Studying specificity in protein–glycosaminoglycan recognition with umbrella sampling

• Mateusz Marcisz,
• Sebastian Anila,
• Margrethe Gaardløs,
• Martin Zacharias and
• Sergey A. Samsonov

Beilstein J. Org. Chem. 2023, 19, 1933–1946, doi:10.3762/bjoc.19.144

• surface and in the extracellular matrix [4]. Due to their charged nature, they bind a large amount of water [5]. Although GAGs were previously considered just an inert glue surrounding the cell, GAG research in the past few decades has illustrated the crucial role in cell signaling processes, including

• functions results principally from their unique physicochemical and structural features, including high negative charge, high viscosity and lubrication propensities, unbranched polysaccharide structures, low compressibility as well as the ability to attract and imbibe large amounts of water [17]. Unlike

• complexes obtained by RS-REMD docking were performed in AMBER20 package [42]. A TIP3P truncated octahedron water box with a distance of 20 Å from the solute to the box’s border was used to solvate complexes. Na+ counterions were used to neutralize the charge of the system. Energy minimization was performed

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• also reported in the same study that the yield of 15b increased up to 62% when the water formed during the reaction was removed with CaH2. The initial results on biphenylene and its more extensively fused counterparts led to another notable study conducted by Jensen and Coleman in 1959 [34]. By

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• . The origin of autocatalysis on π-acidic surfaces was clarified only this year because the involvement of two molecules of water in the decisive transition state XI complicated the situation [70]. This reaction was intriguing for reasons beyond autocatalysis. It is the only example so far where

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• mmol, 3 equiv) was added at 0 °C, the suspension was stirred for 30 min and then, a DMF (5 mL) solution of compound 3 (0.74 g, 1.67 mmol, 1 equiv) was added. The mixture was stirred at rt for 3 h (TLC) before it was poured into ice-water. The suspension was extracted with chloroform (5 × 30 mL) and

• degassed with Ar. Then, ethynyltrimethylsilane (0.34 mL, 2.38 mmol, 2 equiv) was added and the reaction mixture was stirred at 55 °C overnight. The mixture was poured into sat. aqueous solution of NH4Cl and extracted with dichloromethane (4 × 60 mL). The combined extracts were washed with water, brine, and

• -dicarbonitrile (430 mg, 0.5 mmol, 1 equiv) in methanol (70 mL) and diethyl ether (20 mL) and the mixture was stirred under Ar for 1 h (TLC control). Then, the reaction mixture was diluted with dichloromethane and poured into water. The aqueous layer was extracted with dichloromethane (2 × 50 mL), the combined

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• under N2 atmosphere (Figure 4). The initial mass loss (5%) around 120 °C could be due to residual water and/or solvent. The highest decomposition was observed at around 405 oC and 14% of DMB-TT-TPA (8) remained without ash up to 750 °C, indicating that the compound has an excellent thermal stability

• reaction flask sealed and the mixture stirred at 75 °C for 48 h. Afterwards, the reaction mixture was filtered through celite eluting with CH2Cl2, extracted with CH2Cl2/water, and the organic phase was washed with sodium carbonate solution (10%) and water, dried over sodium sulfate, filtered, and the

• , dimesitylborofluoride (130 mg, 0.490 mmol) was added rapidly. The mixture was further stirred at −78 °C for 1 h, then, allowed to warm to room temperature and stirring was continued overnight. The solution was extracted with dichloromethane, and the organic layer was washed with Na2CO3 solution (10%) and water. The

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• acid ester 9 was hydrolyzed under basic conditions in an ethanol/water mixture. After the reaction, the pH of the mixture was adjusted to 4 with hydrochloric acid, which resulted in the precipitation of the product 10 in excellent yield (95%). Next, carboxylic acid 10 was converted into the

• , 2.5 equiv, Scheme 2) was added dropwise. The reaction mixture was stirred at 50 °C for 8 hours. The volatile components were removed under reduced pressure. To the resulting orange oil, water (60 mL) was added, and the product was extracted with dichloromethane (3 × 60 mL). The combined organic phase

• was washed with water (2 × 60 mL), dried over MgSO4, and concentrated in vacuo. The intermediate (1.24 g) was used in the next reaction without purification. The crude, N-Boc-protected intermediate was dissolved in dichloromethane (25 mL) and the solution cooled to 0 °C with an ice bath. Next

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• hydrogenation or hydrogen transfer [40], electrocatalysis coupled with water oxidation [41], and sustained visible-light-induced photocatalysis [42]. Among the different strategies available, the use of a mild photocatalytic process involving hole-driven hydrogen transfer with hydrogen donors or hole scavengers

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• NaN3 (1.40 g, 21.56 mmol, 6 equiv) were dissolved in MeCN (100 mL) and toluene (50 mL) in a round-bottom flask. The mixture was refluxed until reaction completion as monitored by TLC. Upon cooling, water was added (100 mL) and the compound was extracted with DCM (3 × 75 mL). The combined organic phases

• were washed with water and brine, followed by drying over MgSO4. After solvent removal the compound was obtained as a white solid (2.14 g, 97%). 1H NMR (CDCl3, 600 MHz) δ 7.23 (d, 3J = 8.5 Hz, 6H, HAr), 7.10–7.04 (overlapped signals, 8H, HAr), 6.75 (d, 3J = 8.8 Hz, 2H, HAr), 3.94 (t, 3J = 6.2 Hz, 2H

• 50% (2.25 g, 56.28 mmol, 26.4 equiv) was added dropwise, followed by TBAB (0.17 g, 0.53 mmol, 0.25 equiv). 2,6-Bis(bromomethyl)pyridine (0.56 g, 2.11 mmol, 1 equiv) was added after 30 minutes and the mixture was stirred for 2 days at room temperature. After solvent evaporation, water (50 mL) was

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• solvents and with water, it has been used in a large variety of (electro)chemical reactions [53]. The hydroxy group of this alcohol has a pKa of 9.3 [54][55], so we can expect that it is a suitable proton donor for this kind of reaction. We performed the photocatalytic CO2 reduction by dissolving in 5 mL 1

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• EtOH, and NaOH in water (Scheme 1). The key intermediate of the macrocycle preparation, imidate 4, was synthesized using the reported procedure [43] by refluxing a solution of aminopyrazole 3 in triethyl orthoformate. First, we studied the reaction of imidate 4 with hydrazine hydrate in EtOH under

• under reflux for 23 h. After the reaction had completed (monitored by 1H NMR spectroscopy), the obtained solution was concentrated under water pump vacuum upon heating in a water bath at 65 °C. The product was extracted from the resulting dense brown oil by trituration 4 times with a mixture of ether

• (1.026 g) was recrystallized from boiling DMF (255 mL). After precipitation completed, the solid was filtered, washed with cold DMF (3 × 5 mL). The filter cake was suspended in water (10 mL) for 5 min followed by suction, this procedure was repeated 3 times to remove DMF from crystals. After drying in a

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• liquors and, in both cases, XRD confirmed the obtention of the (E)-isomer, in an anti-conformation. Computational calculations (gas and water phases) were performed in order to confirm some of the structural and vibrational aspects of the compounds. An important intramolecular H bond involving the

• species (ROS) in vitro, which may be another mechanism through which the compound exerts its protective effects in the brain. From a drug development perspective, however, INHHQ has some pharmacological limitations, such as low solubility and certain susceptibility to hydrolysis in a water-rich medium

• water molecules in the network (calcd.: 9.47% for C18H20O5N2·2H2O, MW = 380.39 g mol−1). On the other hand, hdz-NO2 did not show any mass loss below 250 °C, indicating the absence of solvation molecules in the sample (C17H17O7N3, MW = 375.34 g mol−1). Single crystals of both compounds, as monohydrates

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• aggregation-induced emission (AIE) luminogen. The experimental (solvatochromic and emission in THF/water mixtures studies) and theoretical investigations prove that TPECNz retains cooperative hybridized local and charge transfer (HLCT) and weak AIE features. Thanks to its D–A–D-type structure with a proper

• solution. However, the moderate PLQY in thin films still makes TPECNz suitable for the deep-red OLEDs. In addition, the AIE characteristic of TPECNz was further investigated by observing its PL emissions in water/THF mixtures with different water fractions (fw = 0–95%). In such diverse solvent mixtures

• , the molecule will demonstrate different degrees of aggregation since it can dissolve really well in THF but is insoluble in water, resulting in colloidal nanoaggregates being formed in solutions with high water contents. As shown in Figure 4a and 4b, in pure THF, TPECNz deep-red emission color with

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• chlorobenzene at 293 K in the absence of light, air, and water. In each case the reaction is apparently first order in dopant, consistent with the rate law: previously demonstrated for 1bH and VI [9]. The rate constants, k, obtained assuming this rate law are shown in Table 2 (the value for 3b being similar to

• strongly bound dimers. Figure 8b compares the evolution of one of the distinctive VII •– absorptions when doping VII with excess 12 derivatives in chlorobenzene at 293 K in the absence of light, air, and water. In the case of the Y = 4-dimethylaminophenyl dimers 1b2 and 1g2, the VII•– absorption grows in

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• commercially available. Regarding the molecular design and their properties, porphyrins and crown ethers are like water and fire – they constitute the opposite elements (Figure 1). Porphyrins are built of four pyrrole rings, two of which are considered amine-like due to the presence of NH groups, whereas the

• , interacting with the calixpyrrole macrocycle through hydrogen bonds. The water molecule was bound near the fluoride and was further stabilised through hydrogen bonding to the oxygen atoms in the central part of the receptor. This selective fluoride binding was evidenced with the help of 1H NMR spectroscopy

• axially bound H2O. The water molecule was stabilised by hydrogen bonding to the diaza-crown-6 core. Over the years, significant advancements have been made in crown ether-capped porphyrins, demonstrating their versatile applications in host–guest chemistry, multitopic receptor design, and cation sensing

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• adding a methanol/water mixture; thus, no lengthy purification steps were required for any of the syntheses. Yields of 52.4%, 80.2%, 58.1%, and 68.3% were obtained for PDIN-FB, PDIN-B, CN-PDIN-FB, and CN-PDIN-B, respectively. All compounds were structurally characterized using 1H NMR spectroscopy, 13C

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• ), and the extract suspended in water was sequentially partitioned with ethyl acetate and n-butanol. Breynin J (1), epibreynin J (2), and probreynin I (4) together with known compounds 6 and 7 were isolated from the n-butanol fraction (Figure 1). Probreynogenin (3) and known compound 5 were obtained from

• the solution was evaporated in vacuo to afford a MeOH extract (47.2 g). The MeOH extract was partitioned three times with 1.6 L of ethyl acetate and water 1:1 (v/v), and the water-soluble fraction was further partitioned three times with 800 mL of n-butanol. The ethyl acetate and n-butanol solutions

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• lacquerwares several thousand years ago [5]. The surface coating of lacquerwares was made up of a sap from a lacquer tree growing in Asia. The lacquer sap obtained from Rhus vernicifera lacquer tree mainly consists of urushiol (60–65%), water (20–30%), lacquer polysaccharide (3–7%), water-insoluble

• water phase and oil phase into an emulsion phase. The simultaneous presence of a hydrophobic head and a hydrophilic tail on emulsifiers provides the ability to combine water and oil phase into an emulsion. In emulsion polymerization, high molecular weights can be achieved at fast polymerization rates

Cyclodextrins permeabilize DPPC liposome membranes: a focus on cholesterol content, cyclodextrin type, and concentration

• Ghenwa Nasr,
• Hélène Greige-Gerges,
• Sophie Fourmentin,
• Abdelhamid Elaissari and
• Nathalie Khreich

Beilstein J. Org. Chem. 2023, 19, 1570–1579, doi:10.3762/bjoc.19.115

• internal cavity and a hydrophilic outer surface [1]. The common CDs are the native α-CD, β-CD, and γ-CD consisting of 6, 7, and 8 ᴅ-glucopyranose units, respectively. Due to their limited water solubility (especially β-CD), native CDs can be chemically or enzymatically modified (by e.g., alkylation

• , arylation, hydroxypropylation, amination, etherification, etc.) giving rise to synthetic CD derivatives with greater water solubility [2]. Thanks to their unique structure, CDs can offer exclusive advantages by allowing the entrapment of lipophilic molecules inside their inner cavities. This inclusion

• improves the chemical stability and aqueous solubility of the guest molecule and results in most of the cases in the formation of a water-soluble CD–guest complex [3]. Being recognized as non-toxic, biodegradable, and sustainable carriers, CDs have attracted wide interest as potential carriers in different

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• × 50 mm, Phenomenex), and Nucleosil 120 OH Diol (7 µm, 250 × 21 mm, Machery-Nagel, Düren, Germany) columns maintained at room temperature. Normal phase p-HPLC equipped with DAD detector (Agilent 1100 Series, Santa Clara, USA) was connected to a Nucleosil 120 OH Diol column. Deionized water used for RP

• p-HPLC was obtained from a Milli-Q water purification system (Millipore, Schwalbach, Germany) and all organic solvents and reagents were of analytical grade. Evaporation of solvents from fractions was performed using rotary evaporators equipped with a vacuum controller and diaphragm pump vacuum (Hei

• Erlenmeyer flasks of 500 mL, each containing 80 g of rice and 100 mL distilled water and incubated at 25 °C. After 28 days, the cultures were harvested. The fungal mycelia were further extracted with ethyl acetate and the solution was concentrated under reduced pressure to yield 12.2 g of crude extract. 12 g

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

• Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

• potential environmental impacts [14]. For a synthetic purpose, the melting point of the DES and its viscosity are key parameters for the convenience of their use. Indeed, DES viscosities are generally higher than those of water and other common organic solvents and a too high viscosity can act as an

• proline/lactic acid/water (1:2:2.5). The authors studied their use in the synthesis of aurones via a Knoevenagel condensation and compared them to the classical choline-based DES, ChCl/Gly (1:2). They demonstrated that the ʟ-proline-based DES were superior to ChCl/Gly and obtained aurones from the

• aldehydes to study the scope of this reaction (Scheme 1). It must be noted that in most of the cases, the reaction mixture changed its appearance from colorless to yellow or orange and that some solid precipitate formed during the reaction. The addition of water at the end of the reaction clearly led to the

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• -catalyzed sulfenylation by N-(sulfenyl)succinimides/phthalimides In 2012, Chen and co-workers found that in the reaction of N-(organothio)succinimides 1 and sodium sulfinates 2 using a Lewis acid in ionic liquids (ILs) and water as a green solvent system leads to the formation of thiosulfonates 3 (Scheme 2

• by Guo and Wu et al. (Scheme 19) [56]. Employment of a reusable heterogeneous nanomaterial, mild reaction conditions, avoiding the use of any additive, or base, and water/EtOH as a green solvent system were the advantages of this new method. N-Sulfenyl sulfoximines 45 were synthesized as coupling

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs

• Binbin Gu,
• Lin-Fu Liang and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1452–1459, doi:10.3762/bjoc.19.104

• higher concentrations (10 μg L−1) [15]. The compound has received considerable attention because of its potential to cause odour episodes in water supply systems [16][17]. The production of 1 by Penicillium can add to the flavour of cheese [18], while its occurrence in fish and coffee leads to an

• by two sequential cyclisation reactions to A and B, and terminal quenching with water. This hypothesis was confirmed by the discovery of the biosynthetic genes coding for a GPP methyltransferase (GPPMT) and a type I terpene synthase termed 2-methylisoborneol synthase (2MIBS) [23][24]. Interestingly

• , 0 °C) solution of (E)-2,3,7-trimethylocta-2,6-dien-1-ol [22] (500 mg, 2.97 mmol, 1.0 equiv) was added PBr3 (322 mg, 1.19 mmol, 0.4 equiv) dropwise. The mixture was stirred at 0 °C for 45 min, and then quenched by pouring onto ice-water (20 mL). The aqueous phase was extracted with Et2O (3 × 20 mL

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• yields of the products were poor. Then, a non-chlorinated solvent such as toluene was used which furnished the complexes in moderate to excellent yields (Scheme 20). The use of water as solvent was found to be viable in the case of the NHCs bearing aryl substituent groups. However, the reaction of alkyl

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• presence of sodium ascorbate as reducing agent and sodium carbonate as base as well as ʟ-proline as ligand in a DMF/water mixture at 60 °C provided this promising result. These conditions applied are similar to those described by Fokin et al. [24], which had also been employed by other groups [37][38]. The

• acetonitrile/water as solvent furnished the exclusively isolated bis(1,2,3-triazole) derivative 12 in excellent 94% yield. These conditions of the one-pot nucleophilic substitution double-click reaction became the standard reaction conditions and were applied in most of the following experiments. When the

Functional characterisation of twelve terpene synthases from actinobacteria

• Anuj K. Chhalodia,
• Houchao Xu,
• Georges B. Tabekoueng,
• Binbin Gu,
• Kizerbo A. Taizoumbe,
• Lukas Lauterbach and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

• 26 can be well understood from the cyclisation mechanism towards 23 (Scheme 1B). After substrate ionisation to A a 1,10-cyclisation leads to the (E,E)-germacradienyl cation (B) that can either be deprotonated to 24 or captured with water to yield 26. Both compounds are important neutral intermediates