N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• debenzylation of 7a gave product 7b which was transformed to the desired product 7c by reaction with sodium methoxide and subsequent treatment with acidic ion exchange resin Amberlyst 15. The synthesis of akashins A–C was studied next. This required the synthesis of the corresponding indigo and carbohydrate

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• -exchange resin, with no apparent presence of tin impurities by NMR when the sequence was executed in this order and sulfated target 2 was obtained in a 66% yield on a one-gram scale. Comparing the 1H,13C HSQC spectra of compounds 1 and 2, there is a clear downfield shift of the H-3’/C-3’ signal from 1 to

• , led to isolation of a mixture of 2 and a tin-related impurity (n-butyl chain evident by NMR). Acetylation of this material followed by flash chromatography proved ineffective in removing the unwanted entity. To overcome this problem, flash chromatography was performed before stirring with the ion

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• has not been isolated from natural sources. This material was obtained by treatment of (+)-6,11-epoxyeudesmane (41) with acidic ion exchange resin (Scheme 12A) [94]. Also 4βH,5α-eremophila-1(10),7(11)-diene (39), biosynthetically accessible from I2a by 1,2-methyl shift to I2b and deprotonation (Scheme

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• was cyclized under acidic conditions with Amberlyst 15TM ion exchange resin embedded inside the flow reactor. However, successful conversion to an industrial process was hindered by the fact that polymerization of the starting material myrcene (85) could not be suppressed, leading to fouling of the

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• ). When a solution of 15a in dichloromethane was treated with Amberlyst 15, an ion exchange resin with a strongly acidic sulfonic acid [40], it was rapidly adsorbed and presumably protonated, but it could be displaced from the resin upon treatment with aqueous sodium hydrogen carbonate (Table 1, entries

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• ion-exchange resin containing sulfonic acid sites in the one-pot conversion of ball-milled cellulose to isosorbide [26]. A yield of 8% of isosorbide was obtained at 190 °C in the presence of Pt/C (Pt = 2 wt %) catalyst (0.2 g), 1 g of Amberlyst 70 from 0.324 g of milled cellulose diluted in 40 g of

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Indium-mediated C-allylation of melibiose

• Christian Denner,
• Manuel Gintner,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2019, 15, 2458–2464, doi:10.3762/bjoc.15.238

• main product was crystallized and the configuration was determined by X-ray analysis proving the expected syn-configuration (compound 2-syn) [CCDC 1922520] (Figure 1). Epimer 2-syn was applied to Zemplén conditions prior to the ozonolysis. Conventional work-up, neutralization with acidic ion exchange

• resin followed by filtration and removal of the solvent under reduced pressure, led to precipitation of compound 3-syn, thereby causing problems during the ozonolysis. Thus, dichloromethane was added to the reaction mixture immediately after completed Zemplén-deprotection (as indicated by TLC) without

Influence of per-O-sulfation upon the conformational behaviour of common furanosides

• Alexey G. Gerbst,
• Vadim B. Krylov,
• Dmitry A. Argunov,
• Maksim I. Petruk,
• Arsenii S. Solovev,
• Andrey S. Dmitrenok and
• Nikolay E. Nifantiev

Beilstein J. Org. Chem. 2019, 15, 685–694, doi:10.3762/bjoc.15.63

• -sulfated furanosides is reported. Results and Discussion Synthesis of per-O-sulfated furanosides Propyl α-D-mannofuranoside (1) was prepared from D-mannose and n-propanol via Fischer reaction using ion-exchange resin IR-120(H+) as acidic catalyst. The reaction was performed under kinetic control and was

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes

• Fabienne Speck,
• David Rombach and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 52–59, doi:10.3762/bjoc.15.5

• conditions or heated ion exchange resin [21][22]. These methods are therefore not suitable for the alkoxylation of acid or base-labile substrates. To overcome the current limitations of reduction potentials of single electron transfer processes in photoredox catalysis we present herein a range of new N

Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH

• Femke Beiroth,
• Tomas Koudelka,
• Thorsten Overath,
• Stefan D. Knight,
• Andreas Tholey and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163

• at room temperature for 3 h. After complete conversion, the solvent was removed under reduced pressure, co-distilled with toluene and neutralized with basic ion exchange resin in methanol. The crude product was then dried together with diazirine 8 [28] (27.6 mg, 120 µmol) and HATU (83.7 mg, 220 µmol

• basic ion exchange resin in methanol. The resin was filtered off and the solvent removed under reduced pressure. The primary amine was then dried under vacuum together with the diazirine 8 [28] (56.0 mg, 250 µmol) und HATU (114 mg, 300 µmol) for 30 min. The substances were dissolved in dry DMF (10 mL

• (140 µL) were added. The reaction solution was stirred at room temperature for 15 h. The solution was neutralized with an acidic ion exchange resin (Amberlyst-A21), filtered and concentrated under reduced pressure. The crude product was purified by column chromatography (ethyl acetate/methanol 3:1

N-Propargylamines: versatile building blocks in the construction of thiazole cores

• S. Arshadi,
• E. Vessally,
• L. Edjlali,
• R. Hosseinzadeh-Khanmiri and
• E. Ghorbani-Kalhor

Beilstein J. Org. Chem. 2017, 13, 625–638, doi:10.3762/bjoc.13.61

• cyclocondensation and the desired products were obtained in excellent yields [77]. Other systems such as Pd(OAc)2/THF [78], D301R (a tertiary amine-functionalized ion-exchange resin)/biphenyl [79], and diethylamine/NaOH/H2O [80] were also successfully employed in this transformation. Despite all these successes

Exploring architectures displaying multimeric presentations of a trihydroxypiperidine iminosugar

• Camilla Matassini,
• Stefania Mirabella,
• Andrea Goti,
• Inmaculada Robina,
• Antonio J. Moreno-Vargas and
• Francesca Cardona

Beilstein J. Org. Chem. 2015, 11, 2631–2640, doi:10.3762/bjoc.11.282

• flash column chromatography (Scheme 4). Subsequent treatment of 7 in acidic MeOH at room temperature for 18 hours gave the hydrochloride salt 8 (Scheme 4), which was passed through ion exchange resin Dowex 50WX8-200 eluting successively with MeOH, H2O and 6% NH4OH. This general purification procedure

• (13) in the presence of CuSO4/sodium ascorbate in THF/H2O 2:1 at room temperature affording adduct 14 in 96% yield (Scheme 6). Final deprotection by treatment with MeOH/HCl and eluting over ion exchange resin Dowex 50WX8-200, afforded the monovalent compound 15 in 77% yield. Searching for a

• , H2O and 6% NH4OH over ion exchange resin Dowex 50WX8-200 afforded 9 mg (0.008 mmol) of corresponding free amine and 42 mg (0.032 mmol) of hydrochloride salt (MeOH fraction). This fraction was dissolved in pyridine (1.2 mL) and acetic anhydride (0.8 mL) was added. The solution was stirred at room

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

• with dry acidic ion exchange resin and filtered off. The solvent was removed by evaporation and the crude product was used in the next reaction without purification. 2-(Pyridine-2-yldisulfanyl)ethanol (581 mg, 3.11 mmol) was added to the crude compound in degassed MeCN/DCM/MeOH (4 mL, 2:1:1 v/v/v

Are D-manno-configured Amadori products ligands of the bacterial lectin FimH?

• Tobias-Elias Gloe,
• Insa Stamer,
• Cornelia Hojnik,
• Tanja M. Wrodnigg and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 1096–1104, doi:10.3762/bjoc.11.123

• NaOMe (1.0 M in MeOH) was added dropwise at rt until the pH of 10 was reached and the reaction mixture was stirred at rt for 2 h until TLC (Cy/EtOAc, 1:2 v/v) showed complete consumption of the starting material. The reaction mixture was neutralized by addition of ion exchange resin (Amberlite IR 120 H

• starting from compound 6. The NMR data are in accordance with those reported [19]. To a solution of 3,4:6,7-di-O-isopropylidene-protected heptose (2.50 g, 8.61 mmol) in a mixture of MeCN/H2O (50 mL, 1:1 v/v,), acidic ion exchange resin (Amberlite IR 120 H+, washed with H2O) was added until a pH of 2 was

• leads to C-glycosyl-type glycoconjugates, namely 1-amino-1-deoxyketoses. Synthesis of D-glycero-D-galacto/D-talo-heptopyranose 8a and 8b: a) O3, NaOAc, Me2S, CH2Cl2/MeOH, −50 °C, b) NaOMe, MeOH; c) ion exchange resin IR 120 H+, H2O/MeCN. Amadori rearrangement of heptoaldose 8 with propargylamine and

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

• vanillin (1) was investigated and no loss of activity was observed. This indicates that adsorption of vanillin (1) has no negative influence on stability of the ion exchange resin (see Supporting Information File 2). Conclusion In conclusion, our approach combines a highly selective electrochemical

• exchange resins. Experiments were performed at two different NaOH concentrations and desorption was realized by acidic treatment of the loaded resins. Different attractive interactions between ion exchange resin and the vanillate anion. Recovery of vanillin (1) by adsorption from lignin containing reaction

Synthesis of divalent ligands of β-thio- and β-N-galactopyranosides and related lactosides and their evaluation as substrates and inhibitors of Trypanosoma cruzi trans-sialidase

• María Emilia Cano,
• Rosalía Agusti,
• Alejandro J. Cagnoni,
• María Florencia Tesoriero,
• José Kovensky,
• María Laura Uhrig and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 3073–3086, doi:10.3762/bjoc.10.324

• Compounds 10, 12, 15, 17, 19 and 21 (0.10 mmol) were deacetylated by treatment with a solution of Et3N/MeOH/H2O 1:4:5 as previously described [45]. Further purification by a mixed bed ion-exchange resin and an octadecyl (C18) mini column was accomplished. Purity was checked by TLC (n-BuOH/EtOH/H2O, 2.5:1:1

Synthesis and solvodynamic diameter measurements of closely related mannodendrimers for the study of multivalent carbohydrate–protein interactions

• Yoann M. Chabre,
• Alex Papadopoulos,
• Alexandre A. Arnold and
• René Roy

Beilstein J. Org. Chem. 2014, 10, 1524–1535, doi:10.3762/bjoc.10.157

• 15 min period. After removal of the solvents with a Pasteur pipette, the residue was dissolved in H2O (3 mL), and the pH was adjusted to 7 by the addition of ion-exchange resin (Amberlite IR 120 H+). After filtration, the solvent was removed under vacuum with a rotary evaporator and lyophilized to

• of H2O, and the pH was adjusted to 7 with addition of ion-exchange resin (Amberlite IR 120 H+). After filtration, the solvent was removed under vacuum with a rotary evaporator and lyophilized to yield the fully deprotected 27-mer 23 as a white solid (17.0 mg, 1.63 μmol) in 82% yield. 1H NMR (600 MHz

A novel family of (1-aminoalkyl)(trifluoromethyl)- and -(difluoromethyl)phosphinic acids – analogues of α-amino acids

• Natalia V. Pavlenko,
• Tatiana I. Oos,
• Yurii L. Yagupolskii,
• Igor I. Gerus,
• Uwe Doeller and
• Lothar Willms

Beilstein J. Org. Chem. 2014, 10, 722–731, doi:10.3762/bjoc.10.66

• acetaminomethylenemalonate have been used to prepare the title compounds. Experimental All reactions with P–H compounds were performed under an argon atmosphere. Flash chromatography was carried out using Merck silica gel 60 (230–400 mesh ASTM) and Aldrich ion-exchange resin Dowex WX-50. The NMR spectra were recorded on

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• performed with Amberlyst-15 ion-exchange resin. This approach was used in the multistep synthesis of the natural endoperoxide 9,10-dihydroplakortin, which exhibits antimalarial and anticancer activities as do its structural analogues [320][321]. 2-(3,6,6-Trimethyl-1,2-dioxan-3-yl)ethanol (224) was

Synthesis and stability study of a new major metabolite of γ-hydroxybutyric acid

• Ida Nymann Petersen,
• Jesper Langgaard Kristensen,
• Christian Tortzen,
• Torben Breindahl and
• Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2013, 9, 641–646, doi:10.3762/bjoc.9.72

• -exchange resin provided the required GHB glucuronides 2 and d4-2 in good yield. 1H NMR analysis of d4-2 showed the complete absence of methylene groups b and c (Figure 2). In addition, analysis of d4-2 by mass spectrometry showed the presence of less than 0.14% of 2, thus satisfying the demand for a highly

• alcohol 11 in good yield. Oxidation of alcohol 11 was carried out similarly to that reported elsewhere [19], using Epp and Widlanski’s TEMPO oxidation procedure [28] to furnish carboxylic acids 12 and d4-12 (Scheme 3). Finally, deprotection under basic condition followed by treatment with an acidic ion

Synthesis and testing of the first azobenzene mannobioside as photoswitchable ligand for the bacterial lectin FimH

• Vijayanand Chandrasekaran,
• Katharina Kolbe,
• Femke Beiroth and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2013, 9, 223–233, doi:10.3762/bjoc.9.26

• mL), a catalytic amount of solid NaOMe was added under N2 atmosphere, and the reaction mixture was stirred for 5 h at rt. Then it was neutralized with Amberlite IR 120 ion-exchange resin and filtered. The filtrate was evaporated under reduced pressure to yield the deprotected mannoside 6 as a pale

• atmosphere. The reaction mixture was stirred for 5 h at rt, and then it was neutralized with Amberlite IR 120 ion-exchange resin. It was then filtered and thoroughly washed with MeOH (2 × 20 mL), and the filtrate was evaporated to obtain the crude product, which after purification by flash column

S-Fluorenylmethyl protection of the cysteine side chain upon N^α-Fmoc deprotection

• Johannes W. Wehner and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2012, 8, 2149–2155, doi:10.3762/bjoc.8.242

• acidic ion-exchange resin (Amberlite IR 120) was added, and the mixture was stirred for 5 min to allow neutralization of the solution. After filtration of the resin, the solvent was removed under reduced pressure, and the crude product was purified on silica gel (ethyl acetate/ethanol, 7:1) yielding 9