Phenotellurazine redox catalysts: elements of design for radical cross-dehydrogenative coupling reactions

• Alina Paffen,
• Christopher Cremer and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112

• chemical stability, to such an extent that it could be in large part recovered at the end of the reaction (see previous study) [33]. In other words, PTeZ2 (2-methoxy substituent) features the best compromise in terms of electronic effects, which affect both the stability and reactivity of the key

Synthesis and physical properties of tunable aryl alkyl ionic liquids based on 1-aryl-4,5-dimethylimidazolium cations

• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2024, 20, 1278–1285, doi:10.3762/bjoc.20.110

• aryl alkyl ionic liquid; viscosity; Introduction Ionic liquids (ILs) are a special class of solvents generally defined as salts with melting points below 100 °C [1]. Due to their unique properties, e.g., their high thermal stability and their negligible vapor pressure [2][3], ILs have found widespread

• already reported by our group [34] and piqued our interest on the performance of TAAILs based on this motif. Since the introduction of methyl groups in the backbone of the imidazolium core increases the stability and basicity of the corresponding imidazolium derivatives [35][36][37], we wanted to

• -term thermal stability was investigated using ramped temperature analysis. The thermal decomposition temperatures (Table 1) for the ILs with the NTf2 anion are in the range from 266 °C (IL 59) to 409 °C (IL 37). In general, most ionic liquids with a butyl chain show higher decomposition temperatures

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

• derivatives with an emphasis on tuning solubility and energy levels. Meanwhile, less attention has been devoted to improving the thermal stability of fullerene derivatives. One well-known example is [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which is recognized for its excellent solubility in solution

• improving their thermal stability, and more specifically, of designing evaporable fullerene derivatives [16][17][18]. Recently, we reported on perovskite solar cells fabricated with indano[60]fullerene ketone (FIDO), which was synthesized through fullerene cation chemistry. These cells demonstrated long

• -term stability and a remarkable PCE of 22.11%, surpassing that of the commonly used C60 (20.45%). This improved performance can be attributed to the evaporated amorphous film, which prevents the transformation of the film into a crystalline state during the heating and aging of the devices

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• -covalent interactions plots. Despite the structural similarities between germacrene A and hedycaryol cations, they possess a somewhat different stability trend. These differences are attributed to C+···OH intramolecular interactions present in some hedycaryol cations, which are absent in the carbocations

• derived from germecrene A. Keywords: carbocation; germacrene A; hedycaryol; stability trend; terpenes; Introduction Terpenoids form a large and highly diverse group of natural products with a wide range of usage in the pharmaceutical, cosmetic, agricultural, food, and energy industry. Among their

• reaction trajectory towards this pathway and make sure that it stays along this pathway and does not rearrange to a similar, more stable carbocation. Here, using density functional theory (DFT) calculations, we provide a rationale for the relative stability of the intermediate carbocations formed from

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

• perpendicularly. Unfortunately, the matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry of 3 afforded no molecular ion peak expected for adducts derived from Dip2Si and C60 while a base peak at m/z 720 due to C60 was observed probably because of the low stability of radical

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

• . In addition to the synthetic simplicity, the moisture stability of bismuth triflate allows the protocol to be carried out under ambient atmospheric conditions. Results and Discussion Preparation of β-ketoesters We initiated our studies with the preparation of the β-ketoesters, which were synthesized

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

• isoelectronic π-system (i.e., the same total number of rings). Isoacenofurans show limited stability due in part to the highly reactive 1,3-carbons of the furan ring. Both 1,3-dimesitylisobenzofuran and 1,3-di(2’,4’,6’-triethylphenyl)isobenzofuran, each bearing sterically congesting ortho-alkyl groups on their

• stabilized hexacenes. Their beautiful work documented the lack of stability associated with isoanthracenofurans. Thus, their 1,3-diarylisoanthracenofurans rapidly oxidized in solution to form endoperoxides [3]. These compounds persisted longer in the solid state, but clearly the lack of stability and

• (see Supporting Information File 1). The mesityl and 2’,4’,6’-triethylphenyl substituents both provide a strong measure of kinetic stabilization. Solution phase stability is particularly important if isoacenofurans are to be utilized as thin-film organic semiconductors cast from solution. Conclusion We

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

• characterised as the most potent inhibitor of human CDA, but the quick degradation in water limited the applicability as a potential therapeutic. To improve stability in water, we synthesised derivatives of phosphapyrimidine nucleoside having a CH2 group instead of the N3 atom in the nucleobase. A charge

• -neutral phosphinamide and a negatively charged phosphinic acid derivative had excellent stability in water at pH 7.4, but only the charge-neutral compound inhibited human CDA, similar to previously described 2'-deoxyzebularine (Ki = 8.0 ± 1.9 and 10.7 ± 0.5 µM, respectively). However, under basic

• scaffold, compounds Va–c (Figure 1B), in which the N3 atom present in the nucleobase of IV is replaced by CH2. We assumed that this change should not significantly affect the inhibitory potential but rather increase the stability of the target nucleosides in water and allow chemical incorporation into

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

• results on various substrates, the direct use of molecular bromine poses sustainability challenges. Its innate reactivity requires stringent safety protocols during transportation, storage, and handling [24]. A related concern involves the stability of the diluting media, often requiring the use of toxic

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

• Akanksha Ashok Sangolkar,
• Rama Krishna Kadiyam and
• Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

• the most versatile solvent to exhibit the best photoswitching behaviour which is beneficial for real-life energy storage applications. Additionally, the stability and reversibility of the photoswitching system with elongated unsaturated bridges have also been assessed. By means of the studied

• /kg), and TBR barrier (121.76 kJ/mol) of prototype NBD/QC in the gas phase. The outcomes render useful insights into the stability and properties of bicyclic diene-based photoswitches having elongated unsaturated bridges and indeed paves the way for the rational design of practical MOST systems

• solvents on the photoswitching properties has also been investigated for a real-life MOST application. The stability and the reversibility of the photoswitches have also been verified to attain a closed cyclic photoswitching process for practical MOST system. Results and Discussion As can be seen from

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

• studies. Conversion of the DCPQs into hydrogen-bonding capable DPQDs results in modulation of frontier MO energies, higher molar extinction coefficients, enhanced crystallinity, and on-average higher thermal stability (where in some cases the 5% weight loss temperature is increased by up to 100 °C

• and charge injection/extraction processes [7]. The additional merits of H-bonding designs in organic optoelectronic materials include higher thermal stability, synergistic stabilizing effects with π-stacking interactions, etc. [8]. Acenes and N-heteroacenes are two prominent π-conjugated scaffolds for

• functionality as well as Buchwald–Hartwig amination involving aryl halides. Thermal studies Thermal stabilities of DCPQs 1a–6a and DPQDs 1b–7b were evaluated using thermogravimetric analysis (TGA; Figure 2 and Table S4 in Supporting Information File 1). The thermal stability of the DCPQs is attributed to their

Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• attractive class of reagents due to their stability, accessibility, and diverse chemical reactivity [1]. Diaryliodonium(III) salts, in particular, have been widely recognized as efficient arylating reagents for a range of carbon, nitrogen, oxygen, sulfur, and other nucleophiles, and can be employed in the

• modifying their physical properties, and stability and controlling the reactivity of arylation processes, as demonstrated in various studies [9][10]. For instance, the Gaunt group reported that the use of a fluoride counterion in diaryliodonium(III) salt can trigger phenol O-arylation by activating the

Innovative synthesis of drug-like molecules using tetrazole as core building blocks

• Jingyao Li,
• Ajay L. Chandgude,
• Qiang Zheng and
• Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

• , metabolic stability, conformational rigidity, and potency [7][8][9]. Recently, the use of the tetrazole moiety in drug development has been increased and exhibited prevalent occurrence in bioactive compounds; being present in more than 20 marketed drugs with a very broad range of biological activities such

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

• therefore plays a very important role in many vital biological processes in the human body and other life forms. Uracil is rarely found in DNA, due to its lower stability and mutagenic properties when mismatched with guanine [2][3][4][5]. This fact can be used to differentiate between RNA and DNA-dependent

(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

• candidates in development. Bioisosteres of para-benzenes, such as those based on bicyclo[1.1.1]pentane, are now very common and can be used to increase aqueous solubility and improve metabolic stability, among other benefits. Bioisosteres of ortho- and meta-benzenes were for a long time severely

• early drug discovery process. In many cases, the primary aim is the enhancement of biological activity, but in others, modulation of other critical properties such as aqueous solubility, metabolic stability, polarity, or lipophilicity is the target. In the latter cases, there is often a desire to retain

• partition coefficient (logP) as a measure of compound polarity, aqueous solubility (desired value: >200 μM [26]), and intrinsic clearance rate (CLint, lower indicates higher metabolic stability) as a measure of metabolic stability. Additional properties will be discussed if comparative values have been

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• alkene reactivity is essential. Two reactivity scales for alkenes are available in the literature, one considering the reactivity of the alkene itself (Mayr scale) [25] and the other the stability of the corresponding cation after protonation (hydride affinities) [26]. In the polar hydrochlorination

• ). Conveniently, these parameters are freely available on Mayr's database of reactivity parameters [28]. On the other hand, one can assess the stability of the in situ-generated cation. The greater its stability, the easier the protonation of the alkene will be, making it more reactive towards hydrochlorination

• , HCl gas was bubbled through neat alkene 1 for several hours, as depicted in Scheme 3A [35]. This example highlights an intriguing regioselectivity that might have been challenging to predict through a simple analysis of the stability of the corresponding cations. Alternatively, the HCl gas was bubbled

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• biomacromolecule [10][11]. In this context, fluorinated porphyrins have attracted considerable interest due to their biological properties such as low toxicity, metabolic stability, and cellular uptake. The introduction of a fluorine atom into the molecule is the feasibility to change drastically its biological

• meso-pentafluorophenyl-substituted porphyrins. Carboranes, due to their unique physical and chemical properties such as high chemical and biological stability [28][29], three-dimensional aromaticity [30][31], low toxicity [28], high hydrophobicity, and enriched boron content [32][33] are perspective

• compounds in drug development [34][35][36][37]. Owing to their stability, carboranes also may increase the in vivo stability and bioavailability of pharmaceuticals that might otherwise rapidly metabolize [38]. The functionalization of porphyrins with carborane clusters provides dual-action photo(radio

Research progress on the pharmacological activity, biosynthetic pathways, and biosynthesis of crocins

• Zhongwei Hua,
• Nan Liu and
• Xiaohui Yan

Beilstein J. Org. Chem. 2024, 20, 741–752, doi:10.3762/bjoc.20.68

• ) ameliorates myocardial ischemia or myocardial infarction induced by coronary ligation. Although crocin and crocetin derivatives exhibit a diverse scope of biological activity, they are characterized by poor stability and low bioavailability, which has significantly impeded clinical developments. Recently

• , novel pharmaceutical systems, such as liposomes, microcapsules, and nanoparticles, were adopted to enhance the stability and bioavailability of these compounds [13][14][15]. To find a sustainable way of supplying crocins, researchers have developed various approaches to produce them, including plant

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• stability, etc. Emerging research methods on bioinformatics, computational modeling, deep learning, protein engineering, and high-throughput screening will accelerate the pace of enzyme discovery to provide a broader platform of tools for employing chemoenzymatic strategies [64][87][88][89]. More

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• ]. On the other hand, the nature of the alkene might be limited as it would strongly influence the oxidation potential of the carbon radical and the stability of the resulting carbocation. Recently, we reported the first successful application of an RPC strategy for the azido-alkynylation of styrenes

Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• orthogonal processing. One of the biggest challenges with n-type materials is air stability. This is explained by the redox potentials of water (−0.66 V vs standard calomel electrode (SCE)) and oxygen (+0.024 V vs SCE, +0.57 V vs SCE) [2][3]. Therefore, it has been observed that once the overpotential

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• is known for its chemical and thermal stability. Herein, we report a straightforward approach to the GBB-3CR using HPW as catalyst in ethanol under microwave (μw) heating. This convenient environmentally benign methodology is broad in scope, provides the heterobicyclic products in high yields (up to

• green catalyst with greater chemical and thermal stability in comparison to other heteropolyacids [43]. HPW has been shown to catalyze MCRs in the synthesis of heterocyclic compounds with high efficiency and chemoselectivity (Figure 2), including functionalized benzo[c]chromeno[2,3-a]phenazine [44

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• the potential energy surface, a curved conformation (conformation 2 in Figure 1d) exists. Our previous results suggested that conformation 2 is a metastable state. The relative stability of these conformations is known to vary depending on the surrounding environment, e.g., solvents and solutes [9

• ]. Actually, the presence of solutes consisting of water and proteins improves the stability of conformation 2. This stabilization is explained partly by the formation of hydrogen bonds between water molecules and PASE. Conformation 2 increases the number of sites where hydrogen bonds can form with water

• molecules because the chain portion of PASE turns upward. Therefore, the stabilization energy of hydrogen-bond formation is greater in conformation 2 than in conformation 1. To improve the stability of conformation 2, hydration effects by electrostatic interactions between PASE and the solvent are also

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• tackle catalyst stability by changing the chloride scavenger [23] or adding other coordinating moieties [24][25]. Hartwig et al. have argued that a Brønsted acid generated in situ from metal triflates may be the “real” catalyst promoting some alkene functionalizations [26]. Therefore, the possibility of

• other in the NMR spectrum. Although we observed reaction inhibition in a number of instances with [JPhosAu(NCCH3)]SbF6 we have never yet observed the formation of this byproduct. On the one hand, this is a testament to the high stability of gold supported by JPhos, on the other hand, it suggests as yet

• utilizing a dinuclear gold phosphine. These enhancements are likely correlated with increased catalyst stability. The earliest reports of alkene hydroamination revealed NHC’s and JPhos (t-Bu2)P(o-biphenyl) as the most active ligands [12][13][14], but this was in comparison to Ph3P which has since been