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

Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin

• Anna R. Bockman and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2020, 16, 509–514, doi:10.3762/bjoc.16.46

• entirely unreactive under the typical reaction conditions. In this case the reaction required 3 h at 130 °C before product formation was observed. Interestingly, much like the improved results for serine, a β-hydroxy group dramatically overcame this issue for secondary amines, as 2-(methylamino)ethanol

• obtained from N-methylbenzylamine was found to be a near 1-to-1 mixture of rotamers, while product 9 from 2-(methylamino)ethanol appeared as a 2-to-1 mixture favoring the s-cis form. Another noteworthy entry from Table 2 was methyl 2-aminomethyl-5-furanoate (for 14). As the DBU amidation relies on an

• β-hydroxy group discussed previously. The 1-amino-2-propanol reacted faster than serine, likely due to a lack of α-substitution. The effect of the β-hydroxy group was again seen in the swift rate of 2-(methylamino)ethanol. This was in stark contrast to the effectively unreactive N-methylbenzylamine

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

• Qiao Lin,
• Shiling Zhang and
• Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

• investigated, and 88% yield of 2-(dibenzylamino)ethanol (6) was successfully produced in the presence of 2.0 equiv of K2CO3 in MeOH at room temperature for 24 h (Scheme 6). This result indicated that these types of 2-aminoethyl acetate products are useful building blocks for functionalized alcohols. Next, to

• -dihydrothiazole (0.5 mmol), benzyl bromides (1.0 mmol), I2 (1.0 mmol) in DMC (2 mL), at 80 °C, under air for 16 h. aWith chloromethyl derivative. Transformation of 2-aminoethyl acetate derivative to 2-(dibenzylamino)ethanol. Control experiments and 18O-labeling experiment. Control experiments with radical

Six-fold C–H borylation of hexa-peri-hexabenzocoronene

• Mai Nagase,
• Kenta Kato,
• Akiko Yagi,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37

• , diethyl ether, ethanol, CH2Cl2 and CHCl3. To compare the efficiency of the current method, the stepwise synthesis of 1 was also examined. The synthesis of hexaiodoinated HBC 3 was conducted through Scholl reaction according to a literature procedure [19]. The subsequent Miyaura–Ishiyama borylation [22

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• appropriate pyridine carboxaldehyde 143 in refluxing ethanol/magnesium sulfate solution. The targeted ferrocenylphosphine imines 144 were obtained in almost quantitative yield. The α-ferrocenylethyl(dimethyl)amine 141 can be synthesized from ferrocenylethanol using phosgene and subsequent treatment with

Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku,
• Nobuyasu Matsuura,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 297–304, doi:10.3762/bjoc.16.29

• . Microorganism Strain C5-9 was collected from a stony coral, Catalaphyllia sp., obtained from an aquarium vendor in Osaka, Japan. A piece of the coral specimen (ca. 1 g) was surface-sterilized by washing with 70% ethanol, followed by rinsing with sterile natural seawater. The coral piece was homogenized by

Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

• Xingyu Xu,
• Shiqing Huang,
• Zengyu Zhang,
• Lei Cao and
• Xiaoyu Yan

Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

• good yield (Scheme 1). The product 2-I was characterized by 1H NMR, 13C NMR, and high-resolution mass spectrometry. 2-I has a poor solubility in most organic solvents such as dichloromethane, trichloromethane, tetrahydrofuran, and ethanol. A single crystal of 2-I was obtained by slow diffusion of ether

Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

• Andreas H. Heindl and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

• switchable multistate photoswitches: previous [11][12] and present work. a) UV–vis spectra of tris(arylazo)benzenes 3a/3b in ethanol. b) Reversible photoisomerization of 3a and c) 3b using light of 365 nm wavelength to induce E→Z isomerization and of 448 nm wavelength for photochemical back-conversion

A green, economical synthesis of β-ketonitriles and trifunctionalized building blocks from esters and lactones

• Daniel P. Pienaar,
• Kamogelo R. Butsi,
• Amanda L. Rousseau and
• Dean Brady

Beilstein J. Org. Chem. 2019, 15, 2930–2935, doi:10.3762/bjoc.15.287

• , which further contributed to the increased yield of 5. Varying the amount of IPA resulted in lower yields and more complex product mixtures. Substitution of IPA with tert-butanol or ethanol resulted in significantly lower product yields and a more complex product profile, as observed by crude product 1H