Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• compounds with high yields (84–92%). The three most promising compounds of the library (13a, 13b, and 13c) were selected for further detailed characterization. In vitro evaluation was performed employing a high-performance liquid chromatography (HPLC)-based methodology, using the fluorogenic histone

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

• is conceptually appealing, radical additions of X–Y across 1 in practice can be challenging to control and often lead to complex mixtures of functionalized [n]staffanes, n = 1–5 (Figure 1, top) [2][31][32][33][34]. Even though [n]staffanes are often separable by column chromatography, the yields for

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

• and tested them as HER electrocatalysts using acetic acid as an alternative proton source [124]. Preliminary results indicated that the biscorrole (1.5 mg, 1 μM) could produce 0.84 mL of H₂ during 1 hour of electrolysis, as confirmed by gas chromatography (GC). Villagrán and co-workers reported a

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

• -disubstituted tetrazole-methanesulfonylindole derivatives, with yields ranging from 16% to 55% after purification by column chromatography. Despite some yields being modest, they are deemed reasonable considering the reaction’s structural complexity, atom economy, and the efficiency achieved in terms of time

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

• structure analysis, and is purified by simple precipitation without requiring chromatography; (3) various end-capping agents are available, and well-optimized conditions can ensure a high yield (e.g., 2-methoxyphenyl isocyanate obtains an 85% yield after 3 h of reaction [49]). Owing to such a high-yield

• species. As these modifications proceeded effectively with high yields (>90%) without any taxing purification by chromatography, a simple filtration-based purification was sufficient. This synthetic method enabled a flexible molecular design of the CD-based rotaxane framework in an easy, scalable manner

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

• 4 (65%), 5 (50%), and 6 (40%) by chromatography was straightforward. However, the subsequent oxidation of the alcohol with the usual oxidizing agents (Jones reagent, KMnO4, etc.) was not successful. A radical oxidation with TEMPO, potassium bromide (KBr), sodium hypochlorite (NaOCl), and sodium

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

• single step by an aldol-Tishchenko reaction [30] starting from commercially available difluoromethyl phenyl ketone [41][42] and an excess of benzaldehyde (4 equiv), under basic conditions (Scheme 3). Diol rac-2 was obtained in a 62% yield after recrystallization from CHCl3 with no need for chromatography

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

• dichloromethane (3 × 20 mL). The combined organic extract was dried over MgSO4, filtered and concentrated under reduced pressure. The crude product was purified by silica column chromatography (SiO2, CH2Cl2/diethyl ether 98:2) to give the title compound as a dark solid (30.0 mg, 13%). Mp 295–296 °C; 1H NMR (400

• extracted with dichloromethane (3 × 20 mL). The combined organic extract was dried over MgSO4, filtered and concentrated under reduced pressure. The crude product was purified by column chromatography (SiO2, petroleum ether/CH2Cl2 1:9) to give the title compound as a dark solid (110 mg, 48%). Analysis is in

• × 20 mL). The combined organic extracts were dried over MgSO4, filtered and concentrated under reduced pressure. The crude product was purified by silica column chromatography (SiO2, CH2Cl2/diethyl ether 98:2) to give the title compound as a dark solid (120 mg, 36%). Mp 241–242 °C; 1H NMR (400 MHz

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

• collected separately, dried over MgSO4, and concentrated in vacuo. The crude was purified by column chromatography on silica gel, flash chromatography to afford the desired product 2–6. State of the art and this work. Reaction conditions: hydrazone (0.3 mmol, 1.0 equiv), NBS (0.33 mmol, 1.1 equiv), in CH3CN

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

• reaction mixture was stirred at temperatures of 100 or 80 °C for 2 h using a magnetic stirrer. After making sure that the reactions were completed (monitored by TLC), the reaction mixture was cooled to ambient temperature. Then, the crude mixture was purified using a silica gel chromatography column and

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

• intermediate C which underwent extrusion of iodine and dipropyl disulfide to give intermediate D. Subsequent reaction with acetic anhydride, pyridine and KHF2 resulted in the replacement of the TMS by acetyl groups which was important for practical reasons (stability during chromatography). The reaction of 13

• cyclization of 4e with oxalyl chloride afforded yellow isatin-N-glycoside 16a as an anomeric mixture from which the pure α- and β-anomer could be separated by chromatography. Likewise, isatin-N-glycosides 16b–f were prepared which were all isolated (except from rhamnoside 16b) as the pure β-anomers. The

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

•  3) [13][14]. To a dry THF solution of adduct 4a, butyllithium was added, and the reaction mixture was stirred at −78 °C for 5 min. Following the addition of acetic acid, the reaction mixture was concentrated and subjected to silica gel column chromatography, resulting in the isolation of ethyl 5

• ), 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

• acetic acid (0.1 mL), the solvent was removed under reduced pressure. The residue was purified by column chromatography on silica gel (eluent: hexane/ethyl acetate 70:30, eluent for TLC: hexane/ethyl acetate 80:20, Rf 0.61) to afford ethyl 2-(4-methylphenyl)-5-(phenylmethyl)oxazole-4-carboxylate (5a

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines

• Dmitriy Yu. Vandyshev,
• Daria A. Mangusheva,
• Khidmet S. Shikhaliev,
• Kirill A. Scherbakov,
• Oleg N. Burov,
• Alexander D. Zagrebaev,
• Tatiana N. Khmelevskaya,
• Alexey S. Trenin and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2024, 20, 2806–2817, doi:10.3762/bjoc.20.236

• hemisulfate to its basic form in situ. Thin-layer chromatography (TLC) and high-performance liquid chromatography with mass-spectrometric detection (HPLC–MS) were used to monitor the reaction and to identify the products obtained. It should be noted that in the case of HPLC–MS analysis, the signals registered

Mechanochemical difluoromethylations of ketones

• Jinbo Ke,
• Pit van Bonn and
• Carsten Bolm

Beilstein J. Org. Chem. 2024, 20, 2799–2805, doi:10.3762/bjoc.20.235

• spectroscopy with 1,2-dichloroethane as the internal standard. After these analyses, isolating the products by column chromatography was attempted. Unfortunately, many products were highly volatile and very non-polar, rendering the purification difficult. As a result, in several cases only little or no product

• chromatography, which afforded the products in 53% and 39% yield, respectively. Product 3e with an isobutyl group in para-position was obtained in 63% yield and isolated in 35% yield. Changing the position of the methyl group to the ortho-position led to a decrease in yield (3f: 34%). ortho-Methoxy-substituted

• ketone 1g provided the corresponding product 3g in 56% yield. Difluoromethyl enol ether 3h with three methyl groups was obtained in 56% yield and column chromatography allowed to isolate it in 42% yield. 2-Acetonaphthone was successfully converted to 3i in 66% yield. Besides aryl ketones, arylalkyl

Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light

• Francesco Gambuti,
• Jacopo Pizzorno,
• Chiara Lambruschini,
• Renata Riva and
• Lisa Moni

Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230

• yield of 88% each step). Since, during the optimization of the reaction conditions, we have noticed a certain instability of the spiro-compounds through chromatography on silica gel, we have initially carried out the purifications using alumina as the stationary phase. However, during the scope studies

• the solvent and using Et3N as additive for the eluent of the chromatography on silica gel. With these improvements, we have demonstrated that the yields are comparable to those obtained with purification on alumina but reaching significantly higher degrees of purity of the final products (see

• °C at 451 nm (blue LEDs) under magnetic stirring for 24 h. The reaction mixture was treated with Et3N (3 equiv, 1.44 mmol, 200 µL), concentrated and the residue was purified by column chromatography on silica gel with PE/Et2O (from 85:15 to 75:25) to give 3a (121 mg, 61%), as yellow oil; IR (ATR) ν̃

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

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

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• -Flight (TOF) LC–MS. The solvent, toluene, was purchased as dry solvent and applied without further purification. Other reagents, catalysts, ligands, acids, and bases were used as purchased from commercial suppliers. Column chromatography was performed on Merck Silica gel 60 (particle size 63–200 μm

• ). Solvents for extraction and column chromatography were distilled prior employment. Synthesis of 4a–i The synthesis of 4a–f has been previously reported. Novel derivatives 4g–i were prepared according to our previously reported procedure [65]. 1,3-Dimethyl-5-phenyl-6-(phenylethynyl)pyrimidine-2,4(1H,3H

• combined organic layers were dried over Na2SO4, concentrated under reduced pressure, and purified by column chromatography (heptane/ethyl acetate). 2,4,8-Trimethyl-6-(p-tolyl)benzo[f]quinazoline-1,3(2H,4H)-dione (5a). According to general procedure, compound 5a was obtained as a brown solid in 99% yield

Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers

• Yukiko Karuo,
• Keita Hirata,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226

• and 11). We predicted that the product yield would decrease because 2k is labile in column chromatography. Utilizing a boronic acid bearing an n-butyl group as a primary alkyl group (4m), the cross-coupling did not proceed due to β-elimination (Table 3, entry 12). In contrast, the reaction with

• EtOAc. The organic phase was washed with brine (40 mL), dried over Na2SO4 and filtered. Then, the filtrate was concentrated under reduced pressure. The residue was purified by column chromatography and preparative TLC to afford 2. 2-Chloro-1-fluoro-2-phenylethenyl phenyl ether (2a): Compound 2a was

• purified by column chromatography and preparative TLC (hexane only), and obtained in 96% yield (122.0 mg) as a pale yellow oil; 1H NMR (400 MHz, CDCl3) δ 7.04–7.22 (m, 2H), 7.26–7.50 (m, 6H), 7.55–7.69 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 101.4 (d, J = 30.9 Hz), 102.5 (d, J = 48.0 Hz), 116.5 (d, J = 3.8 Hz

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

• vacuum, and the residue was purified using silica-gel column chromatography. Compounds 3aa [21], 3ba [21], 3ea [21], 3eb [21], 3fa [21], 3fb [22], 3ga [21], and 3ja [21] were synthesized using the similar method as reported previously by us. General procedure for the synthesis of 2-hydroxybenzophenones

• 4aa–ka. 1 mmol Cs2CO3 was added to a solution of 3-arylbenzofuran-2(3H)-ones 3aa–ka (1 mmol) in 2 mL of freshly distilled THF, and the mixture was heated at 50 °C with stirring under open atmosphere. The progress of the reaction was monitored by thin-layer chromatography (TLC). After completion of 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

• , including piperidone [10], amines [5][10], and amides [3][5][10] have been also observed in certain species. The analyses of SGS in vipers (Viperidae) focused on New World pit vipers (Crotalinae). Early analyses of SGS lipids by thin-layer chromatography (TLC) [14], indicated that two pit vipers, the Timber

• acids, comparison with in-house and other spectral libraries revealed no close match with known compounds. High-resolution EI gas chromatography (HREI–GC–MS) of compound D suggested a molecular formula of C14H26O2 (m/z 226.18962 [M]+, calcd 226.19328), and two double-bond equivalents. The characteristic

• diastereomers were then subjected to silver nitrate column chromatography to separate the geometric isomers. This separation was only partially achieved (Supporting Information File 1, Figure S10), but one diastereomer was enriched and the sample was subjected to NOESY NMR experiments. Coupling was observed

Synthesis and cytotoxicity studies of novel N-arylbenzo[h]quinazolin-2-amines

• Battini Veeraiah,
• Kishore Ramineni,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Hélène Solhi,
• Rémy Le Guevel,
• Chada Raji Reddy,
• Frédéric Justaud and
• René Grée

Beilstein J. Org. Chem. 2024, 20, 2592–2598, doi:10.3762/bjoc.20.218

• traces of residual moisture. Reactions were monitored by thin-layer chromatography (TLC) using E. Merck silica gel plates and components were visualized by illumination with short wavelength UV light and/or staining (ninhydrin or basic KMnO4). All aldehydes were distilled right before use. All aryl

• better accuracy on small coupling constants, resolution in 1H NMR was enhanced using Traficante. All compounds were purified by flash column chromatography on silca gel unless otherwise noted. Melting points were obtained using an Electrothermal IA9200 series digital apparatus with thin-wall glass tube

• temperature, the mixture was filtered through Celite and washed with EtOAc (2 × 10 mL). The filtrate was evaporated under reduced pressure and the crude product was purified by using 60–120 silica mesh column chromatography using 10–20% ethyl acetate in hexane as eluent afforded target compound 4a (69% yield

Transition-metal-free synthesis of arylboronates via thermal generation of aryl radicals from triarylbismuthines in air

• Yuki Yamamoto,
• Yuki Konakazawa,
• Kohsuke Fujiwara and
• Akiya Ogawa

Beilstein J. Org. Chem. 2024, 20, 2577–2584, doi:10.3762/bjoc.20.216

• benzotrifluoride (BTF, 0.4 mL). The mixture was heated at 80 °C for 24 h in air. After the reaction was completed, the mixture was filtered through a short Celite pad with AcOEt (20 mL). The filtrate was concentrated under reduced pressure. Finally, the residue was purified by preparative thin-layer chromatography

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• sheets coated with silica gel 60 (Merck 5554). Column chromatography was performed on Wakogel C-300. Preparation of ion pairs 4,8,12-Tris(2,6-dimethylphenyl)-4,8,12-triazatriangulenium as a BF4− ion pair, 2+-BF4−. According to the literature procedure [26], to a Schlenk tube were added 2,6

• gel column chromatography (Wakogel C-300, eluent: MeOH/CH2Cl2 with an increment of MeOH). The residue was chromatographed over ion-exchanged resin (Amberlite IRA402BL, eluent: MeOH/CH2Cl2) and solvents were removed by evaporation. Then, to a MeOH solution (150 mL) of the solid was added AgBF4 (269 mg

• , 1.38 mmol), and the reaction mixture was stirred at rt for 10 min, followed by filtration, and evaporation to dryness. The residue was purified by silica gel column chromatography (Wakogel C-300; eluent: MeOH/AcOEt/CH2Cl2 1:2:8) and was recrystallized from CH2Cl2/n-hexane to afford 2+-BF4− (143 mg

Machine learning-guided strategies for reaction conditions design and optimization

• Lung-Yi Chen and
• Yi-Pei Li

Beilstein J. Org. Chem. 2024, 20, 2476–2492, doi:10.3762/bjoc.20.212

• . [47]. Literature-extracted yields can be derived from different methods, such as crude yield, isolated yield, quantitative NMR, and liquid chromatography area percentage, and they can also vary in precision due to human bias or equipment quality. HTE data for specific reactions, however, are usually

Phenylseleno trifluoromethoxylation of alkenes

• Clément Delobel,
• Armen Panossian,
• Gilles Hanquet,
• Frédéric R. Leroux,
• Fabien Toulgoat and
• Thierry Billard

Beilstein J. Org. Chem. 2024, 20, 2434–2441, doi:10.3762/bjoc.20.207

• derivative 2k, and the estrone derivative 2l were also successfully bis-functionalized. Some products appeared to be sensitive during purification by chromatography on silica gel. Suspecting acid sensitivity, compound 2a was treated with trifluoroacetic acid to confirm this hypothesis (Scheme 3). The product

• by chromatography. Examples of trifluoromethoxylated drugs. Proposed mechanism of the reaction and 19F NMR of the DDPYOCF3/PhSeBr mixture. Phenylseleno trifluoromethoxylation of various alkenes. Yields determined by 19F NMR spectroscopy with PhCF3 as internal standard (in parentheses isolated yields

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

• Yutaro Miyashita,
• Sae Someya,
• Tomoko Kawasaki-Takasuka,
• Tomohiro Agou and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

• column chromatography using AcOEt/Hex 1:20 as an eluent, 0.2117 g (0.86 mmol) of the title compound (86% yield) were isolated. Rf 0.52 (Hex/AcOEt 5:1); 1H NMR (300.40 MHz, CDCl3) δ 3.71–3.76 (m, 2H), 5.21 (d, J = 12.3 Hz, 1H), 5.28 (d, J = 12.3 Hz, 1H), 7.34–7.44 (m, 5H); 13C NMR (75.45 MHz, CDCl3) δ

• in 79% yield after silica gel column chromatography using Hex/AcOEt 6:1 as an eluent. Rf 0.51 (Hex/AcOEt 4:1); 1H NMR (300.40 MHz, CDCl3) δ 0.88 (t, J = 6.9 Hz, 3H), 1.26 (brs, 14H), 1.60 (quint, J = 6.9 Hz, 2H), 2.49 (t, J = 7.5 Hz, 2H), 2.74 (dd, J = 3.6, 17.7 Hz, 1H), 2.83 (dd, J = 9.0, 17.7 Hz