Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• chemistry is a reaction that can be catalyzed without any metal-containing catalysts and it is selected as an appropriate approach, spontaneously. Phenolic resins can be produced commercially using bases (ammonia and sodium hydroxide) or acids (hydrochloric acid and sulfuric acid) as catalysts via

Detection of therapeutic radiation in three-dimensions

• John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

• high background color. Epoxy resins, which use basic curatives, oxidize leuco dyes making them inappropriate for use as dosimetric matrices. This left the polyurethanes as the most viable option. Transparent polyurethane starting materials are commercially available in two parts where part A is

Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes

• Carmen Moreno-Marrodan,
• Francesca Liguori and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73

• clogging, active sites accessibility, mass transfer limitations, and lack of reproducibility. Additional stabilization of MNP can be also achieved either by: the “electrostatic” effect of charged functional groups grafted to the support, a common strategy in gel-type resins (e.g., sulfonic resins) [93

Solid-phase enrichment and analysis of electrophilic natural products

• Frank Wesche,
• Yue He and
• Helge B. Bode

Beilstein J. Org. Chem. 2017, 13, 405–409, doi:10.3762/bjoc.13.43

• coupled to UV or mass spectrometry. Alternatively, natural products can be immobilized on reactive resins by making use of their chemical functionality and can be eluted after washing off all non-desired substances [8][9][11][13][15]. The recently introduced cleavable azide-reactive resin (CARR (2

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

• Andrew J. Capel,
• Andrew Wright,
• Matthew J. Harding,
• George W. Weaver,
• Yuqi Li,
• Russell A. Harris,
• Steve Edmondson,
• Ruth D. Goodridge and
• Steven D. R. Christie

Beilstein J. Org. Chem. 2017, 13, 111–119, doi:10.3762/bjoc.13.14

• roughness and difficulty with removing un-melted powder from smaller cavities [6]. SL utilises layer-by-layer photopolymerisation of a liquid resin bath to generate fully dense polymer parts [21]. Typically these resins are complex formulations based around a small selection of UV-curable acrylates, epoxies

Formose reaction controlled by boronic acid compounds

• Toru Imai,
• Tomohiro Michitaka and
• Akihito Hashidzume

Beilstein J. Org. Chem. 2016, 12, 2668–2672, doi:10.3762/bjoc.12.263

• -styrenesulfonate) presumably because sulfonate residues capture calcium ions. These observations indicate that the stronger retardation effect of pVPB/NaSS is ascribable to both boronic acid and sulfonate residues. The product was purified by dialysis against water and treatment with ion-exchange resins, and then

Isosorbide and dimethyl carbonate: a green match

• Fabio Aricò and
• Pietro Tundo

Beilstein J. Org. Chem. 2016, 12, 2256–2266, doi:10.3762/bjoc.12.218

• oxides [50][51][52][53][54][55][56], sulfonic resins [57][58][59] and bimetallic catalysts [60] have been investigated. Extensive work has also been conducted on the use of zeolites, which compared to the above mentioned catalysts, have the advantage to be thermal stable and possess tuneable properties

Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

• Raimondo Maggi,
• N. Raveendran Shiju,
• Veronica Santacroce,
• Giovanni Maestri,
• Franca Bigi and
• Gadi Rothenberg

Beilstein J. Org. Chem. 2016, 12, 2173–2180, doi:10.3762/bjoc.12.207

• organic Brønsted acids are very few. In particular, Tejero reported that sulfonic acid supported on polymeric resins could catalyse the esterification of LA, providing conversions up to 94% upon warming at 80 °C for 8 hours in the presence of 3 equiv of n-butanol [33]. Melero described the synthesis of

• h (Table 1, entry 5, 31% yield). We then switched to perfluorinated resins. Nafion® and Aquivion® showed an interesting selectivity towards 3a, but conversion of 1 proved once again below that observed with supported sulfonic acids (72% and 84%, respectively). Finally, a common homogeneous acid was

Thiophene-forming one-pot synthesis of three thienyl-bridged oligophenothiazines and their electronic properties

• Dominik Urselmann,
• Konstantin Deilhof,
• Bernhard Mayer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2016, 12, 2055–2064, doi:10.3762/bjoc.12.194

• Sonogashira–Glaser cyclization synthesis [75] was successfully performed furnishing three symmetrical thienyl-bridged oligophenothiazine dumbbells 3 as yellow greenish resins in yields of 34–54% (Scheme 2). The molecular composition of the thienyl-bridged oligophenothiazines 3 is unambiguously supported by

• the 13C NMR spectra additionally supported the assigned structures. Combustion analyses of compounds 3b and 3c indicate that water and THF (compound 3b) and water (compound 3c) are present as solvent inclusion in the resins that cannot be removed even upon extensive drying under vacuo. However, HPLC

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

• Maurizio Selva,
• Alvise Perosa,
• Sandro Guidi and
• Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

• remarkable example is the recently patented synthesis of sucrose-6-ester – a food sweetener – carried out over a mixture of sulfated oxides of various metals [8]. In addition, acidic ion exchange resins are worth mentioning in this context. Van de Steene et al. have proved the performance of such systems in

• necessarily require transition metal catalysis as did the EniChem and Ube processes. Instead, the reaction can be effectively catalyzed by a combination of supported basic ammonium resins and homogeneous alkaline bases [60], thereby demonstrating the potential of transition metal-free catalytic systems for

Cross-linked cyclodextrin-based material for treatment of metals and organic substances present in industrial discharge waters

• Élise Euvrard,
• Nadia Morin-Crini,
• Coline Druart,
• Justine Bugnet,
• Bernard Martel,
• Cesare Cosentino,
• Virginie Moutarlier and
• Grégorio Crini

Beilstein J. Org. Chem. 2016, 12, 1826–1838, doi:10.3762/bjoc.12.172

• by means of organic resins to remove inorganic pollutants (e.g., metals and anions such as fluorides). Charles et al. [2] recently reported that this type of sequence is acknowledged for its efficiency. However, it is an approach to water treatment that combines two methods of separation using two

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• in the Baeyer–Villiger reaction with increasing frequency. Various catalysts that activate hydrogen peroxide, such as heterogeneous catalysts based on solid acids [201], zeolites [202][203], Se [204], As [205], Co [206], sulfonated organic ion exchange resins [203][207], and homogeneous catalysts

• the presence of H2O2 and arsenic-containing ion exchange resins on polystyrene as the catalyst (Table 4) [203][205]. The mechanism of the oxidation of ketones 58a–f by hydrogen peroxide in the presence of arsonated polystyrene 60 as the catalyst is shown in Scheme 17. First, hydrogen peroxide reacts

Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions

• José M. Andrés,
• Miriam Ceballos,
• Alicia Maestro,
• Isabel Sanz and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2016, 12, 628–635, doi:10.3762/bjoc.12.61

• bifunctional thioureas on sulfonylpolystyrene resins has been studied in the nitro-Michael addition of different nucleophiles to trans-β-nitrostyrene derivatives. The activity of the catalysts depends on the length of the tether linking the chiral thiourea to the polymer. The best results were obtained with

Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

• Helmut Ritter,
• Monir Tabatabai and
• Markus Herrmann

Beilstein J. Org. Chem. 2016, 12, 245–252, doi:10.3762/bjoc.12.26

• polymerization; (meth)acryl polymers; neighboring group effects; solvent polarity; Introduction Amino groups are important functionalities in polymer chemistry, e.g., for hardening various epoxy resins [1]. However, they easily react in an undesired side reaction with electron-poor double bonds of (meth

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• highlights of this approach were the use of scavenger resins for intermediate purification and solvent switching operations as well as the use of in-line UV-monitoring needed to orchestrate the various reagent streams. Although the low solubility of various intermediates proved challenging, the designed

• formation (Scheme 5) [56]. This sequence again makes use of in-line scavenging resins for purification purposes and demonstrates the utility of in-line solvent switching protocols and high temperature reactor coils operating at 130–245 °C, well above the boiling points of the solvents employed. In the

• ]. The synthesis of a small collection of imidazo[1,2-a]pyridine derivatives was realised through the application of different scavenger resins for in-line purification as well as a number of liquid handlers to orchestrate the library synthesis effort (Scheme 24). Using this semi-automated process a

Highly selective generation of vanillin by anodic degradation of lignin: a combined approach of electrochemistry and product isolation by adsorption

• Dominik Schmitt,
• Carolin Regenbrecht,
• Marius Hartmer,
• Florian Stecker and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 473–480, doi:10.3762/bjoc.11.53

• . Electrolysis conditions are optimized regarding reaction temperatures below 100 °C allowing operation of aqueous electrolytes in simple experimental set-up. Employing ion exchange resins gives rise to a selective removal of low molecular weight phenols from the strongly alkaline electrolyte without

• resins was tested. It is known from literature that these resins can be utilized for phenol recovery from waste water streams at different pH [38]. These methods usually take advantage of the combined physi- and ionosorptive interactions between the resin and the adsorptive phase. In the case of

• phenolate stronger, ionic interactions usually dominate at basic pH [39]. But even under acidic conditions strong interactions between the polymer backbone and the adsorptive phase remain [40]. For this reason several commercially available resins were tested concerning their adsorption and desorption

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

• ], and it can be used to separate serine and threonine from mixtures of other amino acids (by acidic O-acetylation followed by O→N acetyl shift under basic conditions and subsequent separation of the N-acetyl derivatives of serine/threonine from other amino acids with ion exchange resins) [19][27

Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers

• Milo Malanga,
• Mihály Bálint,
• István Puskás,
• Kata Tuza,
• Tamás Sohajda,
• László Jicsinszky,
• Lajos Szente and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2014, 10, 3007–3018, doi:10.3762/bjoc.10.319

• into polymeric structures behave differently from their monomeric counterparts [4][5][6]. Depending on the requirements of application both highly soluble and water-insoluble polymers (gels, resins) can be produced. Furthermore, the polymeric structure can constrain the rate of rotation of the CDs. The

Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

• Ji-Hun Seo,
• Shino Nakagawa,
• Koichiro Hirata and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2014, 10, 2623–2629, doi:10.3762/bjoc.10.274

• (PRX) crosslinker with cleavable end groups was synthesized to develop degradable photosetting composite resins. The PRX containing 50 α-cyclodextrins (α-CDs) with disulfide end groups was initially modified with n-butylamine to obtain a resin monomer-soluble PRX. The PRX containing 13 n-butyl groups

• disassembling of PRX by a cytoplasmic reductant such as glutathione. The characteristic property of cleavable PRXs may also be harnessed to develop a stimuli-responsive crosslinker to modulate the hardness of acrylic resins. Acrylic resins are irreversible photosetting polymers adopted to increase the

• mechanical strength in various applied polymer materials used in industrial or biomedical fields [16][17]. For example, composite resins containing 2-hydroxyethyl methacrylate (HEMA) or methyl methacrylate (MMA) have been widely used to increase the mechanical strength of restorative or adhesive materials in

Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salen)Co(III) complex tethering four quaternary ammonium salts

• Jong Yeob Jeon,
• Seong Chan Eo,
• Jobi Kodiyan Varghese and
• Bun Yeoul Lee

Beilstein J. Org. Chem. 2014, 10, 1787–1795, doi:10.3762/bjoc.10.187

• applications. For example, the terpolymerization of CO2/PO/cyclohexene oxide (CHO) was successful, providing resins, of which the glass-transition temperatures (Tg) were modulated in the range of 50–100 °C according to the mole fraction of the incorporated CHO [24][25]. However, the feeding of a third monomer

Investigations of thiol-modified phenol derivatives for the use in thiol–ene photopolymerizations

• Sebastian Reinelt,
• Monir Tabatabai,
• Urs Karl Fischer,
• Norbert Moszner,
• Andreas Utterodt and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1733–1740, doi:10.3762/bjoc.10.180

• organic matrix used in the formulation of dental composites [1][2][3][4]. The shrinkage stress and the leachability of unreacted monomers due to an insufficient double bond conversion are two of the main drawbacks of dimethacrylate based dental resins and are still a driving force for dental researches [2

Orthogonal dual thiol–chloroacetyl and thiol–ene couplings for the sequential one-pot assembly of heteroglycoclusters

• Michele Fiore,
• Gour Chand Daskhan,
• Baptiste Thomas and
• Olivier Renaudet

Beilstein J. Org. Chem. 2014, 10, 1557–1563, doi:10.3762/bjoc.10.160

• directly upon acid cleavage (1% TFA in CH2Cl2). The resins were treated for 3 min repeatedly until the resin beads became dark purple. The combined washings were concentrated under reduced pressure, and white solid peptides were obtained by precipitation from diethyl ether. General procedure for peptide

Rasta resin–triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions

• Xuanshu Xia and
• Patrick H. Toy

Beilstein J. Org. Chem. 2014, 10, 1397–1405, doi:10.3762/bjoc.10.143

• to be an efficient and highly recyclable catalyst for aldehyde and ketone cyanosilylation reactions from which the products could also be obtained pure after only filtration and solvent removal [30]. It should be noted that the grafts of the rasta resins reported are random co-polymers, and the

• ), which bears both triphenylphosphine oxide and tertiary amine moieties, in order to increase the efficiency and appeal of our method. We have extensive experience in preparing functionalized resins with two different catalytic groups [35][36][37][38], and prepared 18 by oxidation of 19, which we

• to the substrate. Use of our rasta resins 16 and 18 required only a 20 mol % excess. Rasta resins 14 and 15. The Masaki–Fukui reaction and halophosphonium salt reduction. Representative reactions involving halophosphonium salts 3a,b. Catalytic Appel reactions reported by Denton and co-workers

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• ) group [43]). For a precise overview, the review of Isidro-Llobet 2009 and detailed manuals of major companies are recommended [44][45][46]. Optimal resins and linkers for peptide synthesis: The solid phase has to meet a number of requirements to be suitable for peptide synthesis. It has to be insoluble

• styrene and cross-linked divinylbenzene [20]. At present, there are mainly three classes of solid carriers: traditional polystyrene (PS), polyethylene glycol (PEG)-functionalized PS (such as TentaGel-supports [47]) and pure PEG-based resins such as PEGA resin [48] and ChemMatrix [49]. Shelton et al

• . recently published a collection of commonly used resins, together with their individual swelling and loading (is defined by the equivalents of amino acid in mmol/g, which can be attached to the resin) properties [50]. With respect to PEG-functionalized linkers, peptide synthesis yields can be improved by

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117