Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• . We then established a robust protocol consisting of successive additions of acetone to the crude mixture, followed by careful rotaevaporation. This procedure gradually removes most of the methanol, allowing the sequential Jones oxidation step to take place without any significant losses (see

• , 1.0 equiv), aryldiazonium salt 2 (0.60 mmol, 2.0 equiv), Pd(TFA)2 (5 mol %), L1 (S)-PyraBox (6 mol %), ZnCO3 (0.15 mmol, 0.5 equiv), and MeOH (1.5 mL, 0.2 M) at 40 °C, 4 h; 2) 1.0 mL of the Jones solution 2.5 M, 6 mL of acetone/water 3:1 (v/v), 1.5 h. Isolated yields were calculated from an average of

• ), Pd(TFA)2 (5 mol %), L1 (6 mol %), ZnCO3 (0.15 mmol, 0.5 equiv), MeOH (1.0 mL, 0.3 M), 40 °C, 4 h. 2) 1.0 mL Jones solution 2.5 M, 6 mL of acetone/water 3:1 (v/v), 1.5 h. Isolated yields were calculated from an average of two runs. Enantiomeric ratio (er) determined by high-performance liquid

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• oxidation of alcohol 175 with Dess–Martin periodinane. Synthesis of cubane 166 was then achieved by [2 + 2] cycloaddition of enone 176 using acetone as the photosensitiser (to 177), the first Favorskii ring contraction (to 178), deketalisation, the second Favorskii ring contraction and esterification (to

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• did not afford the homopropargylic azide (Table 3, entry 3). While alkynyl-BF3K salts are usually well soluble in acetone, carrying the reaction in this solvent only afforded traces of the product (Table 3, entry 4). Ethyl acetate or ether solvents such as dioxane and THF led to similar or slightly

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• kept at room temperature for one hour. The reaction mixtures were concentrated in vacuo, dissolved in acetone, and then injected into a GC–MS system, Zebron ZB-WAX (30 m × 0.25 mm ID × 0.25 µm, Phenomenex), using He as the gas source at a flow rate of 1.41 mL/min. The initial temperature (120 °C) was

• Na2SO4 and concentrated in vacuo. The samples were redissolved in acetone, and then injected into the aforementioned GC–MS system. Determination of amino acid configuration by Marfey’s method A 100 µg portion of each compound (3–5) was hydrolyzed with 6 M HCl at 110 °C overnight. The lyophilized

• hydrolysates were dissolved in water (160 µL), and treated with saturated NaHCO3 (200 µL) and 1% ʟ-FDLA in acetone (160 µL). The mixtures were heated at 40 °C for 30 minutes, quenched with 1 M HCl (200 µL), and concentrated in vacuo. The residue was dissolved in DMSO (400 µL) and passed through a membrane

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• -tolualdehyde afforded the aldol product only with a moderate yield of 30%; however, the diastereo- and enantioselectivity was satisfactory. A similar result was obtained in the reaction of 4-nitrobenzaldehyde with acetone. The comparison of IV with 5-(S)-pyrrolidin-2-yl-1H-tetrazole shows that both proline

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts

• Andrew D. Gillie,
• Matthew G. Wakeling,
• Bethan L. Greene,
• Louise Male and
• Paul W. Davies

Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54

• (I) chloride in acetone led to the formation of the desired AImOxAuCl and AImOxCuCl metal chloride complexes 13 and 14, respectively (Scheme 2) [7]. The 1H NMR spectra of the resulting AImOx metal complexes show a loss of symmetry for the diisopropyl substituents, indicating restricted rotation about

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• polar solvent, acetone, significantly accelerated the cyclization process. Thus, one to three days were required to complete the 5-exo-tet cyclization process in the acetone/DBU system. The results of the syntheses carried out with the participation of various DAS 1 to obtain spirocyclic THFs are

• previously tested using 3-bromopropanol. When the reaction was carried out in a one-pot format, with the replacement of DCM by acetone, the desired product 5a could only be isolated in moderate yield (52%). In the case of preliminary isolation of the OH-insertion product 16a (flash chromatography), the

• cyclization step was more selective and the total yield of the desired product was higher. The 6-exo-tet cyclization of intermediate compounds 16 under the action of DBU in acetone at room temperature proceeded within a few minutes, which is much faster than in the case of compounds 14. This can be explained

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

• Rattiya Janthanom,
• Yuta Kikuchi,
• Hiroki Kanto,
• Tomoyasu Hirose,
• Arisu Tahara,
• Takahiro Ishii,
• Arinthip Thamchaipenet and
• Yuki Inahashi

Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44

• . Advanced Marfey’s analysis A volume of 20 µL of 1 M NaHCO3 was added to each 50 µL of the hydrolysate of the de-sulfurized derivative of 1 and 1 mM standard amino acids (ʟ- and ᴅ-alanine). Then, 50 µL of ᴅ-FDLA (10 mg·mL−1 in acetone) was added to the mixtures and mixed well (the color changed from yellow

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• CC on silica gel eluting with a CH2Cl2/MeOH gradient (from 200:1 to 100:1) and then by preparative TLC (plate: 20 × 20 cm, developing solvents: ether/acetone 2:1) to afford compound 4 (8.6 mg). Fr. 5.4 (538 mg) was separated by CC on Si gel and Sephadex LH-20 (MeOH), after that compounds 1 (12.5 mg

• –6.10). Then, compound 2 (13.7 mg) was isolated by CC on Si gel (CH2Cl2/MeOH, 250:1 to 50:1) and preparative TLC (plate: 20 × 20 cm, developing solvent: ether/acetone 2:1) from Fr. 6.3 (578 mg). Pseudallene A (1): colorless crystals (MeOH); mp 115–117 °C; [α]D25 +20.0 (c 0.4, MeOH); 1H and 13C NMR data

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• forms, for example, the pKa(DMSO) of acetone is ≈26.5, whereas the pKa(DMSO) of acetone enol is ≈18.2 [59]. Thus, assuming a similar difference in pKa values between 1a-keto and 1a-enol, we expect pKa(MeCN) of 1a-enol to be ≈18. On this basis, quinuclidine with pKaH(MeCN) ≈ 18.0–19.5, could also be an

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• clamps were formed, which led to a more complex recovery of the catalyst as firstly the water needed to be removed by decantation and next acetone was added so that the BIMs were dissolved and the nanoparticles could be retrieved with the use of a tiny magnet. All in all, while the iron oxalates

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• radical recombination between C(sp3) radical 152 and the corresponding iodine-centered radical which provides iodination product 153 (Scheme 31B). It is worth noting that the iodination product is formed exclusively when using acetone as the solvent (see compound 154 in scheme C) whereas in DMF a

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• -(5-fluoro-2,4-dinitrophenyl)-ᴅ-leucinamide) in acetone [14]. The samples were incubated for 1 h at 60 °C followed by neutralization with 100 μL of 2 N HCl. The HCl was removed by using N2 gas. Then, the samples were diluted by 2 mL of MeCN/H2O (1:1, v/v) solution, filtered with 0.22 μm filter and

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• after immersion in a 1:10 (v/v) mixture of 85% aq H3PO4 and 95% aq EtOH. 1H, 13C, and 19F NMR spectra of solutions in CDCl3 and acetone-d6 were recorded on a Bruker AVANCE-600 instrument at 600 MHz for 1H and 151 MHz for 13C or on a Bruker AM-300 instrument at 300 MHz for 1H, 75 MHz for 13C, and 282 MHz

• for 19F NMR. The 1H chemical shifts are given relative to the signal of the residual CHCl3 (δH 7.27) or acetone-d5 (δH 2.05), the 13C chemical shifts were measured relative to the signal of CDCl3 (δC 77.0) or acetone-d6 (δC 29.92). The 19F chemical shifts are given relative to the external signal of

• residue was purified by silica gel chromatography (column volume 140 mL, eluent EtOAc/petroleum ether 25:75) to give 6 as a colorless foam (1.06 g, 90%). [α]D23 −105.5 (c 1.0, CHCl3); Rf 0.58 (benzene/CH2Cl2/acetone 2:2:0.8); 1H NMR (300 MHz, CDCl3, δ, ppm, J, Hz) 1.31 (s, 3H, Me), 1.34 (s, 3H, Me), 2.21

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• concentrated under reduced pressure. Flash chromatography on silica gel (toluene→toluene/acetone, 7:3) yielded 5 as a gold-coloured syrup (7.83 g, 96%). Rf = 0.4 (toluene/EtOAc, 3:2); [α]D +67 (c 1.0, CHCl3); 1H NMR (500 MHz, CDCl3) δ 5.58 (d, J = 9.8 Hz, 1H, NH), 4.93 (d, J = 3.6 Hz, 1H, H-1), 4.77 (d, J

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• surrogate readilly unmasked under Hock cleavage conditions. The oxidative cleavage of this alkene would not only release the aldehyde group, but also volatile acetone originated from the traceless isopropylidene motif. Overall, a three-reaction process will thus be performed in one pot (Scheme 1c

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• CH2Cl2 (CD2Cl2, 1H = 5.32 ppm, 13C = 54.00 ppm), deuterated DMSO ((CD3)2SO, 1H = 2.50 ppm, 13C = 39.53 ppm), deuterated acetone ((CD3)2CO, 1H = 2.05 ppm, 13C = 29.84 ppm), or deuterated benzene (C6D6, 1H = 7.16 ppm, 13C = 128.39 ppm) were used as solvents and internal references. Chemical shift values

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• acetone using a bath-type sonicator and were put onto a copper grid with carbon mesh. To perform thermogravimetric analysis (TGA), a TG/DTA7300 instrument from SII Nano Technology Inc. was utilized. The DWCNT powder was preheated at 180 °C for ten minutes under vacuum and subsequently measured under

• ) analysis (CPS Instruments, CPS 24000UHR (CR-39)). The shape and size of the DWCNTs in dispersion were observed by settling them on a silicon substrate, washed with acetone, and exposed to UV light for 20 minutes using an ozone cleaner (Meiwafosis, PC-450 plus) via dip-coating. The structures of DWCNTs were

• , the glass slide was washed with acetone and then irradiated with UV light for a duration of 1 hour via an ozone cleaner (Meiwafosis, PC-450 plus). Later, the substrate was coated using a bar coater (OSG SYSTEM PRODUCTS Co., LTD, Select-Roller L60, OSP-10 (bar groove pitch: 0.2 mm, depth: 24 μm)) with

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• dried over Na2SO4. After evaporation of the solvent, the crude residue was purified by flash chromatography on silica gel using a mixture of chloroform/petroleum ether/acetone 9:12:0.4 as eluent. 2,6-Bis(3,6-di-tert-butyl-9H-carbazol-9-yl)-4-(4-(trimethylsilylethynyl)phenyl)pyridine-3,5-dicarbonitrile

• was purified by flash chromatography on silica gel with chloroform/petroleum ether/acetone 9:15:0.4 by volume. The product 8 was obtained as orange powder (172 mg, 20%). Mp > 200 °C; IR νmax (film): 2252, 2240, 1538, 1532, 1425; 1H NMR (400 MHz, CDCl3) 8.11 (d, J = 2.0 Hz, 8H), 7.93–7.80 (m, 8H), 7.73

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• (SiO2, hexane/acetone 1:3, Rf 0.85); mp 61–69 °C; −5.7 (c 1.00, CHCl3); IR (cm−1) νmax 2941, 2860, 1780, 1744, 1709, 1637, 1553, 1493, 1448, 1433, 1416, 1367, 1339, 1299, 1272, 1223, 1184, 1133, 1091, 1068, 1036, 1014, 998, 976, 956, 912, 49, 825, 783, 743, 718, 679, 654, 530, 425; 1H NMR (500 MHz

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• light irradiation at either 440 nm or 456 nm, and they occurred in acetone at room temperature, without the need for transition metals or organic dyes as photosensitizers. Interestingly, it was discovered that solvation played a vital role in the overall process. These findings shed light on the

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• (1.52 g, 3.02 mmol, 1 equiv) was dissolved in acetone (100 mL), followed by the addition of K2CO3 (4.17 g, 30.2 mmol, 10 equiv). After 30 min of stirring 1,5-dibromopentane (3.47 g, 15.1 mmol, 5 equiv) was added and the mixture was kept under reflux for 48 hours. Upon cooling, the compound was isolated

• added and the compound was extracted with DCM (3 × 50 mL). The combined organic phases were washed with water and brine, followed by drying over MgSO4. After solvent evaporation the compound was purified by column chromatography (silica, acetone/toluene = 1:6, Rf = 0.47) to afford a yellowish solid

• (0.69 g, 77%); mp 128–130 °C, Rf = 0.47 (silica, acetone/toluene = 1:6). 1H NMR (CD2Cl2, 600 MHz) δ 7.72 (t, 3J = 7.7 Hz, 1H, Hpyridine), 7.36 (d, 3J = 7.7 Hz, 2H, Hpyridine), 7.33 (d, 3J = 8.6 Hz, 4H, HAr), 6.96 (d, 3J = 8.6 Hz, 4H, HAr), 4.70 (d, 3J = 2.4 Hz, 4H, CH2 (propargyl)), 4.60 (s, 4H, CH2

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• considered ways to further enhance this activity. We first explored the effects of structural modifications to berberine itself. The cationic iminium within berberine and its derivatives is susceptible to nucleophilic attack [10][14]. Through use of an acetone enolate, as well as partial or full reduction by

• effects of each modification. It was found that the acetone adduct B9 and the partially reduced variant B10 were more potent, while the fully reduced variant B11 was significantly less active (Table 2). These results suggested the activity of B1 could be similarly altered by the same modifications to the

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• pyrazolone derivatives with N-thiophthalimides catalyzed by 1 mol % of chiral iminophosphorane organocatalyst was carried out under mild conditions [103]. Solvent control in the procedure can affect the yield of products due to the solubility of the catalysts. Various solvents, such as acetone, ethyl acetate

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• stereocenter. α-(Aminomethyl)acrylates 5–7 reacted smoothly at −33 °C within 2 h with Et2Zn in the presence of cyclohexanone to afford amino alcohols 18–20 in quite good yields (63–68%). Even better yields were obtained with enoates 8a and 8b both with cyclohexanone and acetone as carbonyl partners. Starting