Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• activity towards AβpE3-42 but accomplishing increased solubility. Due to the multifactorial pathogenesis of AD, one of the current drug discovery approaches is the so-called multitarget-directed ligands (MTDLs). In 2015, Benchekroun et al. [38] reported the design, synthesis, and biological evaluation of a

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• activates the Cu–Cl bond via chloride···calixpyrrole (N–H···Cl) hydrogen-bonding interactions toward the formation of the nitrene intermediate from chloramine-T (NaCl=NTs). Additionally, calix[4]pyrrole served as a phase-transfer catalyst in this reaction. Since chloramine-T had low solubility in

• acetonitrile, calix[4]pyrrole enhanced its solubility, contributing to its indirect activation. Various control experiments, such as using CuI with and without calix[4]pyrrole and using dipyrromethane as another potential co-catalyst, have confirmed the role of calix[4]pyrrole as a promoter. Recently

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• acetylenes at ca. 85 ppm and 95 ppm were observed. The norbornadienes 1h–l,n exhibit very good solubility in organic solvents, like ethyl acetate, chloroform, or benzene, whereas they have poor solubility in cyclohexane, acetonitrile, or ethanol. In polar protic solvents, like methanol or water, they are

• reactions of 1i and 1l (20 µM) were investigated in the presence of [Ru(phen)3](PF6)2 (20 µM) at λex = 520 nm in acetonitrile (Scheme 4). This solvent was required because of the solubility of the sensitizer. Under these conditions, both derivatives 1i and 1l showed the same development of absorption

• be investigated in the presence of the photosensitizer because these substrates have no sufficient solubility in acetonitrile. To assess the efficiency of the photoreactions, photoisomerization quantum yields were determined in cyclohexane by actinometry (λex = 310 nm or 340 nm) [41][42]. The quantum

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• ]rotaxane 11 (Figure 12). In this synthesis, the hydroxy groups on CDs were completely acetylated to facilitate ROP only from the axle-end diol moieties and increase the solubility of [3]rotaxane. Further, subjecting the polymer to heat treatment induced the deslipping of CDs from the central alkyl chain on

Tailored charge-neutral self-assembled L₂Zn₂ container for taming oxalate

• David Ocklenburg and
• David Van Craen

Beilstein J. Org. Chem. 2024, 20, 3007–3015, doi:10.3762/bjoc.20.250

• be volatile to simplify complex purification. Second, the solubility of the neutral host complexes usually needs to be improved by the installation of solubility groups, which must be considered during ligand design. The biggest strength of metallocages and metallocontainers, whether they are

• previously reported methods. Building block S2, based on dipropargylamine, is synthesized via a Schotten–Baumann reaction with benzoyl chloride, resulting in the flexible dialkyne backbone with a yield of 95%. The functionalization was envisioned to enhance the solubility of the ligand as we usually have

• ligand resulted in no clean formation of a charge-neutral metallocontainer with zinc(II) acetate. We believe that the modification with benzoyl chloride does not only alter the solubility but also shields the secondary amine which might act as additional coordination site. Binding of monocarboxylate

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• properties. Due to the low solubility of violanthrone in the majority of organic solvents, special attention has been drawn to its dihydroxy derivative (Figure 1), which allows further modification to the materials via etherification or esterification [29][30]. There has been a report on the structural

• mobilities (μh) of 3b and 3c are calculated as 1.07 × 10−2 and 1.21 × 10−3 cm2 V−1s−1, respectively. However, the hole mobility of 3a is only 3.62 × 10−6 cm2 V−1 s−1. Side chain engineering is crucial for OFET performance since it plays an important role in determining solubility, molecular packing, polarity

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• nature of X− [45][46]. Anions like tetrafluoroborate, hexafluorophosphate, and trifluoromethanesulfate are commonly used in DAIS due to their good solubility and weak nucleophilicity. If the two aryl groups (Ar1 and Ar2) in DAIS are different, they are termed unsymmetric diaryliodonium salts 3. The

• when a minimal quantity of water was used as a solvent in the presence of a base. The ball-milling method efficiently simplified the reaction process because, in contrast to typical solution methods, it may realize product formation without being affected by the solubility of the substrate and other

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

• represent promising candidates for drug discovery, because of their improved water solubility, membrane permeability, and improved recognition by the respective receptors [16]. The present article aims to provide an updated review of the chemistry and biological applications of N-glycosides of indigo

• -rhamnosides α-17a and α-17c, respectively (Scheme 14) [23]. Water solubility plays an important role with regard to the pharmacological activity. It was previously shown that the water solubility and anticancer activity of non-glycosylated indirubins can be improved by conversion of the keto to an oxime group

• -glycosylated indirubins act as a ligand for the aryl hydrocarbon receptor (AhR) and also directly inhibit several cyclin-dependent kinases (CDK). A problem is generally the low water solubility of these compounds. The commercially available indirubin-3’-monoxime (34) shows a better solubility, due to the

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• − in the aqueous state at a pH of 7.4 due to its weak acidic nature and high solubility in water (80 mM at 37 °C) [6]. Elevated levels of H2S in groundwater pose high risks to both human health and aquatic ecosystems [7], compelling rigorous monitoring of water sources. Even though sensors for

• aqueous hydrogen sulfide and 100 ppb for gaseous hydrogen sulfide [16]. However, due to the limited aqueous solubility and ligand dissociation of this chemosensor, and to the weakly luminescent bis species at usable concentrations, we extended this work to the lanthanide–macrocycle binary complexes [Ln

• -DPA)3]3−, Tb.1 exhibited limited solubility in water, becoming insoluble at concentrations exceeding 100 μM. Therefore, a 1 mM stock solution of Tb.1 was prepared in DMSO, with the final concentration of DMSO in analytical solutions kept at ≤5%. Initial luminescence analysis of a 5 μM solution of Tb.1

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines

• Dmitriy Yu. Vandyshev,
• Daria A. Mangusheva,
• Khidmet S. Shikhaliev,
• Kirill A. Scherbakov,
• Oleg N. Burov,
• Alexander D. Zagrebaev,
• Tatiana N. Khmelevskaya,
• Alexey S. Trenin and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2024, 20, 2806–2817, doi:10.3762/bjoc.20.236

• on the analysis of existing data [28], taking into account experimentally obtained data on the solubility of the starting reagents. The tested solvents were dioxane, PhMe, MeOH, EtOH, iPrOH, MeCN, and DMF (dimethylformamide). Sodium acetate as an additive was necessary for converting 2-aminoimidazole

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• bicolor [8]. These ethers are also found in the scent glands of other reptiles such as lizards [40] and probably act as detergents to increase the solubility of apolar lipids. Amides have been found in Dumeril's Boa and the western diamondback rattlesnake, among others [5][11]. The secretion has also been

Deciphering the mechanism of γ-cyclodextrin’s hydrophobic cavity hydration: an integrated experimental and theoretical study

• Stiliyana Pereva,
• Stefan Dobrev,
• Tsveta Sarafska,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2024, 20, 2635–2643, doi:10.3762/bjoc.20.221

• increased solubility of the entrapped molecules, led to the wide range of applications in the pharmaceutical, food, cosmetic, agricultural, and other industries. It is well established that in the absence of other candidates, water molecules fill the CDs void [6][7][8][9][10]. The number and geometric

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• crystallise and disrupt the network, or change the stability and solubility of any charged structures present. All of these issues could result in statistics which are not representative of the structures in situ [31]. To overcome this, cryogenic techniques are widely used to allow the investigation of a

Transition-metal-free synthesis of arylboronates via thermal generation of aryl radicals from triarylbismuthines in air

• Yuki Yamamoto,
• Yuki Konakazawa,
• Kohsuke Fujiwara and
• Akiya Ogawa

Beilstein J. Org. Chem. 2024, 20, 2577–2584, doi:10.3762/bjoc.20.216

• ). We first investigated the solubility of 1 and 2 in various solvents. It was found that both 1 and 2 showed excellent solubility towards benzotrifluoride (BTF) [61] (for diboron 2: 637 mg/mL (BTF); 567 mg/mL (AcOEt)). Therefore, BTF is chosen as the solvent. Surprisingly, heating the mixture of 1 and

• arylboronates. For example, the use of triarylbismuthines with o-methyl, m-methyl, p-methyl, p-methoxy, and p-chloro groups successfully afforded the corresponding arylboronates 3a–e and 3g in 62–73% yields, respectively. The low solubility of tri(p-fluorophenyl) and tri(1-naphthyl)bismuthines 1h and 1k in BTF

Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling

• Jiapeng Guo,
• Weike Su and
• An Su

Beilstein J. Org. Chem. 2024, 20, 2408–2420, doi:10.3762/bjoc.20.205

• significance and practical value for process optimization. Results and Discussion In this section, we perform kinetic modeling for the continuous flow synthesis of NIO from IO and mixed acid (Scheme 1). The reaction was then optimized by kinetic modeling. Prescreening experiments The solubility of IO in H2SO4

Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• )AuCl was applied with a catalyst loading of 2 mol %, activated by an equal amount of the DAI salt. Due to solubility issues, the reaction had to be performed in methylene chloride instead of chloroform. The gold-catalyzed cyclization reaction (Scheme 2) was followed via 1H NMR spectroscopy (Figure 3

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

• Hisanori Senboku and
• Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

• intermediates at the anode. The produced acetate ion D and a magnesium ion form the salt E, which upon acid treatment during workup gives a diphenylacetic acid 2. The effects of DMSO as solvent are not clear at present, and one reasonable and acceptable aspect might be the solubility of the salt of intermediate

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• with a 1,2,4-triazole-5-thione ring was studied in a MeCN–DMSO mixture to increase its solubility. The first redox transition is detected at early potential values (0.85 V) which coincides with the value obtained for the corresponding starting thiol. However, there is a peak at E = −0.11 V on the

Tandem diazotization/cyclization approach for the synthesis of a fused 1,2,3-triazinone-furazan/furoxan heterocyclic system

• Yuri A. Sidunets,
• Valeriya G. Melekhina and
• Leonid L. Fershtat

Beilstein J. Org. Chem. 2024, 20, 2342–2348, doi:10.3762/bjoc.20.200

• low yield of 4-(mesityldiazenyl)-3-(p-tolylcarbamoyl)-1,2,5-oxadiazole 2-oxide (4) is likely due to the moderate solubility of the starting amide 2a in TFA. To improve the solubility of compound 2a, we tested mixtures of acids as solvent (Table 1, entries 5–8). Thus, the best yield of product 4 was

Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

• Phong Thai,
• Lauv Patel,
• Diyasha Manna and
• David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

• of HFIP (Scheme 4). First, 1H NMR was employed to examine the interaction between HFIP and iminoiodinane 2c in CD3CN (compound 2c was chosen over 2a due to its increased solubility in nonprotic solvents). In a sample of 2c with 4 equivalents of HFIP, a broad signal for O–H proton of HFIP was observed

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

Cell-free protein synthesis with technical additives – expanding the parameter space of in vitro gene expression

• Tabea Bartsch,
• Stephan Lütz and
• Katrin Rosenthal

Beilstein J. Org. Chem. 2024, 20, 2242–2253, doi:10.3762/bjoc.20.192

• different concentrations of water-soluble solvents are shown in Table 2. MTBE and n-hexane have low solubility in water and formed a second phase on top of the aqueous CFPS solution. For experiments with n-hexane and MTBE, the size of the vessel was reduced and the reaction volume was increased to 100 µL to

• precipitation of proteins [54], which would decrease the amount of detectable CFPS product. Other publications describe that the solubility of proteins can be improved with increasing salt concentration by the addition of NaCl [55]. Testing of other salts at high concentrations is necessary to clarify whether

• -hexane due to the low solubility of n-hexane in water, a limited interfacial area, and evaporation in the headspace. There is no clear trend for the influence of the polarity or log P of the added solvents. Among the water-miscible additives, methanol, whose dipole moment is relatively close to that of

Selective hydrolysis of α-oxo ketene N,S-acetals in water: switchable aqueous synthesis of β-keto thioesters and β-keto amides

• Haifeng Yu,
• Wanting Zhang,
• Xuejing Cui,
• Zida Liu,
• Xifu Zhang and
• Xiaobo Zhao

Beilstein J. Org. Chem. 2024, 20, 2225–2233, doi:10.3762/bjoc.20.190

• by other acids such as H2SO4 and CF3SO3H, the reaction showed poor effectiveness due to the poor solubility of 1a in water (Table 1, entries 4 and 5). Most notably, 2a was an inseparable mixture of keto and enol isomers, reaching a keto/enol ratio of 5:4 as determined by 1H NMR spectroscopy. Thus

• ). Firstly, we chose NaOH to optimize the reaction conditions. Apparently, in the absence of a solubilizer, no reaction occurred due to poor solubility of 1a in boiling water (Table 1, entry 6). Macrogol 400 (PEG-400) is emerging as an environmentally friendly nonionic solubilizer due to its unique merits

• , such as nontoxicity, inexpensiveness, nonflammability, low volatility and good water solubility, which are consistent with the concept of green chemistry [74][75]. Therefore, we tested the reaction in the presence of PEG-400 (Table 1, entries 7–9). It was found that the reaction uniquely produced 3a in

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• partial solubility of ethylene glycol in methoxycyclopentane as ethylene glycol could be clearly seen in the 1H NMR spectrum of the crude reaction extracts. It should also be noted that the lower isolated yields most likely reflect mechanical losses during extraction and chromatographic separation as the

Heterocycle-guided synthesis of m-hetarylanilines via three-component benzannulation

• Andrey R. Galeev,
• Maksim V. Dmitriev,
• Alexander S. Novikov and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2024, 20, 2208–2216, doi:10.3762/bjoc.20.188

• diketone 1b, bearing the less electron-withdrawing 1,3,4-oxadiazole moiety (σm/σp 0.335/0.443), with alkylamines proceeded well (73–74% yields), but required the addition of CHCl3 as co-solvent due to the low solubility of the starting 1,3-diketone 1b. On the other hand, the reaction of 1,3-diketone 1b