Synthesis of pyrrolo[3,2-d]pyrimidine-2,4(3H)-diones by domino C–N coupling/hydroamination reactions

• Ruben Manuel Figueira de Abreu,
• Robin Tiedemann,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2025, 21, 1010–1017, doi:10.3762/bjoc.21.82

• , leading to 43% isolated yield with full conversion of starting material and different byproducts derived from decomposition. Interestingly, no conversion of the starting material could be observed with the other ligands. In the following, different solvents, temperatures and bases were tested, but did not

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

• Shyam Sathyamoorthi,
• Appasaheb K. Nirpal,
• Dnyaneshwar A. Gorve and
• Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

• equivalent of commercial iodomesitylene diacetate (CAS [33035-41-5]) and 1 equivalent of MsOH (Table 1, entry 4). Here, it was necessary to maintain a temperature of 0 °C, as vigorous bubbling and rapid decomposition occurred when the reaction was initiated at room temperature. In all cases (Table 1), only a

• compatible with our optimized conditions (Table 2, poor performers). In many cases, complex mixtures of recovered starting material and multiple products were observed. Carbamate tethers with N-alkoxy substituents were essential for clean reactions; indeed, extensive decomposition was observed with N-ethyl

• unpurified reaction residues showed a complex mixture of products. There were some signals suggestive of terminal alkenes, implying that olefin transposition was a competing pathway. With alkyne substrate 59, decomposition occurred, and the 1H NMR of the unpurified reaction mixture was illegible. With

A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

• Zhiyang Zhang,
• Jialei Hu,
• Hanfeng Ding,
• Li Zhang and
• Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

• .) of 24 led only to epimerization at C10 or slow decomposition of the starting material (see Supporting Information File 1, Table S1). Pleasingly, treating 24 with HMDS and TMSI regioselectively generated the expected TMS enol ether [46], which underwent a Li/Si exchange in the presence of MeLi

• stage was set for the construction of the target skeleton through a 1,2-addition (Scheme 4). Preliminary trials to generate organometallic species via Li/I exchange under various conditions (n-BuLi, t-BuLi, or t-BuLi in combination with CeCl3 or MgBr2) led to rapid decomposition, likely due to inherent

• Nazarov cyclization under a variety of conditions (Table 1). Initial trials under acid-mediated Nazarov conditions (AlCl3, BF3·Et2O and Me2AlCl) led to complete decomposition, while the exposure to AcOH resulted in recovery of the starting material (Table 1, entries 1–4). Recognizing the limitations of

Cu–Bpin-mediated dimerization of 4,4-dichloro-2-butenoic acid derivatives enables the synthesis of densely functionalized cyclopropanes

• Patricia Gómez-Roibás,
• Andrea Chaves-Pouso and
• Martín Fañanás-Mastral

Beilstein J. Org. Chem. 2025, 21, 877–883, doi:10.3762/bjoc.21.71

• reaction was carried out under standard conditions with ethyl crotonate derivatives bearing a methyl group, hydrogen or bromine atoms at the γ position. Either β-borylation or decomposition products were obtained in those cases (Scheme 3c). On the basis of our experimental results, we propose the following

• aliphatic gem-dichloride, we explored the feasibility of a base-mediated formation of chlorocyclopropanes (Table 2). Evaluation of bases such as metal tert-butoxides, phosphates, acetates, and organic amines resulted in either low conversion or decomposition of 2 (see Supporting Information File 1 for

Synthesis and photoinduced switching properties of C₇-heteroatom containing push–pull norbornadiene derivatives

• Daniel Krappmann and
• Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

• signal in the range of 6.15–5.90 ppm. However, due to the lack of new formed aliphatic signals, and in comparison to literature [35], formation of N-QC1 is very unlikely. Furthermore, additional signals in the region below 2.0 ppm indicate the formation of decomposition products. Studies conducted by

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• , or phenyl groups at the α-position. The researchers noted that the lower yields were due to substrate decomposition or poor conversion rather than regioselectivity issues. Additionally, this method was also suitable for the phosphorylation of ferrocenes. For mechanistic studies, the reaction was

• decomposition leads to the generation of O₂, the primary oxygen source in the reaction process. A radical process was proposed in the reaction. Diphenylphosphine oxide and carbazole radicals were formed via anodic oxidation in the presence of a base, followed by a coupling reaction to give the final P–N product

• . Changing the electric current intensity reduced the yield, and using dry acetonitrile also led to a significant decrease in yield. These results indicate that water undergoes decomposition in the reaction, generating oxygen as the primary oxygen source in the system. The reaction proceeded via the anodic

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

• formaldehyde and ammonia in situ by heating [83]. Under these conditions, the water present in hydrated HMTA is sufficient for this hydrothermal decomposition to occur. On the other hand, an excess of ammonia must be added to the reaction mixture to shift the equilibrium towards the imine. Using this procedure

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• achieved due to chemical modification of ANTH [25][32]. Changes in the UV–vis spectra were typically used as an indication of the compounds’ decomposition. It is well established that ANTH is rapidly oxidized to form anthraquinone upon exposure to light in the presence of oxygen. Furthermore, endoperoxides

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• ). However, reducing the concentration to 0.014 M increases the enantioselectivity (entries 6 and 7, Table 4), and an excellent enantiomeric ratio was maintained over time (entries 8 and 9, Table 4). These results suggest that at very dilute concentrations, the decomposition of the enantiomer (3R,4S)-1 is

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• instead of 2 h in a row) proved beneficial to minimize heat accumulation resulting in product decomposition. Next, the authors proved the generality of mechanoluminescence by performing the sulfonylation of alkenes via EDA-complexes photochemistry (Scheme 12B). Thus, when a mixture of 1,1-diphenylethylene

Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• renders them particularly suitable for the generation of arynes for subsequent use in a wide range of synthetic applications. The common approach to generate cyclic biaryl λ3-bromanes is based on thermal decomposition of hazardous diazonium salts. Herein, we disclose a mild and straightforward approach to

• molecular nitrogen in diazonium compounds. Accordingly, pre-formed [12] or in situ-generated 2,2’-bromodiazonium salts 2 [11][13][14] furnish cyclic bromine(III) species 1 under thermal decomposition conditions (Scheme 1, reaction 1). The diazonium intermediates 2 are obtained by diazotation of 2'-bromo

• required thermal decomposition of the diazonium salt to effect the cyclization. In the quest for mild (room temperature) and scalable conditions toward cyclic diaryl λ3-bromanes 1 we realized that bromanyl units possess leaving group abilities comparable to the diazonium moiety [1][15]. Hence, the

Unraveling aromaticity: the dual worlds of pyrazole, pyrazoline, and 3D carborane

• Zahra Noori,
• Miquel Solà,
• Clara Viñas,
• Francesc Teixidor and
• Jordi Poater

Beilstein J. Org. Chem. 2025, 21, 412–420, doi:10.3762/bjoc.21.29

• a Kohn–Sham molecular orbital analysis together with an energy decomposition analysis (Figure S1 in Supporting Information File 1). To form the broken bonds, both fragments have two unpaired electrons (at their triplet state). The interaction between both fragments amounts to −227.9 kcal mol−1

• , the energy decomposition analysis has been performed at the ZORA-BLYP-D3(BJ)/TZ2P level of theory with AMS software [81][82][83][84]. Series o-carborane-fused pyrazoles under analysis. Bond lengths (in Å) of systems under analysis (top row) and reference systems (second and third rows) from the fusion

• clockwise/anticlockwise. Figure S3 in Supporting Information File 1 encloses the rest of the systems. Supporting Information Supporting Information File 22: Energy decomposition analysis of pyrazoleCC (fragments used, molecular orbitals overlaps, and fragment molecular orbitals), cartesian coordinates and

Identification and removal of a cryptic impurity in pomalidomide-PEG based PROTAC

• Bingnan Wang,
• Yong Lu and
• Chuo Chen

Beilstein J. Org. Chem. 2025, 21, 407–411, doi:10.3762/bjoc.21.28

• formed due to the decomposition of DMF. Whereas switching the solvent could prevent its formation, the accumulation of 7 remained an issue, giving no substantial improvement in the yield of 3 in, for example, NMP. In MeCN, glutarimide displacement became a major reaction. Because NMP was significantly

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• sacrificial reducing agents (Scheme 6), contrasting with traditional blue-light photocatalysis which led to substrate decomposition [33][34]. The axial ligands on the ruthenium phthalocyanin complex, particularly electron-deficient pyridyl groups, were found to influence the catalytic activity by stabilizing

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• electrophiles in various nucleophilic transformations due to their susceptibility to rapid decomposition into the corresponding isocyanates (Scheme 1a) [2][3]. They have attracted increasing interest as electrophilic amide sources in amidation using transition-metal catalysts such as ruthenium, rhodium, and

• functionalities were well tolerated in this transformation (26e–g). Moreover, an olefin-containing terminal alkyne was suitable to afford product 26h, demonstrating excellent chemoselectivity. However, the formation of 26i was not observed under the standard reaction conditions. Instead, the decomposition of

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• , such as increasing the amount of DDQ or elevating the reaction temperature in the Scholl reaction of 10, only resulted in complex mixtures. Further attempts to subject 3 to the Scholl reaction conditions did not yield further cyclized products but led to the decomposition of the starting material

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• the targeted benzo[j]fluoranthene product 32 was isolated in 45% yield. It should be noted that this reaction was not successful when an analogue of compound 31 with -OTIPS instead of the -OMOM group was tested as the boronic ester reaction partner, due to the decomposition of this compound presumably

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• gravimetric analysis (TGA) under a N2 atmosphere in the dynamic mode. The TGA curves (Figure S35 and Table S4 in Supporting Information File 1) show that all compounds undergo two thermal decomposition processes; an initial thermal event with a decomposition temperature (Tdec, at weight loss 5%) between 283

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• , Tomilov et al. described the formation of tetrahydropyridazine 3,4,5,6-tetracarboxylic esters in 42% yield upon the decomposition in chloroform at 60 °C of methyl diazoacetate in the presence of pyridine and catalyzed by rhodium(II) acetate (Scheme 1b) [24][25]. More recently, an unusual [4 + 2

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

• spectra were observed. In the case of compounds 1j and 1n, the endpoint of the photoreaction could not be identified, as a steady decrease of the whole absorption spectra during irradiation indicated secondary decomposition reactions. We previously reported triplet energy transfer between 3[Ru(phen)3](PF6

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

• to the VSC-based system, this crosslinker can be applied to various vinyl polymerizations, and the resulting RCP showed properties depending on the monomers used. Meanwhile, since the size-complementary framework was integrated with this crosslinker, heating induced the decomposition of the rotaxane

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

• can easily replace ligand strands leading to a partial or full receptor decomposition. Herein, we present a charge-neutral zinc(II)-based metallocontainer which was tuned to contest oxalate as most competitive dicarboxylate. The dianion is bound in a 1:1 fashion with a binding constant of log K = 4.39

• limiting solubility. a) Generally desired guest recognition by encapsulation of the analyte within self-assembled metal-based containers or cages (left reaction). Often observed challenge with very competitive anionic guests which tend to result in decomposition of the initial receptor structure (right

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• colleagues firstly demonstrated that the decomposition of tert-butyl hydroperoxide (TBHP) by Co(II) naphthenate proceeds via a chain mechanism, leading to the formation of tert-butoxy and tert-butylperoxy radicals (Scheme 4) [24]. When cyclohexene (1) and oct-1-ene (3) were added, the corresponding products

• product 32 formation is similar to the metal-catalyzed peroxidation described in Scheme 12 in the case of using the Cu(II)/TBHP oxidation system. Under metal-free conditions the tert-butoxy radical A is probably formed via homolytic thermal decomposition of TBHP. Recently, the electrochemical generation

• were achieved using 1 equiv TBHP. This can be explained by reoxidation of Fe(II) to Fe(III) by oxygen, which is released during thermal decomposition of pyridinium nitrate presented in the system. Later, Mn-catalyzed peroxidation of alkylarenes 47 [50][62] and peroxidation of alkylarenes 49 using Ru

gem-Difluorovinyl and trifluorovinyl Michael acceptors in the synthesis of α,β-unsaturated fluorinated and nonfluorinated amides

• Monika Bilska-Markowska,
• Marcin Kaźmierczak,
• Wojciech Jankowski and
• Marcin Hoffmann

Beilstein J. Org. Chem. 2024, 20, 2946–2953, doi:10.3762/bjoc.20.247

• -difluoroalkenes and trifluoroalkenes in reactions with Grignard reagents [13][31]. Although, similar compounds are reported to be unstable molecules that are prone to decomposition under reaction conditions [32][33]. The goal of this work was the formation of gem-difluoro- and trifluorovinyl Michael acceptors by