Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• identical molecular peak ion and C, H, N values within acceptable deviation of 0.4%. The decomposition temperature (Td, corresponds to 5% weight loss) was measured by thermogravimetric analysis (TGA) indicating excellent thermal stability for 4BGIPN with Td = 425 °C, which is similar to the benchmark

• particular isomer that could show superior photophysical TADF characteristics important for fabricating TADF OLED devices with improved operating stability. Experimental General considerations All reactions were performed under a N2 atmosphere. Solvents were dried as required. Sodium hydride was washed from

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• on increasing solubility and stability while decreasing the reduction potential, weight, and cost of the anolyte species. To this end, Sanford and co-workers have worked on developing pyridinium analogues to out-perform the bipyridinium viologens [65][66]. The pyridinium analogue represented in

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• mercaptopurine (Figure 1), containing an intracyclic thioamide group, are antagonists of purine bases and are well known as cytostatic drugs [13]. The thioamide group as an amide isostere is used in medical chemistry to increase thermal and proteolytic stability and improve the pharmacokinetic properties of

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• include nucleophile σ-hole selectivity, and how ylide structural modifications and intramolecular halogen bonding (e.g., the ortho-effect) can improve ylide stability or solubility, and alter reaction outcomes. Keywords: electron donor–acceptor complex; halogen bonding; σ-holes; iodonium ylides; ortho

• potential to alter the physical properties (e.g., stability, solubility, UV–vis absorption) of an ylide, as well as bias a Lewis base’s σ-hole selectivity through σ-hole blocking, which represent emerging avenues for tuning an ylide’s reactivity and improving its reaction outcomes. Review 1 Halogen bonding

• appreciation and understanding of σ-holes in iodonium ylides, many examples exist where inter- or intramolecular halogen bonding has been invoked to provide a meaningful explanation of unexpected reactivity, of reagent stability, or as a reaction control element. Examples of these include spontaneous

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• unit, the ECS state of the NI-PTZ-F-O, NI-PTZ-Ph-O, and NI-PTZ-C5-O was increased by ca. 0.8 eV. Thus, we do not expect TADF for these three dyads, especially in HEX. In polar solvents, such as ACN, no TADF was observed. Thermal stability analysis (thermogravimetry analysis, TGA) The thermal stability

• % thermal weight loss) of each compound were determined as follows: NI-PTZ-F (422 °C), NI-PTZ-Ph (375 °C), NI-PTZ-CH3 (436 °C), NI-PTZ-OCH3 (432 °C), NI-PTZ-F-O (371 °C), NI-PTZ-Ph-O (362 °C), NI-PTZ-C5 (436 °C), NI-PTZ-C5-O (373 °C). The results show that the thermal stability of these compounds is

• excellent, and the thermal stability of dyads containing unoxidized PTZ units is better than those containing oxidized PTZ units. Femtosecond transient absorption (fs-TA) spectra In order to study the CS, charge recombination (CR), and ISC of the compounds, the femtosecond transient spectra were studied

Linker, loading, and reaction scale influence automated glycan assembly

• Marlene C. S. Dal Colle,
• Manuel G. Ricardo,
• Nives Hribernik,
• José Danglad-Flores,
• Peter H. Seeberger and
• Martina Delbianco

Beilstein J. Org. Chem. 2023, 19, 1015–1020, doi:10.3762/bjoc.19.77

• , photocleavage, hydrogenolysis of the remaining PGs, and purification (Figure 2C). The latter is commonly employed for compounds synthesized on L2 because of the poor stability of free-reducing glycans in basic conditions needed for the methanolysis step [33]. The isolated yields of the fully protected compound

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• . The reversibility of the acid hydrolysis is quite typical for furans and is more pronounced for di- and polysubstituted furans, due to the higher stability of the latter [49][50][51]. 3-(2-Oxopropyl)piperidin-4-one 5a could be involved into the Paal–Knorr pyrrole synthesis in a one-pot manner. Thus

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• solid acid catalyst, which features strong acidity, larger surface area and high stability. Pyrrole derivatives 73 were prepared in 83–95 % yields by condensation reactions between various alkyl-, aryl-, heteroaryl-, and sulfonylamines 72 and 2,5-dimethoxytetrahydrofuran (2) under MW conditions at 100

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• essential for product production (Table 1, entries 6 and 7), despite the fact that the removal of base did not result in a significantly reduced efficiency (Table 1, entry 5). The regioselectivity outcome was explained by the relative stability of the intermediate radicals involved, with strong evidence of

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• interaction between the drug candidate and the target protein, to further improve the efficacy of the potential drug [9]. The nitrile group can also function as a metabolic blocking site to inhibit the oxidative metabolism of molecules to improve metabolic stability in vivo [10]. Consequently, the development

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• , because of their particular chemical and physical properties [15]. In addition to ester/amide synthesis, enoyl imidazolides were developed as excellent Michael acceptors. Acylimidazoles are unique electrophiles that demonstrate moderate reactivity, relatively high stability, chemical selectivity, and high

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• materials [1][2][3][4][5][6][7][8][9][10]. Due to its different characteristics such as basicity, stability, water solubility, small molecular size, and ability to form hydrogen bonds, pyridine continues to be a suitable moiety in organic synthesis. In addition, it has been observed that pyridine rings

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• their unique stability, defined reactivity, and versatility in organic synthesis [2]. Leveraging their electron-deficient nature, N-arylsulfonylimines are widely used in organic transformations including nucleophilic addition, cycloaddition, imino-aldol reaction, ene reactions, aza-Friedel–Crafts

• using K2S2O8 in the presence of pyridine as a base. The key findings include a) requirement of a mild base for the formation N-arylsulfonylimines, and b) stability of N-arylsulfonylimines, unlike N-arylimines, under the oxidative conditions. Further, to demonstrate the scope and applicability of this

• conditions. Distinctly, the use of a base is the key to success in this oxidation. Perhaps more importantly, the stability of N-benzenesulfonylimine 2a, unlike N-arylimines, under the oxidative conditions is noteworthy. With the optimized reaction conditions in hand (Table 1, entry 5), we further

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• . Meanwhile, this NG 70 can also be synthesized from compound 68 through oxidative cyclodehydrognation and dimerization in one pot. The isomerization barrier was determined as over 35 kcal/mol at 170 °C, and 37 kcal/mol by DFT calculation, indicating a high degree of optical stability of pure enantiomers [51

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• of CS-TPE, i.e., the hydrophilicity of the protonated amino groups in an acidic environment combined with the hydrophobicity of the TPE units. Their morphologies under alkaline conditions were studied to investigate the effect of pH on the stability of the CS-TPE nanoparticles. When the pH of the

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• oxidative stability. The reactivity of the glycine and dehydroalanine complexes in the nucleophilic functionalization of amino acids was compared to the corresponding derivatives of the parent ligand L1. The results clearly demonstrated the advantages of the new complexes as stereocontrolling templates

• stability of the (S)- and (R)-diastereomers which is related to the conformational flexibility of the template. The rigidity of the chiral Ni–Schiff base complexes is mainly determined by the noncovalent interactions in the Ni coordination environment. Among them, the most important is the π-stacking

• fragment in the oxidized (GlyNi)L7 and (ΔAlaNi)L7 complexes bears a certain spin density (as it has been previously shown for the t-Bu-free analogs [31]), the bulky t-Bu substituent does prevent dimerization of the radical cations formed in the electron-transfer step increasing their kinetic stability

Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• molecules to double stranded DNA or RNA polynucleotides usually affect the double helix stability. This stabilization or destabilization was revealed as a change of the polynucleotide’s melting temperature (ΔTm value) which was the difference of the Tm value of free polynucleotide and the Tm value of

• polynucleotide–small molecule complex [36]. Thermal melting experiments showed that conjugates Phen-Py-1 and Phen-Py-2 had only a negligible effect on the double helix stability (below 0.5 °C), both for DNA and RNA (Table S1, Figures S6–S8, Supporting Information File 1). Spectrophotometric titrations The

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• . Phosphonates containing CF2 groups can sterically and electronically mimic oxygen, enabling the second dissociation constant, pKa2, to closer mirror those of the phosphates due to the electron-withdrawing effect of fluorine [39]. As a result, improved lipophilicity, metabolic stability or bioavailability of

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• ] followed by an ester hydrolysis led to the formation of seco-acid 46. By using Mitsunobu conditions at high dilution and slow addition of reagents, the authors were able to synthesize the macrolide 47 in excellent yield, thus confirming their initial hypothesis regarding the stability of oxyphosphonium

• stability when subjected to Mitsunobu conditions with the slow addition of the seco-acid into the DEAD/PPh3 reaction mixture over a 7 h period. The desired macrolide 63 was obtained in 91% yield, without formation of the diolide being observed. Subsequent removal of the TBS group gave the corresponding

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• complexes was kneading the components at various molar ratios (1:1:1 and 3:1:1 for β-CD hydrate:hazelnut oil (average molar mass of 900 g/mol):flavonoid). The recovering yields of the ternary complexes were in the range of 51.5–85.3% and were generally higher for the 3:1:1 samples. The thermal stability was

• cheap method for the evaluation of quality and similarity/characteristics of these new types of cyclodextrin-based ternary complexes having enhanced properties and stability. Keywords: antioxidant; cyclodextrin; flavonoid; hazelnut vegetable oil; ternary supramolecular inclusion complex; Introduction

• compounds [5]. The resulting supramolecular inclusion complexes provide enhanced water solubility and bioavailability/bioaccessibility of the nanoencapsulated bioactive compounds, higher oxidative and thermal stability or photostability of labile compounds, and their controlled release [6][7]. Vegetable oil

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• reactions (Scheme 6). The authors selected the hydrogen sulfate salt of imidazole-1-sulfonyl-azide for the formation of azide porphyrins 39a–c due to its greater shock stability and storage than its HCl salt. After the successful preparation of the zinc triazoloporphyrins 40a,b, their corresponding free

• . These prepared porphyrin nanowires were subjected to surface microscopy and fluorescence energy transfer experiments, which elucidated their stability and resistance to disassembly. Conclusion Cu(I)-catalyzed “click chemistry” is a well-established protocol for the facile access of complexes from simple

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

• Swantje Lerch,
• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20

• proved to be a remarkable class of compounds due to their high thermal and chemical stability, their negligible vapor pressure and high versatility in terms of chemical structure and usage [21][22][23][24]. Successive research for the Friedel–Crafts acylation lead to the development of various reaction

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• main product [36]. Based on molecular mechanics calculations, four conformers 1a–d have been described for 1 (Scheme 3B) [37]. The calculations revealed all four conformers are of similar stability, with 1a being the most stable conformer. The fact that 1 shows a defined set of fifteen sharp signals in

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• using polymeric nanoparticles for anticancer drug delivery have not been developed yet. Previous data showed encapsulation in non-ionic uncoated or coated cyclodextrin (CD) nanoparticles enhanced the CPT stability and GI absorption [9][11], and compared to PCL and PLGA nanoparticles, CD nanoparticles

• also had better release, physical stability, and cytotoxicity [13]. CPT is an anticancer small molecule drug that inhibits the topoisomerase I enzyme, which has a critical role in cellular DNA functions [14], and is effective in a wide spectrum of cancers such as metastatic colon cancer, breast cancer