Novel solid-phase strategy for the synthesis of ligand-targeted fluorescent-labelled chelating peptide conjugates as a theranostic tool for cancer

• Sagnik Sengupta,
• Mena Asha Krishnan,
• Premansh Dudhe,
• Ramesh B. Reddy,
• Bishnubasu Giri,
• Sudeshna Chattopadhyay and
• Venkatesh Chelvam

Beilstein J. Org. Chem. 2018, 14, 2665–2679, doi:10.3762/bjoc.14.244

• differentially protected Fmoc-Lys-(Tfa)-OH plays a vital role in attaching fluorescent tags while growing the peptide chain in an uninterrupted manner. The methodology is versatile for solid-phase resins that are sensitive to mild and strong acidic conditions when acid-sensitive side chain amino protecting

• in commercial resins such as Universal Nova tag or hyperacid labile resins such as Rink acid [26], 4-hydroxymethylphenoxybutyryl (HMPB), chlorotrityl [27], SASRIN [28] and Sieber amide [29]. Even though such resins are very useful, they suffer from several disadvantages. For example, i) they are cost

• commonly available and less expensive cysteine-labelled 2-chlorotrityl resin (Figure 1b). The methodology is general and can be significantly useful for acid-sensitive resins that contain acid-labile orthogonal amino acids with 4-methoxytrityl (Mmt) and 4-methyltrityl (Mtt) protecting groups. Results and

Defining the hydrophobic interactions that drive competence stimulating peptide (CSP)-ComD binding in Streptococcus pneumoniae

• Bimal Koirala,
• Robert A. Hillman,
• Erin K. Tiwold,
• Michael A. Bertucci and
• Yftah Tal-Gan

Beilstein J. Org. Chem. 2018, 14, 1769–1777, doi:10.3762/bjoc.14.151

• reagents and instrumentation. All chemical reagents and solvents were purchased from Sigma-Aldrich and used without further purification. Water (18 MΩ) was purified using a Millipore Analyzer Feed System. Solid-phase resins were purchased from Chem-Impex or P3 Biosystems. Reversed-phase high-performance

Recyclable hypervalent-iodine-mediated solid-phase peptide synthesis and cyclic peptide synthesis

• Dan Liu,
• Ya-Li Guo,
• Jin Qu and
• Chi Zhang

Beilstein J. Org. Chem. 2018, 14, 1112–1119, doi:10.3762/bjoc.14.97

• equiv of Fmoc-protected amino acids, 3.0 equiv of FPID, 3.0 equiv of (4-MeOC6H4)3P and 3.0 equiv of TEA in DMF. After chain elongation and deprotection of Fmoc, the resulting resins were treated with 0.5% TFA/DCM to give the N,C-unprotected peptides as final products. The peptides were purified by

Liquid-assisted grinding and ion pairing regulates percentage conversion and diastereoselectivity of the Wittig reaction under mechanochemical conditions

• Kendra Leahy Denlinger,
• Lianna Ortiz-Trankina,
• Preston Carr,
• Kingsley Benson,
• Daniel C. Waddell and
• James Mack

Beilstein J. Org. Chem. 2018, 14, 688–696, doi:10.3762/bjoc.14.57

• the ones obtained under traditional solution-based conditions. First, we observed that using functionalized resins allowed us to isolate the desired product in an easy and environmentally benign manner. Second, we observed that the incorporation of liquid-assisted grinding (LAG) increased the rate of

Synthetic mRNA capping

• Fabian Muttach,
• Nils Muthmann and
• Andrea Rentmeister

Beilstein J. Org. Chem. 2017, 13, 2819–2832, doi:10.3762/bjoc.13.274

• translational activity in an in vitro translation assay. Besides their use in the preparation of cap-modified RNAs via IVT, cap analogues have found alternative applications. Since cap-binding proteins (e.g., eIF4E and DcpS) have high affinity to cap analogues, resins functionalized with the cap analogue m7GTP

• can be used to purify binding proteins from fractionated cell lysates [74][75][76]. Using m7G-modified sepharose resins, novel cap-binding proteins such as gemin-5 could be identified [77]. The affinity resins can be stabilized via methylene moieties, preventing enzymatic degradation of the cap

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