Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• -coupling was carried out using Pd(PPh3)4 as catalyst with K3PO4 as base in toluene as solvent which gave a mixture of different products. Further investigation revealed the presence of the two-fold Sonogashira–Hagihara product, starting material 2, and the desired product 3. Hence, starting material 2 and

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• , DMF/H2O, 60 °C, 18 h. (b) Pd(OAc)2, PPh3, CuI, phenylacetylene, Et3N, 50 °C, 5 h. (c) CuI, neocuproine, 4-MeOC6H4SH, NaOt-Bu, toluene, 110 °C, 13 h. (d) CuI, ʟ-proline, DMF, 80 °C, 14 h. (e) CuI, imidazole, Cs2CO3, DMF, 120 °C, 15 h. (f) 3-Methoxy-2-(trimethylsilyl)phenyl triflate, CsF, MeCN, rt, 18 h

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• solvents including dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), toluene, acetic acid (AcOH) and water (Table 1, entries 9–13) were carried out. However, polar solvents such as AcOH and H2O were proved to be unsuitable for this reaction. For catalysts, we found that Cu(OAc)2 gave the best results

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• ) could be prevented when switching to BCl3 (10 mol %). Interestingly, toluene (94), which is generated as a byproduct of the Grob fragmentation, must react more sluggishly with the generated cationic intermediates compared to chloride, as no alkylations of toluene were reported. In 2017, the Snyder group

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• . In addition, 5a was not highly soluble in most nonpolar solvents, including toluene and CH2Cl2, but slightly soluble in other polar solvents, including MeOH and DMSO. The solubility of C60–peptide conjugates 5a–c was in line with DLS data of the aqueous solutions or dispersions. While 5a (blue line

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• )amine) [33] in toluene. Conclusion To summarize, an approach toward 4-azido-6,7-dimethoxy-2-alkyl/arylsulfonylquinazolines was developed employing a sulfonyl group dance caused by the azide–tetrazole equilibrium in quinazolines. 4-Azido-6,7-dimethoxy-2-alkyl/arylsulfonylquinazolines were obtained using

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• temperature [23] led to the cleavage of the thiazole ring, furnishing disulfides 18b and 18c exclusively (Table 1, entries 7–10). Interestingly, the reaction of 5 with ammonia borane at elevated temperature in toluene [20] furnished three reaction products with a low yield since 2,3-dihydro[1,3]thiazolo[4,5-b

• quinolines and indoles [24], pyridines [25], and imines [26], the reactions of 5 and 15c with ammonia borane (3 equiv) in the presence of a catalytic amount of B(C6F5)3 in toluene as an aprotic solvent at a temperature of 80 °C afforded aminoboranes 17b (R1 = F) and 17c (R1 = CH3) as main products along with

• accordance with the results obtained for dimethylated [1,3]thiazolo[4,5-b]pyridine 15c, the corresponding aminoboranes 17d and 17e were formed when 6-bromo[1,3]thiazolo[4,5-b]pyridine 12c was treated with ammonia borane in toluene at 45 °C in the presence of a catalytic amount of B(C6F5)3 (Scheme 3). Whilst

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• % conversion after 24 h, estimated t1/2 = 96 h, kobs = 1.4 × 10−6 s−1). With 55 μL MeOH in DCM, the relative rates for each substrate are 3,850:50:1 with urea 1a > carbamate 1b > benzamide 1c. The analogous toluene sulfonamide substrate 1d did not react on measurable timescales at room temperature (no product

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• condensation and Schiff base formation, which is then cyclized [12][16]. The reaction of 1 with arylamines 2a is performed in toluene solution in the presence of a catalytic amount of p-toluenesulfonic acid. This readily affords 6,8-di-tert-butyl-N-aryl-3H-phenoxazin-3-imines 3 but proceeds smoothly only with

• recorded on a Varian Excalibur 3100 FTIR instrument using the attenuated total internal reflection technique (ZnSe crystal). UV–vis spectra were recorded at c = 2⋅10−5 M in toluene solutions with a Varian Cary 100 spectrophotometer. Photoluminescent spectra were recorded at c = 2⋅10−5 M (compounds 5a–c and

• 6a,b) and c = 2⋅10−6 M (compound 10c) in toluene solutions with a Varian Cary Eclipse fluorescence spectrophotometer. UV–vis and fluorescence spectra were recorded using standard 1 cm quartz cells at room temperature. Toluene of spectroscopic grade (Aldrich) was used to prepare the solutions. The

Synthesis of spiropyridazine-benzosultams by the [4 + 2] annulation reaction of 3-substituted benzoisothiazole 1,1-dioxides with 1,2-diaza-1,3-dienes

• Wenqing Hao,
• Long Wang,
• Jinlei Zhang,
• Dawei Teng and
• Guorui Cao

Beilstein J. Org. Chem. 2024, 20, 280–286, doi:10.3762/bjoc.20.29

• ketimine and its subsequent [4 + 2] annulation reaction with 1,2-diaza-1,3-diene in the presence of Et3N (2.0 equiv) in diethyl ether at room temperature (Table 1, entry 1). However, no product was detected under these conditions. We then replaced diethyl ether with toluene, which resulted in the desired

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• heating at 90 °C for 4 hours. The crude reaction mass obtained with these conditions was then purified by column chromatography (toluene). After eluting unreacted pristine C70, a dark reddish fraction was isolated and analyzed by HPLC. A major peak was observed at a retention time of 17.5 minutes, which

• were run using other solvents such as toluene and chlorobenzene, increasing the C70 concentration from 1.2 M to 2.4 M, and decreasing the catalytic load to 5 mol % (Table S1 in Supporting Information File 1). However, none of these trials improved the yield of bis(fulleroid) 2a. The same reaction was

• (BIPHEP)]+. 1H NMR (CS2/CDCl3, 400 MHz) spectrum of compound 3a as a mixture of three isomers. X = residual toluene. Rhodium(I)-catalyzed cycloaddition of C60 with diynes to afford bis(fulleroid) derivatives [33]. Rhodium-catalyzed cycloaddition of C70 with diynes 1a and 1b. Oxidative cleavage of bis

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• activity/inactivity in amination reactions. It is known that acenaphthylenes are usually readily formed from acenaphthenes by dehydrogenation with chloranil, dichlorodicyanobenzoquinone (DDQ) or active MnO2 on reflux in toluene/xylene and other inert solvents. However, attempts to obtain acenaphthylene 8

• nitrobenzene. For example, quinoquinoline 5 reacts with chloranil upon heating in toluene to give a dark brown, high-melting product, in which, however, the methylene bridge remains unchanged. According to 1H NMR spectroscopy and combustion analysis data, this is complex 9 with a composition close to the ratio

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• to the presence of the electron-withdrawing ester groups. Importantly, only the Z-form of 18c was found to be stable enough with a half-life of 2.8 min at room temperature in acetonitrile (77% of Z-isomer in PSS) and 4.1 minutes in toluene (91% of Z-isomer in PSS) after irradiation with red light

• forward and backward isomerization of N,N'-diacetylindigo (9a) in toluene without isolation of the Z-form [49]. The Fischer method remains relevant up to date and is frequently used for the characterization of the photoinduced forms of various indigoid photoswitches [50][51][52][53][54]. To assess an

• , depending on the solvent, the thermal half-lives varied within a wide range from seconds to days. For example, for compound 17e, the half-lives changed from 8 s (in MeOH) to 11 h (in toluene). In addition, the Z-form of compound 17d was unusually stable in 1,4-dioxane, lasting for almost 6 days. The 2021

Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles

• Yumei Wang,
• Guangzhu Wang,
• Yanping Zhu and
• Kaiwu Dong

Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20

• achieving high selectivity. Also, an obvious solvent effect on the enantioselectivity was observed (Table 1, entries 7–10). Very low ee values of product 2a were detected when the reaction was performed in DMSO or MeOH (Table 1, entries 7 and 8), while using DCE or toluene as the solvent the

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• , we screened other ligands such as XPhos and DPEPhos in the presence of Cs2CO3 as base in dioxane, however, the undesired phenazine product 6 was still obtained in moderate yield under these conditions (entries 12 and 13, Table 2). In the presence of SPhos as ligand, Cs2CO3, and toluene as solvent

• , the desired intermediate 3a was obtained in 20% yield along with 55% of the phenazine 6 (entry 14, Table 2). Although toluene was shown to be a good solvent for this B–H coupling reaction, we were unable to prevent the double B–H reaction from occurring leading to the phenazine 6, even when shortening

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• permeation chromatography was performed in toluene on a column (400 × 20 mm) packed with Bio-Beads S-X3 gel (200–400 mesh, Bio-Rad) using a differential refractive index detector (Knauer). TLC was carried out on Silica Gel 60 F254 plates (Merck), spots were visualized under UV light and by heating plates

• solution of 8,9-O-isopropylidene derivative 6 (871 mg, 1.4 mmol) in CH2Cl2 (60 mL), 90% aq CF3CO2H (6 mL, freshly prepared) was added at 0 °C (ice–water bath). The reaction mixture was stirred at 0 °C for 25 min. The mixture was allowed to warm to ≈20 °C, toluene (20 mL) was added, and then concentrated

• was filtered off and washed with t-BuOMe/petroleum ether 1:1 (v/v) mixture to give 7 as white crystals (576 mg, 70%). [α]D27 −116.0 (c 2.9, acetone); Rf 0.21 (toluene/acetone 5:1); 1H NMR (600 MHz, acetone-d6, δ, ppm, J, Hz) 2.20 (dd, J3a,3e = 13.6, J3a,4 = 11.9, 1H, H-3a), 2.83 (dd, J3e,3a = 13.6

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• Celite® and concentrated in vacuo. The resulting residue was taken up in EtOAc (700 mL) and washed with 10% aq Na2S2O3 (700 mL), water (700 mL) and brine (700 mL). The organic phase was then dried over MgSO4, filtered and reduced to dryness. Flash chromatography on silica gel (toluene→toluene/EtOAc, 3:2

• ) yielded 4 as an orange syrup (8.74 g, 85%). Rf = 0.4 (toluene/EtOAc, 7:3); [α]D +92 (c 1.0, CHCl3); 1H NMR (500 MHz, CDCl3) δ 5.44 (d, J = 10.2 Hz, 1H, NH), 4.98 (dd, J = 11.1, 2.9 Hz, 1H, H-3), 4.95 (d, J = 3.6 Hz, 1H, H-1), 4.87 (d, J = 12.1 Hz, 1H, CH2(A)Troc), 4.69–4.58 (m, 2H, H-4, CH2(B)Troc), 4.49

• concentrated under reduced pressure. Flash chromatography on silica gel (toluene→toluene/acetone, 7:3) yielded 5 as a gold-coloured syrup (7.83 g, 96%). Rf = 0.4 (toluene/EtOAc, 3:2); [α]D +67 (c 1.0, CHCl3); 1H NMR (500 MHz, CDCl3) δ 5.58 (d, J = 9.8 Hz, 1H, NH), 4.93 (d, J = 3.6 Hz, 1H, H-1), 4.77 (d, J

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

• conditions, particularly the solvent employed. For instance, when toluene is used as the reaction solvent, a reaction at 100 °C for 15 h affords an E/Z mixture of 7 (E/Z ≈ 1:1) with 90% yield, 8 with 10% yield, and 9 with 0% yield. In contrast, a reaction at 25 °C for 15 h in N,N-dimethylformamide (DMF

• imperative to suppress the generation of 8 and 9, as well as the conversion reaction of 7 into 10. Therefore, it is important to use toluene as the solvent. Accordingly, pentacyanoocta-1,3,5,7-tetraene (PCOT) 12 was synthesized with 75% yield as a mixture of 3Z,5E/3E,5E isomers in the ratio of 71:29 via a

• one-pot reaction involving TCNE and one equivalent of 3-(4-(dimethylamino)phenyl)propionitrile in toluene at 90 °C for 24 h. Subsequently, one equivalent of 1 was added at 90 °C for 24 h (Scheme 6) [101]. While the separation of the isomers was not achieved, the structure of the 3Z,5E isomer was

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• Cary 50 UV–vis spectrophotometer scanning between 800 and 200 nm. All spectra were recorded with baseline correction in CH2Cl2 or toluene (HPLC grades) at 25 °C in a quartz cuvette with a 10 mm path length. Electrochemistry Cyclic voltammograms (CV) and differential pulse voltammograms (DPV) were

• ) and 2 (176 mg, 534 μmol) in anhydrous toluene (5 mL) and P(OEt)3 (10 mL) was heated to reflux for 5 h, resulting in a color change from orange to dark red. The reaction mixture was then allowed to cool to rt before it was concentrated under reduced pressure. The resulting dark red solid was purified

• ) and Lawesson’s reagent (23.1 mg, 57.0 μmol) in anhydrous, N2-degassed toluene (20 mL) was heated to reflux for 21 h. The reaction mixture was then allowed to cool to rt, diluted with toluene (50 mL), washed with 1 M NaOH (3 × 50 mL), and then with H2O (3 × 50 mL). The organic phase was dried over

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

• in these cases (Supporting Information File 1, Figures S54 and S74). Crystal structures The solid-state structures of 2a and 2f were determined by single-crystal X-ray diffraction. The crystals were grown from concentrated solutions in toluene. A representation of the molecular structure of 2a is

• room temperature for 24 h and the solvent evaporated. The product was recrystallized from a hot toluene/THF mixture. Yield: 38.8 mg (42%) off-white solid. 1H NMR (δ in ppm, 300 MHz, CDCl3, 298 K) 1.07 (s, 9H, CH3), 1.40 (s, 9H, CH3), 2.66–2.81 (m, 2H, CH2), 3.30–3.46 (m, 2H, CH2), 5.21 (br, 1H, NH2

Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

• Xing Liu,
• Wenjing Shi,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1923–1932, doi:10.3762/bjoc.19.143

• triethylamine, the reaction in other solvents such as DCE, THF, and CHCl3 gave the product 3a in 61%, 46% and 56% yields, respectively (Table 1, entries 12–14). However, the reaction did not proceed in toluene and acetonitrile (Table 1, entries 15 and 16). When lowering the amount of triethylamine to one

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• toluene and bibenzyl, i.e., RH and R2 products, which were identified by the masses observed through GC–MS and through comparison of the GC–MS retention times with authentic samples. Higher concentrations and reaction times (entries 7–9 in Tabe 1) lead to larger extents of conversion (up to 61% at 18 h

• ) and favor formation of bibenzyl over toluene (up to 52% yield at 18 h). [BnBr]•– presumably cleaves to afford Bn•, which can react further to form Bn2 (see following section) or can form toluene through reaction with THF, which is known to have a reasonably weak α-CH bond and act as a H• donor towards

• lower for a given reaction time (compare entries 12 and 15 to 11 and 14 in Table 1) and the sole detected product is toluene rather than bibenzyl. Furthermore, in one of the cases of complete conversion (Table 1, entry 14), 1H NMR spectroscopy indicated that the reductant-based side product is a salt of

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

• groups to achieve optimal charge-transporting and fluorescent properties within one TADF compound (Figure 1) [5]. The obtained TADF emitters (453 to 550 nm) show photoluminescence quantum yields of up to 98% in oxygen-free toluene solutions. These TADF emitters are suitable for OLEDs with brightness of

• -carbonitrile (REF) [5]. Absorption spectra of dilute toluene, tetrahydrofuran (THF), and chloroform solutions as well as of the films of compounds 6–9 are shown in Figure 2a,b. The nonstructured low-energy bands at wavelengths of 350–450 nm are well seen in the absorption spectra of 6–9. The wavelengths of

• compound 8 had a slight impact on its red-shifted absorption spectra in comparison to that of other compounds (Figure 2a,b and Table 1). The photoluminescence spectra of toluene solutions of the compounds are characterized by non-structured shapes typical for ICT emissions (Figure 2c and Figure S1 in