Total synthesis of the O-antigen repeating unit of Providencia stuartii O49 serotype through linear and one-pot assemblies

• Tanmoy Halder and
• Somnath Yadav

Beilstein J. Org. Chem. 2021, 17, 2915–2921, doi:10.3762/bjoc.17.199

• (TCCA) in aqueous acetone [51] resulting in compound 11. Treatment of compound 11 with trichloroacetonitrile and DBU in dry DCM resulted in the formation of the desired trichloroacetimidate donor 12 in 93% yield (Scheme 4). The first stage of the one-pot synthesis was carried out using donor 12 and

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• reported 2-chloropyridine reduced the product yield slightly to 60% [25]. The subsequent epoxidation of 9 with in situ-generated DMDO (a combination of oxone and NaHCO3 in acetone/water) provided isoxazolidinyl epoxide 10 in almost quantitative yield as a sole trans isomer (dr > 95:5). Finally, the acid

• -catalyzed hydrolysis of 10 with concentrated hydrochloric acid in acetone/water afforded diol 3 in excellent 93% yield. The crystallization of the crude product from a hexanes/CH2Cl2 mixture led to the preferential formation of the thermodynamically more stable 4,5-cis isomer (determined on the basis of a

• rt, 16 h, 68%; (c) oxone, NaHCO3, acetone/H2O 3:2, 0 °C to rt, 80 min, 99%; (d) HCl (37 wt % in H2O), acetone/H2O 4:1, 0 °C, 30 min, 93%. Synthesis of final pyrrolidines (±)-1 and (±)-2. Reagents and conditions: (a) vinyl-MgBr, CeCl3, THF, 0 °C to rt, 16 h, 73%; (b) Zn dust, AcOH, 40 °C, 24 h, 85

Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B

• Emmanuel T. Oluwabusola,
• Olusoji O. Adebisi,
• Fernando Reyes,
• Kojo S. Acquah,
• Mercedes De La Cruz,
• Larry L. Mweetwa,
• Joy E. Rajakulendran,
• Digby F. Warner,
• Deng Hai,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2021, 17, 2390–2398, doi:10.3762/bjoc.17.156

• nitrogen stream. The hydrolysates were treated with 1 M NaHCO3 solution (20 µL) and 1% solution of ʟ-FDAA (Marfey's reagent, 1-fluoro-2-4-dinitrophenyl-5-ʟ-alanine amide) in acetone (40 µL). The reaction mixtures were gently heated at 40 °C for 1 h, after which the solutions were neutralized by the

A visible-light-induced, metal-free bis-arylation of 2,5-dichlorobenzoquinone

• Pieterjan Winant and
• Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 2315–2320, doi:10.3762/bjoc.17.149

• reaction site) of the aryldiazonium salt were required to obtain significant conversion of the starting material. Changing the solvent to acetone significantly increased the reaction yield, while dichloromethane as a solvent only resulted in trace amounts of the product (Table 1, entries 2 and 3). Due to

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

• Tülay Yıldız,
• İrem Baştaş and
• Hatice Başpınar Küçük

Beilstein J. Org. Chem. 2021, 17, 2203–2208, doi:10.3762/bjoc.17.142

• 78% (Table 1, entry 2). The second-best yield was 65% when FeCl3·6H2O was used (Table 1, entry 1). Then the solvent was investigated. Toluene, methyl alcohol, ethyl acetate, THF, DMF, dichloromethane, chloroform, acetone, and acetonitrile were tested as solvents. As a result, it was determined that

Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)

• Tania Xavier,
• Sylvie Condon,
• Christophe Pichon,
• Erwan Le Gall and
• Marc Presset

Beilstein J. Org. Chem. 2021, 17, 2085–2094, doi:10.3762/bjoc.17.135

• route where the substituent was introduced prior to the protection step. Commercially available substituted malonic acids 9 were first protected with acetone under acid conditions [46], and the desired intermediates 7 were simply isolated after aqueous work-up, usually in good yields (Table 3). The

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli,
• Noureddine Chaaben,
• Kamel Alimi,
• Stefan Jopp and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 1629–1640, doi:10.3762/bjoc.17.115

• cooled to room temperature and concentrated to give a slurry. The residue was diluted with dichloromethane, neutralized with aqueous NaHCO3, and washed with brine. The organic layer was dried over anhydrous K2CO3 and concentrated to afford a yellow solid. It was recrystallized from acetone to give 2 as

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• complex (ʟ-proline-MCM-41-CuCl) was obtained by the reaction of ʟ-proline-MCM-41 with CuCl in acetone at mild temperature (Scheme 21) [51]. A possible mechanism for this reaction is shown in Scheme 22. Initially, copper(I)-substituted acetylide intermediate 70 is produced via the reaction of copper

Breaking paracyclophane: the unexpected formation of non-symmetric disubstituted nitro[2.2]metaparacyclophanes

• Suraj Patel,
• Tyson N. Dais,
• Paul G. Plieger and
• Gareth J. Rowlands

Beilstein J. Org. Chem. 2021, 17, 1518–1526, doi:10.3762/bjoc.17.109

• , 143.4, 137.0, 132.1, 131.0, 129.9, 129.3, 129.1, 69.6, 42.9, 34.5, 33.1, 31.1; 1H NMR (700 MHz, acetone-d6) δ (ppm) 7.45 (d, J = 7.9 Hz, 1H, H-13), 7.15 (dd, J = 1.6, 7.7 Hz, 1H, H-12), 6.70 (dd, J = 1.6, 7.7 Hz, 1H, H-15), 6.56 (dd, J = 1.7, 7.7 Hz, 1H, H-16), 6.47 (dd, J = 2.9, 10.0 Hz, 1H, H-5), 5.87

• , acetone-d6) δ (ppm) 186.8, 147.0, 146.6, 143.1, 137.7, 130.7, 130.0, 198.8, 194.4, 128.3, 128.3, 68.6, 43.2, 34.1, 32.8, 30.8; HRMS-EI m/z: [M + Na]+ calcd for C16H16O2Na, 263.1043; found, 263.1054; ESIMS (m/z): [M]+ 241, 224, 118, 104; IR: 3386, 2918, 2849, 1651, 1622, 1261, 1020, 829, 813 cm−1; mp: 206

Total synthesis of ent-pavettamine

• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2021, 17, 1440–1446, doi:10.3762/bjoc.17.99

• that the new route doubled the overall yield to 16% for a similar number of steps. The specific optical rotation for 4 of +28.1° in acetone was comparable to that obtained previously [1]. Single crystal X-ray analysis of compound 4 (Figure 3), further confirmed the identity and stereochemistry of the

• compound 9. Stereoselective reduction of intermediate 8 as key step towards intermediate 4. Reaction conditions: a) i) ZnCl2, rt, 2 h; ii) DIBALH, THF, −78 °C to rt, 2 h, 87%; b) TBAF, THF, 0 °C, 4 h, 87%; c) 5% p-TsOH, 2,2-dimethoxypropane, acetone, rt, 1 h, 86%. Synthesis of the C5 fragments from

Analogs of the carotane antibiotic fulvoferruginin from submerged cultures of a Thai Marasmius sp.

• Birthe Sandargo,
• Leon Kaysan,
• Rémy B. Teponno,
• Christian Richter,
• Benjarong Thongbai,
• Frank Surup and
• Marc Stadler

Beilstein J. Org. Chem. 2021, 17, 1385–1391, doi:10.3762/bjoc.17.97

• filtered and the supernatant extracted with 2% AmberliteTM XAD 16N (Rohm & Haas, Frankfurt a. M., Germany), subsequently resuspended in acetone and evaporated to dryness, resulting in 2.5 g of crude extract. This supernatant crude extract was filtered using a SPME StrataTM-X 33 u Polymeric RP cartridge

Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96

• reported procedure [35]. l-Indanone (1, 6.8 g, 51.4 mmol) was added 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 solid precipitate was obtained by pouring the reaction mixture into crushed ice, washing with water, acetone

• with CH2Cl2, acetone, and finally with ethyl acetate to give 11 (3.13 g, 92%) as a yellow solid. Synthesis of 2,7,12-tribromo-5,5,10,10,15,15-hexabutyl-10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene (5): Compound 11 (1.5 g, 2.59 mmol), dimethyl sulfoxide (20 mL), and potassium tert-butoxide (2.61 g

Icilio Guareschi and his amazing “1897 reaction”

• Gian Cesare Tron,
• Alberto Minassi,
• Giovanni Sorba,
• Mara Fausone and
• Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

• reported in 1874 and was synthesized by refluxing of a saturated solution of ammonia in acetone, but the structure of this trimer had not yet been established [39]. Guareschi obtained triacetonamine in high yield (>70%) by treatment of phorone (7), the trimer of acetone, with ammonia and established the

• Guareschi” [42]. Triacetonamine bears a certain similarity to tropinone (9), the heterocyclic core of tropane alkaloids, and the one-pot preparation from acetone and ammonia reminds of, and anticipates by two decades, the Robinson synthesis of tropinone and the Willstätter synthesis of the corresponding 2

• Zentralblatt summary. Additionally, ambiguities exist on the molecularity of the various reactions since Guareschi was often preparing β-aminocarbonyl derivatives in situ from the self-condensation of acetone and the aza-Michael trapping of mesityl oxide. This method works well only for acetone, while further

Photoinduced post-modification of graphitic carbon nitride-embedded hydrogels: synthesis of 'hydrophobic hydrogels' and pore substructuring

• Cansu Esen and
• Baris Kumru

Beilstein J. Org. Chem. 2021, 17, 1323–1334, doi:10.3762/bjoc.17.92

• mL acetone to remove the remaining vTA, then left in a fume hood for drying overnight. Pore substructuring of HGCM by photoinitiation: 100 mg as-prepared HGCM and certain amounts of patching monomer (consisting 10 mol % crosslinker) were added into a capped glass vial containing 2 g distilled water

A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry

• Marine Vallet,
• Filip Kaftan,
• Veit Grabe,
• Fatemeh Ghaderiardakani,
• Simona Fenizia,
• Aleš Svatoš,
• Georg Pohnert and
• Thomas Wichard

Beilstein J. Org. Chem. 2021, 17, 1313–1322, doi:10.3762/bjoc.17.91

• , 4 μL of ectoine at concentration 50 μM was pipetted onto a clean glass slide (washed with dH2O, acetone) and overlaid with 2 μL of a methanolic solution of the DHB matrix at a concentration of 4 mg mL−1. For a bacterial isolate, the sample was prepared from one colony smeared onto a glass slide and

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• flow reacting acetone with a wide range of aldehydes. In batch, acetone-based aldol reactions are typically performed under biphasic conditions by slow addition of the aldehyde to an acetone/NaOH mixture kept at low temperatures. Upon scale-up, this carries with it problems such as inefficient mixing

• , difficulty in maintaining the reaction temperature and the occurrence of greater amounts of acetone and aldehyde self-condensation/polymerisation. By adopting a flow protocol and using a Comet X-01 micromixer (with linear scalability), more efficient mixing was attained and less aldehyde self-condensation

• was evident (Scheme 3). Within the microreactor acetone was first deprotonated by merging with a 2.5 M sodium hydroxide stream at room temperature, then, after a residence time of just 45 seconds, the resultant enolate was introduced to a stream containing the aldehyde as a 5.5 M solution also in

Synthesis of multiply fluorinated N-acetyl-D-glucosamine and D-galactosamine analogs via the corresponding deoxyfluorinated glucosazide and galactosazide phenyl thioglycosides

• Vojtěch Hamala,
• Lucie Červenková Šťastná,
• Martin Kurfiřt,
• Petra Cuřínová,
• Martin Dračínský and
• Jindřich Karban

Beilstein J. Org. Chem. 2021, 17, 1086–1095, doi:10.3762/bjoc.17.85

• configuration. Thioglycosides 22–31, 34 and 36 were then hydrolyzed into the corresponding hemiacetals 37–48 using treatment with NBS in acetone/water (Scheme 4). To obtain the target fluoro analogs, the hemiacetals 37–48 were debenzylated and their azide group converted to an acetamide. Although palladium

Recent advances in palladium-catalysed asymmetric 1,4–additions of arylboronic acids to conjugated enones and chromones

• Jan Bartáček,
• Jan Svoboda,
• Martin Kocúrik,
• Jaroslav Pochobradský,
• Alexander Čegan,
• Miloš Sedlák and
• Jiří Váňa

Beilstein J. Org. Chem. 2021, 17, 1048–1085, doi:10.3762/bjoc.17.84

• . At first, they tested in situ-generated complexes of L14 and Pd(TFA)2 in methanol or acetone, but the reduction to catalytically inactive Pd(0) occurred faster. The reoxidation by Cu(BF4)2·6H2O led to the loss of enantioselectivity presumably because of the complexation of the bisoxazoline by Cu(II

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

• Soumyaranjan Pati,
• Renata G. Almeida,
• Eufrânio N. da Silva Júnior and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

• in the yield, the reaction was carried out in different solvents such as THF, EtOAc, toluene, DCM, 1,2-DCE, 2-MeTHF, isopropanol and acetone. Unfortunately, these attempts led to inferior results (Table 1, entries 5–12). Since, there was no further improvement in the yield, the conditions described

Total synthesis of pyrrolo[2,3-c]quinoline alkaloid: trigonoine B

• Takashi Nishiyama,
• Erina Hamada,
• Daishi Ishii,
• Yuuto Kihara,
• Nanase Choshi,
• Natsumi Nakanishi,
• Mari Murakami,
• Kimiko Taninaka,
• Noriyuki Hatae and
• Tominari Choshi

Beilstein J. Org. Chem. 2021, 17, 730–736, doi:10.3762/bjoc.17.62

• oxidation of tetrahydroquinoline 31 was examined. Following the evaluation of various reaction conditions [32][33][34], the best outcome was obtained upon treatment of 31 with KMnO4 and MgSO4 in an acetone–H2O solvent system [35]. Employing these conditions, trigonoine B (1) was obtained in 43% yield. The

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

Designed whole-cell-catalysis-assisted synthesis of 9,11-secosterols

• Marek Kõllo,
• Marje Kasari,
• Villu Kasari,
• Tõnis Pehk,
• Ivar Järving,
• Margus Lopp,
• Arvi Jõers and
• Tõnis Kanger

Beilstein J. Org. Chem. 2021, 17, 581–588, doi:10.3762/bjoc.17.52

• until further analysis. Synthesis of substrates 11β-Hydroxyandrost-4-ene-3,17-dione (2) To a stirred solution of cortisol (1, 1.2 g, 3.36 mmol) in a 1:1 mixture of EtOH and CH2Cl2 (23 mL), NaBH4 (51.2 mg, 1.35 mmol) was added in one portion at room temperature. After 2 h, acetone (5.8 mL) was added

• . The residue was chromatographed on silica gel with gradient 10% to 40% acetone in petroleum ether to give acetate 3 (213.2 mg, 93%) as pale yellow oil. [α]D20 +180.0 (c 0.58, CHCl3); 1H NMR (CDCl3, 400 MHz) δ 5.68 (d, J = 1.4 Hz, 1H), 5.47 (q, J = 3.1 Hz, 1H), 2.57–2.21 (m, 6H), 2.20–2.05 (m, 4H

• ) was added, after which this was mixed and extracted with EtOAc (5 mL). The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel with gradient 7% to 30% acetone in petroleum ether to give monoacetate 3 (151 mg, 52%) and

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• = Me, 85%; 3b R1 = iPr, 84%) were obtained by the direct alkylation of bromophthalazinone 2 with methyl or isopropyl iodide in the presence of K2CO3 in dry acetone as the solvent (conventional heating). In the similar way also the 2-aminoethyl lactams 3c (R1 = CH2CH2NMe2) and 3d (R1 = CH2CH2(morpholin

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

• Lucía Rossi-Fernández,
• Viviana Dorn and
• Gabriel Radivoy

Beilstein J. Org. Chem. 2021, 17, 519–526, doi:10.3762/bjoc.17.46

• lithium. The resulting solid was filtered under vacuum in a Büchner funnel and washed successively with water (10 mL) and acetone (10 mL). Finally, the solid was dried under vacuum (5 Torr). Catalytic test – typical procedure for olefin epoxidation To a vigorously stirred suspension of the CoNPs/MgO

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• allylic triflates 18 and 19, showing a significant solvolysis retardation with CF3-substituted substrates (Figure 3) [46]. These results are in accordance with an earlier study that revealed that 20 was unreactive in acetone/H2O 70:30, even over a period of 35 days at 50 °C [47]. Encouraged by these

• be observed in the case of a displacement–elimination mechanism. Promising results were first obtained during investigations conducted on CF3-substituted derivatives in SN1- and SN2-mechanism-based reactions (Scheme 23). A profound retardation effect for the solvolysis of 81 in acetone–H2O (SN1) with