Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• equivalents of dihydroxyazobenzene 6 were used for the selective monoglycosylation step, with the excess of azobenene being recovered after column chromatography. Under these conditions, no bisglycosylated azobenzene was observed [28]. The observed 1,2-trans glycosylation could be explained either by the

• with 10% H2SO4 in EtOH and heating about 30 s at 400–600 °C. Column chromatography purification was performed on CombiFlash® Rf+ and RediSep® RF or RF Gold normal phase silica columns (with UV detection at 254 and 350 nm for all azobenzene derivatives), or by flash column chromatography employing

• concentrated under reduced pressure and purified by flash chromatography (cyclohexane/EtOAc 7:3) to give the thioglycoside. General procedure IV for the Zemplén deacetylation: To a seal tube containing the galactose derivatives in dry MeOH (0.15 M), NaOMe (30 mol %, 0.5 M sol. in MeOH) was added. The mixture

Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• purified by column chromatography on silica gel to give product 4. In the case of reacting with 3-NO2 bearing 2f, 2-benzylphenol 5f was partially obtained together with normal product 4fa. 4-CN substituted 2o generated 2-benzylphenol 5o exclusively. Synthesis of aniline derivatives from 2-cyclohexenones or

Rapid construction of tricyclic tetrahydrocyclopenta[4,5]pyrrolo[2,3-b]pyridine via isocyanide-based multicomponent reaction

• Xiu-Yu Chen,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2024, 20, 1436–1443, doi:10.3762/bjoc.20.126

• one hour. After removing the solvent by rotatory evaporation at reduced pressure, the residue was subjected to column chromatography with a mixture of ethyl acetate and petroleum ether (v/v = 1:4) as eluent to give the pure product for analysis. Pentamethyl rel-(4R,4aR,4bS,8aS)-1-benzyl-8-cyclohexyl-4

Synthesis of cyclic β-1,6-oligosaccharides from glucosamine monomers by electrochemical polyglycosylation

• Md Azadur Rahman,
• Hirofumi Endo,
• Takashi Yamamoto,
• Shoma Okushiba,
• Norihiko Sasaki and
• Toshiki Nokami

Beilstein J. Org. Chem. 2024, 20, 1421–1427, doi:10.3762/bjoc.20.124

• was further washed with aqueous 1 M HCl solution and dried over Na2SO4. Then, the solvent was removed under reduced pressure, and the crude product (220 mg) was purified with recycling preparative gel permeation chromatography equipped with two series-connected JAIGEL-2HH columns (eluent: CHCl3, flow

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• dissolved in DCM (10 mL), FeCl3 (30 mol %) added and magnetically stirred at room temperature. Within 2–30 h, the reactions went to completion (TLC monitoring), affording, at last, N,O-aminals 5a–r (42–82%) and the corresponding hemiaminals 6a–p (4–35%) after column chromatography (Scheme 3). An increased

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• . Louis, MO), or Acros Organics (Thermo Fisher Scientific, Geel, Belgium) and used without further purification. Thin-layer chromatography was performed using silica gel (60 F254, Merck, Darmstadt, Germany) plates. Melting points were recorded by Büchi melting point B-540 apparatus (Büchi Labortechnik AG

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• depend on their structures [1]. To obtain specific structures, remarkable progress has been made in separation of SWNTs by various methods such as gel column chromatography [2][3], aqueous two-phase extraction (ATPE) [4][5], and polymer wrapping [6][7]. As compared with these methods, our separation by

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• amount of Lawesson's reagent was increased to 3 equiv (Table 1, entry 5), the signal of thioketone was observed for the first time by high-performance liquid chromatography (HPLC) and MALDI time-of-flight mass spectrometry. Subsequently, a conversion of 99% was achieved by further increasing the amount

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• dienes has to proceed with full conversion and in high yield as the they cannot be purified by chromatography. Distillation is also problematic, as dienes containing substituents located at carbon atom C-2 readily undergo isomerization reactions. The reactions of 1,3-bis(silyloxy)-1,3-butadienes with

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• oxidative polymerization in the presence of SeO2. After recognizing the polymeric nature of the solid, we analyzed the small molecular species present in the supernatant. Thin-layer chromatography (TLC) of the supernatant revealed that it contained a mixture of compounds. We could not isolate monoselenide 1

• as a pure compound through column chromatography. The obtained fraction was a black solid as reported by Bhat et al., and HRMS analysis revealed a peak at m/z 265.0229, corresponding to [M + H]+ (Figure S4, Supporting Information File 1). However, we could not ascertain the identity of the compound

• methyl anthranilate with SeO2 (vide infra), which was also supported by single-crystal X-ray analysis. However, for aniline, in addition to the major polymerization and poor selenation process, solvent oxidation was also noted. Importantly, through column chromatography, the oxamide derivative 3 formed

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• -morpholino)propanesulfonic acid (MOPS) buffer (pH 7.5), and the cells were disrupted by ultrasonication to obtain the cell extract. Cell debris was removed by centrifugation (14,000g, 15 min). The proteins were purified by Ni-NTA agarose chromatography, desalted, and concentrated by centrifugation (8,000g

• , 30 min) in 10 kDa ultrafiltration tubes (Centriplus YM series, Merck Millipore). Protein concentration was quantified by the Bradford method. AlpJ, JadG, JadH, and E. coli flavin reductase (Fre) were overproduced and purified by Ni-NTA agarose chromatography as described previously [10][11][43][44

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• accompanied by mono-adduct 2 (22% yield) by silica gel flash column chromatography using mixed solvents of hexane/CH2Cl2 by changing the ratios of volumes from 10:1 to 3:1. In thin-layer chromatography (TLC) analysis using silica gel, the Rf values are 0.55 for 2 and 0.33 for 3, respectively, with hexane

• column chromatography (SiO2) using mixed solvents of hexane/CH2Cl2 by changing the ratios of volumes from 10:1 to 3:1. TLC analysis (SiO2, hexane/CH2Cl2 5:1) afforded Rf = 0.55 for 2 and Rf = 0.33 for 3, respectively. Data for compound 3: 1H NMR (CDCl3/CS2 3:1) δ 7.61 (t, J = 7.5 Hz, 1H), 7.56 (t, J

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• yields. For derivatives 9af,ag,bq, we observed the formation of an E/Z mixture of products that was inseparable by column chromatography. Synthesis of 3-aryl-2-ethoxycarbonyl-1-indanones and 3-aryl-1-indanones With the starting materials prepared, we began evaluating the use of bismuth salts to promote

• different compounds containing the indanone moiety. Synthesis of unsaturated β-ketoesters (Knoevenagel derivatives). aIsolated yield after purification using silica gel column chromatography. Synthesis of 3-aryl-2-ethoxycarbonyl-1-indanones mediated by bismuth triflate. aIsolated yield after purification

• using silica gel column chromatography. bExtensive degradation. cRecovery of starting material. Basic protocol: The Knoevenagel product 9 (0.5 mmol), dry acetonitrile (2 mL), and Bi(OTf)3 (0.05 mmol) were added to a sealed tube. The reaction mixture was stirred at 60 °C and monitored by TLC. Controlled

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• obtained using a solvent purification system (Innovative Technologies, Inc.) and handled under a nitrogen atmosphere, unless otherwise noted. Flash chromatography was performed using SiliaFlash® F60 40–63 µm (230–400 mesh) 60 Å silica from Silicycle Inc. and RediSep® Rf Silica Flash Columns (12 g, 24 g or

• 40 g) on a CombiFlash® Rf 200 instrument (Teledyne Isco, Inc.). Evaporation of solvents was accomplished using an IKA® RV 10 digital rotary evaporator. Baker-flex® silica gel IB2-F thin-layer chromatography (TLC) plates were purchased from J.T. Baker. A 4 watt 254 nm lamp (Analtytik Jena Co.) and a

• gel CombiFlash chromatography (hexane/EtOAc 9:1) to obtain 22 as a yellow solid (0.44 g, 35%, Scheme 5). Mp 59–60 °C; 1H NMR (500 MHz, CDCl3) δ 7.43 (s, 4H), 6.93 (s, 4H), 2.64 (q, J = 7.6 Hz, 4H), 2.53 (q, J = 7.5 Hz, 8H), 1.25 (t, J = 7.6 Hz, 6H), 1.08 (t, J = 7.5 Hz, 12H); 13C NMR (126 MHz, CDCl3

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• /Et3N, followed by silica gel column chromatography, led to the triethylammonium salt of 2-N-Boc-aminoethylphosphinic acid 5 in 50 % yield. Alkylation of acid 5 with methyl chloroacetate in the presence of TMSCl and Et3N took five days at room temperature, and compound 6 as triethylammonium salt was

• phosphinic acid 7 was further protected with benzyl alcohol by a procedure adopted from reference [67] using TBTU and Et3N in refluxing dichloroethane. Compound 8 was obtained in 65% yield after silica gel column chromatography. To synthesise a nucleobase for nucleosides Va and Vb, we first obtained

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• the addition was complete, the mixture was left under stirring for 1 h and 30 min. After the workup, operated as described previously, a brown slurry was obtained. Yield: 42%. The crude product was purified via column chromatography on silica gel 60, eluting with petroleum ether. The pure product

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• . Palladium(II) acetate and anhydrous 1,4-dioxane were purchased from Strem Chemicals or Sigma-Aldrich and used as received. Thin-layer chromatography (TLC) was performed on SiO2-60 F254 aluminum plates with visualization by UV light or staining. Flash column chromatography was performed using Purasil SiO2-60

A Diels–Alder probe for discovery of natural products containing furan moieties

• Alyssa S. Eggly,
• Namuunzul Otgontseren,
• Carson B. Roberts,
• Amir Y. Alwali,
• Haylie E. Hennigan and
• Elizabeth I. Parkinson

Beilstein J. Org. Chem. 2024, 20, 1001–1010, doi:10.3762/bjoc.20.88

• easily identifiable on liquid chromatography–mass spectrometry (LC–MS). The molecular probe, which undergoes this reaction with a variety of furans, was designed with both a UV-tag and a mass tag to enable easy identification. The probe has been tested with a variety of purified furans, including natural

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• two runs. Enantiomeric ratios (er) were determined by high-performance liquid chromatography (HPLC) analysis of the purified compounds. Heck–Matsuda reaction of N-tosyl-2,5-dihydro-1H-pyrrole (1b). Reaction conditions: 1) pyrroline 1b (0.30 mmol, 1.0 equiv), aryldiazonium salts 2 (0.60 mmol, 2.0 equiv

• chromatography (HPLC) analysis of the purified compounds. Heck–Matsuda reaction of the protected 2,5-dihydro-1H-pyrrole with Ns and 2-Ns groups (pyrrolines 1c, 1d). Reaction conditions: 1) pyrroline 1c or 1d (0.30 mmol, 1.0 equiv), aryldiazonium salts 2 (0.60 mmol, 2.0 equiv), Pd(TFA)2 (5 mol %), L1 (6 mol

• %), ZnCO3 (0.15 mmol, 0.5 equiv), MeOH (1.5 mL, 0.2 M), 40 °C, 4 h. 2) 1.0 mL Jones solution 2.5 M, 6 mL of acetone/water 3:1 (v/v), 1.5 h. Isolated yields were calculated from an average of two runs. Enantiomeric ratio (er) determined by high-performance liquid chromatography (HPLC) analysis of the

Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• of the desired amide 5a after 16 h at rt, which could be isolated in 80% yield after column chromatography. A survey of carboxylic acids 1 revealed that the one-pot approach is efficient for a variety of substitution profiles (Scheme 2). Aromatic acids bearing methyl substituents at the para-, ortho

• the optimised one-pot conditions with benzylamine (4a) resulted in the formation of the desired amide product, however, significant by-products were also observed. Careful column chromatography of the crude reaction mixture allowed for the partial isolation and characterisation of the

• benzothiazolium species would avoid the formation of thiocarbonyl difluoride, which is most likely responsible for the generation of thiourea 7. Pleasingly, under these conditions, amide 5s was formed smoothly with isolation by column chromatography providing the pure product in 71% yield (Scheme 3b). Furthermore

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• the reported procedures [41], the Ugi-azide reaction of 2-bromobenzaldehyde (1a, 1 mmol), allylamine hydrochloride (2, 1 mmol), trimethylsilyl azide (3, 1 mmol) and tert-butyl isocyanide (4a, 1 mmol) in MeOH at 40 °C for 24 h afforded 1,5-DS-1H-T 5a in 92% yield after chromatography purification. Our

• at 40 °C for 24 h in a sealed vial. Upon completion of the reaction, the reaction mixture was filtered and evaporated under vacuum to give crude products 5a. Further purification was conducted by flash chromatography with 1:6 petroleum ether/EtOAc to afford 5a in 92% yields. The adduct was confirmed

• was purified by flash chromatography with 1:4 ethyl acetate/petroleum ether to afford product 6a. General procedure for the one-pot synthesis of tetrazole-containing 1,2,3,4-tetrahydroisoquinolines 6 A mixture of 2-bromobenzaldehyde 1 (1 mmol), allylamine hydrochloride (2, 1 mmol), trimethylsilyl

Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• performed on a Bruker Apex Kappa-II CCD diffractometer. The solvents used, dimethyl sulfoxide and 1,4-dioxane, were purchased as dry solvents and applied without further purification. Other reagents, catalysts, ligands, acids, and bases were used as purchased from commercial suppliers. Column chromatography

• was performed on Merck Silica gel 60 (particle size 63–200 μm). Solvents for extraction and column chromatography were distilled prior employment. Representative method for the preparation of starting materials 5-Bromo-6-chloro-1,3-dimethyluracil (2). Uracil 1 (22.9 mmol; 4.00 g) was dissolved in

• by column chromatography (heptane/ethyl acetate). Representative procedure B for the synthesis of 4a–j. A mixture of 2 (402 µmol; 102 mg), Pd(CH3CN)2Cl2 (5 mol %; 23 µmol; 6 mg), CuI (5 mol %; 21 µmol; 4 mg) was dissolved in 1,4-dioxane (5 mL) and stirred for 5 min under an argon atmosphere. NEt3 (11

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• intramolecular crossed [2 + 2] cycloaddition strategy (Scheme 4C) [36]. They were able to avoid purification by column chromatography by transformation of BCH ester (±)-53 into BCH acid (±)-54, allowing isolation of pure 1,2-BCH (±)-54 by crystallisation. Through their synthesis they were able to access both

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• homologs to Vs NnlA, each homolog was recombinantly expressed in E. coli and purified. One of the five homologs, Pj NnlA, was found to be substantially insoluble and thus, could not be isolated. The remaining four homologs were isolated by immobilized metal affinity chromatography. While the most prominent

• contaminants but are either undissociated higher oligomer states or are oligomers whose formation is induced by SDS treatment, which has been observed for other proteins [29][30]. To characterize these oligomer states of native protein, analytical size exclusion chromatography data were collected (Figure 2B

• pET-28a(+)-TEV by GenScript. For protein expression, plasmids were electroporated into E. coli BL21(DE3) cells and protein was expressed and purified by immobilized metal affinity chromatography (IMAC) as previously described for Vs NnlA [21]. The only modification was that plasmids using pET-28a

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• mixture of ketone 9e and the O-alkylated enol ether by-product, which was then reduced using NaBH4 to give alcohol 10e with 98:2 selectivity. Similarly, the reaction of 4-methoxybenzyl bromide and 2 gave ketone 9f in 35% yield without chromatography, and when reduced resulted in only a single alcohol

• chiral auxiliary 10a, and following a survey of conditions and isolation protocols, a 90% yield was obtained when 10a was heated in the presence of 2 equivalents of SOCl2 and 5 equivalents of pyridine in DCE. Flash chromatography of the chloroalkyl ether 11a resulted in significant loss due to hydrolysis

• sulfites were not intermediates in the reaction manifold. Furthermore, the isolation of some starting alcohols in the reactions of 10b and 10d following chromatography was attributed to hydrolysis of the corresponding dialkyl sulfite 13b and 13d on silica, a process that can be acid or base-catalysed [26