Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• an exception, the irradiation of the nitro-substituted styrylpyridine derivative 2a in MeCN or H2O led to disappearance of the long-wavelength absorption maximum with no formation of a distinct new band (Figure 2A), which usually indicates photoinduced decomposition. This observation is in agreement

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• adduct 2d. Stability studies were conducted in the solid state and in solution. When storing the zwitterion under ambient conditions for a duration of two months, minor decomposition can be observed. The proton NMR gives rise to new signals appearing at 6.81 ppm (dd, J = 14.5, J = 2.2 Hz) and 11.23 ppm

• main decomposition product, giving resonance at 41.4 ppm [42]. Besides, a number of new minor phosphorous species were detected. However, the total decomposition as indicated by 31P NMR can be estimated to be less than 5% (intensity of all phosphorous peaks from decomposition vs the intensity of the

• temperature the observable decomposition after 72 h is very low in both solvents. NMR spectra (1H and 31P) show trace amounts of the phosphine oxide of 1. The total amount of phosphine oxide is somewhat lower in DMSO-d6 when compared to CDCl3. Additionally, in CDCl3 further unknown decomposition products were

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• diethyl ether traces and then analysed by NMR to check for BMIm-F presence, whereas the fluoride ion could originate from IL decomposition in the presence of water or from the evolution of electrogenerated F2. However, the 19F NMR spectrum showed no detectable peak around −122 ppm, reported in the

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• excess to compensate for the possible formation of sodium O-tert-butyl xanthate [72][73][74]. We reasoned that these conditions should favor a quantitative deprotonation of the starting triazolium salts and the concomitant trapping of the free carbenes by CS2 prior to their potential decomposition

• on 13C NMR spectroscopy (see below). We suspect that deleterious hydrophilic effects caused the subsequent decomposition of the CAAC·CS2 and MIC·CS2 zwitterions when an aqueous work-up was applied. Structural analysis Several analytical techniques were employed to characterize the nine aldiminium and

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

• growth factor, which when pulled back into the binding site led to low binding energies but a drastically different pose (partially perpendicular) of the ligand. Energy contributions of sulfated and unsulfated parts of the GAG were investigated from per residue decomposition of MM/GBSA analysis (Table 2

• energies obtained from MM/GBSA analysis and RMSD values of the ligand for all frames of the merged MD trajectories. Energy contributions in kcal/mol of the sulfated and unsulfated parts of GAGs obtained from MM/GBSA per residue decomposition. Pearson correlation coefficients obtained for all frames of the

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

• under a nitrogen atmosphere. TGA allows us to observe the weight changes of the samples as a function of temperature, providing valuable insights into processes such as decomposition, volatilization, and oxidation. In the case of DSC measurements, the samples were heated at a rate of 10 °C/min in a

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

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• acknowledged to be effective in introducing substituents to the nitrogen atoms of NH-heterocycles by means of carbene insertion into the N–H bond upon catalytic or photolytic decomposition of diazo compounds [25]. Furthermore, the reaction of N-heterocycles containing multiple non-equivalent nitrogen atoms

• tetrazoles, had not been previously utilized in the CRBN ligands design. Catalytic decomposition reactions of diazo compound 5 with NH-heterocycles were conducted in a dry DCM solution using dirhodium espinoate (Rh2(esp)2, 0.06–0.18 mol %). The Rh2(esp)2 catalyst was selected for its excellent versatility

• yield. As a side process, а carbenoid's repeated attack at the 6-position of the tetrahydroquinoline ring of compound 6x was observed according to NMR data. Introducing a bromine atom to block the 6-position led to a significant increase in the target product 6y yield. The decomposition of diazo reagent

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

• of a water molecule on the carbon bound to it (C7), culminating in the generation of a carbinolamine intermediate. Decomposition of this species gives the respective carbonyl compound and N-acylhydrazide [48][49]. In the phenol-deprotonated form of hdz-NO2, both electron-withdrawing groups (namely

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

• scanning calorimetry (DSC) under N2 atmosphere at a scanning rate of 10 °C min−1. As displayed in Figure 5a, the compound has a high thermal stability with a decomposition temperature at 5% weight loss (T5d) of 498 °C, a glass transition temperature (Tg) of 236 °C, and a melting temperature (Tm) of 376 °C

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

• more soluble than the iodides in THF, so were reductively dimerized to 12 in THF using Na:Hg, although reduction of 1i+PF6− failed to afford 1i2. As we have noted before for other 12 species, amides (V, Scheme 1) are encountered as both byproducts of dimer synthesis and dimer decomposition products [14

• ]. V derivatives have also been obtained as pyrolysis products of a variety of Y = aryl 1H derivatives [33], while Vb has also been found to be both a solution decomposition product of 1bH [27][34] and a beneficial additive for a 1bH-doped polymer [27], and has been crystallographically characterized

• stable (at least 4 months for solid 1b2). Both 1H and 12 derivatives decompose more rapidly on exposure to air in solution. In CDCl3 decomposition is rapid, consistent with the reactivity of many reductants with that solvent. In C6D6 these compounds are more stable, allowing, for example, rapid

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

• initiator is needed to start the radical crosslinking. Besides sulfur, peroxides such as di-tert-butylcumyl peroxide (BCUP) and dicumyl peroxide (DCP) are often used in radical crosslinking. Free radicals are generated at the peroxides’ decomposition temperature and attack the polymer chains to achieve

• . Radicals can be generated by a broader selection of homogeneous and heterogeneous approaches, including hydrogen atom abstraction, decomposition of immobilized initiators, electrochemical redox reaction, or irradiation because the reactions only need to take place at the surface. Small-molecule oxidants

• decomposition of polymers, especially upon radiation with an electron beam, because of its narrow wavelengths, are still regarded as a promising alternative. Poly(methyl methacrylate) has a long history of being used as a positive resist [191][192]. It undergoes a scission by a Norrish-type I reaction followed

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• decomposition of azides at higher temperatures required the use of 2a or 2b in excess. No significant difference in yields between 1.5 equiv and 2 equiv of the aryl azide was observed. Adding fluorophilic additives (TMSCl, Table 1, entry 5) or using copper as other transition metal (CuCl or Cu(OAc)2, Table 1

• , entries 6 and 7) resulted in poor yields. Since the gem-difluoroalkenes are volatile compounds and as we observed decomposition of the azides at high temperatures resulting in reduced yields, we wanted to monitor the temperature and time course of this reaction. The time course study was carried out via

• morpholine as solvent (0.4 M) and 0.4 equiv LiHMDS as a base at 75 °C for 48 h. The only byproducts observed are anilines as a result of thermal decomposition of the organic azides via reactive nitrene species. No other byproducts were observed by TLC or crude 1H NMR. The volatility of the gem

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• complete decomposition. With the desired naphthylamines in hand, we were able to complete our synthesis of four chelerythrine variants as shown in Scheme 7. After N-formylation providing intermediates 11 and 12 in good yield, a three-step sequence was performed: Suzuki coupling of the aryl bromide with one

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

• as σ-donor ligands only. However, subsequent experimental [18] and theoretical [19] studies revealed that a simultaneous back donation from the d-orbital of the metal to the π*-orbital of the NHC occurs in these species, which was also corroborated by energy decomposition analysis (EDA) calculations

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• protective gas atmosphere, leads to slow decomposition. Therefore, storage at low temperature in a dark vial is strongly recommended. Upon using 2,4-dibromoaniline (1c) as the substrate and an excess of phenylacetylene (2a), both carbon–bromine bonds are transformed in the alkynylation step affording the

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

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• pathway. Initially, a tert-butoxyl radical is generated by thermal decomposition. Then, the tert-butoxyl radical extracts an α-hydrogen atom from tetrahydrofuran to form tetrahydrofuran radical A. Sc(OTf)3 as a Lewis acid activates pyridine forming the pyridine complex B. Then, radical A adds to the more

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

• decomposition [1][102]. They discovered that an iodonium ylide (e.g., 6/I-12) reacts with hydrochloric acid to produce a chlorinated β-dicarbonyl 7, opposite their expectation that the C–I bond with the lower electron density would be cleaved. While both of these reaction pathways are viable, the iodonium ylide

• produced in 74% yield after six days at room temperature in the absence of catalyst (Scheme 2a) [107]. At that time, the authors did not articulate any theory as to how the reaction might initiate under such mild conditions, though they recognized that the decomposition of 8 into a free carbene would not

• and Liang modified the iodonium ylide’s β-dicarbonyl skeleton (Scheme 11), and while derivatives of barbituric acid (54a) and Meldrum’s acid (54b) were moderately effective, replacing the gem-dimethyl with spirocyclic motifs 54c–e provided [18F]fluorobiphenyl 55 in 47–85% yield [134]. Decomposition

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

• , or it is trapped with pyrrole derivatives 3 in a C–C bond formation to afford arylated products 4. Based on the ultrashort lifetime of *PDI•− (τ = 145 ps), the notion of its photochemistry has attracted skepticism and it has been suggested decomposition products of *PDI•− may instead serve as

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• with excess hydrochloric acid and further evaporation of the solvent at 40 °C led to decomposition products, two of which were isolated and characterized by NMR spectroscopy including 2D experiments and HRMS data. The target acids 5k,m were obtained using equivalent amounts of HCl at room temperature

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

• of TADF emitters is very important for the application in OLED devices. Therefore, the compounds were investigated by thermogravimetric analysis (TGA) and the results are shown in Figure 6 and Figure S34 in Supporting Information File 1. The thermal decomposition temperature (temperature at 5

• an approximate 3LE state. Thermogravimetric analysis (TGA) shows that the thermal decomposition temperature of these compounds is higher than 360 °C, and the thermal stability is excellent. From the above studies, TADF properties of such compounds can be studied with conventional spectroscopic

• components to be used for Global analysis was estimated by performing a preliminary singular values decomposition (SVD) analysis. All data were chirp-corrected before global fitting. Nanosecond transient absorption spectroscopy The nanosecond transient absorption spectra were measured on a LP920 laser flash

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

• -carbaldehyde (2p) was used. In this case, we observed abundant tarring and decomposition of the reaction mixture, which is probably due to the acidophobic nature of monosubstituted pyrroles. Surprisingly, the reaction of 4-(methylthio)benzaldehyde (2h) with 2-(5-methylfuran-2-yl)ethylamine (1a) under the

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

• shown in Scheme 20b. In this mechanism, calcium nitrate first activates the decomposition process of 2,5-DMTHF (2) from A to B. Further, a nucleophilic attack of amines 42 on B generates imine intermediate C. Finally, intramolecular nucleophilic attack by enamine D on the aldehyde group, dehydration and

• of acid-sensitive pyrrole derivatives without decomposition in a short time. Abid et al. [89] described the synthesis of N-substituted pyrrole derivatives in good yields using K-10 montmorillonite as an effective solid acid catalyst under microwave irradiation. K-10 monomorillonite is a widely used