Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• ), 0.1 M, 135 h at rt, 43%, (b) 1.5 equiv mCPBA, 3.0 equiv TfOH (at 0 °C), (DCM), 0.1 M, 20 h at rt, 85%, (c) 1.0 equiv NaBArF24, (acetone), 0.5 M, 2 h at 50 °C under microwave irradiation, 72%. Gold(I)-catalyzed cyclization of propargylic amide 11 as benchmark reaction for Au–Cl activation. Determined

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• synthesis, the deprotected derivatives such as 69 are desired for the synthesis of natural products. Therefore, an easy-to-perform two-step deprotection procedure was developed that is based on methylation of the phenolic hydroxy group with an excess of MeI in acetone at rt (68), followed by oxidative

Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers

• Andreas Wiest and
• Pavel Kielkowski

Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199

• or scale down and partially automatize the protocol or both. The standard mass spectrometry-based chemical proteomics workflow requires up to 1 mg of total protein, acetone protein precipitation after the ‘click’ reaction to remove the excess of the biotin-containing reagent, desalting of the

• probe–proteins enrichment [94]. The underlying and unifying advantage of these protocols is the use of a mixture of hydrophilic and lipophilic carboxylate-coated magnetic beads to replace the protein acetone precipitation after CuAAC. After the ‘click’ between the probe–protein conjugates and affinity

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• flash column chromatography. In between reactions, the tin electrodes were rinsed with DI water and acetone, then polished using diamond polish. This helped prevent buildup on the electrode surfaces. General C/C procedure with TBAB/EG To a 10 mL ElectraSyn 2.0 vial containing a magnetic stir bar were

• sulfate, filtered, and the solvent removed in vacuo to afford the crude product, which was first analyzed by 1H NMR spectroscopy and then purified using flash column chromatography. The graphite electrodes were not polished in between reactions, but were rinsed with DI water and then acetone. General Sn

• column chromatography. The electrodes were washed with DI water and acetone before polishing. General C/C procedure with CC/EG To a 10 mL ElectraSyn 2.0 vial containing a magnetic stir bar were added the carbonyl compound (0.5 mmol), allyl bromide (0.6 mmol), CC/EG DES (2 mL), and 10% DI water (0.2 mL

Heterocycle-guided synthesis of m-hetarylanilines via three-component benzannulation

• Andrey R. Galeev,
• Maksim V. Dmitriev,
• Alexander S. Novikov and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2024, 20, 2208–2216, doi:10.3762/bjoc.20.188

• situ-generated acetone imines in a (3 + 3) manner to afford meta-substituted anilines (Scheme 1C) [53][54]. Various EWGs (ester, carbamoyl, ketone, trifluoromethyl) have been successfully employed which motivated us to evaluate other possible EWGs. Results and Discussion Based on the fact, that many

• 2356151). No significant improvement in the yield was observed by varying the reaction conditions. Surprisingly, the reaction of 1,3-diketone 1a, morpholine and acetone without the use of molecular sieves and acid catalysis (conditions A) resulted in 81% yield of meta-substituted aniline 3ab. Applying the

• of acetone and amines 2 leads to the formation of acetone imine/enamine (reaction 1, Scheme 6). Nucleophilic addition of an enamine to the most electron-deficient carbonyl group (C1=O, adjacent to the EWG) of the 1,3-diketones 1 gives the acyclic carbinol I (reaction 2, Scheme 6), followed by the

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• cytotoxic effects but showed no activity. A number of natural products seem to be produced by reaction of altenuene diastereomers (or of related compounds) with C3 building blocks, i.e., with lactic acid, pyruvic acid, or with acetone (Figure 17). Alternatain D (65) was isolated from Alternaria alternata

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• to a mixture of 60 mL acetic acid and 30 mL concentrated HCl, then the reaction mixture was stirred for 16 h at 100 °C. The creamy precipitate (4.7 g, 80%) was obtained after pouring the reaction mixture into crushed ice, washed with water, acetone and dichloromethane (DCM), then dried under vacuum

Novel oxidative routes to N-arylpyridoindazolium salts

• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

• diaryldihydrophenazine was increased (10%). Thus, protonation completely suppressed the intramolecular cyclization route. Heterocyclic salts S1–S3 were obtained as amorphous solids, soluble in polar solvents (acetonitrile, DMF, acetone) and chlorinated hydrocarbons (CHCl3, CH2Cl2). The structure of new N

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• /ketalization cascades of generated (S)-34 proceeded predominantly, achieving the chemoenzymatic total synthesis of trichodimerol (2) in 27% yield from 33. In contrast, the use of acetone as the co-solvent resulted in the homodimerization of (S)-34 via Diels–Alder reaction between the cyclohexadienone moieties

Mining raw plant transcriptomic data for new cyclopeptide alkaloids

• Draco Kriger,
• Michael A. Pasquale,
• Brigitte G. Ampolini and
• Jonathan R. Chekan

Beilstein J. Org. Chem. 2024, 20, 1548–1559, doi:10.3762/bjoc.20.138

• (sodium (2,4-dinitro-5-fluorophenyl)-ʟ-alaninamide) in acetone were added. The reaction mixture was incubated at 40 ºC for 1 h with periodic agitation. The reactions were quenched by adding 10 µL of 2 M HCl and dried under a nitrogen stream. Dried samples were dissolved in 1.7 mL of MeOH and injected both

• . Afterward, 25 µL of water, 10 µL of 1 M NaHCO3 and 50 µL of 1% Marfey’s reagent in acetone were added to the reaction vial. The reaction was incubated for 1 h at 40 ºC with periodic agitation. The reaction was quenched by adding 5 µL of 2 M HCl and dried under a nitrogen stream. The dried peptides were

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• compound in anhydrous MeOH (≈10 mL per mmol) was added dropwise AcCl (1.0–3.0 equiv) at 0 °C, slowly warmed to rt, and stirred overnight. After the reaction was completed (TLC monitoring), the mixture was evaporated to dryness under reduced pressure. The residue was dissolved in MeOH, acetone was added

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• carbonyl compounds, such as dimethyl acetone-1,3-dicarboxylate and 1,3-diphenylacetone, and with 1,3-bis(silyloxy)-1,3-butadienes, electroneutral equivalents of 1,3-dicarbonyl dianions, allow for a convenient synthesis of a great variety of products. The regioselectivity and course of the reaction depends

• ) allow for the synthesis of complex products with formation of several bonds in only one step [1][2][3][4][5]. In contrast to non-activated acetone (1a), methylene-active compounds, such as 1,3-dicarbonyl compounds, are of considerable relevance as building blocks in domino reactions (Scheme 1). For

• example, methyl acetoacetate (2a) possesses one CH-acidic methylene carbon which can be deprotonated in equilibrium by weak organic bases, such as triethylamine, piperidine or DBU, under thermodynamic conditions. Dimethyl acetone-1,3-dicarboxylate (3a) contains even two reactive methylene groups which can

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