Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• reaction media led to higher yields. More precisely, dimethoxyethane (DME) gave a superior result to THF, affording 4aa in 82% yield (Table 1, entries 10–16). Subsequently, modification of the reaction temperature or concentration turned out to be unsatisfactory (Table 1, entries 17–19). We also added 4 Å

Selectfluor and alcohol-mediated synthesis of bicyclic oxyfluorination compounds by Wagner–Meerwein rearrangement

• Ziya Dağalan,
• Muhammed Hanifi Çelikoğlu,
• Saffet Çelik,
• Ramazan Koçak and
• Bilal Nişancı

Beilstein J. Org. Chem. 2024, 20, 1462–1467, doi:10.3762/bjoc.20.129

• used as nucleophiles. First, optimization experiments were carried out for fluoroalkoxy reactions with benzonorbornadiene (1a, Table 1). As a result of experiments conducted in six different solvents at room temperature with 1.0 equivalent of selectflor and 1.0 equivalent of methanol, it was observed

• temperature, the best result was obtained with 1.2 equivalents of selectfluor and 2.4 equivalents of methanol with 21% conversion (Table 1, entry 7). There was no significant change at higher equivalents. At 50 °C, 30% conversion was achieved with 1.2 equivalents of selectfluor and 2.4 equivalents of methanol

Synthesis of 4-functionalized pyrazoles via oxidative thio- or selenocyanation mediated by PhICl₂ and NH₄SCN/KSeCN

• Jialiang Wu,
• Haofeng Shi,
• Xuemin Li,
• Jiaxin He,
• Chen Zhang,
• Fengxia Sun and
• Yunfei Du

Beilstein J. Org. Chem. 2024, 20, 1453–1461, doi:10.3762/bjoc.20.128

• oxidant (Scheme 1a–c) [49]. For example, Xu reported that a series of 4-thiocyanated 5-hydroxy-1H-pyrazoles was synthesized by a K2S2O8-promoted direct thiocyanation of pyrazolin-5-ones at room temperature, using NH4SCN as thiocyanogen source (Scheme 1a) [20]. Similarly, utilizing NH4SCN and K2S2O8

Rapid construction of tricyclic tetrahydrocyclopenta[4,5]pyrrolo[2,3-b]pyridine via isocyanide-based multicomponent reaction

• Xiu-Yu Chen,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2024, 20, 1436–1443, doi:10.3762/bjoc.20.126

• ), dimethyl but-2-ynedioate (2a) and 5,6-unsubstituted dihydropyridine 3a as standard reaction. The main results are summarized in Table 1. The expected product was not observed when the three-component reaction was carried out in methanol, ethanol or tetrahydrofuran at room temperature (Table 1, entries 1–3

• ). The reaction in toluene, methylene dichloride or acetonitrile at room temperature afforded an unexpected tricyclic compound 4a in 12–18% yields (Table 1, entries 4–6). 1H NMR spectra clearly indicated that two molecules of dimethyl but-2-ynedioates took part in the reaction. The yields of the product

• 4a slightly increased to 29–45% yields when the reaction was carried out at elevated temperature in toluene, methylene dichloride or acetonitrile (Table 1, entries 7–10). When the reaction was carried out in refluxing acetonitrile, the tricyclic compound 4a can be obtained in 47% yield (Table 1

Synthesis of cyclic β-1,6-oligosaccharides from glucosamine monomers by electrochemical polyglycosylation

• Md Azadur Rahman,
• Hirofumi Endo,
• Takashi Yamamoto,
• Shoma Okushiba,
• Norihiko Sasaki and
• Toshiki Nokami

Beilstein J. Org. Chem. 2024, 20, 1421–1427, doi:10.3762/bjoc.20.124

• current conditions until 1.2 F/mol of total charge had been consumed. Then, the reaction temperature was elevated to 0 °C, and this temperature was kept for 1 h. The reaction was quenched with Et3N (0.5 mL), and the reaction mixture was dissolved in EtOAc and washed with water to remove electrolyte. It

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• . Based on our previous findings [17][18][19], the initial nucleophilic addition of α-aminoacetals 2a,b as nitrogen source to the activated heterodiene system of 4-methoxycarbonyl-DDs 1a–f in dichloromethane (DCM) or ethanol (EtOH) at room temperature affords N-aminohydrazone derivatives I (Scheme 2

• goal, different Lewis acids (10 mol %) such as Zn(OTf)2, CuCl2, and FeCl3 were screened at room temperature in different solvents, employing compound 4a as the model substrate (Table 1). From the set of data collected, both the formation of N,O-aminal 5a and corresponding hemiaminal 6a were observed

• dissolved in DCM (10 mL), FeCl3 (30 mol %) added and magnetically stirred at room temperature. Within 2–30 h, the reactions went to completion (TLC monitoring), affording, at last, N,O-aminals 5a–r (42–82%) and the corresponding hemiaminals 6a–p (4–35%) after column chromatography (Scheme 3). An increased

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• represented below (Scheme 2) [34]. Morken and coworkers [36] set forth an intramolecular Lewis acid-mediated Cannizzaro reaction of aryl glyoxals 7 at room temperature using appropriate chromium or copper catalysts. The strategy afforded moderate to good yields of Mandelic esters 8 in the presence of Cr(ClO4

• proceeded with modest to good yields, in the range of 40–82%, and depicts the Cannizzaro reaction in the transfer hydrogenation process [35]. A facile room temperature Cannizzaro reaction protocol was established by Abaee et al. employing magnesium bromide etherate and triethylamine in dichloromethane [77

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• the progress of photoredox-mediated catalysis in this domain [18]. Conventional procedures, such as Barton–McCombie deoxygenation [19] and use of thiocarbonyl-based activating groups [20], are quite popular. However, they have certain limitations, such as the use of toxic reagents, high temperature

• relevance. In 2022, Yu et al. [29] showcased a very mild procedure for the effective synthesis of α,α′-diarylated ketones (Scheme 2). Compared to previous procedures, this methodology was a significant improvement as it did not require an excessive amount of additives or high temperature. The methodology

Rhodium-catalyzed homo-coupling reaction of aryl Grignard reagents and its application for the synthesis of an integrin inhibitor

• Kazuyuki Sato,
• Satoki Teranishi,
• Atsushi Sakaue,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai,
• Hiroyuki Takeda,
• Tatsuo Kinashi and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 1341–1347, doi:10.3762/bjoc.20.118

• solvent as the best conditions (Table 2, entry 1). As shown above, the commercially available Grignard reagent 4a gave the corresponding homo-coupled product 3a in a short reaction time at room temperature. Subsequently, for the purpose of expanding the scope of substrates, we examined the in situ

• ]. Conclusion In conclusion, we have developed a novel Rh-catalyzed one-pot Ullmann-type homo-coupling reaction of Grignard reagents. The use of commercially available Grignard reagents gave the corresponding homo-coupling products even when carried out at room temperature and short reaction time. However

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• easily undergoes Cope rearrangement at 90 °C to generate the stereospecific 6/6-bicyclic product 10 in 96% yield (Figure 3A) [10]. This Cope rearrangement product was found as two inseparable atropisomers (10a/10b) at room temperature, which coalesced into a single conformer at 130 °C [10]. We

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• what some previous studies have reported, hydrophobic packing did not accelerate the reaction and there was no transformation in the reaction within 10 h at room temperature [99][100][101][102][103][104][105][106]. This result suggests that it would be difficult to carry out the relevant IMDAF

• liquid form over a wide temperature range, is economical and is at the forefront of production and use in various sectors worldwide [112]. In addition, despite its high unsaturation content, SSO has very good thermal stability compared to OO, even at temperatures above 150 °C under normal atmospheric

• in a much shorter time (Table 1, entry 4) when the temperature of the reaction medium was increased to 50 °C. According to X-ray and Raman spectroscopy techniques, triglyceride molecules in liquid form are arranged in a dynamic chain-like conformation [114][115][116]. As the temperature of the

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• extraction, the square Cu-nanobrackets 1b were successfully obtained by the reaction between the nanobracket 4b and copper(II) acetylacetonate in THF at room temperature. The product was characterized as 1b by MALDI-TOF mass spectrometry (Figure 1a), absorption (Figure 1b) and Raman (Figure 2c

Phenotellurazine redox catalysts: elements of design for radical cross-dehydrogenative coupling reactions

• Alina Paffen,
• Christopher Cremer and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112

• while PTeZ16 (2-dimethylamino) shows promising initial catalytic activity, it is not robust enough to survive the oxidative high temperature conditions for a prolonged period of time. In contrast, as was previously demonstrated in the literature, PTeZ2 (2-methoxy substituent) features a far greater

Synthesis and physical properties of tunable aryl alkyl ionic liquids based on 1-aryl-4,5-dimethylimidazolium cations

• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2024, 20, 1278–1285, doi:10.3762/bjoc.20.110

• was achieved via anion exchange using LiNTf2. The synthesized TAAILs with the NTf2 anion are all ionic liquids with a melting point well below 100 °C and the majority of these ILs can also be described as room temperature ionic liquids (RTIL), with a melting point below room temperature. The short

• -term thermal stability was investigated using ramped temperature analysis. The thermal decomposition temperatures (Table 1) for the ILs with the NTf2 anion are in the range from 266 °C (IL 59) to 409 °C (IL 37). In general, most ionic liquids with a butyl chain show higher decomposition temperatures

• 6.3 V, which is currently the largest window for a bis(trifluoromethylsulfonyl)imide tunable aryl alkyl ionic liquid. Temperature-dependent viscosity measurement of NTf2− TAAILs 37–63 with a butyl chain and different aryl substitution R. Conductivity of NTf2− TAAILs 37–63 measured at 25 °C. Compounds

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• of Lawesson's reagent and the reaction temperature. The transformation from ketone to thioketone was confirmed by 13C NMR, which showed a downfield shift from 198 ppm for the carbonyl carbon to 235 ppm for the thiocarbonyl carbon. With the optimized conditions (Table 1, entry 9) in hand, different

• pump and heater. The internal pressure of heater was reduced to 0.1 Pa or lower. Figure 1c shows the weight loss of the three fullerene derivatives under vacuum conditions. In contrast to C60, both t-Bu-FIDO and t-Bu-FIDS exhibited similar two-stage weight-loss curves. The sublimation temperature (Tsub

• ) was determined by analyzing the onset of weight loss for these compounds. Tsub was lower for t-Bu-FIDO and t-Bu-FIDS, at 410 °C and 417 °C, respectively, than for C60, which began to sublimate at 460 °C (Table 3). The lower sublimation temperature was attributed to the steric hindrance of the tert

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• is, on the other hand, significantly more difficult and usually requires the use of the Schlenck technique to avoid hydrolysis of the moisture sensitive compounds. The handling of these reagents, which have to be stored at low temperature, requires some experience. In fact, the synthesis of the

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• radical ions of polyazahelicenes. The moderate fluorescence quantum yield of 48% (in MeCN) [46] implies that a non-emissive triplet-excited state (at room temperature) could also be generated via intersystem crossing, potentially initiating electron transfer reaction sequences. 77 K emission measurements

• chloride. We believe that our findings pave the way for a broader usage of the inherently chiral polyazahelicene photocatalyst class, both in photoredox and energy transfer catalysis. A) Room-temperature absorption (black) and emission (yellow) spectra of Aza-H recorded in MeCN/H2O (9:1), and fluorescence

The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids

• Carolina S. Marques,
• Aday González-Bakker and
• José M. Padrón

Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104

• -acetamide carboxamide oxindole hybrids 5 was obtained in moderate yields (26–63%), at room temperature, in short time (2 hours), proving the efficiency and the generality of this methodology. Aliphatic (2a, 2c and 2m), aromatic (2d, 2f, 2g, 2k and 2l), heterocyclic (2e, 2h, 2i, 2n and 2o), alkyne 2b and

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• low-temperature apparatus providing a constant temperature at 100 K. Crystal data for C60(Dip2Si)2: C108H68Si2: Mr = 1421.87, black plate, 0.11 × 0.16 × 0.025 mm, λ = 0.71073 Å, monoclinic, space group P21/n (no. 14), a = 18.3631(3), b = 13.6696 (2), c = 27.6360 (5) Å, β = 92.857 (2)°, V = 6928.5(2

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• reaction of aryl vinyl ketones, leading to the synthesis of 3-aryl-2-ethoxycarbonyl-1-indanones and 3-aryl-1-indanones. By changing the temperature and reaction time, it was possible to modulate the reactivity, allowing the synthesis of two distinct product classes (3-aryl-2-ethoxycarbonyl-1-indanones and

• ][39][40][41][42][43], and other strategies [44][45]. Although methodologies involving catalysis by Lewis acids are very efficient, including asymmetric versions of the Nazarov reaction, the experimental protocols are quite laborious in most cases, requiring low temperature, an inert atmosphere, or the

• the Nazarov reaction, using models already studied in the literature [33][34][35][36][37][38][39][40][41][42][43]. We investigated several conditions, such as the type of catalyst, temperature, solvent, and amount of catalyst (Table 1). Our optimization studies began with the reaction of substrate 9aa

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• optimized with 5 mol % of Mn1 and 10 mol % of K2CO3 in xylene at high temperature (150 °C) for 24 h afforded the desired N-alkylated sulfonamide compounds [40]. A wide range of aryl and alkyl sulfonamides were alkylated with various benzylic and aliphatic alcohols, providing good to excellent yields (Scheme

• temperature [41]. The coupling of several aromatic amines with aliphatic and benzylic alcohols was studied with bis-NHC-manganese complex (Mn6). A catalyst loading of 1.5 mol % in the presence of t-BuOK (1 equiv) at room temperature produced the corresponding N-alkylated amines with 40–93% yield (Scheme 11

• -alkylation of aniline with secondary alcohols required a high temperature (100 °C) compared to substituted benzylic alcohols (60 °C). Interestingly, this protocol was used to synthesize the drug cinacalcet, via alkylating the challenging benzylamine substrate under non-optimized conditions. Later, Madsen’s

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• conditions by utilizing a 7000-fold excess of dimethyl acetylenedicarboxylate (DMAD) at room temperature. The reactions were monitored by UV–vis spectroscopy. Compound 2 undergoes rapid reaction with DMAD under these conditions and is more than 90% consumed after 2.5 hours (Figure 8, top). Conversely

• -dicarboxylate (26) In a similar manner to [15], 1,3-diphenylisobenozfuran (2, 0.10 g, 0.37 mmol), 5 mL CH2Cl2 and dimethyl acetylenedicarboxylate (DMAD, 0.116 g, 0.814 mmol) were added to a round bottom flask. The reaction mixture was stirred at room temperature for 2 hours. The solvent was removed by rotary

• 1,4-dimesityl-1,4-dihydro-1,4-epoxynaphthalene-2,3-dicarboxylate (27) To a round bottom flask was added 1,3-dimesitylisobenozfuran (3, 0.05 g, 0.14 mmol), 5 mL CH2Cl2 and dimethyl acetylenedicarboxylate (DMAD, 2.31 g, 16.3 mmol). The reaction mixture was stirred at room temperature for 4 hours. The

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• /Et3N, followed by silica gel column chromatography, led to the triethylammonium salt of 2-N-Boc-aminoethylphosphinic acid 5 in 50 % yield. Alkylation of acid 5 with methyl chloroacetate in the presence of TMSCl and Et3N took five days at room temperature, and compound 6 as triethylammonium salt was

• obtained in 84% yield after silica gel purification. Removal of the Boc protecting group from 6 in the presence of trifluoroacetic acid in DCM at room temperature overnight, followed by cyclisation in boiling pyridine/triethylamine, led to 4-hydroxy-1,4-azaphosphinan-2,4-dione (7) in 84% yield. The free

• the linear amide 11 was performed in DCM using a 10-fold excess of trifluoroacetic acid at room temperature, providing 1,4-azaphosphinine 12 in 68% yield. Various conditions used for the coupling of nucleobase 8, such as using silylated derivatives (HMDS, BSA) or salts obtained by base treatment (NaH

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• , after prolonged reaction time (Table 2, entry 5). Furthermore, a slight improvement was observed at higher temperatures (Table 2, entry 6), while the removal of CH2Cl2, possibly limiting the temperature inside the flask, had a negative impact (entry 7). Nevertheless, yields and selectivity seemed to

• ), H2SO4 (96 wt %, 3.00 g, 30 mmol, 2.5 equiv), I2 (0.04 g, 0.16 mmol, 0.01 equiv), and CH2Cl2 (1.50 mL) were inserted. The flask, kept under stirring at room temperature (rt), was light-shielded with aluminium foil and a water-cooled condenser was installed on its top. A solution of NaBr (2.88 g, 28 mmol

Mild and efficient synthesis and base-promoted rearrangement of novel isoxazolo[4,5-b]pyridines

• Vladislav V. Nikol’skiy,
• Mikhail E. Minyaev,
• Maxim A. Bastrakov and
• Alexey M. Starosotnikov

Beilstein J. Org. Chem. 2024, 20, 1069–1075, doi:10.3762/bjoc.20.94

• . Cyclization of the latter under the action of K2CO3 in MeCN at room temperature gave previously unknown ethyl isoxazolo[4,5-b]pyridine-3-carboxylates 4a–c (Scheme 2). To the best of our knowledge only one compound (ethyl 5,7-dimethylisoxazolo[4,5-b]pyridine-3-carboxylate) has been synthesized using a similar