Sequential two-step, one-pot microwave-assisted Urech synthesis of 5-monosubstituted hydantoins from L-amino acids in water

• Wei-Jin Chang,
• Sook Yee Liew,
• Thomas Kurz and
• Siow-Ping Tan

Beilstein J. Org. Chem. 2025, 21, 596–600, doi:10.3762/bjoc.21.46

• ][15][16], but reaction times are significantly shorter. In addition, TLC analysis confirmed complete consumption of starting material, which was further confirmed by NMR analysis showing no detectable impurities or unreacted starting material. Variations in yields (34–89%) may be due to differences in

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

• Figures S1 and S2 in Supporting Information File 1). The 1H NMR analysis of the crude reaction mixture indicated 60% conversion of 9,10-ANTH(Br)2 and a 1:1 ratio of only two products, 9,10-ANTH(BnF)2 and 9-Br-10-BnF-ANTH. Even after only 2 h, it was possible to observe both products by 1H NMR, indicating

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

• ] using 20 mol % of catalyst A and 20 mol % of p-nitrobenzoic acid (PNBA) as co-catalyst in different solvents at room temperature. The results obtained are summarized in Scheme 3 and Table 1. The progress of the reaction was monitored using thin-layer chromatography (TLC) and 1H NMR analysis of the

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

• corresponding orthophosphate intermediates. However, the NMR analysis showed the formation of covalent α-glycosyl triflates 72 as the intermediate indicating an SN2-like mechanistic pathway where the acceptor attacked from the opposite face of the α-triflate intermediates (path A, Scheme 13) which was triggered

Nickel-catalyzed cross-coupling of 2-fluorobenzofurans with arylboronic acids via aromatic C–F bond activation

• Takeshi Fujita,
• Haruna Yabuki,
• Ryutaro Morioka,
• Kohei Fuchibe and
• Junji Ichikawa

Beilstein J. Org. Chem. 2025, 21, 146–154, doi:10.3762/bjoc.21.8

• , excluding boronic acid 2a (Scheme 6). The reaction was monitored using 19F and 31P NMR spectroscopy. The 19F NMR analysis showed that 79% of 1b remained and revealed a new broad double doublet peak at 55.0 ppm (JFP = 53, 42 Hz) relative to internal C6F6 (δ = 0.0 ppm). The 31P NMR spectrum depicted broad

Controlled oligomerization of [1.1.1]propellane through radical polarity matching: selective synthesis of SF₅- and CF₃SF₄-containing [2]staffanes

• Jón Atiba Buldt,
• Wang-Yeuk Kong,
• Yannick Kraemer,
• Masiel M. Belsuzarri,
• Ansh Hiten Patel,
• James C. Fettinger,
• Dean J. Tantillo and
• Cody Ross Pitts

Beilstein J. Org. Chem. 2024, 20, 3134–3143, doi:10.3762/bjoc.20.259

• the equivalents of [1.1.1]propellane (1) relative to SF5Cl and evaluating the impact on selectivity (Table 1). A 0.1 M solution of SF5Cl in n-pentane was added to a 0.8 M solution of 1 in Et2O at room temperature, and the mixture was stirred for 3 hours prior to 19F NMR analysis. Upon increasing from

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• (cis/trans) determined by 19F NMR analysis. Kitamura’s synthesis of 3-fluoropyrrolidines. Values in parentheses represent the cis:trans ratio. Jacobsen’s enantio- and diastereoselective protocol for the synthesis of syn-β-fluoroaziridines 15. Different HVI reagents lead to different

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

• porphyrins, and provided evidence for aryl radical formation through mass spectrometry and NMR analysis of the adduct formed from the reaction between the radical intermediate and the scavenger 2,2,6,6-tetramethyl-1-piperidin-1-oxyl (TEMPO). Furthermore, they used the catalysts for borylation of arylamines

Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

• Noble Brako,
• Sreerag Moorkkannur Narayanan,
• Amber Burns,
• Layla Auter,
• Valentino Cesiliano,
• Rajeev Prabhakar and
• Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

• propargyltrichlorosilane free of allenyltrichlorosilane on a 50 mmol scale albeit in 43% chemical yield (determined by 1H NMR analysis of the reaction mixture using freshly distilled anhydrous methylene chloride as an internal standard, Scheme 3). There was no sign of allenyltrichlorosilane observable by 1H NMR in the

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

• anticipated α-substituted compound (Table 1, entry 9). The NMR analysis revealed that the obtained compounds were Michael addition products. The formation of the presented compounds (Table 1) was due to the earlier generation of gem-difluoroalkenes by the elimination of one of the fluorine atoms from the CF3

Structure and thermal stability of phosphorus-iodonium ylids

• Andrew Greener,
• Stephen P. Argent,
• Coby J. Clarke and
• Miriam L. O’Duill

Beilstein J. Org. Chem. 2024, 20, 2931–2939, doi:10.3762/bjoc.20.245

• spectrometry (MS) and NMR analysis were carried out on aborted TGA runs of compounds 1e, 1i, 1j and 1k that had been held at a constant temperature T1 (50–140 °C, see Supporting Information File 1) under an N2 atmosphere in open pans for 30 min or until a mass loss >5% of the original mass was observed, then

• heated to temperature T2 (136–205 °C, see Supporting Information File 1) until 20–40% mass loss of original weight. Based on this data, the following decomposition mechanism is proposed (Figure 4a): MS, 1H and 31P NMR analysis after heating to T1 showed the presence of (methyloxycarbonylmethyl

• involving scission of the C(ylid)–I bond or the C(Ar)–I bond was proposed based on ex situ MS and NMR analysis, resulting in the formation of (methyl)triphenylphosphonium intermediate 8. The nature of the arene substituent (I–Ar) and anion (X) appear to play an important, yet currently unquantifiable, role

Synthesis of pyrrole-fused dibenzoxazepine/dibenzothiazepine/triazolobenzodiazepine derivatives via isocyanide-based multicomponent reactions

• Marzieh Norouzi,
• Mohammad Taghi Nazeri,
• Ahmad Shaabani and
• Behrouz Notash

Beilstein J. Org. Chem. 2024, 20, 2870–2882, doi:10.3762/bjoc.20.241

• δ = 4.65 and δ = 5.84 ppm corresponding to hydrogen I and hydrogen II. Remarkably, at higher temperatures (85 °C), the rapid inversion of the seven-membered ring results in it being observed as a single structure on the 1H NMR time scale (see Figure 3, spectrum F) [19][47][48]. Furthermore, 13C NMR

• analysis, mass spectrum, and IR are consistent with the structure (for details see Supporting Information File 1). Finally, a single crystal X-ray analysis of compound 6a was performed, confirming the structure (Figure 4). The proposed mechanism for an isocyanide-based multicomponent domino reaction for

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• experiments were conducted in the same way. In the deuteration experiment, the reaction was quenched with deuterium oxide (0.2 mL) instead of acetic acid. The decrease of the integral of the signal of the benzyl proton was confirmed by 1H NMR analysis. Synthesis of polyfunctionalized methane derivatives

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

• Bhaskar B. Dhotare,
• Seema V. Kanojia,
• Chahna K. Sakhiya,
• Amey Wadawale and
• Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

• , all the structures corroborated with the expected structure, as shown in Figure 3. To confirm the formation of hydroperoxide in THF via autooxidation, freshly distilled THF was heated under open atmosphere at 50 °C for 4 h, and was concentrated under vacuum to obtain the hydroperoxide residue. 1H NMR

• analysis of the residue, recorded in CDCl3 (Supporting Information File 1, Figure S1) confirmed the presence of hydroperoxide. Resonances attributable to O–CH–O were observed as a quartet centered at δ 5.40 ppm in the NMR spectrum. The –O–OH group in hydroperoxide gave rise to a singlet at 10.91 ppm. The

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

• ) were observed with similar mass spectra. The amount of secretion available and the complex mixture did not allow for the isolation of enough material for NMR analysis. Therefore, for the structure elucidation of these unknown compounds, we used different analytical methods, including GC–MS, GC–IR, and

• product research has recently been published by our team [41]. Conclusion 4,6-Dimethylalk-5-enoic acids are important components of the scent gland secretion of Protobothrops mangshanensis. Since NMR analysis was not possible due to the low amounts present, the compounds were identified only with the help

Photoredox-catalyzed intramolecular nucleophilic amidation of alkenes with β-lactams

• Valentina Giraldi,
• Giandomenico Magagnano,
• Daria Giacomini,
• Pier Giorgio Cozzi and
• Andrea Gualandi

Beilstein J. Org. Chem. 2024, 20, 2461–2468, doi:10.3762/bjoc.20.210

• , entry 1). Assignment of the relative configurations as cis or trans was achieved by 1H NMR analysis, considering the chemical shifts of the proton in the α-position of the β-lactam nitrogen atom and the geminal protons in the benzylic position (see Supporting Information File 1). The difference in the

• stereocenter in the five-membered ring was attributed by 1H NMR analysis for 11c. Moreover, the configuration was also confirmed by NOE studies on the two isolated diastereoisomers, which confirmed the preferred trans-isomer formation (see Supporting Information File 1). Analysis of the dr values revealed that

• intramolecular photoredox reaction. Photoredox-catalyzed intramolecular N-alkylation reactions of various β-lactams. The trans/cis dr was determined by 1H NMR analysis of the crude reaction mixture. Synthesis of the model substrate 14 and its photoredox-catalyzed intramolecular N-alkylation reaction. The trans

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• order to decipher the key physical properties of complex pyran inter-halides, we performed 19F NMR analysis of halogenated talose analogues 12–15 (Figure 2). First, all analogues adopt standard 4C1-like conformations. Comparison of the vicinal and geminal coupling constants for each organohalogen

• −200.55 ppm for 15. Talopyranose analogues 12–15 incorporate a 2,3-cis, 3,4-cis relationship for the halogens. We previously prepared a small set of trihalogenated allopyranose analogues that also included the 2,3-cis, 3,4-cis relationship for the halogens (Figure 1a) [23]. 19F NMR analysis of halogenated

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

• in less than 10% yield, determined through 1H NMR analysis, except for Table 1, entries 3 (13%) and 5 (25%). It should also be noted that electrolysis was carried out at room temperature, but the temperature of the reaction mixture increased to 40–50 °C at the end of the electrolysis in every case

• of dechlorinated diphenylmethanol (1a) in the recovered starting material were confirmed by 1H NMR analysis. These results suggested that 2a was produced from 1a, which was generated in situ by electroreductive dechlorination of 1b. In other words, electroreductive dechlorination of 1b, producing 1a

• , took place preferentially over electroreductive C(sp3)–O bond cleavage of 1b. It should also be noted that no aromatic carboxylic acids were detected by 1H NMR analysis. In contrast, the electrochemical carboxylation of 1c, containing a fluorine atom, gave a mixture of fluorine-containing carboxylic

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• two enantiotopic faces of acylimine 2, exposing only one face to the attack by the allyl group. The replacement of one isopropoxy (iPrO) group between allylboronate 1 with BINOL was confirmed by ESI-MS and NMR analysis of the reaction mixture. Interestingly, both (E)- and (Z)-crotyl boronates 6 and 8

gem-Difluorination of carbon–carbon triple bonds using Brønsted acid/Bu₄NBF₄ or electrogenerated acid

• Mizuki Yamaguchi,
• Hiroki Shimao,
• Kengo Hamasaki,
• Keiji Nishiwaki,
• Shigenori Kashimura and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2024, 20, 2261–2269, doi:10.3762/bjoc.20.194

• in the presence of the substrate. The total electricity of 3.0 F/mol vs 1a was passed to the solution. Interestingly, the result gave the corresponding difluorinated compound 2a in 29% yield in the case of 8 mA, as shown by 19F NMR analysis. In addition, 2a was obtained in 42% yield by 19F NMR

• the formation of the corresponding product 2d in 40% yield as the 19F NMR analysis (Table 2, entry 6), but the isolation of 2d was difficult [54]. Method B gave 2d in 35% yield, as shown by the 19F NMR analysis (Table 2, entry 7). Another alkyne, namely, octadec-1-yne (1e), was found to be a nice

• yield (Table 2, entry 16). Likewise, method B also gave 2i in 21% yield, as shown by the 19F NMR analysis (Table 2, entry 17), but it was difficult to purify and isolate the product 2i in this case. Finally, the internal aliphatic alkyne such as dodec-6-yne (1j) was found to be effective for the gem

Electrochemical radical cation aza-Wacker cyclizations

• Sota Adachi and
• Yohei Okada

Beilstein J. Org. Chem. 2024, 20, 1900–1905, doi:10.3762/bjoc.20.165

• with stirring. The solution was diluted with water and extracted with dichloromethane. The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. Yields were determined by 1H NMR analysis using benzaldehyde as an internal standard (Table 1). Silica gel column

A facile three-component route to powerful 5-aryldeazaalloxazine photocatalysts

• Ivana Weisheitelová,
• Radek Cibulka,
• Marek Sikorski and
• Tetiana Pavlovska

Beilstein J. Org. Chem. 2024, 20, 1831–1838, doi:10.3762/bjoc.20.161

• source in this reaction, a deuterium labelling experiment was conducted (Scheme 2C). Indeed, the deazaalloxazine derivative 6-d with quantitative incorporation of deuterium in C(5) position, was isolated and confirmed by 1H NMR analysis and mass spectrometry (for more details on possible reaction

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• and NMR analysis of the natural product, no knockout studies were performed to identify which enzyme is responsible for the S-methylation. The authors propose LopH as the most likely enzyme, as it shares modest sequence and structural similarity with other MTs. This also hints at a possible new MT

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

• Koichi Mitsudo,
• Atsushi Osaki,
• Haruka Inoue,
• Eisuke Sato,
• Naoki Shida,
• Mahito Atobe and
• Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

• synthesis. Therefore, the electroreduction of pyridine (8a) was performed (Table 6). First, the electroreduction of 8a was performed with 0.1 equiv of PTSA, and 1.0 equiv of PTSA was added after electrolysis to determine the yield by 1H NMR analysis (Table 6, entry 1). The yield of 9a·PTSA (26% yield) was

• mmol; solvent, CH2Cl2 (0.5 M); flow rate of the solution of 6a, 0.75 mL min−1; flow rate of H2 gas, 100 mL min−1; reaction temperature, room temperature; current density, 50 mA cm−2. The solution was circulated until the passage of 50 F mol−1 (10 h). The yields were determined by 1H NMR analysis using

• H2 gas, 100 mL min−1; reaction temperature, room temperature; current density, 50 mA cm−2 (10 h). The solution was circulated until the passage of 50 F mol−1. The yields were determined by 1H NMR analysis using 1,1,2,2-tetrachloroethane as an internal standard. Plausible mechanism for the reduction

Bioinformatic prediction of the stereoselectivity of modular polyketide synthase: an update of the sequence motifs in ketoreductase domain

• Changjun Xiang,
• Shunyu Yao,
• Ruoyu Wang and
• Lihan Zhang

Beilstein J. Org. Chem. 2024, 20, 1476–1485, doi:10.3762/bjoc.20.131

• product structures were experimentally determined, such as by crystallography, nuclear magnetic resonance (NMR) analysis or by chemical synthesis, were obtained for further analysis. The modules in PKSs were categorized as α-module (containing KS-AT-ACP tridomain), β-module (KS-AT-KR-ACP), γ-module (KS-AT