Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• the desired mono-O-nitrate rac-19 and rac-20 had formed (Scheme 3) and it seemed that the corresponding di-O-nitrate esters (not shown) had also formed; all attempts at flash chromatographic separation and purification met with failure; a fact that hindered our ability to confidently analyse and

Separation and identification of indene–C₇₀ bisadduct isomers

• Bolong Zhang,
• Jegadesan Subbiah,
• David J. Jones and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2016, 12, 903–911, doi:10.3762/bjoc.12.88

• device performance. In a previous communication [9], an isomer of IC70BA was obtained by chromatographic separation using both flash chromatography and high pressure liquid chromatography (HPLC). X-ray crystallography revealed that this sample contained the 2 o’clock-B isomer (Figure 2b). This material

• noteworthy that there are a handful of other studies in the literature that reported on chromatographic separation of fullerene bisadduct isomers [8][12][13][14]. To the best of our knowledge, this is the first comprehensive analysis of IC70BA mixture using HPLC. Eleven fractions were collected and analyzed

• configuration were deduced using a variety of analytical techniques including 1H and 13C NMR and UV–vis spectroscopy. The electrochemical properties and the organic solar cell device performance were investigated for fractions where a reasonable quantity of sample could be isolated. Keywords: chromatographic

Synthesis of 2,1-benzisoxazole-3(1H)-ones by base-mediated photochemical N–O bond-forming cyclization of 2-azidobenzoic acids

• Daria Yu. Dzhons and
• Andrei V. Budruev

Beilstein J. Org. Chem. 2016, 12, 874–881, doi:10.3762/bjoc.12.86

• observed and the yield did not improve further when more than 1 equivalent of the base was used (Table 1). Without irradiation, the reaction did not proceed at all. Replacing EtOH as the solvent with iPrOH did not change the yield of 2a. A chromatographic separation of the reaction mixture obtained by

A convenient route to symmetrically and unsymmetrically substituted 3,5-diaryl-2,4,6-trimethylpyridines via Suzuki–Miyaura cross-coupling reaction

• Dariusz Błachut,
• Joanna Szawkało and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2016, 12, 835–845, doi:10.3762/bjoc.12.82

• - and bromoarypyridines, which difficult chromatographic separation also accounted for the low yield of the isolated final products. Attempted cross coupling of pyridine 1 with 4 mol excess of 2-chlorophenylboronic acids afforded a complex mixture of products with 3,5-bis(2-chlorophenyl)-2,4,6

• -bromo-2,4,6-trimethylpyridines. We also proved that a similar set of unsymmetrical products could be accessible via a one-pot double cross coupling by treatment of dihalopyridine with a mixture of arylboronic acids. However, chromatographic separation of the products is tedious and requires more

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

• of the basic reaction mixture and the extraction of the unreacted dithiols with chloroform. The prepared CD-thiols form disulfides very quickly under basic conditions but are reasonably stable under neutral and acidic conditions. Therefore, the final chromatographic separation could not be done in

• prepared in larger amounts and used for a long term storage. The corresponding pure thiol can be then prepared when needed by a simple one step high yielding procedure developed for compound 6e (Scheme 2), which does not require any chromatographic separation and uses ethanethiol in basic solution as the

Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes

• Norbert Vida,
• Jiří Václavík and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 110–116, doi:10.3762/bjoc.12.12

• . Maleic acid 4 was identified in the mixture (25% 19F NMR yield, Scheme 4) but chromatographic separation, crystallization or derivatization (CH2N2) attempts were not successful. Nevertheless, these results show that SF5-substituted para-benzoquinones are most likely intermediates in the formation of 4 by

Supramolecular structures based on regioisomers of cinnamyl-α-cyclodextrins – new media for capillary separation techniques

• Gabor Benkovics,
• Ondrej Hodek,
• Martina Havlikova,
• Zuzana Bosakova,
• Pavel Coufal,
• Milo Malanga,
• Eva Fenyvesi,
• Andras Darcsi,
• Szabolcs Beni and
• Jindrich Jindrich

Beilstein J. Org. Chem. 2016, 12, 97–109, doi:10.3762/bjoc.12.11

• regioisomers, chromatographic separation of the per-O-acetylated derivatives and the de-O-acetylation of the separated per-O-acetylated regioisomers would be necessary. This three-step reaction procedure makes the large scale preparation of the single regioisomers expensive and time-consuming. For α-CD we were

A convergent, umpoled synthesis of 2-(1-amidoalkyl)pyridines

• Tarn C. Johnson and
• Stephen P. Marsden

Beilstein J. Org. Chem. 2016, 12, 1–4, doi:10.3762/bjoc.12.1

• . Although the regioselectivities are not exceptionally high, the ready chromatographic separation of the various isomers makes this a synthetically tractable approach to 4-substituted (1-amidoalkyl)pyridine derivatives. Conclusion In summary, we have demonstrated a new umpoled disconnection for the one-pot

Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

• Chompoonut Rungnim,
• Sarunya Phunpee,
• Manaschai Kunaseth,
• Supawadee Namuangruk,
• Kanin Rungsardthong,
• Thanyada Rungrotmongkol and
• Uracha Ruktanonchai

Beilstein J. Org. Chem. 2015, 11, 2306–2317, doi:10.3762/bjoc.11.251

• ) using the following method. The photodiode array (PDA) detector was set to monitor at a λmax of 320 nm. The chromatographic separation was performed at 25 °C using a C18 column (Waters, 250 mm × 4.6 mm, 5 µm). The eluents were composed of 1% acetic acid in DI water as a mobile phase A, and methanol as

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

• chromatographic separation of the diastereomeric mixtures. In contrast, we have shown that the Katsuki–Sharpless epoxidation of (+)-neoisopulegol (4) is much more selective [9]. In the following we describe an improved version of our previously reported synthesis of 1. First we have focused our initial efforts on

Asymmetric 1,4-bis(ethynyl)bicyclo[2.2.2]octane rotators via monocarbinol functionalization. Ready access to polyrotors

• Cyprien Lemouchi and
• Patrick Batail

Beilstein J. Org. Chem. 2015, 11, 1881–1885, doi:10.3762/bjoc.11.202

• account of its notable polar character that makes for efficient chromatographic separation steps. In addition, the carbinol group offers large opportunities for orthogonal functionalization and it is readily removed [14][15]. As reported herein, this proved quite efficient in the development of a large

• , we have chosen to explore the nucleophilic addition to acetone of the monometallated acetylenide, a reaction that requires a precise control of both the amount of n-BuLi/acetone reactants and temperature. Thus, after chromatographic separation, 1 is readily obtained with excellent purity and good

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

• -exo. After chromatographic separation, NOESY experiments indicated that 10b-endo shows two nOe correlations: one between H1 and H2 (which indicates the cis-fusion of the two cycles) and another one between H1 and the aromatic proton H3. These two nOe interactions, together with the absence of a

A new method for the synthesis of α-aminoalkylidenebisphosphonates and their asymmetric phosphonyl-phosphinyl and phosphonyl-phosphinoyl analogues

• Anna Kuźnik,
• Roman Mazurkiewicz,
• Mirosława Grymel,
• Katarzyna Zielińska,
• Jakub Adamek,
• Ewa Chmielewska,
• Marta Bochno and
• Sonia Kubica

Beilstein J. Org. Chem. 2015, 11, 1418–1424, doi:10.3762/bjoc.11.153

• orthoformate, diethyl phosphite and monoethyl methylphosphonite, followed by chromatographic separation of the three possible condensation products and the final hydrolysis, gave the expected phosphinylalkylphosphonic acid in only 17% yield [20]. The stepwise method consisted in the condensation of diethyl

The chemical behavior of terminally tert-butylated polyolefins

• Dagmar Klein,
• Henning Hopf,
• Peter G. Jones,
• Ina Dix and
• Ralf Hänel

Beilstein J. Org. Chem. 2015, 11, 1246–1258, doi:10.3762/bjoc.11.139

• tentatively assign structures 35. Our attempts to obtain pure products by chromatographic separation have in this latter case so far failed. To summarize the epoxidation experiments, it appears that MCPBA prefers to attack the terminal double bonds of our sterically shielded oligoenes, whereas there are

• extension of the polyene chain. When heptaene 22 is treated with an equimolar amount of 36, a complex mixture is obtained consisting of starting material, mono-adducts (25%, MS analysis) and bis-adducts (12%). Chromatographic separation of the products turned out to be impossible, but we believe that

Synthesis and characterization of the cyanobenzene-ethylenedithio-TTF donor

• Sandrina Oliveira,
• Dulce Belo,
• Isabel C. Santos,
• Sandra Rabaça and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 951–956, doi:10.3762/bjoc.11.106

• pyrazine groups substituted TTFs recently reported by our group [13][22][23]. Conclusion In conclusion, we have prepared in fair yield a new non-symmetrically substituted cyanobenzene TTF-type electron donor, CNB-EDT-TTF, by a cross coupling reaction followed by chromatographic separation. The crystal

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

• product 6 was obtained with reproducible yield (89%) after chromatographic separation. Compound 7 was thus prepared by methylation of 6 and subsequent hydrolysis at appropriate conditions in good yield (Scheme 1). Synthesis of 3-O-methylkaempferol (12), 5,4′-di-O-methylkaempferol (16) and 4′-O

Synthesis of dinucleoside acylphosphonites by phosphonodiamidite chemistry and investigation of phosphorus epimerization

• William H. Hersh

Beilstein J. Org. Chem. 2015, 11, 184–191, doi:10.3762/bjoc.11.19

• foam, which was assumed to be the color of the desired products due to its similarity to 7 and 9. However, the presence of unreacted 5′-O-DMTr-thymidine, the starting acyls 7 and 9, and downfield 31P NMR peaks that are characteristic of diesters necessitated chromatographic separation. The isolation of

• cm−1, see Supporting Information File 1). The absence of room-temperature epimerization was apparent from both the chromatographic separation as well as the distinct peaks in the NMR spectra, and is well-known (as is facile chromatographic separation) for the analogous β-cyanoethoxyphosphoramidites

• orange color of the trityl cation was not seen. The diesters were less robust than the precursor monoester amidites. For instance, rapid chromatographic separation of the products from the ammonium salts formed during the synthesis was required to prevent further decomposition. The best procedure was

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

• by HF followed by chromatographic separation afforded chito-oligosaccharides as long as hexasaccharides in reasonable yields [13]. In most of these oligomerizations the reducing end of the oligomer is a hemi-acetal, or a reduced or protected derivative thereof, and both anomers are present [14]. An

Synthesis and biological evaluation of novel N-α-haloacylated homoserine lactones as quorum sensing modulators

• Michail Syrpas,
• Ewout Ruysbergh,
• Christian V. Stevens,
• Norbert De Kimpe and
• Sven Mangelinckx

Beilstein J. Org. Chem. 2014, 10, 2539–2549, doi:10.3762/bjoc.10.265

• natural and α-haloacylated analogues. Supporting Information File 638: 1H and 13C NMR data and spectra, IR, HRMS, optical rotation and melting point data, chromatographic separation and yields of synthesized compounds. Acknowledgments The authors are indebted to the “Research Foundation Flanders (FWO

Regio- and stereoselective synthesis of new diaminocyclopentanols

• Evgeni A. Larin,
• Valeri S. Kochubei and
• Yuri M. Atroshchenko

Beilstein J. Org. Chem. 2014, 10, 2513–2520, doi:10.3762/bjoc.10.262

• nucleophilicity. Moreover, there was not much effect on the outcome of the reactions conducted either under solvent-free conditions or using DMSO as a solvent. The regioisomers 9a–d and 10a–d were isolated through column chromatographic separation and fully characterized in order to avoid ambiguity. The

Relay cross metathesis reactions of vinylphosphonates

• Raj K. Malla,
• Jeremy N. Ridenour and
• Christopher D. Spilling

Beilstein J. Org. Chem. 2014, 10, 1933–1941, doi:10.3762/bjoc.10.201

• case, a single cross metathesis product would be formed from a crude mixture of mono-allyl and diallyl vinylphosphonates, avoiding the inefficiencies of chromatographic separation. A mixture of mono- and diallyl vinylphosphonates 14a and 14b was subjected to cross metathesis reaction with methyl

• acrylate (Scheme 10). The reaction progress was monitored by 31P NMR spectroscopy. After the reaction was complete, the 31P NMR spectrum showed the formation of the two oxaphospholes 22 and 32 in a ratio corresponding to the amount of vinylphosphonates 14a and 14b in the starting material. Chromatographic

• separation of the crude product gave the unsaturated ester 16b in 86% isolated yield. It is proposed that the Grubbs catalyst first reacts with the terminal alkene (Scheme 11) of the allyl phosphonate ester 21a to give the metal alkylidene 33. The metal alkylidene then reacts with the vinylphosphonate in a

A complete series of 6-deoxy-monosubstituted tetraalkylammonium derivatives of α-, β-, and γ-cyclodextrin with 1, 2, and 3 permanent positive charges

• Martin Popr,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2014, 10, 1390–1396, doi:10.3762/bjoc.10.142

• methylation. The majority of the presented reactions are very straightforward with a simple work-up, which avoids the need of chromatographic separation. Thus, these reactions are suitable for the multigram-scale production of monosubstituted cationic CDs. Keywords: cationic; cyclodextrins; monosubstitution

• decomposition of DMF or by the formylation side reactions. The authors recovered pure 4 after lengthy chromatographic separation on a carboxymethylcellulose column, involving the collection of 150 fractions. We decided to optimize the reaction conditions with the goal of improving the yield and avoiding the

cis–trans Isomerization of silybins A and B

• Michaela Novotná,
• Radek Gažák,
• David Biedermann,
• Florent Di Meo,
• Petr Marhol,
• Marek Kuzma,
• Lucie Bednárová,
• Kateřina Fuksová,
• Patrick Trouillas and
• Vladimír Křen

Beilstein J. Org. Chem. 2014, 10, 1047–1063, doi:10.3762/bjoc.10.105

• ], and at the preparatory scale by lipase-catalyzed discrimination [4][5]. However, chromatographic separation of 2,3-cis- and 2,3-trans-silybins is feasible after their C-23 O-acetylation, which can be accomplished with Novozym 435 in an acetone/vinyl acetate mixture, giving a nearly quantitative yield

Addition of H-phosphonates to quinine-derived carbonyl compounds. An unexpected C9 phosphonate–phosphate rearrangement and tandem intramolecular piperidine elimination

• Łukasz Górecki,
• Artur Mucha and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 883–889, doi:10.3762/bjoc.10.85

• catalysis, transition metal complexing, molecular recognition, chromatographic separation and analysis of enantiomers [2][3][4][5]. Synthetic modifications of the basic structure, motivated by an improved stereoselectivity potential of quinine, are an issue of ongoing trials [6][7][8][9]. Surprisingly

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50