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

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• . Chiral solvents The only report on asymmetric electrochemical reaction in chiral solvent was published by Seebach and Oei in 1975 [53]. The asymmetric photodimerization of acetone to pinacol was conducted using amino-ether DDB 54 as a chiral solvent. Under the optimized reaction conditions, this

Emission solvatochromic, solid-state and aggregation-induced emissive α-pyrones and emission-tuneable 1H-pyridines by Michael addition–cyclocondensation sequences

• Natascha Breuer,
• Irina Gruber,
• Christoph Janiak and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 2684–2703, doi:10.3762/bjoc.15.262

• , and 6g recorded in dichloromethane at T = 298 K. Absorption (top) and fluorescence (bottom) of compound 6c with variable solvent polarity (left to the right: toluene, ethyl acetate, acetone, DMF and DMSO, c(6c) = 10−4 M; λexc = 365 nm, handheld UV lamp). Absorption (solid lines) and emission (dashed

Acid-catalyzed rearrangements in arenes: interconversions in the quaterphenyl series

• Sarah L. Skraba-Joiner,
• Carter J. Holt and
• Richard P. Johnson

Beilstein J. Org. Chem. 2019, 15, 2655–2663, doi:10.3762/bjoc.15.258

• °C via a dry ice/acetone bath. TiCl4 (0.14 g, 0.65 mmol) was added dropwise via syringe and the reaction mixture was warmed to 0 °C via an ice/water bath and stirred for 1 h. The product was extracted with ethyl acetate (3x) and dried with Na2SO4. The crude product was purified by chromatography with

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• coverage of the grains. Extraction of the grains with acetone, followed by partitioning of the aqueous residue with EtOAc and defatting with hexane, provided an enriched extract of non-polar secondary metabolites. Fractionation by reversed-phase preparative HPLC (Figures S1 and S2 in Supporting Information

• individual flasks, and extracted with acetone (2 × 3 L). The combined extracts were evaporated under vacuum to produce an aqueous slurry (500 mL). The slurry was partitioned against ethyl acetate (2 × 2 L) and the ethyl acetate was reduced in vacuo to an oily residue. The residue was dissolved in methanol

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• receptors for fluoride anions. Experimental General methods and materials 1H NMR spectra were recorded at 400 MHz or 500 MHz and 13C NMR spectra were recorded at 100 MHz or 125 MHz. Chloroform-d (CDCl3), acetone-d6 ((CD3)2CO) and benzene-d6 (C6D6) were used as solvents and the solvent peak was employed as

Synthetic terpenoids in the world of fragrances: Iso E Super^® is the showcase

• Alexey Stepanyuk and
• Andreas Kirschning

Beilstein J. Org. Chem. 2019, 15, 2590–2602, doi:10.3762/bjoc.15.252

• assigned as C13H20O [10]. In an attempt to recreate this compound by condensation of acetone with citral (28) a compound with “a strange but not very characteristic odour” was formed, later named pseudoionone (29, Scheme 1). It turned out not to be suited for further investigations. However, after cleaning

Safe and highly efficient adaptation of potentially explosive azide chemistry involved in the synthesis of Tamiflu using continuous-flow technology

• Cloudius R. Sagandira and
• Paul Watts

Beilstein J. Org. Chem. 2019, 15, 2577–2589, doi:10.3762/bjoc.15.251

• suitable azidating agent undergoes a highly regio- and stereoselective nucleophilic substitution of allylic O-mesylate at the C-3 position affording azide compound 5 (Scheme 3). Nie and co-workers [19] reported the treatment of mesyl shikimate 4 with NaN3 (4 equiv) in aqueous acetone (Me2CO/H2O 5:1) at 0

• (Chemtrix) was used to optimise the synthesis of azide compound 5 from mesyl shikimate 4 using aqueous NaN3 (Figure 2). Initial studies had shown the same conversions in both acetone and acetonitrile as solvents. Although acetone is a greener solvent than acetonitrile [21][22], its use was accompanied with

• eventual microreactor blockage caused by a resulting precipitate from the acetone/aqueous NaN3 mixture. Fortunately, acetonitrile is also an acceptable green solvent [21][22]. Furthermore, acetonitrile has a higher boiling point than acetone which is desirable for high temperature reaction interrogation

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• the solvent polarity properties are listed in Table 1. The data points for the dipolar aprotic solvents acetonitrile, acetone and ethyl acetate and the nonpolar n-hexane, shown by filled circles in Figure 3a, lie along a straight line. From its slope of −7210 cm−1 and μg = 11.97 D the value of μe

• = 18.30 D is calculated. The fluorescence spectra of NR in the protic solvents ethanol and methanol are substantially shifted to the red (Figure 2a), although they possess similar f(ε) − f(n2) values compared to those for acetone and acetonitrile, respectively (Table 1). This effect is reminiscent of the

• , namely the points for dipolar acetonitrile, acetone, ethyl acetate and nonpolar n-hexane fit to a straight line (2), NR in other solvents exhibits again a stronger red shift due to specific and inductive solute–solvent interactions. In order to eliminate any scaling effect of the Onsager radius on the