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

• 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

• purification. Ketalization of rac-2 with liquid crystal-like ketone 1 [43] (in toluene) or 2,2-dimethoxypropane 5 (in THF) provided dioxanes rac-3 and rac-4 in 56% and 62% yields, respectively (Scheme 2). Samples of rac-3 and rac-4 were separated by preparative HPLC on a chiral phase. Suitable crystals of all

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• . The reaction of H2A with the diaryliodonium salt in phosphate buffer resulted in the expected arylated conjugate in an hour with a maximum of 98% conversion, yielding sulfur arylated product in 54% isolated yield after purification by HPLC. Additionally, the functionalization of the ketone with a

• high conversions (83–93%) in 1–20 hours. Purification by HPLC yielded the isolated oxime conjugates in excellent amounts. This methodology presents a promising approach for the late-stage variation of proteins and peptides, offering versatility and efficiency in aqueous environments. In addition to

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

• being explained by a tedious purification. Interestingly, the methodology was successfully applied to the functionalization of aliphatic hydrazones 1s and 1t and even the hydrazone derived from citronellal 1u. The method was functional group-tolerant to various functional groups (nitro, CN, ester

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

• information All commercially available reagents and chemicals were bought from Merck & Co. and utilized without extra purification. The melting points of all synthesized compounds were measured utilizing an Electrothermal 9200 apparatus. 1H and 13C NMR and spectra in CDCl3 and DMSO-d6 solvents were recorded

• purification process must be carried out under the mentioned personal protective equipment. The reaction on a larger scale is carried out under special safety conditions [57][58][59]. 3-(Cyclohexylamino)-2-phenyldibenzo[b,f]pyrrolo[1,2-d][1,4]oxazepine-1-carbonitrile (4a); ethyl 2-(4-chlorophenyl)-3

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

• latter were treated, without chromatographic purification, with MsCl (methanesulfonyl chloride), NEt3, and DMAP to give the desired products E-β-43a,b. Similarly, glucosides E-β-43c,d and galactoside E-β-43e were obtained. In contrast to oxoindirubin-N-rhamnoside β-41a, all glycosides were obtained as

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

• were purchased from commercial sources (Kanto Chemical Co., Inc. or Fujifilm Wako Pure Chemical Corp.) and used without further purification. Super dehydrated, stabilizer-free THF was used as solvent and purchased from Fujifilm Wako Pure Chemical Corp. DEMO was supplied by Kumiai Chemical Industry Co

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

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

• Yuta Kabumoto,
• Eiichiro Yoshimoto,
• Bing Xiaohuan,
• Masato Morita,
• Motohiro Yasui,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

• a smooth [1,3]-proton shift reaction with a high chirality transfer, affording the corresponding rearranged products in acceptable yields. Without purification, these products were subjected to acid hydrolysis and the subsequent N-Cbz protection, providing the optically active tetrafluoroethylenated

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

• materials (Scheme 1d). The synthetic procedure is achieved using blue light irradiation and bromotrichloromethane (BrCCl3), as a one-pot procedure, minimizing chemical wastes, avoiding purification of intermediates, and simplifying practical aspects. Results and Discussion We have recently published the one

• point, allowing the easy purification of the products. As expected, the reaction conducted in the absence of the carbocatalyst led to the obtainment of 2a with comparable yield (Table 1, entries 3 and 4), demonstrating that 1a is a sufficiently activated substrate for the 3C Ugi-type reaction to occur

• 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

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

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

• purification. All experiments were carried out under argon atmosphere in flame-dried glassware using standard inert techniques for introducing reagents and solvents unless otherwise noted. Suzuki–Miyaura cross-coupling with multihalogenated vinyl ethers 1 To a solution of 1 (1.0 equiv), triphenylphosphine (10

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

• -hydroxybenzophenones as efficient UV-protectors. Experimental All chemicals were procured from Sigma-Aldrich (AR grade) and used without any further purification. All solvents were purchased from Merck, and were distilled or dried, wherever applicable, following standard procedures. The organic extracts were dried

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

• distilled before use. All other chemicals were used without purification unless otherwise stated. Air- and H2O-sensitive reactions were performed under N2. ASAP-APCI-MS was performed on an Expression MS (Advion) mass spectrometer equipped with an APCI ionization source operated in positive mode. The

• freshly distilled propanal (1, 2.1 mL, 30 mmol) were added to a 50 mL flask. The mixture was stirred at 0 °C for 1 h. The residue was filtered and washed twice with diethyl ether, and the solvent was removed in vacuo. The crude product was used without further purification. EIMS (70 eV) m/z (%): 125 (40

• room temperature. The solvent was removed and the residue was washed twice with pentane and dried under vacuum. The product was used without further purification. Analytical data were identical to those reported earlier. 1-Methylheptyltriphenylphosphonium iodide (5): In a manner similar to [31

Deciphering the mechanism of γ-cyclodextrin’s hydrophobic cavity hydration: an integrated experimental and theoretical study

• Stiliyana Pereva,
• Stefan Dobrev,
• Tsveta Sarafska,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2024, 20, 2635–2643, doi:10.3762/bjoc.20.221

• , whereas in β-CD it is a one-step process. Experimental Materials γ-CD was used as received (without further purification or modification) from Wacker Chemie AG (CAVAMAX FOOD) with a purity of ≥98%. Experimental measurements The thermal behavior of γ-CD was investigated with a Perkin Elmer DSC7

Base-promoted cascade recyclization of allomaltol derivatives containing an amide fragment into substituted 3-(1-hydroxyethylidene)tetronic acids

• Andrey N. Komogortsev,
• Constantine V. Milyutin and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 2585–2591, doi:10.3762/bjoc.20.217

• purification. The synthetic utility of the prepared tetronic acids was demonstrated by further transformations at the hydroxyethylidene fragment. The structures of one obtained tetronic acid and one product of derivatization were confirmed by X-ray analysis. Keywords: allomaltol; base-promoted recyclization

• purification procedure are the advantages of the considered method. The synthetic utility of obtained tetronic acids was demonstrated by preparation of enamine and enehydrazine derivatives. The structures of one target tetronic acid and synthesized enehydrazine were established by X-ray analysis. Experimental

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

• without further purification. All solvents were used without distillation. Triarylbismuthines 1 were synthesized according to the previously reported procedures [62]. 1H, 13C{1H}, and 11B NMR spectra were recorded in CDCl3 using a Bruker AVANCE III HD 500 spectrometer at 500, 126, and 160 MHz

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

• further purification unless otherwise stated. According to the previous procedure [30], 4,8,12-tris(2,6-dimethylphenyl)-4,8,12-triazatriangulenium as a Cl− ion pair, 2+-Cl−, was prepared. NMR spectra used in the characterization of products were recorded on a JEOL ECA-600 600 MHz spectrometer. All NMR

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

• interdependencies between different reaction sequences, such as additional separation and purification steps, could reduce the overall yield [202]. This indicates that the suboptimal combination of each reaction does not necessarily represent the global optimum for multistep synthesis [203][204][205]. In contrast

• , telescoped flow sequences [206][207][208] or one-pot batch synthesis [209] emphasize the use of chemically compatible reagents and solvents in each reaction step to minimize intermediate purification steps. Volk et al. [210] developed AlphaFlow, which utilizes reinforcement learning as an optimization

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

• nucleophilic than chloride in an aprotic solvent such as acetonitrile. Gratifyingly, an excellent yield was obtained (Table 1, entry 6) without detection of the brominated by-product. To facilitate purification, the amount of DNTFB was reduced to 2 equiv without significantly changing the result (Table 1

• 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

• separatory funnel and 10 mL of water are added. The aqueous layer is extracted three times with 10 mL of diethyl ether. The organic layers are combined and washed with 10 mL of water. The organic layer is dried with MgSO4, filtered, and concentrated under vacuum. Compounds 2 are obtained after purification

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

• of compound 1b [42] (0.23 g, 1.00 mmol) in 3.0 mL of CH3CN was added NaClO aq. (5% in H2O, 1.50 g, 1.00 mmol) and the solution was stirred for 4.5 h at room temperature. This mixture was extracted with CH2Cl2 and the usual workup and purification afforded 0.15 g (0.60 mmol) of the pure title compound

• in 60% yield. GP-1B (by use of NaClO·5H2O): To a solution of compound 1b [42] (0.2302 g, 1.00 mmol) in 3.0 mL of CH3CN was added NaClO·5H2O (0.3290 g, 2.00 mmol) at 0 °C, and the solution was stirred for 6 h at the same temperature. After the same workup process and purification with silica gel

• room temperature. Then, 0.1477 g (0.60 mmol) of 2b in 0.8 mL of DMSO was introduced to the resultant solution and the stirring was continued for 0.5 h. The same workup process and purification furnished 0.1717 g of an inseparable mixture of anti,syn-7a (dr = 99:1) and anti,syn-7b (7a:7b = 83:17). Anti

Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling

• Jiapeng Guo,
• Weike Su and
• An Su

Beilstein J. Org. Chem. 2024, 20, 2408–2420, doi:10.3762/bjoc.20.205

• , 98.0%) was purchased from Sinopharm Chemical Reagent Co., Ltd.; pure water from AR, Hangzhou Wahaha Group Co., Ltd.; all reagents were used without further purification. Sulfuric acid solutions of different mass fractions were prepared with pure water and 98% concentrated sulfuric acid in an ice bath

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

• were used as received without further purification. Electrochemical reactions were carried out using a constant current power supply (model 5944), Metronix Corp., Tokyo. Diphenylmethanol (1a) [21], bis(4-chlorophenyl)methanol (1b) [22], (2-fluorophenyl)phenylmethanol (1c) [23], (4-methylphenyl

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

• employing a bulkier allyl-transfer reagent 116. They used a novel pre-formed chiral triborate catalyst 115 in tandem with a non-chiral Brønsted acid and expanded the scope to aliphatic homoallylic amines (Scheme 24). The new method established a scalable, chromatography-free purification protocol for the

• purification. The bulky aryl groups in 116 were synthesized in a one-pot procedure, starting from 3,5-dimethylbenzonitrile, by the addition of 3,5-dimethylphenylmagnesium bromide and allylmagnesium chloride (24% combined yield on a 1 g scale). The authors also optimised the protocol for a large-scale synthesis

• scale (Scheme 27). Thus, the hydrolysis of the N=CPh2 group in the N-morpholinyl product 129 with hydroxylamine hydrochloride afforded the deprotected homoallylic amine 133 in a 99% yield without need for chromatographical purification. In a separate experiment, the sequential reduction of the N

Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

• Phong Thai,
• Lauv Patel,
• Diyasha Manna and
• David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

• unprotected alcohol is tolerated in our procedure, with product 3l delivered at 50% NMR yield; 3l is sensitive to column chromatography, and thus aziridine-opening to a cyclic ether was observed (31% isolated yield) during purification. Aziridination of cis- or trans-4-octene afforded aziridine 3m as a 1.3