Intramolecular C–H arylation of pyridine derivatives with a palladium catalyst for the synthesis of multiply fused heteroaromatic compounds

• Yuki Nakanishi,
• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2024, 20, 3256–3262, doi:10.3762/bjoc.20.269

• /MeOAc 1:1) to give 31.0 mg (87% yield) of 2a as a colorless solid. (NMR yield: 94%); mp 85.1–86.6 °C; 1H NMR (CDCl3) δ 8.98 (s, 1H), 8.43 (d, J = 8.4 Hz, 1H), 8.31 (dd, J = 8.0, 1.2 Hz, 1H), 7.95 (d, J = 8.4 Hz, 1H), 7.76 (ddd, J = 8.0, 7.6, 1.2 Hz, 1H), 7.62 (ddd, J = 7.6, 7.6, 1.2 Hz, 1H), 7.54 (ddd

• , J = 8.4, 8.0, 1.2 Hz, 1H), 7.37 (d, J = 8.4 Hz, 1H), 7.30 (dd, J = 8.0, 7.6 Hz, 1H), 4.40 (dd, J = 8.0, 7.6 Hz, 2H), 1.76–1.88 (m, 2H), 1.44–1.56 (m, 2H), 1.18–1.42 (m, 8H), 0.86 (t, J = 6.8 Hz, 3H); 13C{1H} NMR (CDCl3) δ 160.1, 148.4, 142.0, 136.7, 131.1, 130.5, 130.2, 130.1, 129.1, 128.7, 127.7

• . Supporting Information File 48: Additional experimental details and copies of 1H and 13C{1H} NMR spectra. Acknowledgements We thank Professor Shigeki Mori and Ms. Rimi Konishi (Ehime University) for the X-ray crystallographic analysis.

Ceratinadin G, a new psammaplysin derivative possessing a cyano group from a sponge of the genus Pseudoceratina

• Shin-ichiro Kurimoto,
• Kouta Inoue,
• Taito Ohno and
• Takaaki Kubota

Beilstein J. Org. Chem. 2024, 20, 3215–3220, doi:10.3762/bjoc.20.267

• /bjoc.20.267 Abstract A new psammaplysin derivative, ceratinadin G (1), was obtained from the Okinawan marine sponge Pseudoceratina sp., and the gross structure was clarified through spectroscopic and spectrometric analyses. The absolute configuration of compound 1 was established by comparing its NMR

• , after which the extract was partitioned between EtOAc and H2O. The EtOAc-soluble fraction was subjected to silica gel column chromatography. A detailed analysis of the 1H NMR spectrum of the fraction eluted after the one containing ceratinadins E and F revealed signals corresponding to psammaplysin F (2

• existence of a substituted benzenoid chromophore was suggested by the UV absorption maximum at 258 nm. The presence of hydroxy and/or amino groups and a carbonyl group was indicated by IR absorptions at 3337 cm−1 and 1671 cm−1, respectively. The analysis of the HSQC spectrum, along with the 1H and 13C NMR

Discovery of ianthelliformisamines D–G from the sponge Suberea ianthelliformis and the total synthesis of ianthelliformisamine D

• Sasha Hayes,
• Yaoying Lu,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2024, 20, 3205–3214, doi:10.3762/bjoc.20.266

• aeruginosa biofilm inhibitors and antibiotic enhancers. Large-scale extraction and isolation studies resulted in the discovery of four new and minor natural products, ianthelliformisamines D–G (4–7) and the known steroid, aplysterol (8). Compounds 4–7 were fully characterised following 1D/2D NMR, MS and UV

• brown gum. The LRESIMS of 4 indicated the presence of two bromine atoms due to a 1:2:1 ion cluster at m/z 459/461/463 [M + H]+, whilst the HRESIMS data allowed a molecular formula of C17H20Br2N2O3 to be assigned. The 1H NMR (Table 1) and edited HSQC spectra of 4 in DMSO-d6 indicated the presence of one

• protons indicating the presence of a symmetrical aromatic moiety, were observed. The 13C NMR (Table 1) spectrum of 4 showed two carbonyls (δC 164.4, 173.9), with the carbonyl at δC 164.4 readily assigned to an acrylamide group, which is present in all previously published ianthelliformisamine molecules [7

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

• John M. Halford-McGuff,
• Thomas M. Richardson,
• Aidan P. McKay,
• Frederik Peschke,
• Glenn A. Burley and
• Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

• ) Functionalisation of germylated triazoles. Isolated yields unless stated. (i) Pd(PPh3)4 (10 mol %), 2-bromothiazole (1.2 equiv), KCl (3.0 equiv), PhMe/EtOH 4:1, N2, 100 °C, 16 h. NMR yield in parentheses. (ii) Pd2(dba)3 (2.5 mol %), iodobenzene (1.5 equiv), AgBF4 (1.5 equiv), DMF, N2, 80 °C, 16 h. (iii) NBS (2.0

• /53959471-068e-483e-bcd4-920e6761926b and CCDC 2355570 contains the supplementary crystallographic data for this study. Supporting Information File 38: Characterization data and copies of NMR spectra. Supporting Information File 39: Crystallographic information file (cif) for compound 13. Supporting

Direct trifluoroethylation of carbonyl sulfoxonium ylides using hypervalent iodine compounds

• Radell Echemendía,
• Carlee A. Montgomery,
• Fabio Cuzzucoli,
• Antonio C. B. Burtoloso and
• Graham K. Murphy

Beilstein J. Org. Chem. 2024, 20, 3182–3190, doi:10.3762/bjoc.20.263

• studies using methyl ester sulfoxonium ylide 1a and 2,2,2-trifuoroethyl(mesityl)iodonium triflate salt (2a), as model substrates (see also Table S1 in Supporting Information File 1). Combining these at room temperature in acetonitrile produced 3a in 8% 1H NMR yield (Table 1, entry 1). Repeating the

• , entry 15). An additional solvent screen under microwave conditions offered no improvement (Table 1, entries 16–18). Finally, multivariate screening ultimately showed that 3a could be obtained in 79% 1H NMR yield (75% isolated yield, Table 1, entry 19) when using 1a (1.0 equiv), 2a (2.0 equiv) in ACN (1

• Information File 32: Experimental part, NMR spectra, computational details and crystallgraphic data. Acknowledgements We would like to acknowledge the Schipper lab at the University of Waterloo for providing access to the microwave reactor used in this study. We would also like to acknowledge Boris Ragula

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

• intramolecular Michael addition. Preliminary conformational studies on tripeptides including this scaffold in the central position show an extended conformation in solution (NMR) and in the solid state (X-ray). Keywords: fluoroalkyl groups; heterocycles; hydrazino acids; peptides; tetrahydropyridazines

• analysis (Figure 5). Consequently, it was possible to assess the stereochemistry of the other diastereoisomer 8f’ and their precursors 7f and 7f’. On the other hand, considering the similarities of the 1H NMR spectra of the CF2H and CF3 analogs, by comparison, we could hypothesize the absolute

• phenylalanine) indicate that they are not involved in hydrogen bonds. Furthermore, the 2D 1H-1H NOE NMR spectra and the chemical shifts of the NH protons of compounds 8f’, 8e, and 8e’ did not show any significant differences compared to 8f. Overall, the ability of the new fluorinated β-analogs of

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

• be accounted for in the formation of these two products alone by 19F NMR. To the best of our knowledge, this is an exceptionally rare instance whereby oligomerization of 1 appears to be stunted beyond formation of the [2]staffane; only trace yields of putative higher-order staffanes (n > 2) were

• detected in the crude reaction mixture. Remarkably, using 20 equiv of 1, the observed 4:2 product ratio improved to 1:3, with 2 formed in 72% yield. In an even more extreme case, the [2]staffane still remained the major product formed in 66% yield when using 50 equiv of 1 (19F NMR signals of presumed

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

• . The level of this chemoselectivity was dependent on the iodane ligand: OPiv was more selective for aminofluorination than OAc, which was proposed to be due to differences in basicity and nucleophilicity (Scheme 10). Detailed mechanistic studies were carried out using multinuclear NMR spectroscopy

• , deuterium labelling, rearrangements on stereodefined substrates, and structural analyses (NMR and X-ray) of the reaction products. RT-NMR-derived data strongly supported a pathway of alkene activation by the iodane, as opposed to the formation of an N-I(III) adduct. The presence of 5-exo-products, with

• activated after coordination to PhI(OAc)2, then intramolecular nucleophilic attack from oxygen and nucleophilic attack by bromide forms the final product. NMR studies of PIDA and the substrate indicated that there was no interaction between them, thereby discounting this second pathway and thereby providing

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

• one remaining –NH group is catalytically active while both tri- and tetraalkylated analogues 40 and 41, without an –NH unit, are not. Further, the authors performed 1H NMR experiments with a different substrate:macrocycle ratio and suggested a bifunctional reaction mechanism involving both inner amine

• concluded that both the presence of hydrogen-bond donor moieties (pyrrolic –NH groups) and a basic β-substituent are necessary to make the compound catalytically active. Further, authors have performed 1H NMR binding and kinetic studies and suggested that the reaction mechanism involves a simultaneous

• porphyrin radical anion. Ultimately, protonation of intermediate E led to the final product. Formation of intermediates, such as enamine A and cation radical B, was confirmed using techniques like ESIMS, 1H NMR, and EPR, Stern–Volmer quenching experiments, respectively. All these mechanistic studies

Synthesis of the 1,5-disubstituted tetrazole-methanesulfonylindole hybrid system via high-order multicomponent reaction

• Cesia M. Aguilar-Morales,
• América A. Frías-López,
• Nadia V. Emilio-Velázquez,
• Alejandro Islas-Jácome,
• Angelica Judith Granados-López,
• Jorge Gustavo Araujo-Huitrado,
• Yamilé López-Hernández,
• Hiram Hernández-López,
• Luis Chacón-García,
• Jesús Adrián López and
• Carlos J. Cortés-García

Beilstein J. Org. Chem. 2024, 20, 3077–3084, doi:10.3762/bjoc.20.256

• and resource optimization. In addition, all the target compounds were fully characterized using 1H and 13C NMR spectroscopy and HRMS. It is important to mention that this protocol cannot be considered a true one-pot synthesis, as it requires a solvent exchange between reaction steps (e.g., from

• Information File 12: Experimental procedures, compound characterization data, and copies of NMR spectra. Funding C.M. A-M. (756225) and América A. Frías-López (833463) acknowledges the support of CONACHYT through a graduate scholarship. This work was financially supported by Instituto De Ciencia, Tecnología

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

• reaction mixture, but a trace amount of it was detected after the distillation (propargyltrichlorosilane/allenyltrichlorosilane = 200:1 by 1H NMR spectroscopy, see Supporting Information File 1 for details). With distilled propargyltrichlorosilane (>99% isomeric purity) in hand, we set out on our study on

• propargyltrichlorosilane. Evaluation of C2-symmetric catalysts with benzaldehyde (1a) as a model aldehyde. Reaction conditions: 1a (0.1 mmol), silane (0.15 mmol), catalyst (0.01 mmol), CH2Cl2 (0.4 mL); yields were determined by 1H NMR spectroscopy with 1,1,2,2-tetrachloroethane as an internal standard following workup and

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

• because by-products interfered with the chromatographic separation; however, these yields are similar to the ones reported for resembling norbornadienes [34][37]. The novel compounds 1h–l,n were identified and fully characterized by NMR spectroscopy (1H, 13C, COSY, HSQC, HMBC), melting point, and

• elemental analysis. All products showed the characteristic 1H NMR spectroscopic signals of norbornadienes, in particular two signals at ca. 2.10 ppm and 2.20 ppm (7-CH2) and two broad singlets between 3 and 4 ppm (bridgehead 1- and 4-CH). In addition, typical 13C NMR shifts of the aryl-substituted

• by 1H NMR spectroscopy. Initially, all derivatives showed the isomerization reactions to the corresponding quadricyclane derivatives, as identified by the characteristic 1H NMR signal pattern of the quadricyclane fragment with five multiplets at around 1.6 ppm, 1.7 ppm, 1.8 ppm, 2.1 ppm, and 2.2 ppm

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

• formation of this inclusion complex, circular dichroism spectroscopy represents a powerful tool when combined with nuclear magnetic resonance (NMR) and X-ray single-crystal analysis. This is because the induced circular dichroism (ICD) can be observed on the guest molecule of the inclusion complex derived

• end-capping reaction. As a pseudorotaxane structure could be decomposed during measurements (e.g., a solution-based NMR measurement), a more stable rotaxane structure is preferred for the analysis. Therefore, we developed a facile [3]rotaxane synthesis method based on a urea end-capping method to

• such structural regulation of the rotaxane framework, NMR was deployed as a very powerful evaluation method, especially the nuclear Overhauser effect or rotating-frame Overhauser effect, which is used to analyze the spatial adjacency of the components. It provides critical data for detecting the

Tunable full-color dual-state (solution and solid) emission of push–pull molecules containing the 1-pyrindane moiety

• Anastasia I. Ershova,
• Sergey V. Fedoseev,
• Konstantin V. Lipin,
• Mikhail Yu. Ievlev,
• Oleg E. Nasakin and
• Oleg V. Ershov

Beilstein J. Org. Chem. 2024, 20, 3016–3025, doi:10.3762/bjoc.20.251

• and compound characterization data, solvatochromic studies for compound 1с, titration data, and 1H and 13C NMR spectra for compounds 1a–i. Funding This work was performed within the framework of the state task of the Ministry of Science and Higher Education of the Russian Federation (project no. FEGR

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

• anions and oxalate. Acetate and benzoate as monocarboxylates were investigated alongside oxalate because we expected also a different binding scenario for these small guests as a result of the altered zinc–zinc distance compared to our previous study [74]. Indeed, 1H NMR host–guest titrations showed a

• determined by NMR (see Supporting Information File 1, Figures S7, S9, S11, S13, S15, and S17). 1H NMR dicarboxylate binding studies were carried out with oxalate (C22−) and longer variants C(2+n)2− up to adipate (with n = 4). Oxalate addition to [L2Zn2] results in an intermediate exchange with broadened NMR

• undesired unknown aggregates. On the other hand, the 1H NMR spectrum does not match the one of the free ligand which shows that neither full metal extrusion took place as a result of the competitive nature of oxalate. Negative ESI-MS of a host–guest mixture with 5 equiv of oxalate gave the final proof that

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• Information File 42: Experimental procedures, characterization data of all products, and copies of 1H, 13C, and 19F NMR spectra. Acknowledgements We thank Dr. Claus Bier for the help with the HPLC–ESIMS measurements.

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

• characteristic (Table 1, entry 7). A slightly higher reactivity was achieved when the BF3·(OEt2) was used instead of TiCl4 (Table 1, entry 8) [28]. The reactions were monitored by 19F NMR of the crude mixtures. The full conversion was reached by applying exclusively n-BuLi, but the formed product was not the

• 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

• products. These highly stable compounds were isolated after purification on silica gel in good yields (Scheme 2) and characterized by spectroscopic methods. The reaction proceeded with very high Z-stereoselectivity (Scheme 2, compounds 9a–d). In the 19F NMR spectra of crude mixtures, only trace amounts of

4,6-Diaryl-5,5-difluoro-1,3-dioxanes as chiral dopants for liquid crystal compositions

• Maurice Médebielle,
• Peer Kirsch,
• Jérémy Merad,
• Carolina von Essen,
• Clemens Kühn and
• Andreas Ruhl

Beilstein J. Org. Chem. 2024, 20, 2940–2945, doi:10.3762/bjoc.20.246

• ,R)-3, (S,S)-3, (R,R)-4 and (S,S)-4. Supporting Information Supporting Information File 38: Experimental procedures, analytical data and copies of NMR spectra. Acknowledgements The Centre Commun de Spectrométrie de Masse (CCSM) et de RMN (CCRMN) of the Université Claude Bernard Lyon 1 are thanked

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

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• solid (440 mg, 60%). 1H NMR (400 MHz, CDCl3) δ 8.79 (d, J = 8.0 Hz, 2H), 8.65 (d, J = 8.1 Hz, 2H), 8.56 (d, J = 7.6 Hz, 2H), 8.40 (d, J = 7.8 Hz, 2H), 8.30 (s, 2H), 7.82 (t, J = 7.6 Hz, 2H), 7.62 (t, J = 7.4 Hz, 2H), 4.05 (m, 4H), 1.77 (m, 2H), 1.38 (m, 16H), 0.93–0.51 (m, 12H); 13C NMR (100 MHz, CDCl3

• ), and the resulting precipitate was filtered, then washed with water (300 mL) to give the title compound as a dark solid (1.90 g, 65%). 1H NMR (400 MHz, CDCl3) δ 8.72 (d, J = 8.0 Hz, 2H), 8.60–8.47 (m, 4H), 8.37 (d, J = 8.2 Hz, 2H), 8.27 (s, 2H), 7.80 (t, J = 7.2 Hz, 2H), 7.60 (t, J = 7.3 Hz, 2H), 4.25

• (br, 4H), 1.94–1.80 (m, 4H), 1.34 (d, J = 90.2 Hz, 20H), 0.82 (d, J = 6.9 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 183.2, 156.3, 135.6, 134.5, 133.2, 131.0, 129.4, 128.6, 128.3, 127.7, 127.5, 127.1, 123.6, 123.2, 122.7, 117.2, 113.5, 69.8, 31.9, 29.9, 29.6, 29.5, 26.2, 22.8, 14.2; HRESIMS (m/z): [M + Na

C–H Trifluoromethylthiolation of aldehyde hydrazones

• Victor Levet,
• Balu Ramesh,
• Congyang Wang and
• Tatiana Besset

Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242

• mixture. When the reaction was conducted in the presence of NBS in acetonitrile for 10 min, followed by the addition of AgSCF3, the desired product was isolated in 91% yield. A total selectivity for the formation of the Z isomer was observed as ascertained by 2D NMR (for more details, see Supporting

• expected product was detected (Scheme 4C). Having in mind that in the presence of an oxidant, the SCF3 dimer (SCF3)2 might be generated, an additional test was realized. In the presence of NCS in THF, AgSCF3 was converted into the corresponding dimer in 5 min (monitored by 19F NMR). Then, the reaction was

• room temperature. α,α,α-Trifluoroacetophenone (42 μL, 0.3 mmol, 1.0 equiv) was added as an internal standard for determining the 19F NMR yield. The mixture was then filtered on a pad of celite and rinsed with CH2Cl2. The solution was then washed with brine twice (20 mL) and the organic layers were

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

• product compared to the substitution of phenyl (Scheme 4, 6c). Furthermore, n-butyl isocyanide was used to increase the variety of products and the n-butyl-substituted products 6f–h were obtained with 72–78% yield . All the products were characterized by 1H NMR, 13C NMR, and infrared spectroscopy, and

• mass spectrometry. Taking 4h as an example for the analysis of its structure, in its 1H NMR spectrum, one singlet signal appears at δ = 0.67 (9H) corresponding to the three methyl groups in the tert-butyl substituent. A singlet at δ = 2.39 (3H) is assigned to the protons of the CH3-group on the phenyl

• . The signal at δ = 3.42 is the NH group. All the protons of the aromatic rings are located from δ = 7.10 to 7.99. In its 13C NMR spectrum, all of the carbon signals appear at δ = 158.3, 152.5, 134.7, 134.2, 133.9, 133.2, 130.8, 130.4, 129.2, 129.1, 129.0 128.9, 128.4, 127.4, 125.8, 122.6, 121.1, 120.6

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• -glycosides had to be employed in order to obtain anomerically pure indirubin-N-glycosides. As expected, no epimerization was observed during the base-mediated condensation as no aqueous acid was employed. All products were isolated as the pure Z-configured isomers (determination by NMR, the other isomer was

• very good yield. Likewise, glucoside β-33b, galactoside β-33c, and mannoside β-33d were prepared. All products were isolated as the pure Z-configured isomers (determination by NMR, the other isomer was not visible, E/Z < 2:98). The configurations were determined by comparison of chemical shifts of our

• pure Z-configured isomers (determination by NMR, the other isomer was not visible, E/Z > 98:2). Deprotection of E-β-43a,b under acidic conditions gave rhamnosides E-β-44a,b in good yields. However, deprotection of E-β-43c–e failed. Kornienko et al. reported the synthesis and antiproliferative activity

Multicomponent synthesis of α-branched amines using organozinc reagents generated from alkyl bromides

• Baptiste Leroux,
• Alexis Beaufils,
• Federico Banchini,
• Olivier Jackowski,
• Alejandro Perez-Luna,
• Fabrice Chemla,
• Marc Presset and
• Erwan Le Gall

Beilstein J. Org. Chem. 2024, 20, 2834–2839, doi:10.3762/bjoc.20.239

• Supporting Information File 22: Experimental procedures, compound characterization data, and NMR spectra for all compounds. Funding The authors acknowledge the support of the French Agence Nationale de la Recherche (ANR) under reference ANR-20-CE07-0003 (BILIOMAR project).

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

• . Ltd. and purified by distillation. 1H and 13C{1H} NMR spectra were recorded on a JEOL JMN-ECZ400S spectrometer (400 MHz and 100 MHz, respectively) using TMS as internal standard. The assignments of the 13C{1H} NMR signals were reaffirmed by DEPT experiments. IR spectra were recorded with a JASCO FT/IR

• ), the mixture was concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (eluent: hexane/ethyl acetate 70:30, Rf 0.55) to afford diethyl 2-[(4-methylbenzoyl)amino]-2-(phenylethynyl)propanedioate (4a, 122 mg, 0.31 mmol, 78% yield) as yellow oil. 1H NMR (400

• MHz, CDCl3, δ) 7.78 (d, J = 8.0 Hz, 2H), 7.65 (br s, 1H), 7.48 (d, J = 8.0 Hz, 2H), 7.32–7.25 (m, 5H), 4.37 (q, J = 7.2 Hz, 4H), 2.40 (s, 3H), 1.35 (t, J = 7.2 Hz, 6H); 13C{1H} NMR (100 MHz, CDCl3, δ) 165.6 (C), 165.3 (C), 142.8 (C), 130.2 (C), 129.4 (CH), 128.9 (CH), 128.2 (CH), 127.5 (CH), 122.0 (C