A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates

• Olusesan K. Koleoso,
• Matthew Turner,
• Felix Plasser and
• Marc C. Kimber

Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165

• product was observed when ethanol was used as the nucleophile giving product 39 in 52% isolated yield. In contrast, isopropanol gave an inseparable mixture of the α- and γ-addition products, 40a/b in 33% isolated yield. As with the case for the formation of 19, all of the starting allenes were consumed in

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• pyridines via C–N, C–C, and C–S bond formations in a mixture of ethanol and H2O under ultrasound irradiation. The catalyst is characterized by XRD, FTIR, Raman spectroscopy, SEM, and EDAX analysis. The main advantages of this methodology include the wide substrate scope, cleaner reaction profile, short

• 1 and 2a in the presence of 5.0 wt % of the NDL in a mixture of ethanol and water 1:1 for 10 min under both conventional stirring and ultrasound irradiation. The obtained results are presented in Table 4. It was observed that the reaction proceeded with an improved yield of 3a (70–98%) by increasing

• . Conclusion An environmentally benign NDL catalyst was characterized and utilized as a heterogeneous catalyst for the synthesis of 2-aryl-1-arylmethyl-1H-benzo[d]imidazoles, dihydropyrimidinones/ -thiones, and 2-amino-4-(hetero)aryl-3,5-dicarbonitrile-6-sulfanylpyridines in a mixture of ethanol and H2O 1:1

Stereoselective Biginelli-like reaction catalyzed by a chiral phosphoric acid bearing two hydroxy groups

• Xiaoyun Hu,
• Jianxin Guo,
• Cui Wang,
• Rui Zhang and
• Victor Borovkov

Beilstein J. Org. Chem. 2020, 16, 1875–1880, doi:10.3762/bjoc.16.155

• set as a model reaction (Table 1). Screening of solvents indicated that chiral phosphoric acid 3 stereoselectively promoted this reaction in aprotic solvents (Table 1, entries 1–6), while in protic solvent, such as ethanol, the racemic product was obtained (Table 1, entry 7). To our pleasure, the

• prepared from ʟ-tartaric acid and ethanol. THF was freshly distilled after refluxing with Na, while SOCl2, pyridine, PCl3, and I2 were purchased and used directly. Commercially available starting materials were used without further purification if not specified otherwise. Chiral phosphoric acid 3 was

• the mixture after cooling to rt. The resulting solution was extracted with EA (20 mL × 3), dried, and concentrated. The residue was recrystallized from 80% ethanol (ethanol/H2O 4:1, v/v) to give 7.2 g of (2R,3R)-1. Yield 56%; mp 149–151 °C; [α]D25 +153.9 (c 0.5, CHCl3); 1H NMR (CDCl3, 400 MHz) δ 7.31

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• dissolved in anhydrous ethanol (8 mL), and pyridinium p-toluenesulfonate (PPTS, 286 mg, 1.14 mmol, 2 equiv) was added. The solution was stirred at 60 °C for 2.5 h. The reaction mixture (at rt) was poured into a separating funnel containing diethyl ether (40 mL) and brine (16 mL). The organic layer was dried

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

• Dalel El-Marrouki,
• Sabrina Touchet,
• Abderrahmen Abdelli,
• Hédi M’Rabet,
• Mohamed Lotfi Efrit and
• Philippe C. Gros

Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144

• reaction, using sodium ethoxide in ethanol, followed by the hydrolysis with concentrated sulfuric acid at a low temperature [56], leading to the corresponding new γ-diketones 5a–d in 61–87% yield (Scheme 2). Despite the efficiency of the Nef reaction, the diversity at the R1 position via this synthetic

• aprotic solvents, other than toluene (Table 1, entries 7 and 8), the reaction produced complex mixtures of degradation products, and using alcohols had a notable impact on the reaction contents. Indeed, going from ethanol to propanol, and thus increasing the refluxing temperature, led to the indolone 7b

• of the intermediately formed imine to the Michael acceptor (Scheme 3). We then investigated the synthesis of cinnoline derivatives by mixing the diketone 5a and hydrazine monohydrate under various conditions (Table 2). We first investigated the reactivity in ethanol, as a protic solvent, at room

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• 1.5 h in an ethanol/water (50:50) mixture at 210 °C, and ii) CIMV (Compagnie Industrielle de la Matière Végétale) technology, where wheat straw was treated during 3.5 h of acetic acid/formic acid/water (50:30:15 m/m/m) extraction at 105 °C and then in the presence of H2O2 and organic acids (peracetic

Microwave-assisted efficient one-pot synthesis of N²-(tetrazol-5-yl)-6-aryl/heteroaryl-5,6-dihydro-1,3,5-triazine-2,4-diamines

• Moustafa Sherief Moustafa,
• Ramadan Ahmed Mekheimer,
• Saleh Mohammed Al-Mousawi,
• Mohamed Abd-Elmonem,
• Hesham El-Zorba,
• Afaf Mohamed Abdel Hameed,
• Tahany Mahmoud Mohamed and
• Kamal Usef Sadek

Beilstein J. Org. Chem. 2020, 16, 1706–1712, doi:10.3762/bjoc.16.142

• sodium hydroxide (50%) in aqueous ethanol (Scheme 1). Although, these methods have specific merits, they sometimes suffer from drawbacks such as extended reaction temperatures, lengthy procedures, low yields and atom economy, which consume excess reagents. Extensive efforts have been devoted to adopting

• experimental conditions and the results revealed that performing the reaction in dioxane, CH3CN, THF, or catalyst-free ethanol resulted in no product formation. However, the same products were obtained with lower yields (≈60%) when performing the reaction under conventional heating utilizing pyridine as the

Synthesis of new dihydroberberine and tetrahydroberberine analogues and evaluation of their antiproliferative activity on NCI-H1975 cells

• Giacomo Mari,
• Lucia De Crescentini,
• Serena Benedetti,
• Francesco Palma,
• Stefania Santeusanio and
• Fabio Mantellini

Beilstein J. Org. Chem. 2020, 16, 1606–1616, doi:10.3762/bjoc.16.133

• achieved as a pure pale yellow solid directly from the reaction medium with the best yields (Table 1, entry 7). In tetrahydrofuran (THF), in ethyl acetate (EtOAc), and in alcohols such as methanol, ethanol, isopropanol (MeOH, EtOH, iPrOH) the reaction furnishes a complicate profile, where the desired 2a is

Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)

• Cora Hertzer,
• Stefan Kehraus,
• Nils Böhringer,
• Fontje Kaligis,
• Robert Bara,
• Dirk Erpenbeck,
• Gert Wörheide,
• Till F. Schäberle,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132

• Ackers et al. in 2007 [86], see also Erpenbeck et al. from 2020 [87] (Supporting Information File 1). Specimens were stored in ethanol (96%) at −20 °C until further extraction and processing in the laboratories at the University of Bonn. A part of the collected sea slug and substrate materials will be

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• . The solubility in various common solvents (water, acetone, ethanol, N,N-dimethylformamide or dimethyl sulfoxide, diethyl ether, and petroleum ether) of the new nanosponges was tested. Like nanosponges obtained from batch experiments, also the ones from ball-mill synthesis, as expected, were insoluble

• , ReagentPlus® grade, ≥99%), methyl red, rhodamine B, and fluorescein (for all dyes, declared dye content 95%), N,N-dimethylformamide (DMF, anhydrous, 99.8%), acetone (ACS reagent, ≥99.5%), and ethanol (ACS reagent, 96%) were purchased from Sigma-Aldrich (Munich, Germany) and used without further purification

Photoredox-catalyzed silyldifluoromethylation of silyl enol ethers

• Vyacheslav I. Supranovich,
• Vitalij V. Levin and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 1550–1553, doi:10.3762/bjoc.16.126

• flash column chromatography on silica gel, presumably, owing to facile β-elimination of hydrogen fluoride. To isolate a stable product, the reaction mixture was treated with sodium borohydride in ethanol, which effected the reduction of the keto group affording the corresponding alcohol 4a in 52% yield

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

The McKenna reaction – avoiding side reactions in phosphonate deprotection

• Katarzyna Justyna,
• Joanna Małolepsza,
• Damian Kusy,
• Waldemar Maniukiewicz and
• Katarzyna M. Błażewska

Beilstein J. Org. Chem. 2020, 16, 1436–1446, doi:10.3762/bjoc.16.119

• glass stopper and additionally secured with parafilm. The flask was placed in a sand bath at 36 °C for 24 h. Afterwards, the solution was evaporated and the mixture subjected to solvolysis, using either acetone, ethanol or methanol/water (20:1, v/v). The isolation of phosphonic acids as the main

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• was synthesized from vitamin C (29) in 1996 (Scheme 6). Vitamin C (29) was converted first into 1,3-dimesylate 30 of 2,4-di-O-protected 1,2,3,4-butane-tetraol in 6 steps. The subsequent treatment with Na2S in refluxing ethanol then gave rise to the protected thietanose 31 in 62% yield [3] (Scheme 6

• S-[2-(3-chloro-2-(chloromethyl)-2-hydroxymethyl)propyl]isothiouronium perchlorate (77). Heating compound 77 with KOH in ethanol for 40 min yielded 3-chloromethyl-3-hydroxymethylthietane (79) through a thiolate intermediate (78). Further reflux for 16 h gave rise to 2-oxa-6-thiaspiro[3.3]heptane (80

• ethanol [18][95] (Scheme 66). N-1-(Cyclopent-1-enyl)ethyl-5-thiopyrrolidin-2-one (343) gave a tetracyclic thietane derivative 344, which further afforded a spirocyclopentane tetrahydropyrrolizin-3-one 346 under the similar treatments [95] (Scheme 67). Similarly, linear and cyclic 3-but-3-enylpyrrolidine

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• three-component method was used for the quinazoline formation by refluxing 2-aminobenzophenone, difluorobenzaldehyde, ammonium acetate, and CuCl2 in ethanol. The synthetic method using a cheap catalyst, easy workup, and the high yield (78%) of quinazoline Q1 makes the compound a promising candidate as

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• ) and the corresponding benzaldehyde (4.87 mmol) were added. The resulting suspension was heated to 110 °C for 2 h and then allowed to cool to room temperature. The resulting deep yellow precipitate was stirred with ethanol (25 mL), filtered off, washed with water (20 mL), additional ethanol (25 mL) and

A simple and easy to perform synthetic route to functionalized thienyl bicyclo[3.2.1]octadienes

• Dragana Vuk,
• Irena Škorić,
• Valentina Milašinović,
• Krešimir Molčanov and
• Željko Marinić

Beilstein J. Org. Chem. 2020, 16, 1092–1099, doi:10.3762/bjoc.16.96

• bicyclo[3.2.1]octenes/octadienes with cholinesterase inhibitory properties. 1H NMR spectra (CDCl3) for the trans-isomers 3–6. UV spectra in ethanol (95%) of the cis- and trans-isomers of compound 3. Photolysis spectra of cis-3 (a) and trans-3 (b) in ethanol (95%). UV spectra in ethanol (95%) of the trans

• compounds 1, 8, and 9. UV spectra of compounds 1 and 12 in ethanol (95%). Photolysis spectra of compound 12 in ethanol (95%). Synthesis of annulated furobenzobicyclo[3.2.1]octadiene compounds. Synthesis of annulated thiophenebicyclo[3.2.1]octadiene compounds 8-10. Synthesis of compound 11. Synthesis of

Palladium-catalyzed regio- and stereoselective synthesis of aryl and 3-indolyl-substituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones

• Valeria Nori,
• Antonio Arcadi,
• Armando Carlone,
• Fabio Marinelli and
• Marco Chiarini

Beilstein J. Org. Chem. 2020, 16, 1084–1091, doi:10.3762/bjoc.16.95

• presence of a catalytic amount of the ligand-free PdCl2 in environmentally friendly ethanol, achieve an efficient regio- and stereoselective synthesis of 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones 4. It is worth noting that, during the preparation of this paper, a related article focused on the

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• . This indicates that the excited state dipole moment is much greater than the ground state dipole moment. Quantum yields The relative fluorescent quantum yields (ϕFL) of compounds 7a and 7b were determined in dichloromethane by using rhodamine B (ϕFL = 49% at λexc=355 nm) in ethanol as reference [45

Fluorinated phenylalanines: synthesis and pharmaceutical applications

• Laila F. Awad and
• Mohammed Salah Ayoup

Beilstein J. Org. Chem. 2020, 16, 1022–1050, doi:10.3762/bjoc.16.91

• derivatives 2-Phenyl- and 2-(4-fluorophenyl)-2,2-difluoroacetaldehyde 164a and 164b proved to be key starting points for the synthesis of β,β-difluorophenylalanine analogs 168a,b. The conversion of 164a,b into their respective cyanohydrins 165a,b followed by acid hydrolysis with gaseous HCl in ethanol

A method to determine the correct photocatalyst concentration for photooxidation reactions conducted in continuous flow reactors

• Clemens R. Horn and
• Sylvain Gremetz

Beilstein J. Org. Chem. 2020, 16, 871–879, doi:10.3762/bjoc.16.78

• made for TPP catalyst (H) concentrations. Rose bengal (D) gave similar results: increasing the amount of the catalyst by 50% provided a slightly higher conversion for high flow rates, and the change of the solvent from ethanol to acetonitrile had the same impact (Figure 10). This can be attributed to

• reaction conditions (0.5 N citronellol, 1 mL/min,1 mol % catalyst, 2 equiv oxygen, 8 bar, 20 °C, reactor volume: 2.7 mL, solvent: ethanol (B, C, D, E, and F) or dichloromethane (A, G, H, and I)). aThe conversion was determined by GC after quenching with PPh3. bTransmission (in %) of the starting solution

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• 42 in aqueous solutions [47]. For the cases where the ketones or the aldehydes were not soluble in, or miscible with water, an amount of ethanol was added. The light source employed was a UV high-pressure mercury lamp (2 kW). All aliphatic ketones tested, including acetone (4), butanone, and pentan-2

• irradiation, the compounds 12, 76, and 77 were obtained in equal amounts. The irradiation of benzaldehyde (8) in ethanol yielded mostly compound 77 and traces of 12 (Scheme 21a). When benzaldehyde (8) was mixed with hex-1-yne (78), after a short irradiation time, the main products that were obtained were 80

• biradical intermediate may lead to all four conformations. Photolysis products of benzaldehyde (8) in different solvents. a) In benzene or ethanol. b) In hex-1-yne. N-tert-Butylbenzamide formation proceeds via a benzoyl radical. Photochemical pinacol coupling. Photochemical ATRA catalyzed by 4-anisaldehyde

Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas

• Zhenghui Liu,
• Peng Wang,
• Zhenzhong Yan,
• Suqing Chen,
• Dongkun Yu,
• Xinhui Zhao and
• Tiancheng Mu

Beilstein J. Org. Chem. 2020, 16, 645–656, doi:10.3762/bjoc.16.61

• (PMP)), and solvents (N,N-dimethylacetamide (DMA), 1,3-dimethyl-2-imidazolidinone (DMI), N-methyl-2-pyrrolidinone (NMP), tetrahydrofuran (THF), 1,4-dioxane, ethanol, methanol, acetonitrile, and toluene) together with aryl iodides and other reagents were purchased from commercial sources (namely J&K

• ethanol (60 mL) and triphenylphosphine (10 mmol) was put in an oil bath at 70 °C under a nitrogen atmosphere. Then, hydrated rhodium(III) chloride (1.5 mmol) dissolved in anhydrous ethanol (10 mL) was added to the solution under stirring and the resulting solution was kept at gentle reflux for 2.5 h

Copper-catalyzed O-alkenylation of phosphonates

• Nuria Vázquez-Galiñanes,
• Mariña Andón-Rodríguez,
• Patricia Gómez-Roibás and
• Martín Fañanás-Mastral

Beilstein J. Org. Chem. 2020, 16, 611–615, doi:10.3762/bjoc.16.56

• products. An acetal-protected aldehyde could also be used providing enol phosphonate 3g in 52% yield. In this case, prolonged reaction times led to partial evolution of 3g into enol ether 4. This transformation may be explained by an acid-mediated elimination of ethanol likely caused by trace formation of

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• and selectivity, and mono- and bistriazole products were formed using a very low amount of the catalyst 36 and sodium ascorbate in a mixture of water and ethanol as the solvent system at room temperature, with good to high yields being achieved within short reaction times (Scheme 6). Furthermore

• a reducing agent in a mixture of water and ethanol as the solvent at 85 °C. In continuation, bistriazoles have been produced using 0.4 mol % of 45 and 10 mg sodium ascorbate as a reducing agent in an ethanol/water mixture at 85 °C. All triazole products were produced in good to high yield (Scheme 7

• silica nanoparticles containing ionic liquid (SNIL, 63) were centrifuged, washed with ether, and dried. The SNIL (63) were treated with Cu(OTf)2 in ethanol as a solvent at reflux for one day. Finally, this solid material was centrifuged, washed with methanol, and dried to produce the catalyst SNIL–Cu(II