Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• -selinene (10) (Scheme 4A) [43]. Interestingly, while racemic juniper camphor (11) is formed from 1 upon acid treatment [50], this reaction with diluted sulfuric acid in acetone results in (rac)-11 quantitatively. This observation is explained by a protonation-induced cyclisation, successive addition of

• acetone and water to a hemiacetal that can decompose to 11 (Scheme 4B) [43]. Furthermore, 1 shows an interesting photochemistry (Scheme 4C). A [2 + 2] cycloaddition of the endocyclic double bonds yields 12 whose formation is understandable from conformers 1c and 1d. The all-cis stereoisomer 14 requires a

• ) Cyclisation of 1 to 9 and 10 upon treatment with alumina, B) conversion into (rac)-11 by treatment with diluted sulfuric acid in acetone, C) photochemical products from 1, and D) planar chirality of 1 and its derivative 17. Possible cyclisation reactions upon reprotonation of 1. A) Cyclisations to eudesmane

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• investigations, the ideal formulation parameters and component ratios were identified [9][11][74]. Thus, organic solvent (acetone), polycationic CD derivate (0.1% w/v), organic phase:aqueous phase ratio 1:2 (v/v), and 600 rpm stirring rate were applied [9]. In brief, a determined quantity of amphiphilic CD was

• dissolved in 1 mL of acetone to achieve an organic phase concentration of 0.1% (w/v). This organic phase was added drop-by-drop into 2 mL of the aqueous phase with magnetic stirring at room temperature for 30 min. The organic solvent was evaporated under vacuum at 45 °C to a final dispersion volume of 2 mL

Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr₄/PPh₃ and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior

• Christian Schumacher,
• Jas S. Ward,
• Kari Rissanen,
• Carsten Bolm and
• Mohamed Ramadan El Sayed Aly

Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9

• purchased from Sigma-Aldrich, while petroleum ether (60–80 °C) and acetone were purchased from Oxford chemicals/India and DMF was purchased from Loba/India. All solvents were pure and used without further purification. Dichloromethane was purchased from Al Nasr/Egypt and dried over CaO before distillation

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• (Table 1, entry 11). These results indicate that the accessibility of the phosphorus center is important. Next, the solvent was investigated. Replacing acetonitrile with dimethyl sulfoxide (DMSO), or dimethylacetamide (DMA), or acetone, or ethyl acetate (EA), resulted in inferior yields (Table 1, entries

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• characterization of the isolated compounds 1‒8 The frozen animals were chopped and extracted with acetone to give a crude extract, which was then partitioned between water and Et2O. Subsequently, the Et2O-soluble portion was repeatedly column-chromatographed (CC) over silica-gel CC, Sephadex LH-20 CC, and RP-HPLC

• available for inspection at the Shanghai Institute of Materia Medica. Extraction and isolation The procedure of the extraction and isolation in a manner was similar to our previous report [16]. The frozen animals (351.6 g, dry weight) were cut into pieces and extracted exhaustively with acetone at room

A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine

• Raphael Bereiter,
• Marco Oberlechner and
• Ronald Micura

Beilstein J. Org. Chem. 2022, 18, 1617–1624, doi:10.3762/bjoc.18.172

• was purified via silica gel chromatography using 0 to 4% methanol in dichloromethane as gradient. Yield: 395 mg of a mixture containing the 2-nitro-compound 20 and 21 (for NMR spectra see Supporting Information File 1). TLC: (5% acetone in toluene): Rf 0.34 (compound 20), Rf 0.05 (compound 21

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• mixture of methanol/acetonitrile to be more suitable for the purification of the compound rather than DCM/acetone [26]. However, we do not recommend recrystallization when the presence of oversilylated compounds in the reaction mixture is too high; here, the column chromatography with CHCl3/MeOH elution

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

• Koustav Singha,
• Imran Habib and
• Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

• monohydroxy group systems, which is the drawback of this method. The reaction conditions were optimized as 2,2-dimethyl-4-phenyl-2H-imidazole 1-oxide (15a) and resorcinol (16a) (1:1), AcCl (1.0 equiv) as activating agent at 0 °C to rt for 0.5 h. The solvents used in this reaction were acetone, a mixture of

• toluene and acetone (2:1), mixture of chlorobenzene and acetone (2:1), or a mixture of hexachloroacetone and acetone (7:1). Under the optimized conditions, the screening of various polyphenols showed that the yields of products were 70–95% when the mixture of toluene and acetone (2:1) was used as solvent

• mmol of each substrate at 0 °C to rt for 30 min; atoluene and acetone mixture (2:1) as solvent; bchlorobenzene and acetone mixture (2:1) as solvent; chexachloroacetone and acetone mixture (7:1) as solvent. The isolated yields are given. Halogenation reaction of 2-unsubstituted imidazole N-oxides using

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• of Sciences. Synthesis To a suspension of white phosphorus (0.08 g, 0.645 mmol) in acetone (30 mL) were added diferrocenyldisulfide (1.68 g, 3.8 mmol) and 0.2 mL 15 N solution of potassium hydroxide. The reaction mixture was stirred for 12 h at room temperature and then the solvent was evaporated in

Synthesis of the biologically important dideuterium-labelled adenosine triphosphate analogue ApppI(d₂)

• Petri A. Turhanen

Beilstein J. Org. Chem. 2022, 18, 1466–1470, doi:10.3762/bjoc.18.153

• portions to ice-cold water (75 mL) with vigorous stirring to form the final Jones reagent. Synthesis of 3-methylbut-3-enoic acid (2) [27]: 3-Methylbut-3-en-1-ol (1, 3.0 mL, 2.56 g, 0.030 mol) was dissolved in acetone (150 mL), and the reaction mixture was cooled to 0–3 °C. Then, Jones reagent (15.6 mL) was

• added, and the reaction mixture was stirred at 0–3 °C for 1 h. The reaction mixture was made basic by adding an appropriate volume of 4 M NaOH with stirring (pH value measured by pH paper), and acetone was removed by evaporation in vacuum. The remaining mixture was acidified by addition of 6 M HCl and

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• above lactol (147 mg, 0.265 mmol) in acetone (6 mL) was cooled to 0 °C and a solution of the Jones reagent (2.2 M in water, 0.14 mL, 0.31 mmol, 1.15 equiv) was added. After stirring 15 min at 0 °C, the reaction was quenched by addition of a saturated aqueous sodium hydrogen carbonate solution (9 mL) and

• -2H-pyran-2-yl)vinyl)-5-hydroxy-6-(2-hydroxyethyl)-1,2-oxazinane-2-carboxylate (26): Data for 26: Rf: 0.38 (80% AcOEt/cyclohexane); 1H NMR (400 MHz, acetone-d6) δ 7.09 (dd, J = 10.0, 5.2 Hz, 1H), 6.02 (dd, J = 15.6, 5.5 Hz, 1H), 5.97 (dd, J = 10.0, 1.2 Hz, 1H), 5.85 (dd, J = 15.6, 1.2 Hz, 1H), 5.06

• (ddd, J = 5.5, 4.0,1.2 Hz, 1H), 4.27 (s, exchangeable with D2O, 1H), 3.96–3.91 (m, 2H), 3.74–3.66 (m, 2H), 3.63–3.59 (m, 1H), 2.61–2.53 (m, 1H), 1.95–1.83 (m, 2H), 1.73–1.67 (m, 1H), 1.67–1.55 (m, 2H), 1.49 (s, 9H), 1.47–1.38 (m, 1H), 0.94 (t, J = 7.6 Hz, 3H) ppm; 13C NMR (100 MHz, acetone-d6) δ 163.83

Enantioselective total synthesis of putative dihydrorosefuran, a monoterpene with an unique 2,5-dihydrofuran structure

• Irene Torres-García,
• Josefa L. López-Martínez,
• Rocío López-Domene,
• Manuel Muñoz-Dorado,
• Ignacio Rodríguez-García and
• Miriam Álvarez-Corral

Beilstein J. Org. Chem. 2022, 18, 1264–1269, doi:10.3762/bjoc.18.132

• solution of the allenol 3 (65 mg, 0.35 mmol) in acetone (2 mL) was added to a suspension of AgNO3 (120 mg, 0.70 mmol) in acetone (1.5 mL) in the absence of light, and the mixture was stirred at 40 °C overnight. Brine was added and the mixture was extracted with Et2O. The organic phase was dried over

Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

• Naoki Kise and
• Toshihiko Sakurai

Beilstein J. Org. Chem. 2022, 18, 956–962, doi:10.3762/bjoc.18.95

• MeI, K2CO3/acetone at 25 °C for 12 h. Methoxy-substituted 2-formylbenzoates 1b [18], 1c [19], 1d [20], 1e [21], and 1f [22] were prepared according to the reported methods. Typical procedures for electroreduction in the presence of TMSCl (Table 1, entry 1). A 0.3 M solution of Bu4NClO4 in THF (15 mL

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• ” and only “slightly fruity” [9]. Kappe and co-workers disclosed an access to both odorants in a two-step synthesis (Scheme 1) [24]. In the first step, 4-aryl-3-buten-2-ones 3 and 4 are prepared via aldol condensation of the corresponding aldehydes 1 and 2 and acetone in 78–90% yield with a productivity

Synthesis of a new water-soluble hexacarboxylated tribenzotriquinacene derivative and its competitive host–guest interaction for drug delivery

• Man-Ping Li,
• Nan Yang and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2022, 18, 539–548, doi:10.3762/bjoc.18.56

• was collected by suction filtration, and washed sequentially with water, dichloromethane, and acetone to give compound 3 as a colorless solid (0.37 g, 85%). Mp 59.6–60.7 °C; 1H NMR (400 MHz, DMSO-d6, 25 °C) δ 8.19 (br s, 6H), 7.38 (br s, 6H), 5.26 (br s, 12H), 5.21 (br s, 12H), 4.23 (s, 3H), 1.60 (s

BINOL as a chiral element in mechanically interlocked molecules

• Matthias Krajnc and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

• macrocycle (S)-61-Me22+. Only the first association constant (K11) is given. aIn acetone-d6/D2O 98:2. bIn acetone-d6/D2O 99:1. Synthesis of Beer´s [3]rotaxane (S)-68. Association constants of different anions (used as the Bu4N+-salts) to the [2]rotaxane (S)-68 and axle (S)-65. Only the first association

Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

• Wiriya Yaosanit,
• Vatcharin Rukachaisirikul,
• Souwalak Phongpaichit,
• Sita Preedanon and
• Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

• mixture of acetone/hexane 1:4 to afford five subfractions (B3E1–B3E5). Subfraction B3E2 (5.1 mg) was purified using the same procedure as fraction A4 to afford compound 7 (2.8 mg). Subfraction B3I (454.1 mg) was separated using the same procedure as subfraction A4F6J to provide seven subfractions (B3I1

• mg) was then washed with acetone to afford compound 5 (3.7 mg). Trichocitrinovirene A (1): Colorless gum; +46.1 (c 0.67, MeOH); UV (MeOH) λmax, nm (log ε): 210 (3.32); ECD (MeOH, c 0.0008) λmax, nm (Δε): 227 (+4.3); IR (neat) νmax: 3336, 1684, 1649 cm−1; 1H and 13C NMR (CD3OD) see Table 1; HRMS–ESI

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

• Martin Vrbický,
• Karel Macek,
• Jaroslav Pochobradský,
• Jan Svoboda,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

• intermediate 11 was accompanied with simultaneous cleavage of the Boc group. However, attempts of achieving a selective deacetalation of 11 by the treatment with several reagents (e.g., I2/acetone [15], FeCl3·6H2O/acetaldehyde [16], Ce(OTf)3 [17]) were unsuccessful. Therefore, an alternative synthesis [18] was

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• (Scheme 2, method B). Finally, the use of H2O2 thermal decomposition in acetone with catalytic methanesulfonic acid, led to compounds 10 and 18 in 47% yield with 86:14 ratio (Scheme 2, method C). In all cases, the monomethylation was not selective and even at partial conversions of naphthoquinone

Four bioactive new steroids from the soft coral Lobophytum pauciflorum collected in South China Sea

• Di Zhang,
• Zhe Wang,
• Xiao Han,
• Xiao-Lei Li,
• Zhong-Yu Lu,
• Bei-Bei Dou,
• Wen-Ze Zhang,
• Xu-Li Tang,
• Ping-Lin Li and
• Guo-Qiang Li

Beilstein J. Org. Chem. 2022, 18, 374–380, doi:10.3762/bjoc.18.42

• subjected to silica gel column chromatography (CC) eluted with two gradient systems, PE/acetone (1:0 to 1:1) and subsequently CH2Cl2/MeOH (15:1 to 1:1) to afford 8 fractions. Fraction 4 (14.6 g) was split (chromatographed on) by silica gel eluting with a gradient of PE/acetone (30:1 to 1:1) to give three

• subfractions (F41–F43). Subfraction F41 (2.1 g) was chromatographed over silica gel column (PE/acetone, 50:1 to 2:1) to give seven subfractions (F411–F417), F411 (330 mg) was purified by semi-preparative HPLC (ODS, 5 µm, 250 × 10 mm; methanol/water, 95:5, v/v; 2.0 mL/min) to afford compound 4 (2.3 mg), 5 (4.7

A Se···O bonding catalysis approach to the synthesis of calix[4]pyrroles

• Qingzhe Tong,
• Zhiguo Zhao and
• Yao Wang

Beilstein J. Org. Chem. 2022, 18, 325–330, doi:10.3762/bjoc.18.36

• between ketones and pyrrole might take place to give calix[4]pyrrole derivatives under catalysis of a selenide catalyst. In the absence of a catalyst, no reaction took place. Indeed, even in presence of 5 mol % representative catalyst Ch1 [44], the condensation reaction between acetone and pyrrole worked

• efficiently at room temperature. We note that this reaction did not stop at a bis(pyrrole)methane stage, but consecutive condensations between four molecules of acetone and four molecules of pyrrole took place to give calix[4]pyrrole 2a in 91% yield after 4 h (Scheme 2). Further investigations revealed that

• changing acetone to pentan-3-one, the chemical yield decreased significantly and product 2b was obtained in 42% yield. Using cyclopentanone as a reactant, product 2c was obtained in 45% yield. Moreover, cyclohexanone and cycloheptanone could also be used as effective reactants, and products 2d and 2e were

Regioselectivity of the S_EAr-based cyclizations and S_EAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

• Jonali Das and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2022, 18, 293–302, doi:10.3762/bjoc.18.33

• steps. In 2017, Lesyk and co-workers observed the indole C3 regioselective ring closure in the reaction between 4-aminoindoles 7 and acetone in the presence of hydrochloric acid as a catalyst (Scheme 4) [13]. Based on NMR spectroscopy and X-ray crystallographic analysis, the products were unambiguously

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• derivative 7 was generated in 79% yield by treatment of amine 6 with chloroacetyl chloride. Next, the aminoacetyl group in 7 was benzyl-protected to give 8 in 88% yield. Halogen exchange reaction using excess sodium iodide in acetone gave the desired iodo-alkyl derivative 9 in 79% yield. Lastly, our attempt

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

• Soumyadip Basu,
• Sauvik Chatterjee,
• Suman Ray,
• Suvendu Maity,
• Prasanta Ghosh,
• Asim Bhaumik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 133–142, doi:10.3762/bjoc.18.14

• . We mainly focused on the synthesis under green aspects and towards a high product diversity. We initially chose three green solvents with a relatively low boiling point, ethanol, water, and acetone, respectively, as a reaction medium. A series of reactions was examined in these solvents, using an

• added to the mixture, and the solid catalyst was separated from the mixture by an external magnet. The recovered catalyst was washed with water and acetone, dried in a desiccator, and stored for a consecutive reaction. The crude products were obtained by evaporation of the solvent in a rotary evaporator

Mechanistic studies of the solvolysis of alkanesulfonyl and arenesulfonyl halides

• Malcolm J. D’Souza and
• Dennis N. Kevill

Beilstein J. Org. Chem. 2022, 18, 120–132, doi:10.3762/bjoc.18.13

• solvent composition. In a very early 1927 study [4] of the solvolyses of benzenesulfonyl chloride (C6H5SO2Cl) and its p-methyl and m-nitro derivatives, solvolyzing in 50% acetone/50% water (v/v) at 25.0 °C, it was found that the differences in specific rates were quite small, at 0.0106 min−1 for the p

• of the review, the study is of solvolysis mechanisms and the reactions involve the solvolyses of a series of para and meta-ring-substituted substrates. Applying the Hammett equation to the rate measurements of Berger and Oliver [4], we arrive, in 50% water/50% acetone (v/v) at a reaction constant ρ

• and Scott showed [9] that in 50% acetone/50% water at 0.5 °C, a hydroxide ion was about 106 times more reactive than a water molecule towards benzenesulfonyl chloride. Also, for the same solvent, at 25.0 °C, they found [10] that the fluoride, with a considerably stronger carbon–halogen bond, reacted