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

• imidazole nucleophilic center not involved in the first step. This process leads to the formation of alternative final products: imidazo[1,2-a]imidazoles 10 and 12, imidazo[1,5-a]pyrimidines 4, 5, 11 and 14, and imidazo[1,2-a]diazines 13 and 15. The analysis of the spectral data (1H and 13C NMR, 2D NMR

• spectroscopy, HPLC–HRESIMS) of the products of the investigated reactions unambiguously confirms the processes proceeding along routes A1 and B1 with the formation of N-aryl(alkyl)-7-oxo-5,6,7,8-tetrahydroimidazo[1,2-a]pyrimidin-5-carboxamides 4a–i and N-aryl-2-(7-oxo-5,6,7,8-tetrahydroimidazo[1,2-a]pyrimidin

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

• standard reaction conditions with difluorocarbene precursor TMSCF2Br (2, 2.0 equiv), activator KFHF (4.0 equiv), and grinding auxiliary CsCl (4.0 equiv), difluoromethyl enol ether 3a was obtained after 90 min reaction time at 25 Hz in 74% yield, determined by quantitative 1H NMR spectroscopy (Table 1

• was obtained. Furthermore, most isolated products had only purities of ca. 90% still containing inseparable impurities (as revealed by NMR spectroscopy). In the first series of substrates, acetophenone derivatives with various para-substituents were applied. Similar to methyl tolyl ketone (1a), which

• scale. Method A: 2 (2.0 equiv), KFHF (4.0 equiv), CH2Cl2 (0.2 mL), H2O (0.2 mL), rt, 10 h; Method B: 2 (2.0 equiv), KOAc (4.0 equiv), CH2Cl2 (0.2 mL), H2O (0.2 mL), rt, 10 h. The yields were determined by 19F NMR spectroscopy using trifluoromethoxybenzene as the internal standard. Scope of ketones. The

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

• scope for the present [1,3]-proton shift reaction. aYields are determined by 19F NMR spectroscopy. Values in parentheses show isolated yields. Enantiomeric excesses are deteremined by HPLC equipped with DAICEL CHIRALPAK AD-H. bCarried our at 50 °C in the [1,3]-proton shift reaction step. Proposed

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

• mixture of diastereomers (diastereomer ratio = 1:1) for cross-coupling, and the corresponding compounds 2 and 3 were obtained as mixtures of diastereomers in a certain ratio as estimated by proton and fluorine NMR spectroscopy. Substrate scope for cross-coupling reactions The substrate scope was

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

• the 7-position does not hinder the reaction. Further, to understand the origin of the product, we monitored the progress of the reaction of 3aa using 1H NMR spectroscopy. Aliquots from the reaction mixture were taken at different time intervals (Figure 4), THF evaporated under vacuum, and the residue

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

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

• formation of various unidentified byproducts. The obtained tetronic acids 4 are solid crystalline compounds, whose structure was proved by 1H, 13C NMR spectroscopy and high-resolution mass spectrometry. The 1H NMR spectra of the synthesized products contain characteristic signals of protons of the methyl

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

• arylboronates 3 using triaylbismuthines 1 and diboron 2. Yields were determined by 1H NMR spectroscopy based on 1 as three transferable aryl groups (internal standard: 1,3,5-trioxane). Isolated yield was shown in parentheses. aCHCl3 (0.4 mL) was used as the solvent. Control experiment of the metal-free

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

• ) [24]. The solution and the solid-state conformational analysis were supplemented with DFT calculations to understand key conformational drivers. This study adds more data to the field of nuclear magnetic resonance (NMR) spectroscopy of polyhalogenated molecules. It should be noted that the NMR

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

• 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

• ). a24 h. b48 h. Degradation of 2a under acidic conditions. Radical deselenylation of 2. Yields determined by 19F NMR spectroscopy with PhCF3 as internal standard (in parentheses isolated yields). Reaction of 1a with PhSeX and DDPyOCF3.a Supporting Information Supporting Information File 116: Additional

Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• )AuCl was applied with a catalyst loading of 2 mol %, activated by an equal amount of the DAI salt. Due to solubility issues, the reaction had to be performed in methylene chloride instead of chloroform. The gold-catalyzed cyclization reaction (Scheme 2) was followed via 1H NMR spectroscopy (Figure 3

• ]. For all catalyst systems, decomposition of the −BArF24 anion was observed via 1H and 19F NMR spectroscopy, which is known to happen in the presence of activated gold complexes [29]. The stability of the DAI cations was checked with 1H NMR: the characteristic doublets belonging to the respective

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

• proton in triphenylmethane (3, Scheme 4, bottom). Further, the yield was determined to be 67% by 1H NMR spectroscopy. These results indicated that the triphenylmethyl anion species generated by electroreductive C(sp3)–O bond cleavage acted not as nucleophile toward carbon dioxide but as base, performing

• MgSO4. Evaporation of the solvent gave a residue that was analyzed by 1H NMR spectroscopy, during which 1,4-dinitrobenzene was used as an internal standard for quantification of the substances. The products diphenylacetic acid (2a) [30][31], (4-methylphenyl)phenylacetic acid (2d) [32], (4-methoxyphenyl

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• , compounds 6–9 are products of alkylation of the nitrogen atom of the heterocycle. Thiones 6–9 were obtained in 40–79% yield (Scheme 1,b). The structures of synthesized compounds were confirmed by the spectral methods IR-, 1H NMR, 13C{1H} NMR spectroscopy (Figures S1–S18 in Supporting Information File 1

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

• active catalytic species in COBI-catalysed allylations, chemical equilibria in a solution containing catalyst 72, triflic acid, and aldimine 73 were investigated by low-temperature NMR spectroscopy (Scheme 15). Protonation of oxazaborolidine 70 with triflic acid resulted in an 8.3:1 mixture of 71 and 72

Tandem diazotization/cyclization approach for the synthesis of a fused 1,2,3-triazinone-furazan/furoxan heterocyclic system

• Yuri A. Sidunets,
• Valeriya G. Melekhina and
• Leonid L. Fershtat

Beilstein J. Org. Chem. 2024, 20, 2342–2348, doi:10.3762/bjoc.20.200

• , indicating that the developed tandem protocol does not depend on the presence of the N-oxide moiety in the parent heterocycle. All synthesized triazinones 1 and 7 were fully characterized by IR, 1H and 13C NMR spectroscopy, and high-resolution mass spectrometry. The structure of compounds 1b and 7h was

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• . Chemical shifts of NMR were reported in ppm relative to the residual solvent peak at 7.26 ppm for 1H NMR spectroscopy and 77.6 ppm for 13C NMR spectroscopy. Coupling constants (J) were given in Hz. The resonance multiplicity was described as s (singlet), t (triplet), and m (multiplet). FTIR spectra were

Selective hydrolysis of α-oxo ketene N,S-acetals in water: switchable aqueous synthesis of β-keto thioesters and β-keto amides

• Haifeng Yu,
• Wanting Zhang,
• Xuejing Cui,
• Zida Liu,
• Xifu Zhang and
• Xiaobo Zhao

Beilstein J. Org. Chem. 2024, 20, 2225–2233, doi:10.3762/bjoc.20.190

• by other acids such as H2SO4 and CF3SO3H, the reaction showed poor effectiveness due to the poor solubility of 1a in water (Table 1, entries 4 and 5). Most notably, 2a was an inseparable mixture of keto and enol isomers, reaching a keto/enol ratio of 5:4 as determined by 1H NMR spectroscopy. Thus

• . Reaction conditions A: 1 (0.25 mmol), DBSA (87.9 mg, 0.25 mmol), H2O (1 mL), reflux, 5 h. Isolated yield is stated. Keto/enol ratio of 2 was determined by 1H NMR spectroscopy. Synthesis of β-keto amides 3. Reaction conditions B: 1 (0.25 mmol), NaOH (0.75 mmol, 30 mg), H2O (1 mL), reflux, 24 h. Isolated

• yield is stated. Keto/enol ratio of 3 was determined by 1H NMR spectroscopy. Gram-scale hydrolysis reactions of 1a. Proposed mechanism for formation of β-keto thioesters 2 and β-keto amides 3. Optimization of the reaction conditions. EcoScale calculations and results for the synthesis of 2a and 3a [75

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• funnel with the aid of 10 mL of deionized (DI) water followed by 20 mL of diethyl ether. The organic layer was separated, dried with anhydrous magnesium sulfate, filtered, and the solvent removed in vacuo to afford the crude product, which was first analyzed by 1H NMR spectroscopy and then purified using

• sulfate, filtered, and the solvent removed in vacuo to afford the crude product, which was first analyzed by 1H NMR spectroscopy and then purified using flash column chromatography. The graphite electrodes were not polished in between reactions, but were rinsed with DI water and then acetone. General Sn

• funnel with the aid of 10 mL of DI water followed by 20 mL of diethyl ether. The organic layer was separated, dried with anhydrous magnesium sulfate, filtered, and the solvent removed in vacuo to afford the crude product, which was first analyzed by 1H NMR spectroscopy and then purified using flash

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• from an unidentified endophytic fungus [124] and later from colletotrichum sp. [125], Lachnum abnorme [126], Diaporthe phragmitis [127] and a further D. sp. [128], and deviantly from the flower buds of the banana species Musa nana [129]. Its structure was determined by NMR spectroscopy [126] and

• -methoxylglucopyranoside] (5) was isolated from Alternaria alternata and its structure was determined by NMR spectroscopy. It showed no antibacterial activity [138]. Lysilactones A–C (7–9) bearing β-glucopyranoside moieties were first isolated from Lysimachia clethroides, where lysilactone B is mentioned in this review

• determined by NMR spectroscopy and unambiguously confirmed by total syntheses [44][177]. It showed cytotoxic activity against SW1116 cells with an IC50 value of 12 μg/mL [168]. Chlorinated alternariol derivatives (Figure 9) together with the respective redox-modified natural products (Figure 20, vide infra

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• derivatives were successfully characterized and their structures were established by means of the 1H and 13C NMR spectroscopy, besides further confirmation by mass spectrometry (see Supporting Information File 1). The UV–vis absorption, emission and time-resolved fluorescence spectra Emission and absorption

O,S,Se-containing Biginelli products based on cyclic β-ketosulfone and their postfunctionalization

• Kateryna V. Dil and
• Vitalii A. Palchykov

Beilstein J. Org. Chem. 2024, 20, 2143–2151, doi:10.3762/bjoc.20.184

• in our study (Table 1, entries 1–6), but in any case, we received a mixture of regioisomeric products 2a/2a’ (3:1 to 2:1) confirmed by 2D NMR spectroscopy (see Supporting Information File 1, Figures S1–S6). Classical conditions for Biginelli reaction (reflux in ethanolic HCl) gave only 23% yield

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• . Because of this conjugation, the aromatic ring at the N of the 1,1-addition product 4 (R = Ar, E = PhS) geometrically isomerizes faster than the NMR timescale, so that the two thio groups of 4 are observed to be equivalent in NMR spectroscopy. In the case of diphenyl diselenide as a representative organic

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• the samples ex-situ for 3.5 hours to achieve a Z-rich PSS, where the percentage isomerised has been determined previously using 1H NMR spectroscopy [20]. The 10 wt % sample was measured over 800 X-ray exposures of 250 ms each. The initial Z-rich PSS SAXS pattern shows a strong interaction peak at Q

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• ]. Additionally, when the reaction was performed using DMSO-d6 (or CD3CN) and CH3ONa, H/D exchange occurred already at ambient temperature (25 °C, 20 h) [78]. The formation of CDF=CDF was confirmed by NMR spectroscopy, namely by the change of signal multiplicity in the 19F NMR spectra of E- and Z-isomers of 1,2

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• Scheme 1 compound 6 was treated with isopropyl iodide (7) in DMF in the presence of sodium hydride to provide products 8 and 9 in 38% and 46% yields, respectively. The structures of both compounds were unambiguously assigned using X-ray crystallography and 1H and nuclear Overhauser effect (NOE) NMR

• spectroscopy (see Supporting Information File 1). From the yield of products 8 and 9, we decided to explore new reaction conditions to improve the yields of the N1-substituted indazole analogs. As shown in Scheme 2, compound 12 was prepared by treating ethanol (10) with tosyl chloride (11) in the presence of 4