −68.3 (c 1, CHCl3), which could not be changed by repeated crystallization steps. Confirmation of the optical purity of compound 7 by HPLC (Daicel OD-H) could not be obtained because of its insufficient

Synthesis of a tricyclic lactam via Beckmann rearrangement and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha,
• Ongolu Ravikumar and
• Jadab Majhi

Beilstein J. Org. Chem. 2015, 11, 1503–1508, doi:10.3762/bjoc.11.163

• = 2:1) (Scheme 2) but the products were inseparable by column chromatography. Next, we attempted to separate the mixture of these isomers (9a and 9b) by selective crystallization using different solvent systems. Finally, one of the lactam derivative 9a (δ = 3.86, dd, J = 5.8, 2.9 Hz, 1H) was isolated

• same Rf value of the individual compounds. Finally, isolation of the required lactam 9a from the mixture was accomplished by using crystallization. Since this method is cumbersome, an alternate method was attempted. To this end, we changed our synthetic route and tried to use the unsaturated ketone 4

Tetrathiafulvalene-based azine ligands for anion and metal cation coordination

• Awatef Ayadi,
• Aziz El Alamy,
• Olivier Alévêque,
• Magali Allain,
• Nabil Zouari,
• Mohammed Bouachrine and
• Abdelkrim El-Ghayoury

Beilstein J. Org. Chem. 2015, 11, 1379–1391, doi:10.3762/bjoc.11.149

• candidates for the formation of metal complexes. We have therefore investigated the complexation of L1 and L2 with various metal cations and we succeeded in the crystallization of a neutral rhenium metal complex with ligand L2. Thus, the equimolar reaction between L2 and the [Re(CO)5Cl] precursor performed

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• nitrogen atoms to form a planar palladium ring system (Scheme 2). Crystallization by slow diffusion of pentane into a solution of 8 in dichloromethane gave suitable crystals for an X-ray diffraction study. The molecular structure is presented in Figure 2 (see Supporting Information File 1 for the cif of

Cathodic hydrodimerization of nitroolefins

• Michael Weßling and
• Hans J. Schäfer

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

• by way of the bisulfite adduct, this facilitated the crystallization and improved the yields. The preparation of the nitroalkenes 1, 4, 8, 9 is described in [25]; the IR, 1H NMR, and MS data are provided in the experimental part (Supporting Information File 1). From a comparison of the experimental δ

• from aldehyde 6c via the n-butylazomethine [24]. Particularly difficult was the synthesis of 12, where a product mixture is formed; additionally 12 decomposes partly during purification by fractional crystallization, furthermore it is air sensitive. All that leads to low yields of 12. The dinitrodiene

Azobenzene-based inhibitors of human carbonic anhydrase II

• Leander Simon Runtsch,
• David Michael Barber,
• Peter Mayer,
• Michael Groll,
• Dirk Trauner and
• Johannes Broichhagen

Beilstein J. Org. Chem. 2015, 11, 1129–1135, doi:10.3762/bjoc.11.127

• -containing azobenzenes 1a–i (Figure 2). The crystallization conditions can be found in Supporting Information File 1). The substitution patterns on the aromatic core together with their electronic characteristics determines the absorption spectra of the individual azobenzenes [11]. We assessed the π–π*-band

• procedures, spectral data and X-ray crystallographic tables. Protein purification, crystallization conditions and measurement of Michaelis–Menten constant. Acknowledgements D.M.B is grateful to the European Comission for a Marie Skłodowska-Curie Intra-European fellowship (PIEF-GA-2103-627990). J.B. is

• as well as Eric P. Trautman and Martin Maier for excellent synthetic assistance. Author Contributions D.T. supervised the research. J.B. and D.T. conceived and designed the study. J.B. and L.S.R. performed chemical, biological and small molecule crystallization experiments. J.B. performed protein

Regioselective synthesis of chiral dimethyl-bis(ethylenedithio)tetrathiafulvalene sulfones

• Flavia Pop and
• Narcis Avarvari

Beilstein J. Org. Chem. 2015, 11, 1105–1111, doi:10.3762/bjoc.11.124

• solutions, respectively. Although both enantiomers crystallize in the orthorhombic system (chiral space group P212121), they are not isostructural, very likely because of the slightly different crystallization conditions. Indeed, the cell parameters are completely different and in the asymmetric unit of (R

Indolizines and pyrrolo[1,2-c]pyrimidines decorated with a pyrimidine and a pyridine unit respectively

• Marcel Mirel Popa,
• Emilian Georgescu,
• Mino R. Caira,
• Florentina Georgescu,
• Constantin Draghici,
• Raluca Stan,
• Calin Deleanu and
• Florea Dumitrascu

Beilstein J. Org. Chem. 2015, 11, 1079–1088, doi:10.3762/bjoc.11.121

• acetylenic dipolarophiles 10 (3.5 mmol) were stirred under reflux in 20 mL 1,2-epoxybutane for 24 h. The products were precipitated with ethanol and removed by filtration. Further purification was made by crystallization from ethanol or by column chromatography on Al2O3 using methylene chloride as eluent. 3

• at reflux in 20 mL 1,2-epoxybutane for 48 h. The products were precipitated with ethanol and removed by filtration. Further purification was made by crystallization from ethanol or column chromatography on Silicagel-60 (Merck, 70–230 mesh) using methylene chloride as eluent. 1-Acetyl-3-(4

• . The products were precipitated with ethanol and removed by filtration. Further purification was performed by crystallization from ethanol or column chromatography on Silicagel-60 (Merck) or neutral Al2O3 by using methylene chloride as an eluent. 1-Acetyl-3-benzoyl-7-(4-pyrimidinyl)indolizine (16a

Donor–acceptor type co-crystals of arylthio-substituted tetrathiafulvalenes and fullerenes

• Xiaofeng Lu,
• Jibin Sun,
• Shangxi Zhang,
• Longfei Ma,
• Lei Liu,
• Hui Qi,
• Yongliang Shao and
• Xiangfeng Shao

Beilstein J. Org. Chem. 2015, 11, 1043–1051, doi:10.3762/bjoc.11.117

• thought to be the cooperative consequence of the molecular geometry of Ar-S-TTF, the shape and size of the fullerene molecule, the solvent adduct, and the crystallization dynamics. The donor–acceptor interaction mode and the packing motif of the fullerenes largely depend on the composition of the co

Trifluoromethyl-substituted tetrathiafulvalenes

• Olivier Jeannin,
• Frédéric Barrière and
• Marc Fourmigué

Beilstein J. Org. Chem. 2015, 11, 647–658, doi:10.3762/bjoc.11.73

• solubility brought by the trifluoromethyl substituent strongly limits the isolation of such salts by crystallization. Experimental General information Commercially available reagents were used without further purification. Solvents were distilled under Ar. THF and Et2O were dried over KOH before distillation

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• asymmetric organocatalysis [54][55][56][57][58][59][60][61]. Chemoselective O-acylation of serine, threonine and cysteine in CF3CO2H with a range of acyl chlorides, followed by crystallization of the product directly from the reaction mixture by addition of Et2O, furnished a comprehensive collection of

Functionalized branched EDOT-terthiophene copolymer films by electropolymerization and post-polymerization “click”-reactions

• Miriam Goll,
• Adrian Ruff,
• Erna Muks,
• Felix Goerigk,
• Beatrice Omiecienski,
• Ines Ruff,
• Rafael C. González-Cano,
• Juan T. Lopez Navarrete,
• M. Carmen Ruiz Delgado and
• Sabine Ludwigs

Beilstein J. Org. Chem. 2015, 11, 335–347, doi:10.3762/bjoc.11.39

• crystals the crystallization procedure was repeated once. DMSO was stored over 3 Å molecular sieves (activated in an oven at 80 °C for several days) under argon atmosphere. All reactions were carried out under argon atmosphere unless otherwise noted. The synthesis of 3T was published elsewhere [61

Stereoselective cathodic synthesis of 8-substituted (1R,3R,4S)-menthylamines

• Carolin Edinger,
• Jörn Kulisch and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 294–301, doi:10.3762/bjoc.11.34

• diastereomeric mixture can be transformed to the corresponding hydrochlorides by passing HCl through a solution of 8 or 12 in diethyl ether followed by a selective crystallization of diastereomers 8c and 12c from 1,4-dioxane or CH2Cl2/heptane, respectively (see Scheme 8). 8c and 12c can thus be obtained in 73

• demanding diphenyl moiety in 8-position. Separation of the diastereomeric 8-substituted menthylamines by crystallization of their hydrochlorides. Effect of temperature onto yield and stereoselectivity of the electrochemical reduction of 7a on a lead cathode. Influence of alkylammonium salts on the

Selective methylation of kaempferol via benzylation and deacetylation of kaempferol acetates

• Qinggang Mei,
• Chun Wang,
• Weicheng Yuan and
• Guolin Zhang

Beilstein J. Org. Chem. 2015, 11, 288–293, doi:10.3762/bjoc.11.33

• gives a mixture of 7-O- and 4',7-di-O-benzylquercetin [29]. Using this strategy, peracetylated derivative 1 was treated with an excess of benzyl bromide and catalytic amounts of potassium iodide in the presence of K2CO3 under reflux for 24 h. Fortunately, only 8 was obtained by crystallization from

Novel biphenyl-substituted 1,2,4-oxadiazole ferroelectric liquid crystals: synthesis and characterization

• Mahabaleshwara Subrao,
• Dakshina Murthy Potukuchi,
• Girish Sharada Ramachandra,
• Poornima Bhagavath,
• Sangeetha G. Bhat and
• Srinivasulu Maddasani

Beilstein J. Org. Chem. 2015, 11, 233–241, doi:10.3762/bjoc.11.26

• molecules in the 13b (C12.Ox.C*Cn) series. The compounds in the 13a (Ph.Ox.C*Cn) series consist of a rigid and bulky phenyl moiety on one end, which tends to keep the molecules away due to the repulsive forces. Also, the crystallization temperatures (i.e., melting temperatures) of the 13a (Ph.Ox.C*Cn

Three-component synthesis of C₂F₅-substituted pyrazoles from C₂F₅CH₂NH₂·HCl, NaNO₂ and electron-deficient alkynes

• Pavel K. Mykhailiuk

Beilstein J. Org. Chem. 2015, 11, 16–24, doi:10.3762/bjoc.11.3

• –9a in excellent yields of 95–99% without any purification. Substrates 4, 5 and 10–12 with weak EWG reacted slowly, and even after one week the reaction was not complete (33–76% conversion). The pure products 4a, 5a, and 10a–12a (Table 2) were obtained in bad yields after crystallization of the

•  4) [51][52]. Replacing one hydrogen atom in alkyne 19 by a bulkier chlorine atom – alkyne 20 – led to mixture of products 20b/a = 4.0/1.0 (the pure product 20b was obtained by crystallization). Replacing two hydrogen atoms in 20 by bulkier fluorine atoms – alkyne 21 – led to mixture 21b/a = 2.6/1.0