Synthesis of an aza[5]helicene-incorporated macrocyclic heteroarene via oxidation of an o-phenylene-pyrrole-thiophene icosamer

• Yusuke Matsuo,
• Aoi Nakagawa,
• Shu Seki and
• Takayuki Tanaka

Beilstein J. Org. Chem. 2025, 21, 1561–1567, doi:10.3762/bjoc.21.119

• acyclic heteroaromatics [26][27]. Thus, to a solution of 4 in CH2Cl2 was added 15 equivalents of PIFA at −78 °C and stirred for 3 h. The mixture was then allowed to warm to room temperature to give a dark solution. The system was worked-up with NaBH4/MeOH for 10 minutes followed by extraction with CH2Cl2

• and evaporation of the solvent to afford a crude product, which was recrystallized from THF to give 5 in 58% yield. Due to its poor solubility in common organic solvents, the 1H NMR spectrum could only be recorded in DMSO. At room temperature, the 1H NMR spectrum in DMSO-d6 exhibited broad signals in

• at 399 nm (Figure 5b). A broad emission was observed at 528 nm, resulting in a relatively large Stokes shift of 6100 cm−1, which can be attributed to the structural relaxation in the excited state, as inferred by the observed broad 1H NMR spectrum at room temperature. Due to the thermal energy loss

Azide–alkyne cycloaddition (click) reaction in biomass-derived solvent Cyrene^TM under one-pot conditions

• Zoltán Medgyesi and
• László T. Mika

Beilstein J. Org. Chem. 2025, 21, 1544–1551, doi:10.3762/bjoc.21.117

• capillary column (15 m × 0.25 mm × 0.25 µm) using H2 as a carrier gas. For the analysis, 10 μL of the reaction mixture was dissolved in 1 mL of ethyl acetate, followed by adding 10 μL toluene as the internal standard. Heating profile of GC–FID analysis: The initial temperature was 100 °C and was hold for

• 0.5 min. Heating rate: 40 °C/min up to the final temperature of 270 °C. The final temperature was held for 4.25 min. The water content of CyreneTM was measured on a Methrom 684 KF Coulometer at Balint Analitika Ltd, Budapest, Hungary. CyreneTM was purchased from Sigma-Aldrich Kft. Budapest, Hungary

• , and 0.01 mmol CuI, were dissolved in 2.5 mL CyreneTM. The reaction mixture was stirred overnight at a given temperature. After the reaction, 20 mL of cold distilled water was added, followed by intensive stirring. The solid product was filtered, washed with distilled water (3 × 5 mL), and dried until

General method for the synthesis of enaminones via photocatalysis

• Paula Pérez-Ramos,
• Raquel G. Soengas and
• Humberto Rodríguez-Solla

Beilstein J. Org. Chem. 2025, 21, 1535–1543, doi:10.3762/bjoc.21.116

• by DME, DMSO or acetone diminished the product yields (Table 1, entries 7–9). The reactivity of acridinium PC1 was superior to that of other photocatalysts, including 4-CzlPN (PC2) and [Ir(dF(CF3)ppy)2(dtbbpy)]PF6 (PC3) (Table 1, entries 10 and 11). Attempts to increase the temperature of the process

Azobenzene protonation as a tool for temperature sensing

• Antti Siiskonen,
• Sami Vesamäki and
• Arri Priimagi

Beilstein J. Org. Chem. 2025, 21, 1528–1534, doi:10.3762/bjoc.21.115

• changes in their absorption and photochemical properties. While azobenzene protonation has been recently used as a tool in photoswitching studies, the factors influencing protonation itself have received little attention. Here, we report a strong temperature dependence of azobenzene protonation in 1,2

• -dichloroethane and highlight its potential for temperature sensing applications. Density functional theory calculations were performed to support our findings and to investigate the mechanisms of azobenzene–acid interactions, aiming to guide the design of azobenzene-based temperature sensors in future research

• . Keywords: azobenzene; protonation; sensing; spectral changes; temperature; Introduction Molecular switches are molecules that can reversibly shift between distinct (meta)stable states in response to external stimuli such as light, pH changes, or electric fields [1]. Over the past decades, they have

Calcium waste as a catalyst in the transesterification for demanding esters: scalability perspective

• Anton N. Potorochenko and
• Konstantin S. Rodygin

Beilstein J. Org. Chem. 2025, 21, 1520–1527, doi:10.3762/bjoc.21.114

• % yields, respectively. The transesterification of soybean oil (1a) with methanol (2a) was carried out as a gram-scale batch reaction using 21 g of soybean oil, 210 mg of catalyst (1 wt %), and 11.7 mL of methanol (Scheme 3). The temperature and reaction time conditions used were the same as in the

Ambident reactivity of enolizable 5-mercapto-1H-tetrazoles in trapping reactions with in situ-generated thiocarbonyl S-methanides derived from sterically crowded cycloaliphatic thioketones

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Marcin Palusiak,
• Heinz Heimgartner,
• Marta Denel-Bobrowska and
• Agnieszka B. Olejniczak

Beilstein J. Org. Chem. 2025, 21, 1508–1519, doi:10.3762/bjoc.21.113

• slightly higher temperature (60 °C). In both cases, evolution of nitrogen was completed after ca. 3 h and pure thiiranes 8a and 8b were isolated as sole products in 62%, and 58% yield, respectively (Scheme 4). Thus, their formation clearly evidenced formation of the respective thiocarbonyl S-methanides 1c

• stable 9 into the more stable 10 was observed in some cases (derived from 1c) in the CDCl3 solution at room temperature. Therefore, it seems likely that the first step of the reaction is the N–H insertion process. The compositions of the obtained crude mixtures suggest that the final addition step

• the sterically most hindered dispiro-cyclohexyl-substituted thiocarbonyl S-methanide 2d. Notably, in some cases spontaneous isomerization of the generally less stable thioaminals 9 in CDCl3 solution at room temperature was also observed. It seems likely that this isomerization follows an

Highly distinguishable isomeric states of a tripodal arylazopyrazole derivative on graphite through electron/hole-induced switching at ambient conditions

• Himani Malik,
• Sudha Devi,
• Debapriya Gupta,
• Ankit Kumar Gaur,
• Sugumar Venkataramani and
• Thiruvancheril G. Gopakumar

Beilstein J. Org. Chem. 2025, 21, 1496–1507, doi:10.3762/bjoc.21.112

• isomer of azobenzene (AB) is a few days. Arylazopyrazole-based molecular switches are one of the profoundly explored systems in recent times due to their superior bidirectional photoswitching and long half-life (over a thousand days at room temperature) of Z isomers. Herein, we utilize an efficient solid

• experimental conditions. The choice of molecules that can be studied under ultra-high vacuum (UHV) is limited due to the requirement of their thermal stability and UHV compatible sublimation temperature. Therefore, the solution-based preparation method and solid-state measurements at ambient conditions hold

• barrier and the long lifetime of the non-equilibrium states are at the origin of their remarkable stability at room temperature. The remarkable stability of the states at ambient conditions provides an opportunity to use a single FNAAP molecule as an 8-bit operation. We propose to switch the molecule

Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides

• Nadezhda M. Metalnikova,
• Nikita S. Antonkin,
• Tuan K. Nguyen,
• Natalia S. Soldatova,
• Alexander V. Nyuchev,
• Mikhail A. Kinzhalov and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110

• . Finally, control experiments without irradiation gave only traces of the benzamide 2aa showing no activation by the Ru complex at room temperature (Table 1, entry 24). An experiment conducted under an air atmosphere yielded only 9% of 2aa (Table 1, entry 25) indicating that the presence of atmospheric

Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper

• Andrei Paraschiv,
• Valentina Maruzzo,
• Filippo Pettazzi,
• Stefano Magliocco,
• Paolo Inaudi,
• Daria Brambilla,
• Gloria Berlier,
• Giancarlo Cravotto and
• Katia Martina

Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108

• , that still required high temperatures, but the excess of amine (2 equiv) was lowered and only a catalytic amount of acid was utilised. Similar acidic protocols were subsequently developed by Li et al. [46], in which benzoxazoles were reacted with secondary amines and amides, with higher temperature

• being applied when reacting amides to achieve their decarbonylation. In 2014, Cao et al. [47] reported the amination of benzoxazole with a secondary amine either in air or an O2 atmosphere, lowering the catalyst amount and the reaction temperature. In 2020, a study by De Vos and co-workers [48] focused

• to 6 hours, with a catalyst loading of 20 mol %, resulted in complete conversion and high selectivity, comparable to the results obtained from an overnight reaction. Notably, decreasing the reaction temperature to 60 °C still yielded excellent results with both catalysts after an overnight reaction

Wittig reaction of cyclobisbiphenylenecarbonyl

• Taito Moribe,
• Junichiro Hirano,
• Hideaki Takano,
• Hiroshi Shinokubo and
• Norihito Fukui

Beilstein J. Org. Chem. 2025, 21, 1454–1461, doi:10.3762/bjoc.21.107

• internally functionalized DBC derivatives [22]. The dihedral angle between the mean planes of the two terminal benzene units is 83°, which is comparable to those of other derivatives. Next, products 3 and 5 were analyzed by variable temperature (VT) 1H NMR spectroscopy. The 1H NMR spectrum of bis-olefin 5 in

• CD2Cl2 at 298 K shows a symmetric pattern, in which the signal due to the methylene protons appears as one singlet (Figure 3). The decrease of temperature to 243 K resulted in the broadening of the 1H NMR spectrum and the appearance of two sets of signals which sharpened upon further decrease of the

• temperature. These are attributable to the mixture of conformers with the figure-eight conformation as minor and the bathtub conformation as major conformer with a ratio of ca. 1:7. The obtained temperature-dependent 1H NMR data were subjected to the van't Hoff plot, affording an enthalpy ΔH and an entropy ΔS

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• core [17]. Compared to 4a, compound 4b exhibits bathochromic shifts of 12 nm in absorption and 45 nm in emission, as well as a higher ΦF (0.75 vs 0.68). Both isomers display TADF at room temperature and phosphorescence at 77 K. Notably, 4a demonstrates a long-lived red afterglow persisting for up to 30

• showed more intense phosphorescence and an extended emission lifetime in dilute solution. Notably, it demonstrated room-temperature dual-emission CPL originating from both prompt fluorescence and long-lived phosphorescence, a rare feature in helicene systems. In a subsequent study, the same group

Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds

• Lidia Zaharieva,
• Vera Deneva,
• Fadhil S. Kamounah,
• Nikolay Vassilev,
• Ivan Angelov,
• Michael Pittelkow and
• Liudmil Antonov

Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105

• influenced by the structural variations and the environment (temperature, solvent properties, acidity and presence of other molecules). The E/Z isomerization of the azodyes, caused by light irradiation [12][13][14] or electrochemically [15][16], has paved the way for the development of innovative materials

• number of industrially used azo dyes [1][3] and therefore its tautomerism is studied in details. The existing experimental data for low polar solvents (cyclohexane and tetrachloromethane) indicate a ΔG value of around 0.4 kcal/mol [53] at room temperature, which gives a prevalence of the E-tautomer (a

• makes possible to analyze the tautomerism in 1 as a function of (E+KE) and KK. The NMR spectra of 1 in acetonitrile-d3 are in agreement with the above analysis of tautomeric equilibration based on theoretical calculations and UV spectra. At room temperature the proton signals are very broad and

Reactions of acryl thioamides with iminoiodinanes as a one-step synthesis of N-sulfonyl-2,3-dihydro-1,2-thiazoles

• Vladimir G. Ilkin,
• Pavel S. Silaichev,
• Valeriy O. Filimonov,
• Tetyana V. Beryozkina,
• Margarita D. Likhacheva,
• Pavel A. Slepukhin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2025, 21, 1397–1403, doi:10.3762/bjoc.21.104

• expectations were not fulfilled. The exception is the data from entry 7 (Table 1), where the yield of compound 3aa was 78%. Thus, the conditions described in entry 7 (absence of a catalyst, use of 1.5 equiv of PhINTs 2a and dichloromethane (DCM) as a solvent at room temperature for 10 min) are optimal and were

• iodonium salts. The search for optimal conditions for the process has been carried out. The optimized reaction found to proceed in the absence of metal catalysts, using 1.5 equiv of the iodonium salt at room temperature in DCM. Using the optimized procedure, a library of 31 novel 2,3-dihydro-1,2-thiazoles

• thioamides 1h,i,k,n,o,s,t,v,w,y,z (general procedure). A mixture of the corresponding thioacetamide (1.0 equiv), aldehyde (1.1–4.0 equiv) and DBU (0.1 equiv or 1.0 equiv for 1h,o) in ethanol was stirred for 2–23 h at room temperature. For thioamide 1i, the reaction time was 96 h at 80 °C. The formed

N-Salicyl-amino acid derivatives with antiparasitic activity from Pseudomonas sp. UIAU-6B

• Joy E. Rajakulendran,
• Emmanuel Tope Oluwabusola,
• Michela Cerone,
• Terry K. Smith,
• Olusoji O. Adebisi,
• Adefolalu Adedotun,
• Gagan Preet,
• Sylvia Soldatou,
• Hai Deng,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2025, 21, 1388–1396, doi:10.3762/bjoc.21.103

• (3 and 4) isolated alongside three known compounds, pseudomonine (5), pseudomonin B (6) and salicylic acid (7) [15] from the Pseudomonas sp. UIAU-6B strain by altering the fermentation conditions using an open system shaker at room temperature [16][17][18]. Results and Discussion The bacterial strain

• Pseudomonas sp. UIAU-6B was investigated by varying the temperature of the culture to elicit production of secondary metabolites after our previous work on the strain [15]. A small-scale culture of the strain (50 mL of SGG medium) shaken at 160 rpm in an open system shaker at room temperature yielded 0.008 g

• previously isolated pseudomonine [15]. This resulted in the decision to upscale the bacterial strain at room temperature in an open orbital shaker. The large crude extract (7.5 g) was subjected to Kupchan solvent partitioning followed by medium pressure liquid chromatography (MPLC) and subsequently

High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

• Kelsey Plasse,
• Valerie Wright,
• Guoshu Xie,
• R. Bernadett Vlocskó,
• Alexander Lazarev and
• Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

• generation. Using water as pressure transmitting fluid, the reaction vessel is immersed in water minimizing fire hazard during the reactions. Finally, most procedures can be carried out at ambient temperature, improving safety and energy efficiency. Energy efficiency is also supported by the nature of the

• -phenylenediamine and acetone was selected as a model reaction. The optimization of the reaction conditions is summarized in Table 1. All reactions were carried out at room temperature without involving any catalyst or additional solvent. While o-phenylenediamine is solid, it dissolves well in the reactant acetone

• subjected to those conditions to provide a representative scope of the reactions and the results are summarized in Scheme 2. For comparison, the yields obtained under ambient pressure (1 bar) are provided in parentheses. The data show that the reactions readily occur at room temperature providing good

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• and colleagues published a one-step synthesis of spirooxindole 2,2-disubstituted oxetanes 11 via an unprecedented addition/substitution cascade (Scheme 4) [39]. The protocol reacts readily available 3-hydroxyindolinones 9 with phenyl vinyl selenone (10) in aqueous KOH at room temperature and gives

• alcohols 13 and a binary Al/TBAB catalyst (Scheme 5) [40]. The reaction is carried out in toluene upon mild heating, providing the bicyclic products in high to excellent yields. Both electron-rich and electron-poor phenyls as well as aliphatic chains worked well, however, increased temperature and catalyst

• chlorides (Scheme 11a) [44]. The authors found that the secondary alcohol precursors were less reactive and that best results were obtained at low temperature (≤−50 °C) and in chlorinated solvents. The synthesis of these cages was later revisited by Le Drian et al. in 2011 who studied a Lewis acid-catalysed

Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer

• Hao-Sen Wang,
• Lin Li,
• Xin Chen,
• Jian-Li Wu,
• Kai Sun,
• Xiao-Lan Chen,
• Ling-Bo Qu and
• Bing Yu

Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100

• and operational scalability [9][10]. Moreover, a high temperature and additive oxidants are generally required, which would limit the substrate scope. The hydrogen atom transfer (HAT) process has emerged as a powerful avenue for addressing these challenges, leveraging the HAT reagents to selectively

• radical from N–S bond cleavage The work of Alexanian’s group has significantly advanced the field of organic synthesis over recent years, particularly in the area of N–S bond homolytic cleavage [92][93][94]. Initial studies demonstrated that high-temperature conditions were required to facilitate this

• ambient temperature and visible-light irradiation, achieving site-selective bromination (products 94–96) in 51–99% yields across electronically differentiated positions. The system's operational mildness and functional group tolerance highlight its suitability for late-stage functionalization of complex

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• ], TPH-graphene (Figure 2b) [23], PHH-graphene [24] and ψ-graphene [25]. Notably, fragments phagraphene and TPH-graphene have already been synthesized via on-surface chemistry and characterized using low-temperature scanning probe microscopy with CO-functionalized tips [23]. These non-alternant carbon

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

• Jiangfei Chen,
• Yi-Lin Qu,
• Ming Yuan,
• Xiang-Mei Wu,
• Heng-Pei Jiang,
• Ying Fu and
• Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

• temperature, and solvents. The optimal conditions were identified as using 10 mol % Sc(OTf)3 and 2 equivalents of Ag2O at 120 °C under an argon atmosphere. The substrate scope was then evaluated using various o-alkynylarylacrylamides and alkyl nitriles under the optimized reaction conditions. Substrates with

• amount of Bu4NPF6 as the supporting electrolyte in a MeOH/TFE 11:1 (v/v) co-solvent mixture under blue LED irradiation at a constant current of 1.5 mA for 12 hours at room temperature. A wide range of substrates exhibited good functional group tolerance, with 3-homoallylquinazolin-4-ones bearing electron

• particularly noteworthy for its use at room temperature, requiring no transition metals, photocatalysts, or additives. Notably, Umemoto's reagent served as the trifluoromethyl source, and the reaction was facilitated under blue LED irradiation, achieving good to excellent yields. Moreover, this approach

Optimized synthesis of aroyl-S,N-ketene acetals by omission of solubilizing alcohol cosolvents

• Julius Krenzer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2025, 21, 1201–1206, doi:10.3762/bjoc.21.97

• -N-benzylbenzothiazolium salts in 1,4-dioxane at room temperature in short reaction time in 20–99% yield. This protocol represents a considerable improvement over the standard synthesis in 1,4-dioxane/ethanol mixtures at elevated temperatures. Keywords: aroyl chlorides; aroyl-S,N-ketene acetals

• examples), the average yield of 57% indicates that the process might require optimization, in particular, for further methodological implementation. Here, we report on the improved synthesis of (hetero)aroyl-S,N-ketene acetals 8 by careful solvent and temperature optimization. Results and Discussion The

• from in the process. For suppressing the formation of side products by self-condensation of S,N-ketene acetal intermediates the reaction temperature has to be kept as low as possible for assuring kinetic control. Therefore, in contrast to the standard protocol [5][6] (Scheme 2), reacting aroyl

Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates

• Alexander S. Budnikov,
• Igor B. Krylov,
• Fedor K. Monin,
• Valentina M. Merkulova,
• Alexey I. Ilovaisky,
• Liu Yan,
• Bing Yu and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96

• the desired product only in trace amounts (Table 1, entry 3). The optimal loading of the catalyst was examined (Table 1, entry 4); the best results were obtained with 20 mol % of copper sulfate, slightly lower yield (64%) was observed with 10 mol % loading of the catalyst. Increased temperature was

• – 4500 V); mass range from m/z 50 to m/z 3000 Da; external calibration with Electrospray Calibrant Solution (Fluka). A syringe injection was used for all acetonitrile solutions (flow rate 3 μL/min). Nitrogen was applied as a dry gas; interface temperature was set at 180 °C. General reaction conditions

• stirred for 3 hours at 70 °C under air (air condenser) and then cooled to room temperature, and rotary-evaporated under reduced pressure. An additional evaporation step using a rotary vane pump (0.5 mmHg) at 80 °C was made for the evaporation of phosphite excess. The residue was isolated by column

Selective monoformylation of naphthalene-fused propellanes for methylene-alternating copolymers

• Kenichi Kato,
• Tatsuki Hiroi,
• Seina Okada,
• Shunsuke Ohtani and
• Tomoki Ogoshi

Beilstein J. Org. Chem. 2025, 21, 1183–1191, doi:10.3762/bjoc.21.95

• ) [55][56][63][64][65][66] yielded the monoformyl product [4.3.3]_CHO, in a selective manner (Table 1, entry 1). To suppress decomposition in the overnight reaction at room temperature, the reaction time was reduced to 1.5 h, which afforded [4.3.3]_CHO in an isolated yield of 80% (Table 1, entry 2). The

• reaction temperature and time. Indeed, bromination of [3.3.3] and [4.3.3] was reported as three/six- and two-fold reactions, respectively [45][47][53]. If the amount of bromine was limited, the resulting nearly random mixtures of brominated compounds would be practically impossible to separate by

• connections, but all of them displayed CO2 adsorption properties at 298 K probably due to the 3D components. The uptake values at standard temperature and pressure (STP) were 15–29 cm3·g−1 at 90 kPa. In this series, a sample with higher T90 and CY values tended to exhibit a higher adsorption capacity for CO2

Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups

• Julius Seumer,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94

• rate constant of the reaction leading to the other regioisomer at the reaction temperature of 90 °C. Experimentally, it is observed that the regioselective C–H activation happens on the more electron-rich aromatic ring with the methoxy substituent as opposed to the one with the alkoxycarbonyl group

A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones

• Ashutosh Nath,
• John Mark Awad and
• Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92

• in 89–98% yields. Reactions of 4 with acryloyl chloride (5, 1.5 equiv) in the presence of Et3N (2 equiv) at room temperature in anhydrous CH2Cl2 for 6 h afforded 19 N-acylated compounds 6 in 80–90% yields [19]. With N-acylated GBB adducts 6 in hand, the synthesis of imidazopyridine-fused

• in 1,2-dichlorobenzene at 180 °C for 4 h, which gave 8a in 85% conversion and 82% isolated yield (Table 1, entry 3). Other solvents like toluene and xylene gave minimal or no product. Different combinations of temperature and reaction time couldn’t improve the yield. Among the various Lewis acids

• irradiation at 100 °C for 1 h (Scheme 2, Table S1 in Supporting Information File 1). Nineteen distinct adducts 4 were obtained in 89–98% yields. The reactions of GBB adducts 4 with acryloyl chloride (5, 1.5 equiv) in the presence of Et3N (2 equiv) at room temperature in anhydrous CH2Cl2 for 6 h afforded 19 N

Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• °C and leaving it at the same temperature for an additional 15 minutes, two products, 47a and 47b, were formed. After desulfonylation with sodium amalgam (Na·Hg) in methanol and column chromatographic purification, the anticipated diols 48a and 48b were obtained in 72 and 11% yield, respectively. The

• presence of DCC and DMAP. The reaction was allowed to proceed for 6 h at room temperature, after which the temperature was reduced to −10 °C, and sodium borohydride was added. The mixture was left to react for 12 hours, yielding compound 53 in 96%. This intermediate was then converted to acrylic acid 54 by

• presence of pivaloyl chloride, triethylamine, and lithium chloride to produce compound 71 in 86% yield. Diastereoselective methylation of 71 was achieved by treating it with NaHMDS at low temperature, followed by the addition of methyl iodide, resulting in a diastereomeric ratio greater than 98:2