Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

• Xingyu Xu,
• Shiqing Huang,
• Zengyu Zhang,
• Lei Cao and
• Xiaoyu Yan

Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

• good yield (Scheme 1). The product 2-I was characterized by 1H NMR, 13C NMR, and high-resolution mass spectrometry. 2-I has a poor solubility in most organic solvents such as dichloromethane, trichloromethane, tetrahydrofuran, and ethanol. A single crystal of 2-I was obtained by slow diffusion of ether

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• MHz) or an Avance 300 (1H: 300 MHz, 13C: 75 MHz) spectrometer. Chemical shifts are reported in ppm (δ) and are referenced to the NMR solvent residual peaks. Abbreviations used are s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet. Reagent grade tetrahydrofuran (THF) was distilled under

An improved, scalable synthesis of Notum inhibitor LP-922056 using 1-chloro-1,2-benziodoxol-3-one as a superior electrophilic chlorinating agent

• Nicky J. Willis,
• Elliott D. Bayle,
• George Papageorgiou,
• David Steadman,
• Benjamin N. Atkinson,
• William Mahy and
• Paul V. Fish

Beilstein J. Org. Chem. 2019, 15, 2790–2797, doi:10.3762/bjoc.15.271

• . Yields are the ranges obtained from repeated reactions. DMF, N,N-dimethylformamide; NBS, N-bromosuccinimide; THF, tetrahydrofuran. Chlorination of 6 with N-chlorosuccinimide (NCS). Reagents and conditions: (a) NCS (1.2 equiv), AcOH, 55 °C, 7 h, 15–32%. Improved synthesis of 5. Reagents and conditions: (a

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• emission band with a maximum at 401, 442, and 420 nm, in acetonitrile, respectively. These are tentatively assigned to π–π* transitions of the variable aryl moiety. Interestingly, in tetrahydrofuran, containing oxygen as donor atom, only the SW emission band is seen, i.e., λfluo,max = 409 nm (16), 402 nm

• LW band is substituted by a strong blue-shifted emission. This leads to a clear ratiometric behavior and a large dynamic response. The blue-shifted emission for the fluoroboronate Lewis adduct is in accordance with the observations made for donor solvents such as tetrahydrofuran (see above). As for

Synthetic terpenoids in the world of fragrances: Iso E Super^® is the showcase

• Alexey Stepanyuk and
• Andreas Kirschning

Beilstein J. Org. Chem. 2019, 15, 2590–2602, doi:10.3762/bjoc.15.252

• yield a new cation, which in turn is nucleophilically trapped by the carbinol moiety. The resulting tetrahydrofuran 59 is chemically stable and this observation was used as rationale for the erosion of the isomeric ratio observed during prolonged reaction times. In the same piece of work Fráter et al

• Plus® (34). Products 58 (α double bond) and product 53 (β double bond) are not desired [26]. Iso E Super Plus® (34) can undergo a third cyclisation to tetrahydrofuran 59 through compound rac-53 [22]. New unnatural terpenoid 70 from unnatural farnesyl pyrophosphate derivative 69 and comparison with

• natural biotransformation (67→68) and olfactory property of tetrahydrofuran 70 [39]. Individual components of the complex Iso E Super® mixture. Top fragrances with regard to their volume percentage (listed down to about 20%; the large number of perfumes with lower percentages are not listed) of Iso E

α,ß-Didehydrosuberoylanilide hydroxamic acid (DDSAHA) as precursor and possible analogue of the anticancer drug SAHA

• Shital K. Chattopadhyay,
• Subhankar Ghosh,
• Sarita Sarkar and
• Kakali Bhadra

Beilstein J. Org. Chem. 2019, 15, 2524–2533, doi:10.3762/bjoc.15.245

• , removal of the O-benzyl group keeping the double bond intact proved to be problematic under a range of conditions. Pleasingly, use of BCl3 in tetrahydrofuran solvent effected the desired transformation but in a modest yield of 51%. Changing the solvent to dichloromethane and using a lower temperature

Sugar-derived oxazolone pseudotetrapeptide as γ-turn inducer and anion-selective transporter

• Sachin S. Burade,
• Sushil V. Pawar,
• Tanmoy Saha,
• Navanath Kumbhar,
• Amol S. Kotmale,
• Manzoor Ahmad,
• Pinaki Talukdar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2019, 15, 2419–2427, doi:10.3762/bjoc.15.234

• stereochemically stable quaternary carbon center [1]. For example, TAA-derived peptides containing a cyclopropane ring and ʟ/ᴅ-dimethyl tartrate showed an α-turn and form 310-helical conformations in higher oligomers [2][3][4]. While, TAA-derived peptides having a tetrahydrofuran ring demonstrated a β-turn type

Effect of ring size on photoisomerization properties of stiff stilbene macrocycles

• Sandra Olsson,
• Óscar Benito Pérez,
• Magnus Blom and
• Adolf Gogoll

Beilstein J. Org. Chem. 2019, 15, 2408–2418, doi:10.3762/bjoc.15.233

• dichloromethane (DCM), ethyl acetate, pentane, tetrahydrofuran (THF) and toluene that were distilled before use. N,N-Dimethylformamide (DMF) was used as supplied (biotech. grade, ≥99.9%). Unless stated differently, all reactions were carried out under atmospheric pressure and with argon atmosphere. Microwave (MW

Synthesis of acremines A, B and F and studies on the bisacremines

• Nils Winter and
• Dirk Trauner

Beilstein J. Org. Chem. 2019, 15, 2271–2276, doi:10.3762/bjoc.15.219

• should then close the tetrahydrofuran ring of the natural product. Upon irradiation of 5 using a Hg lamp, however, the only productive pathway which could be observed was isomerization of the disubstituted double bond (Table 1, entries 17 and 18). Again, we attempted to promote the reaction by tethering

Multiple threading of a triple-calix[6]arene host

• Veronica Iuliano,
• Roberta Ciao,
• Emanuele Vignola,
• Carmen Talotta,
• Patrizia Iannece,
• Margherita De Rosa,
• Annunziata Soriente,
• Carmine Gaeta and
• Placido Neri

Beilstein J. Org. Chem. 2019, 15, 2092–2104, doi:10.3762/bjoc.15.207

• mass spectra were calibrated externally, and a linear calibration was applied. All chemicals were reagent grade and were used without further purification. Tetrahydrofuran was dried by heating under reflux over sodium wire in the presence of benzophenone as indicator while dimethylformamide was dried

Archangelolide: A sesquiterpene lactone with immunobiological potential from Laserpitium archangelica

• Silvie Rimpelová,
• Michal Jurášek,
• Lucie Peterková,
• Jiří Bejček,
• Vojtěch Spiwok,
• Miloš Majdl,
• Michal Jirásko,
• Miloš Buděšínský,
• Juraj Harmatha,
• Eva Kmoníčková,
• Pavel Drašar and
• Tomáš Ruml

Beilstein J. Org. Chem. 2019, 15, 1933–1944, doi:10.3762/bjoc.15.189

• , dicyclohexylurea; Dns, dansyl amide; DMAP, 4-dimethylaminopyridine; DTB, 8-O-(dodecanoyl-8-O-debutanoyltrilobolid); IL-6, interleukin 6; IL-1β, interleukin 1β; INF-γ, interferon gamma; TBTA, tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine; TEA, triethylamine; THF, tetrahydrofuran; TLC, thin-layer chromatography

Complexation of 2,6-helic[6]arene and its derivatives with 1,1′-dimethyl-4,4′-bipyridinium salts and protonated 4,4'-bipyridinium salts: an acid–base controllable complexation

• Jing Li,
• Qiang Shi,
• Ying Han and
• Chuan-Feng Chen

Beilstein J. Org. Chem. 2019, 15, 1795–1804, doi:10.3762/bjoc.15.173

• methyl-substituted derivative H2 were prepared according to previously reported methods [30]. Starting from helic[6]arene H1, helic[6]arene derivatives H3 and H4 were conveniently synthesized by etherification of H1 with bromobutane or 2-bromoethyl methyl ether, respectively, in tetrahydrofuran in the

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• both pairs of ethyl esters [26]. When a mixture of tert-butyl esters (2R,1'S)-5d and (2S,1'S)-5d was subjected to kinetic resolution in the presence of potassium tert-butoxide in tetrahydrofuran (2R,1'S)-5d was produced with low 40% de [27]. The absolute configuration at C2 in esters 5 was established

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• toluene (40 mL), tetrahydrofuran (60 mL) and water (10 mL). After bubbling argon through the mixture for 15 min, Pd(PPh3)4 (300 mg, 0.3 mmol) was added, and the mixture was stirred and refluxed for 8 h. Then, the reaction mixture was extracted with dichloromethane, and the organic layer was dried over

Transient and intermediate carbocations in ruthenium tetroxide oxidation of saturated rings

• Manuel Pedrón,
• Laura Legnani,
• Maria-Assunta Chiacchio,
• Pierluigi Caramella,
• Tomás Tejero and
• Pedro Merino

Beilstein J. Org. Chem. 2019, 15, 1552–1562, doi:10.3762/bjoc.15.158

• tetroxide-mediated oxidation of cyclopentane, tetrahydrofuran, tetrahydrothiophene and N-substituted pyrrolidines has been studied computationally by DFT and topological (analysis of the electron localization function, ELF) methods. In agreement with experimental observations and previous DFT calculations

• oxidation of cyclopentane, tetrahydrofuran, tetrahydrothiophene, and N-methyl- and N-benzylpyrrolidine to evaluate the extension in which transient carbocations can be formed (and whether they can become energy minima) during the rate-limiting step (Scheme 3). The RuO4 oxidation of cyclopentane [44] and

• tetrahydrofuran [45] have been experimentally reported as well as the oxidation of N-acylpyrrolidines to the corresponding lactams [46]. Admittedly, the oxidation of tetrahydrothiophene has been approached only computationally since in that case the sulfur atom would be more easily oxidized. Since the general

A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates

• András György Németh,
• György Miklós Keserű and
• Péter Ábrányi-Balogh

Beilstein J. Org. Chem. 2019, 15, 1523–1533, doi:10.3762/bjoc.15.155

• and HPLC–MS. Based on preliminary experiments in our laboratory, the reaction was performed in tetrahydrofuran (THF) at 40 °C for 1 h using a 1.5 equiv excess of sodium hydride as the base, S8 and the alcohol component (Table 1, entry 1) resulting in the desired thiocarbamate 3a in 58% yield. During

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• 1,1’-bis(diphenylphosphino)ferrocene (dppf) from Frontier Scientific. Absolute tetrahydrofuran, dichloromethane, and toluene were provided from Sigma-Aldrich and purified using a Büchi MB SPS-800. Dimethyl sulfoxide, acetonitrile, and acetone were purchased from Merck and Sigma-Aldrich, purified, and

Stereo- and regioselective hydroboration of 1-exo-methylene pyranoses: discovery of aryltriazolylmethyl C-galactopyranosides as selective galectin-1 inhibitors

• Alexander Dahlqvist,
• Axel Furevi,
• Niklas Warlin,
• Hakon Leffler and
• Ulf J. Nilsson

Beilstein J. Org. Chem. 2019, 15, 1046–1060, doi:10.3762/bjoc.15.102

• -galactoheptulose (3): Compound 2 (3.66 g, 6.82 mmol) was dissolved in dry tetrahydrofuran (130 mL) under nitrogen and cooled to 0 °C. Borane dimethyl sulfide complex in dry tetrahydrofuran (4.78 mL, 9.55 mmol, 2 M) was added slowly, and the reaction was kept at 0 °C for 2 h. The reaction mixture went from light

• , 577.2566. 3,4,5,7-Tetra-O-benzyl-2-deoxy-β-D-mannoheptulose (5): Compound 4 (35 mg, 0.065 mmol) was dissolved in dry tetrahydrofuran (3 mL) under nitrogen and cooled to 0 °C. Borane dimethyl sulfide complex in dry tetrahydrofuran (40 µL, 0.078 mmol, 2 M) was added slowly and the reaction was kept at 0 °C

• , 129.86, 129.49, 129.45, 129.2, 129.1, 128.99, 128.95, 86.7, 81.4, 81.3, 77.4, 76.5, 76.4, 74.8, 73.3, 71.8, 62.9; HRMS (m/z): [M + H]+ calcd for 555.2743; found, 555.2747. 3,4,5,7-Tetra-O-benzyl-2-deoxy-β-D-glucoheptulose (7): Compound 6 (67 mg, 0.125 mmol) was dissolved in dry tetrahydrofuran (3 mL

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• investigated in this work (Scheme 1). Results and Discussion As a common biodegradable polymer, PCL has been frequently reported as the fiber template material for the fabrication of electrospun nanofibers. Various common solvents such as acetone, dichloromethane, chloroform, tetrahydrofuran, DMF or their

Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration

• Sora Park and
• Jeung Gon Kim

Beilstein J. Org. Chem. 2019, 15, 963–970, doi:10.3762/bjoc.15.93

• polymerization usually requires long reaction times to achieve high conversions (Table 1) [27]. The DBU-catalyzed polymerization of trimethylene carbonate in chloroform, tetrahydrofuran, toluene, and methylene chloride converted less than 5% monomer into poly(trimethylene carbonate) (PTMC) within 1 h (Table 1

• ). The RI measurements were carried out using an instrument set composed of a Waters 1515 isocratic pump, a 2414 differential refractive index detector, and a column-heating module with Shodex KF-804, KF-803, and KF-802.5 columns in series. The columns were eluted with tetrahydrofuran (preservative-free

Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors

• Kirill B. Polyanskii,
• Kseniia A. Alekseeva,
• Pavel V. Raspertov,
• Pavel A. Kumandin,
• Eugeniya V. Nikitina,
• Atash V. Gurbanov and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73

• in the presence of air. Boiling in tetrahydrofuran or acetonitrile even under an argon atmosphere leads to a rapid decomposition of the catalysts within 5–10 minutes (the solutions turn black). Therefore, THF and MeCN were excluded from further studies. In the test reactions, three concentrations of

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• TraceGC Ultra (GC–MS). Column chromatography was performed with Fluka silica gel 60 (230–400 mesh) and thin-layer chromatography was carried out by using Merck TLC Silicagel 60F254 aluminium sheets. Tetrahydrofuran (THF) and toluene were refluxed under nitrogen over sodium wire and a small amount of

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• chromatographically and spectroscopically homogeneous materials. Anhydrous methylene chloride, dimethylformamide and acetonitrile were obtained by distillation over CaH2, tetrahydrofuran was obtained by distillation over sodium. Commercial reagents were used as received. NMR spectra were recorded on Bruker Avance 300

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

• then adjusted to 4 and then to 6–7 and the aqueous solution containing the nicotinamide riboside was mixed with an aqueous saturated sodium chloride solution and extracted with a considerable volume of tetrahydrofuran to remove excess of Nam and sodium trifluoromethanesulfonate. After multiple cycles