Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• was stirred at room temperature for 0.1 to 2 h (monitored by TLC). Deionized water (20 mL) was added to the reaction mixture and the aqueous phase was extracted with dichloromethane (3 × 20 mL). The combined organic phases were dried (anhydrous sodium sulfate), filtered, and the solvent was then

• temperature, NIS (338 mg, 1.50 mmol) and 1.00 mL DMSO were added. After complete conversion (via TLC control), methyl iodide (639 mg, 4.50 mmol) was added and also stirred at room temperature for 5 min. Water was added to the mixture and the aqueous phase was extracted with dichloromethane. The combined

• stirring bar under nitrogen. Under nitrogen DMSO (5.00 mL) and deionized water (0.80 mL) were added and the reaction mixture was heated to 85 °C (oil bath) for 2 h. Then, deionized water (20 mL) was added to the reaction mixture and the aqueous phase was extracted with dichloromethane (3 × 20 mL). The

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• of H2O were added to the reaction mixture [40] (Table 1, entry 6), but the addition of more water did not improve the reaction efficiency further (Table 1, entry 7). The structure of nickel catalysts played a significant role in the reaction efficiency. Switching the Ni catalyst to NiCl2(dtbbpy

• LEDs (λmax = 399 nm) for 7 h. After the reaction was complete, the reaction mixture was poured into water and extracted with EtOAc. The combined organic phase was separated and washed with brine, dried over Na2SO4, and concentrated under vacuum. The resulting residue was purified by silica gel flash

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• alcohol functions of 4.5 were deprotected in acidic media to produce 3-O-octadecyl-sn-glycerol (4.6). The enantiomer of 4.6 was obtained from 4.4 by protecting the primary alcohol with a benzyl group to give 4.7. Then, the deprotection of the two alcohol functions with H2SO4 in water followed by the

• followed by the benzylation of the sodium alcoholate produced 21.2 in 95% yield. The deprotection of the acetal was achieved with acetic acid in a mixture of isopropanol and water to give 21.3. Then, a critical step is the alkylation of the primary alcohol in the presence of the unprotected secondary

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• %; GoodFellow, Cambridge, U.K.). The GCE was polished between experiments using alumina slurry (0.3 μm), rinsed in distilled water and subjected to brief sonication to remove any adhering alumina microparticles. The metal electrodes were then dried in an oven at 100 °C to remove residual traces of water, the

• GCE was left to air dry and residual traces of water were removed under vacuum. The Ag wire pseudoreference electrodes were calibrated to the ferrocene/ferrocenium couple in THF at the end of each run to allow for any drift in potential, following IUPAC recommendations [16]. All electrochemical

• reaction mixture was dried under vacuum to remove DMF. The crude product was extracted with DCM and washed with water. The organic phase was collected and dried with MgSO4, filtered and concentrated under vacuo. The product was further purified by column chromatography (ethyl acetate/hexane 1:4) to give

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• methodologies involving ether α-C(sp3)–H and aromatic C(sp2)–H bonds were investigated and these are shown in Scheme 43. Shah et al. reported a catalyst-free CDC method using only 2 equivalents of K2S2O8 in H2O under irradiation with a 27 W CFL (Scheme 43a) [123]. In this reaction, both water and the light

• source played a key role, with lower yields or no product obtained when the reaction was performed without water or under other light source conditions such as 19 W CFL or irradiation with blue or green LEDs. This method is applicable to various heteroatom-containing compounds such as quinolines

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• these substrates and the formation of water as the sole non-toxic byproduct in the reaction [11]. In general, the previous methods for the amination of MBH alcohols needed catalysts or additives such as FeCl3 [12][13], In(OTf)3 [14], MoCl5 [15], AuCl3 [16], and I2 [17] as Lewis acids. Alternatively

• derivatives in Et3N/THF mixtures [20] (Scheme 1, reaction 1, i) and acetates in THF/water [21] (Scheme 1, reaction 1, ii), or MBH alcohols in the presence of CDI (1,1’-carbonyldiimidazole) in acetonitrile (Scheme 1, reaction 1, iii) [22]. In the last case, as the hydroxy moiety is not a good leaving group

• removal of water formed from the direct amination of alcohol 4a by azeotropic distillation shifted the position of the equilibrium in direction to the formation of the allylated imidazole 6a which was obtained in good 88% yield (Table 1, entry 6). The protocol was also successfully extended to the

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• condensation coproducts, such as water, hydrogen chloride or other small molecules [1][2][3]. MCRs have a great advantage over the classical two-component reactions; they allow the construction of complex molecular motifs in only one synthetic operational step starting from simpler building blocks. For this

• developed in our previous work [17], we tried to introduce 6 as an acetaldehyde equivalent, adding water in the reaction system and Amberlyst-15 as a catalyst to accelerate the hydrolysis process (Scheme 2). To our delight, 6 as an acetaldehyde surrogate allows a slightly better yield with doubled

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• , the nucleophilic addition of the amino anion to the carbonyl group in the of 1,3-cyclohexanedione scaffold resulted in cyclic intermediate C. Thirdly, the elimination of water from intermediate C gave the isolated product 3. In the case of the intermediate B2 with a benzoyl group, there are two kinds

• -cyclohexanedione moiety remained unreacted. Then, the final product 4 was formed by elimination of water. Thus, the spiro compounds 3 and 4 were selectively produced due to the different reaction process. Thus, the 3-isatyl-1,4-dicarbonyl compounds derived from 3-ethoxycarbonylmethyloxindoles and 3

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• the reaction was monitored by TLC. After completion of the reaction, the product was extracted by using chloroform (3 × 50 mL). The organic layers were combined and washed with water (3 × 50 mL), dried over anhydrous sodium sulfate and evaporated under reduced pressure. The crude product was purified

• ) in chloroform (20 mL), conc. H2SO4 (1.6 mL) was added and the reaction mixture was stirred at 0 °C for 7 min. After completion of the reaction, the reaction mixture was quenched with water and neutralized with saturated sodium bicarbonate solution. The resulting mixture was extracted with chloroform

• (50 mL). The organic layer was washed with water (3 × 50 mL), dried over anhydrous sodium sulfate and evaporated under reduced pressure. The crude product was purified on a neutral alumina column by using 40% chloroform in hexane as eluent to afford porphyrins 9–13 in 70–80% yields. General procedure

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• artificial photosynthesis. Systems for photocatalytic carbon dioxide reduction are optimized using sacrificial electron donors. One strategy for coupling carbon dioxide reduction and water oxidation to achieve artificial photosynthesis is to use a redox mediator, or recyclable electron donor. This review

• decoupled water splitting research, are introduced as alternative recyclable sacrificial electron donors and their oxidation potentials are compared to the redox potentials of some model photosensitizers. The aim of this review is to act as a reference for researchers developing photocatalytic systems with

• discovery and creation of incredible chemical systems and materials. The ultimate goal is to harness energy from the sun and use it to transfer electrons and protons from water onto carbon dioxide and create molecules to replace fossil fuels [1][2]. However, when developing the components of artificial

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• , Germany), and Avantor Performance Materials (Deventer, Netherlands). An in-house Purelab® flex water purification system (Veolia Water Technologies, Celle, Germany), was used in the preparation of deionized water. Fungal material examined The current study specimen was collected by one of the authors C.D

• , cotton seed flour 5 g/L in distilled water), were mixed, pH adjusted to 7.2, and autoclaved. The media flasks were inoculated with 10 mycelial plugs (5 mm) each and incubated for 28 days, under shaking and static conditions for liquid and solid cultures, respectively. The cultures were extracted after

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• byproducts, and increased efficiency in industrial processes. As such, this field of research is of great importance and interest to both academia and industry. This work showcases a sustainable and catalyst-free oxidation method for heteroatoms (e.g., S, P, and Se) using only air, water and light. An

• additional reaction pathway is proposed in which the incorporated oxygen on the heteroatoms originates from water. Furthermore, the addition of certain additives enhances productivity by affecting kinetics. The industrial potential is demonstrated by conveniently transferring the batch protocol to continuous

• implementation. The protocol utilizes oxygen or air, a water-based solution, and UV-A irradiation at 365 nm. Scaling up such protocols has traditionally been difficult, as demonstrated by a previous oxidation of thioanisole on a 10 g scale, which had a long reaction time of 13 hours [29]. Advantageously, our

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• hand, PEC reactions require tailor-made reactors that present technical challenges, although in principle these challenges are surmountable by adapting engineering from the already well-established fields of PEC water splitting/fuel cells/photovoltaic fields. So far, the examples of large-scale

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• ), phenothiazine (130 mg, 0.650 mmol), Pd(OAc)2 (22 mg, 0.098 mmol), and sodium tert-butoxide (70 mg, 0.732 mmol) were dissolved in dry toluene (8 mL). Then, tri-tert-butylphosphine tetrafluoroborate (19 mg, 0.065 mmol) was added. The mixture was refluxed and stirred for 8 h under N2. After cooling, water (20 mL

• ) was added, and the mixture was extracted with ethyl acetate (3 × 30 mL). After separation, the combined organic layer was washed with water and brine (3 × 30 mL), respectively, dried over anhydrous Na2SO4, and the solvent was evaporated under reduced pressure. The crude product was purified by column

• synthesized by a modified literature method [43]. Compound NI-PTZ-F (36 mg, 0.074 mmol) was dissolved in glacial acetic acid (5 mL), H2O2 (1.5 mL, 30%, 1.184 mmol) was added dropwise and the mixture was stirred at 40 °C for 1 h. Then, the reaction mixture was poured into water and the pH of the mixture was

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• stoichioimetry and that a number of simple and modified cyclodextrins bind CO2 in water with a Kg of 0.18–1.2 bar−1 (7–35 M−1) with per-O-methyl α-cyclodextrin having the highest CO2 affinity. Keywords: carbon dioxide; crystals; cyclodextrin; gas binding; Introduction The concentration of carbon dioxide (CO2

• bind CO2 in water with a Kg of 0.18–1.2 bar−1 (7–35 M−1). Results and Discussion When a saturated solution of 1 was treated with CO2 at a pressure from 6–20 bar in an autoclave for 1–19 days, crystals containing CO2 were obtained in 16–63% yield (Table 1). The most important factor for getting higher

• solubility of this complex in water. X-ray crystallography of the crystals showed a 1:1 complex of CO2 to α-CD with CO2 bound in the center of the wide, secondary rim of the α-CD cavity (Figure 2). Two of the hydroxymethyl side groups on the primary narrow rim are disordered. The disordering was modeled over

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• .19.76 Abstract Copper sulfate catalyzed an efficient, inexpensive, and environment-friendly protocol that has been developed for N-arylation of amines with 1,3-cyclohexadione-derived aryliodonium ylides in water as a green solvent. Aromatic primary amines substituted with electron-donating as well as

• halogenated solvents. Moreover, the use of economic and eco-friendly solvents such as water have always been an attractive area in organic synthesis. Therefore, in continuation of our efforts towards the development of sustainable methods for the synthesis of valuable organic molecules, herein, we report a

• straightforward and efficient method for the N-arylation of primary arylamines and secondary amines with 1,3-cyclohexanedione-derived aryliodonium ylides in the presence of copper catalysts in water as a solvent. Results and Discussion To test our hypothesis, we commenced our studies by treatment of aniline (1a

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• , and bioactivity evaluation of the new compounds. Results and Discussion The dried and powdered agarwood sample was extracted by percolating with 95% EtOH to afford a crude extract, which was suspended in water followed by partitioning with EtOAc to afford an EtOAc-soluble extract. Furthermore, several

• , Shenzhen University, P.R. China. Extraction and isolation The dried and powdered agarwood sample (15.0 kg) was extracted by percolating with 95% EtOH to afford a crude extract, which was suspended in water followed by partition with EtOAc to afford an EtOAc-soluble extract (1.7 kg). The EtOAc extract was

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• procedure is explained in the first section, and the green protocol is covered in the second (Figure 2). The second section is further divided into three subsections that covers the various eco-friendly green processes used, such as, (i) reactions in water, (ii) solvent-free reactions, (iii) microwave

• -assisted reactions in water, solvent-free conditions and in other organic solvents. Clauson–Kaas reaction and its mechanism The Clauson–Kaas reaction refers to the synthesis of various N-substituted pyrroles via an acid-catalyzed reaction between aromatic or aliphatic primary amines and 2,5

• removal of methanol, produces intermediate E. In the next steps, the ring closure of intermediate E due to the lone pair of nitrogen gives F, which after the elimination of methanol and water in subsequent steps provides intermediate H. Finally, an aromatic N-substituted pyrrole 3 is produced by basic

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• resin with methanol. The resulting extract was concentrated to dryness. For an initial separation of its components, the raw extract was resuspended in water and extracted three times with ethyl acetate. The organic phases were pooled. A testing in the CAS assay indicated the presence of iron-chelating

• secreted metabolites. The resin was separated from the culture broth by filtration, washed with distilled water and exhaustively extracted with methanol. Isolation of derivatives The concentrated extract was first fractionated by reversed-phase HPLC using a Nucleodur C18 Isis column (250 × 10 mm, 5 μm

• , Macherey-Nagel) and a gradient of acetonitrile in water supplemented with 0.1% (v/v) trifluoroacetic acid. The gradient conditions were as follows: from 20% acetonitrile to 90% in 30 minutes and kept at 90% for 10 minutes. The flow rate was set to 5 mL/min. The elution of compounds was monitored with a

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• solubility in water. Among exceptional properties belongs to easy post-transformation of acylimidazoles to common carbonyl analogs. These tunable properties allow the use of acylimidazoles in chemical biology research, which includes chemical synthesis of proteins/peptides, structure analysis, and functional

A fluorescent probe for detection of Hg²⁺ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

• Xiaoqian Chen,
• Naqin Yang,
• Yue Ma,
• Xinan Yang and
• Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

• nature can be converted into organic mercury under the action of microorganisms, which cannot be decomposed or degraded into nontoxic substances in the human body [1][2], which will seriously threaten human health. Therefore, China has formulated water pollutant emission limits [3]. Traditional Hg2+ ion

• change in fluorescence intensity can be used for the recognition of Cd2+ and Zn2+ ions [35]. The symmetric tetramethyl cucurbit[6]uril (TMeQ[6]) is one of the earliest characterized modified cucurbit[6]urils [36]. Compared with Q[6], tetramethyl cucurbit[6]uril (TMeQ[6]) has good solubility in water

• chiral space group P-1. Figure 4a shows that the basic crystal structure of complex 1 contains a TMeQ[6] molecule, a G molecule, a free water molecule and a [ZnCl4]2− anion. It can be clearly seen that one pyridyl group of the G molecule enters the cavity of TMeQ[6], whereas the other pyridyl group is

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• materials [1][2][3][4][5][6][7][8][9][10]. Due to its different characteristics such as basicity, stability, water solubility, small molecular size, and ability to form hydrogen bonds, pyridine continues to be a suitable moiety in organic synthesis. In addition, it has been observed that pyridine rings

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• reactions involve the imidothioate IV formed via deprotonation from nitrogen (pKaN in Scheme 2). The imidothioate IV can undergo cyclization to give an energetically favorable five-membered thiazoline ring VII which then either eliminates a leaving group Y− (when Y: alkoxy, amino) or a water molecule (when

• 70–95%). The presence of a base and the type of solvent seems to be an important factor for the reaction course. In toluene, ionic liquid or in refluxing ethanol without a base [16][19][20] or in the presence of weakly basic pyridine [17][18][21] (pKa = 5.23 in water, 3.4 in DMSO, 3.3 in DMF, and

• water) tend to the formation [5][6] of the ECR product (XIV). A similar tendency to produce either ECR or thiazole products depending on the solvent was observed already by Eschenmoser and his co-workers for the reaction of α-bromoketones with thiolactams [23]. On the other hand, Bergman et al

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• (Scheme 6). However, the key difference is the regioselectivity of the process and the absence of a pathway associated with the direct elimination of a water molecule and the formation of the polyaromatic compound 12. It can be assumed that for the considered system a [1,9]-H sigmatropic shift is a much

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

• Masahiro Hosoya,
• Yusuke Saito and
• Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

• , which diminishes the atom economy [2]. To overcome this limitation, the use of molecular oxygen (O2) present in air as an oxidant is one of the ideal solutions [10][11]. The reduction of O2 generates only water as a byproduct, leading to high atom-economy processes. However, the use of O2 as an oxidant

• to handle aerobic oxidation. Therefore, passive mixing should be more suitable for aerobic oxidation. The whole flow reactor with passive mixing can be immersed in incombustible medium such as water, leading to the improvement of the process safety. Passive mixing is commonly realized using slug-flow