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

• isolation Six Doriprismatica stellata nudibranchs (3.7 g wet weight), their egg ribbons (0.7 g wet weight) and pieces of the associated sponge (3.5 g wet weight) were separately frozen, crushed and ultrasonicated for a total of 3 minutes (30 s intervals) on ice, while submerged in a minimum of first acetone

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

• free imidazole (IMH) as byproduct and IM still able to form bonds (for example, with nucleophilic groups of active molecules) βNS-CDI was treated in two different ways: the first one entailed “hard” washing of the samples using acetone and PSE. Since acetone does not react by hydrolyzing the bond

• , as the amount of nitrogen after PSE using acetone dramatically decreased due to release of the IMH byproduct entrapped in the NS network. Furthermore, it could be stated that after about 8 hours, it was possible to eliminate almost completely both IMH and IM, using only water, from all nanomaterials

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

• during the silylation step (Table 4, entry 1). However, the result of the subsequent solvolysis of the thus formed trimethylsilyl ester 23, depended on the conditions applied. The exposure of 23 to acetone or methanol, gave only the expected product 24 (up to 24 h). However, when a mixture of methanol

• 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

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• phosphonates 15a–c to afford derivatives 8a–f in high yields (Table 1, entries 1–6). For the synthesis of pyrroles 8g,h (R1 = Ac), pyrroles 13c and 13e were subjected to condensation reactions at a higher temperature, with acetone as the nucleophile (instead the phosphonate 15) in the presence of KOH as the

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

• mixtures were poured into water, extracted with chloroform (3 × 50 mL) and dried over sodium sulfate. The compounds were purified by column chromatography using hexane as eluent and recrystallized from acetone. 9,9'-(5-(4-Phenylquinazolin-2-yl)-1,3-phenylene)bis(3,6-di-tert-butyl-9H-carbazole) (1

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• 0.1 M NaHCO3 solution (100 μL) was added to the dried hydrolysate of 1, as well as to the standard of ʟ- and ᴅ-proline (Pro). A solution of ʟ-FDLA in acetone (0.05 mg in 50 μL) was added to each reaction vial. Each vial was sealed and incubated at 50 °C for 3 h. To quench reactions, 2 M HCl (50 μL

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

• were synthesized through Wittig reactions and subjected to photochemical cyclization, in terms of obtaining the new annulated structures. As part of this study, the aldol reaction of the starting 2-substituted carbaldehyde with acetone was also performed, which produced the thieno-fused benzobicyclo

• the bicyclo[3.2.1]octadiene aldehyde 1 and acetone was conducted (Scheme 4). After purification of the reaction mixture the product 12 was obtained. The aim of this experiment was to obtain a system with an extended conjugation of the heteroaromatic moiety under mild conditions, while leaving the

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• calibrated photodiode and electroluminescence spectra were recorded with an Ocean Optics modular spectrometer [39]. Synthesis 2,7-Dibromo-10-ethyl-9,9-dimethyl-9,10-dihydroacridine (2). 2,7-Dibromo-9,9-dimethyl-9,10-dihydroacridine (0.7 g, 1.9 mmol) was dissolved in acetone (25 mL), tetrabutylammonium

• conditions: (a) bromoethane, KOH, tetrabutylammonium bromide, acetone, 60 °C, 1 h; (b) napthalen-1-ylboronic acid, 4-vinylphenylboronic acid or 4-fluorophenylboronic acid, K2CO3, PdCl2(PPh3)2, THF/H2O, 80 °C, 24 h. Thermal characteristics of acridan-based compounds 3–6. Electrochemical properties of compound

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• -aryltetrahydroisoquinoline, ketones, and ʟ-proline using a low PdTPFPP loading (Scheme 62) [97]. Zhang and co-workers demonstrated that the MOF-catalyst (UNLPF-12) can also be used for the Mannich reactions. The authors reported that the coupling between N-aryltetrahydroisoquinolines and acetone using visible light and

Synthesis of new asparagine-based glycopeptides for future scanning tunneling microscopy investigations

• Laura Sršan and
• Thomas Ziegler

Beilstein J. Org. Chem. 2020, 16, 888–894, doi:10.3762/bjoc.16.80

• in aqueous acetone according to literature procedures [22][23][24][25][26]. In the case of 2,3,4,6-tetra-O-acetyl-α-ᴅ-mannopyranosyl bromide, however, this procedure only resulted in a complete hydrolysis of the halogenose. Under optimized reaction conditions using Moyle’s procedure (2.1 equivalents

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

• -butyl ketone (1) yields acetone (4) and propylene (3). Reaction (2) of Scheme 1 refers to a type II intramolecular rearrangement of crotonaldehyde (5) to 3-butenal (7). The triplet state energy donors were quenched by diacetyl and cis-2-butene. In 1970, Cocivera and Trozzollo studied the photolysis of

• aldehydes and ketones were studied in the photografting of acrylic acids. In 1988, Allméar and co-workers, while studying the grafting of acrylic acid (34) onto high- or low-density polyethylene and polystyrene using benzophenone as the photoinitiator and acetone (4) as the solvent, observed that the

• grafting was possible even in the absence of benzophenone due to acetone (4), but at a slower rate [39]. Later, Kubota and co-workers found that acetone (4) could act as an efficient photoinitiator for photografting, in contrast to other aliphatic ketones [40]. In 2004, Wang and co-workers also observed

Preparation of 2-phospholene oxides by the isomerization of 3-phospholene oxides

• Péter Bagi,
• Réka Herbay,
• Nikolett Péczka,
• Zoltán Mucsi,
• István Timári and
• György Keglevich

Beilstein J. Org. Chem. 2020, 16, 818–832, doi:10.3762/bjoc.16.75

• 4 and 1 could be accomplished in a mixture of acetone and 2-PrOH. The 2-phospholene oxides 4 obtained were characterized by spectroscopic methods (see Supporting Information File 1 for details). Preparation of 3-methyl-2-phospholene oxides 4 under acidic conditions As the next step of this study, we

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

• ethyl acetate, followed by water and acetone. The CuO–GO composite was reused five times without noticeable loss of catalytic performance. The carbon-supported copper nanomaterial 96 (Scheme 21) was prepared by trapping copper species on carbon graphene and carbon nanotubes [84]. This catalyst was found

• heated at reflux for 18 h to obtain new nanoparticles. The resulting nanoparticles were magnetically collected and washed with toluene, methanol, and diethyl ether. These new nanoparticles were treated with caffeine (119) in dry acetone under reflux conditions for 48 h. The resulting nanoparticles 120

• were magnetically collected and washed with methanol and acetone. Finally, the nanoparticles Fe3O4@SiO2–caffeine–Cu(I) (121) were prepared by the reaction of the nanoparticles Fe3O4@SiO2–caffeine (120), CuI, and KOt-Bu in dry THF at rt for 12 h. The final nanoparticles 121 were magnetically collected

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

• , methanol and acetone. The reaction mixture containing 3 was obtained as a brown solid, which was used for the next reaction without further purifications. A 15 mL Schlenk tube containing a magnetic stirring bar and KOAc (48.0 mg, 0.489 mmol, 6.2 equiv) was dried by a heat gun, cooled to room temperature

Absolute configurations of talaromycones A and B, α-diversonolic ester, and aspergillusone B from endophytic Talaromyces sp. ECN211

• Ken-ichi Nakashima,
• Junko Tomida,
• Takao Hirai,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 290–296, doi:10.3762/bjoc.16.28

• in good agreement with those of 1 (Figure 3b), the absolute configuration of 2 was also assigned to be R. Single crystals of α-diversonolic ester (3) were obtained as colorless prisms by vapor diffusion with acetone/n-hexane, and single-crystal X-ray diffractometry determined the structure shown in

• 5 (1.52 g). The filtrate of F4 was separated by silica gel column chromatography with n-hexane/acetone (stepwise gradient, 3:1 and 2:1, v/v) to yield 3 (434.1 mg). F5 was purified by silica gel column chromatography with n-hexane/acetone (5:2) to yield 2 (31.7 mg). The CH2Cl2-soluble part of F8 was

• separated by silica gel column chromatography with n-hexane/acetone (2:1, v/v) to yield 4 (34.3 mg) and 6 (58.2 mg). Talaromycone A (1) Colorless plates (benzene/n-hexane). mp 176–179 °C; [α]D25 +18.4 (c 0.1, MeOH); 1H and 13C NMR see Table 1; UV (MeOH) λmax (log ε) 327 (3.68), 260 (4.24), 240 (4.39), 229

Synthesis and herbicidal activities of aryloxyacetic acid derivatives as HPPD inhibitors

• Man-Man Wang,
• Hao Huang,
• Lei Shu,
• Jian-Min Liu,
• Jian-Qiu Zhang,
• Yi-Le Yan and
• Da-Yong Zhang

Beilstein J. Org. Chem. 2020, 16, 233–247, doi:10.3762/bjoc.16.25

• , DCM, rt; (e) substituted 1,3-dimethyl-1H-pyrazol-5-ol, EDCI, DMAP, DCM, rt; (f) Et3N, acetone cyanohydrin, DCM, rt. Synthetic route of the title compound III. Reagents and conditions: (a) methyl chloroacetate, K2CO3, CH3CN, 65 °C; (b) K2CO3, H2O, 65 °C; (c) aqueous HCl solution (10%), rt; (d

• ) substituted 1,3-cyclohexanediones, EDCI, DMAP, DCM, rt; (e) substituted 1,3-dimethyl-1H-pyrazol-5-ol, EDCI, DMAP, DCM, rt; (f) Et3N, acetone cyanohydrin, DCM, rt. Synthetic route of the title compounds II. Reagents and conditions: (a) NaOH, TBAB, H2O, 100 °C; (b) concentrated HCl solution, rt; (c) methyl

• chloroacetate, K2CO3, CH3CN, 65 °C; (d) K2CO3, H2O, 65 °C; (e) aqueous HCl solution (10%), rt; (f) substituted 1,3-cyclohexanediones, EDCI, DMAP, DCM, rt; (g) substituted 1,3-dimethyl-1H-pyrazol-5-ol, EDCI, DMAP, DCM, rt; (h) Et3N, acetone cyanohydrin, DCM, rt. Chemical structures of title compound I and their

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• (Figure 1). To determine whether the observation of 19F–H5 coupling for coumarin 6 was a solvent dependent phenomenon, a comparison was made between the 1H and 1H-{19F} spectra in CDCl3 and acetone-d6. Splitting of the H5 signal was observed in both solvents (Figure 1) suggesting that the 19F–H5 coupling

• -fluorophenyl)coumarin (5 ,0.77 g, 3.0 mmol), dimethyl sulfate (0.76 g, 6.0 mmol) and K2CO3 (0.83 g, 6.0 mmol) was refluxed in acetone (20 mL) for 4 h. The reaction mixture was cooled to room temperature and and brine (50 mL) was added then extracted with ethyl acetate (3 × 40 mL). The organic layer was dried

• -{19F} spectrum in CDCl3 and 1H spectrum and 1H-{19F} spectrum in acetone-d6. 13C NMR spectra for coumarin 5 and 6; showing the splitting of the signal corresponding to C5. 19F,1H-HOESY NMR spectrum for coumarin 6 illustrating two through-space interactions. Superposition of single-crystal X-ray

The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• 18a–c. (i) SOCl2, reflux, 2 h; (ii) NH4SCN, acetone, reflux 40 minutes; (iii) acetone, reflux. Synthesis of amides. Part A: (i) SOCl2, reflux; (ii) KOCN, acetone, reflux; (iii) amines 3, 4, 8 and 9, acetone, reflux. Part B: (i) SOCl2, reflux; (ii) amine 4, acetone, reflux. Phase transition

Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

• Jucleiton J. R. Freitas,
• Queila P. S. B. Freitas,
• Silvia R. C. P. Andrade,
• Juliano C. R. Freitas,
• Roberta A. Oliveira and
• Paulo H. Menezes

Beilstein J. Org. Chem. 2020, 16, 168–174, doi:10.3762/bjoc.16.19

• were obtained in short reaction time, high yield and purity without the need of any solvent when allenylboronic acid pinacol ester was used, or using a minimal amount of acetone when potassium allenyltrifluoroborate was used. Keywords: boron compounds; microwave; propargylation; regioselectivity

• only low conversion (Table 4, entry 1). In order to find an appropriate and suitable solvent that could be used in small amounts to promote the reaction different solvents were screened and the best result was observed when a small amount of acetone was used, where 2a was obtained in 92% yield as a

• single regioisomer (Table 4, entry 2). Low conversions were observed when water or a 1:1 mixture of acetone and water was used in the reaction (Table 4, entries 3 and 4). The use of alcohols also gave the desired product in lower yields (Table 4, entries 5–7). Finally, when a less polar solvent was used

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

• Katarzyna Włodarczyk,
• Piotr Borowski and
• Marek Stankevič

Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11

• ketone, and the second is the formation of the adduct with acetone. For 17, the formation of β,γ-alkenylphosphine sulfide was not possible, whereas the transformation of 19 afforded mainly the α,β-unsaturated compound 35. DFT analysis of the C–O bond cleavage in the adducts analogous to I revealed two

Synthesis of C-glycosyl phosphonate derivatives of 4-amino-4-deoxy-α-ʟ-arabinose

• Lukáš Kerner and
• Paul Kosma

Beilstein J. Org. Chem. 2020, 16, 9–14, doi:10.3762/bjoc.16.2

• -configuration of the hexenitol unit was derived from the 3JC,P coupling constant (14.1 Hz), which was in good agreement with reported data [22][28]. Next, selective O-demethylation of the phosphonate diester was elaborated. Using sodium iodide in acetone afforded the mono-O-demethylated derivative 9 in 98

• 14 as the minor isomer in 17% yield. The HPLC-based purification step even allowed for further separation of the diastereomers on phosphorus of both compounds. Selective methyl ester cleavage of 12 and 14 – again using NaI in a minimum volume of acetone – was straightforward and furnished the octyl

Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

• Enrique A. Del Vigo,
• Carlos A. Stortz and
• Carla Marino

Beilstein J. Org. Chem. 2019, 15, 2982–2989, doi:10.3762/bjoc.15.294

• acceptors and donors. Model Galp 3,4-diol acceptors and data obtained with B3LYP. Synthesis of glycosyl acceptors 1α/β and 2α/β. a) BzCl, pyridine, 0 °C, 2 h; b) BF3·OEt2, MeOH, CH2Cl2, 4 h; c) SnCl4, MeOH, CH2Cl2, 20 h; d) NaOMe/MeOH, CH2Cl2, 0 ºC, 2 h; e) (CH3)2C(OCH3)2, p-TsOH, acetone, rt, 16 h; f) 50

Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• the cultures were then harvested. The fermented broths were separated from the mycelia by vacuum filtration, and were both subsequently extracted according to the procedure described by Phainuphong and co-workers [49]. The fungal mycelia were extracted with acetone, followed by EtOAc instead of MeOH

• from both strains were extracted with 4 L of EtOAc, giving dark brown oily residues, while their mycelia were extracted sequentially with acetone, followed by EtOAc to afford mycelial extracts as brown gum. They were all chemically profiled by HPLC–DAD–MS in order to optimize the chromatographic

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• temperature, it is also carried out in benign acetone as solvent and does not require any additional oxidant. It circumvents the additional prefunctionalization of the BQ step usually required for Pd cross-couplings [15], while also showing greater functional group tolerance than radical-based methods [16][17

• mg, 0.027 mmol, 15 mol %). Acetone (2.2 mL) was added and the reaction mixture was stirred for 18 h at rt. The crude mixture was directly adsorbed onto a silica gel column and purified using toluene as the eluent. Further purification using glass-backed silica plates with toluene as the eluent

• (29.9 mg, 0.09 mmol, 15 mol %). Acetone (7.2 mL) was added and the reaction mixture stirred for 48 h at 30 °C. The crude mixture was adsorbed directly onto a silica gel column and subsequent purification with DCM/petroleum ether/toluene, 1:1:0.1 to 2:1:0.1, v/v as the eluent yielded the title product 3

Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• isolation as well as biological and physicochemical characterization. Results and Discussion The fruiting bodies of the fungal specimen MUCL56074 were extracted with acetone and subsequently purified via preparative HPLC, which led to the isolation of five previously undescribed secondary metabolites, 1–5

• quantity of 9.8 g fruiting bodies were extracted using 500 mL of acetone overnight. Then, the extract was filtered and another 500 mL of acetone were added. This was extracted in an ultrasonic bath for 30 min. The extracts were combined and the solvent evaporated to afford 226 mg of crude extract

• control, respectively. HPLC–UV chromatogram of the extract from fruiting bodies of Skeletocutis sp. (detection wavelength λ = 190–600 nm). Chemical structures of compounds 1–6. Inhibition Leu-AMC hydrolysis. a) c (ʟ-Leu-AMC) = 100 µM. b) c (ʟ-Leu-AMC) = 50 µM. 1H and 13C NMR data for 1 (in acetone-d6) and