Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• was then dissolved in acetic acid/ethanol 1:1 and treated with ten equivalents of ammonium acetate, stirred overnight at a temperature of 75 °C. Work-up followed by chromatographic column purification of the reaction mixture furnished (+)-euphococcinine (2) in 91% yield. This single step procedure

Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

• Daria I. Tonkoglazova,
• Anna V. Gulevskaya,
• Konstantin A. Chistyakov and
• Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

• alternating enantiomers form a screw along the a axis. Optical properties All helicenes 10 are well soluble in dichloromethane and chloroform. Solubility in other common solvents such as acetonitrile, DMSO, tetrahydrofuran, ethanol and hexane is markedly lower. Carbazole-based [6]helicene 12 was described as

An atom-economical addition of methyl azaarenes with aromatic aldehydes via benzylic C(sp³)–H bond functionalization under solvent- and catalyst-free conditions

• Divya Rohini Yennamaneni,
• Vasu Amrutham,
• Krishna Sai Gajula,
• Rammurthy Banothu,
• Murali Boosa and
• Narender Nama

Beilstein J. Org. Chem. 2020, 16, 3093–3103, doi:10.3762/bjoc.16.259

• synthesis of 1-phenyl-2-(2-pyridyl)ethanol and 1-phenyl-2-(2-pyridyl)ethene under catalyst- and solvent-free conditions. Despite the low yield of the product of around 4%, this work described crystallographic data and the influence of reaction conditions such as the temperature and the reaction time on the

• stability of 1-phenyl-2-(2-pyridyl)ethanol [32]. Different catalysts such as ionic liquids [33], CuFe2O4 [34], and Ca(OTf)2 [35] were also utilized. Due to the abundant importance of these products, several different approaches were reported (Scheme 1 and Scheme 2). These higher azaarene products were also

Deoxyfluorination of acyl fluorides to trifluoromethyl compounds by FLUOLEAD^®/Olah’s reagent under solvent-free conditions

• Yumeng Liang,
• Akihito Taya,
• Zhengyu Zhao,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2020, 16, 3052–3058, doi:10.3762/bjoc.16.254

• sealed and the reaction mixture stirred at 70 °C for 24 h. Then the mixture was cooled to room temperature and ethanol (3.0 mL) was added to the mixture while stirring for an additional 30 min at room temperature. The mixture was then added to 1 M aqueous NaHCO3 (3 mL) at 0 °C, extracted with Et2O (3 × 5

Chiral anion recognition using calix[4]arene-based ureido receptors in a 1,3-alternate conformation

• Tereza Horáčková,
• Jan Budka,
• Vaclav Eigner,
• Wen-Sheng Chung,
• Petra Cuřínová and
• Pavel Lhoták

Beilstein J. Org. Chem. 2020, 16, 2999–3007, doi:10.3762/bjoc.16.249

• the nitro groups or (ii) concomitant reduction of the nitro groups and the allyl moieties. Thus, the reaction of 4a with SnCl2∙2H2O in ethanol gave the corresponding amine 5 in 57% yield after column chromatography on alumina. On the other hand, the four-day stirring of 4a with Pd/C under a H2

Regioselective synthesis of heterocyclic N-sulfonyl amidines from heteroaromatic thioamides and sulfonyl azides

• Vladimir Ilkin,
• Vera Berseneva,
• Tetyana Beryozkina,
• Tatiana Glukhareva,
• Lidia Dianova,
• Wim Dehaen,
• Eugenia Seliverstova and
• Vasiliy Bakulev

Beilstein J. Org. Chem. 2020, 16, 2937–2947, doi:10.3762/bjoc.16.243

• have found that 1-butyl-1,2,3-triazole-4-carbothioamide (1c) reacts well with benzenesulfonyl azide (2c) in various solvents to form the desired 1-butyl-1,2,3-N-sulfonyl amidine 3n in diverse solvents such as n-butanol, n-propanol, toluene, ethanol, water and even under solvent-free conditions (see

• azide (2c) neither in water, ethanol nor in the absence of a solvent, conditions that were successfully used in the synthesis of 1-alkyl-1,2,3-triazole-4-N-sulfonylimidamides 3a–s (Scheme 2). On the other hand, we have found the formation of a new product 3t in low yield together with the starting

Three-component reactions of aromatic amines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal to access N-(hetero)aryl-4,5-unsubstituted pyrroles

• Wenbo Huang,
• Kaimei Wang,
• Ping Liu,
• Minghao Li,
• Shaoyong Ke and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2920–2928, doi:10.3762/bjoc.16.241

• solvent on the model reaction was also examined. Anhydrous ethanol, acetonitrile, toluene, and DMSO did not bring any improvement with respect to the yield of 4a (Table 1, entries 8–11). The decrease of the catalyst loading from 10 to 5 mol % resulted in a slight decrease of the reaction yield (Table 1

Synthesis of imidazo[1,5-a]pyridines via cyclocondensation of 2-(aminomethyl)pyridines with electrophilically activated nitroalkanes

• Dmitrii A. Aksenov,
• Nikolai A. Arutiunov,
• Vladimir V. Maliuga,
• Alexander V. Aksenov and
• Michael Rubin

Beilstein J. Org. Chem. 2020, 16, 2903–2910, doi:10.3762/bjoc.16.239

• flasks equipped with reflux condensers and magnetic stir bars. All reactions were followed by thin-layer chromatography (TLC) using Silufol UV-254 plates, which were visualized under UV light (254 nm), with acetone, hexane/acetone, or hexane/ethanol/acetone mixtures as eluent. Polyphosphoric acid (87

• (3.01 g, 10 mmol) in DMF (16 mL) was added potassium phthalimide (1.85 g, 10 mmol) in portions. The mixture was stirred at room temperature for 5 h. Then, water (30 mL) was added, and the formed precipitate was collected by filtration and washed with water. Recrystallization from ethanol afforded

• colorless crystals of intermediate 2-((6-bromoquinolin-2-yl)methyl)isoindoline-1,3-dione. This material (3.05 g, 8.3 mmol) was suspended in ethanol, and hydrazine hydrate (50%, 1.0 g, 10 mmol) was added. The reaction mixture was refluxed for 5 h and then cooled down to 0 °C. The precipitated phthalyl

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• –formaldehyde condensation reaction, and therefore equips the generated polymeric support with more sulfonic groups. The heterogeneous Cu catalyst (LS-FAS-Cu) was finally obtained through refluxing of LS-FAS with Cu(OTf)2 in ethanol, and the loading capacity of Cu was confirmed to be 0.92 mmol/g by means of ICP

One-pot multicomponent green Hantzsch synthesis of 1,2-dihydropyridine derivatives with antiproliferative activity

• Giovanna Bosica,
• Kaylie Demanuele,
• José M. Padrón and
• Adrián Puerta

Beilstein J. Org. Chem. 2020, 16, 2862–2869, doi:10.3762/bjoc.16.235

• reagents, in the amount of catalyst, and in the temperature as well as the effect of the chosen green solvents (Figure 1). Increasing the temperature did not significantly change the reaction yield or reduce the reaction time, while the presence of a green solvent, such as water or ethanol, negatively

• reaction was finished. The reaction mixture, obtained as a viscous oil, was filtered through a sinter funnel to remove any catalyst and washed using acetone, which was then evaporated in a rotary evaporator. The resultant crystals were then recrystallized using hot ethanol. The products were then

Selective recognition of ATP by multivalent nano-assemblies of bisimidazolium amphiphiles through “turn-on” fluorescence response

• Rakesh Biswas,
• Surya Ghosh,
• Shubhra Kanti Bhaumik and
• Supratim Banerjee

Beilstein J. Org. Chem. 2020, 16, 2728–2738, doi:10.3762/bjoc.16.223

• , was synthesized from pyrene-1-carbaldehyde (1) following a literature report [46]. In brief, pyrene-1-carbaldehyde (1) was first converted to pyren-1-ylmethanol (2) by reduction with sodium borohydride in ethanol [61] and this was followed by treating of 2 with PBr3 in toluene to furnish 3. Di(1H

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

• Lena Reinke,
• Julia Bartl,
• Marcus Koch and
• Stefan Kubik

Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219

• . Conditions: i) potassium phthalimide, DMF, 25 °C, 18 h, 67%; ii) 2,2'-dipicolylamine, K2CO3, KI, acetone, reflux 14 h, 50%; iii) N2H4⋅H2O, ethanol, 25 °C, 16 h, 56%; iv) (R)-lipoic acid, EDC⋅HCl, DMAP, CH2Cl2, 25 °C, 18 h, 52%. Minimum salt concentrations required to precipitate and to subsequently

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• filtrate was kept in a refrigerator at 4 °C overnight, the precipitate formed was filtered off and the filtrate was mixed with water/ammonia solution of Ba(OAc)2 that was stored at 4 °C overnight. The precipitate formed was centrifuged off, to the supernatant 5 volumes of ethanol added, and the mixture

• kept overnight in a refrigerator. The precipitate formed was filtered off, washed with ethanol, dried in vacuum under CaCl2 at room temperature to give Ara-1Pi (Ba2+) as white powder (244 mg, 96%; TLC: iPrOH/25% NH4OH/water, 11:2:5 (vol), Rf 0.30, development by heating). The NMR data were similar to

• reaction mixture (pH 8.0) was stored at 4 °C overnight. The precipitate formed was filtered off and the filtrate was evaporated to ca. 15 mL. Then, ethanol (75 mL) was added under stirring and the mixture was stored at 4 °C overnight. The precipitate formed was filtered off, washed with ethanol (2 × 15 mL

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• -(OAcG)6 exhibited good solubility in most organic solvents such as dichloromethane, chloroform, tetrahydrofuran, and DMSO, but it was insoluble in solvents like methanol, ethanol, and water. Compound TBTQ-(OAcG)6 was finally deacetylated with sodium methoxide in methanol to afford the desired six-fold

• dichloromethane/ethanol provided the pure product as pale-yellow solid (1.06 g, 1.71 mmol, 31%). Mp 197.3–197.4 °C; 1H NMR (400 MHz, CDCl3) δ 7.09 (s, 6H, HAr), 4.72 (dd, J = 3.7 Hz, J = 2.4 Hz, 12H, OCH2), 4.32 (s, 3H, Ar2CH), 2.53 (t, J = 2.3 Hz, 6H, C≡CH), 1.68 (s, 3H, CH3); 13C NMR (100 MHz, CDCl3) 147.87

A proposed sustainability index for synthesis plans based on input provenance and output fate: application to academic and industrial synthesis plans for vanillin as a case study

• John Andraos

Beilstein J. Org. Chem. 2020, 16, 2346–2362, doi:10.3762/bjoc.16.196

• metrics defined for biomass-based carbon chemicals using ethanol equivalent as a common basis: sustainability value of resource replacement, sustainability value of the fate of waste, and sustainability indicator [5][6][7]. Sikdar defined sustainability as the interplay of three domains: economic aspects

• plans of vanillin: (1) If ethanol is used as an input material then 10% of it was assumed to originate from renewable sources (i.e., biomass), if the publication is dated after 1990 since that is the approximate time frame when biofuels were made widely available in the market. (2) Water was considered

• -butyl ether (7.365), dichloromethane (7.129), methanol (5.426), and ethanol (4.773). The Lampman plan had the highest overall RSGI value of 112,106 kg/kg vanillin due to the high masses of impactful solvents employed to obtain 1 kg of vanillin product, namely, nitrobenzene, diethyl ether, and

Design and synthesis of a bis-macrocyclic host and guests as building blocks for small molecular knots

• Elizabeth A. Margolis,
• Rebecca J. Keyes,
• Stephen D. Lockey IV and
• Edward E. Fenlon

Beilstein J. Org. Chem. 2020, 16, 2314–2321, doi:10.3762/bjoc.16.192

• mL/1 mL/0.1 mL) with [(CH3CN)4Cu]PF6 and ascorbic acid (see Scheme S2 in Supporting Information File 1). After removal of the solvent, the cutting step was performed by heating the crude product with KOH in a water/THF/ethanol mixture to saponify the esters. The pH of the mixture was adjusted to

Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties

• Anka Utama Putra,
• Deniz Çakmaz,
• Nurgül Seferoğlu,
• Alberto Barsella and
• Zeynel Seferoğlu

Beilstein J. Org. Chem. 2020, 16, 2282–2296, doi:10.3762/bjoc.16.189

• having a free amino and strong donor-acceptor groups and a pyridin-2-yl moiety were synthesized by the base-catalyzed condensation of 2 with different aldehyde derivatives in ethanol, as depicted in Scheme 1. Further reactions of the dyes 3–7 with salicylaldehyde under basic conditions resulted in the

• 2 was published previously [31][32]. Dyes 3–7 were synthesized using 2 and the appropriate benzaldehyde. Equimolar (3 mmol) amounts of 2-(1-(4-aminophenyl)ethylidene)malononitrile (2) and the appropriate benzaldehyde derivative in 20 mL of ethanol were refluxed for 2 h. A colored solid formed for

• all dyes 3–7 which was collected by filtration and recrystallized from ethanol to obtain the pure dyes. ((E)-2-(1-(4-Aminophenyl)-3-(2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)allylidene)malononitrile) (3) Dark purple solid; yield: 64%; mp 236–238 °C; FTIR (cm−1): 3441, 3349, 3224, 2920

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• reaction was carried out by stirring in the presence of 4 Å molecular sieves for 6 h at room temperature [27]. The conjugate (Dex-1a, Scheme 1, route A) was precipitated from cooled ethanol (EtOH) and filtered. Then, the pink solid was suspended in ethanol and the suspension was placed in an ultrasonic

• bath (59 kHz, 5 min) and filtered. This protocol was repeated and then, the solid was washed over the filter with ethanol and dried under vacuum. The DMSO/EtOH mixture and the two serial ethanol washings were kept separated for further analysis (vide infra). The mechanochemical reaction was performed

• , route B) was precipitated from cooled ethanol (EtOH) and filtered. The resulting solid was suspended in ethanol and placed in an ultrasonic bath (59 kHz, 5 min) and filtered. This protocol was repeated, and the precipitate washed over the filter with ethanol and dried under vacuum. The DMSO/EtOH mixture

Lipophilicity trends upon fluorination of isopropyl, cyclopropyl and 3-oxetanyl groups

• Benjamin Jeffries,
• Zhong Wang,
• Robert I. Troup,
• Anaïs Goupille,
• Jean-Yves Le Questel,
• Charlene Fallan,
• James S. Scott,
• Elisabetta Chiarparin,
• Jérôme Graton and
• Bruno Linclau

Beilstein J. Org. Chem. 2020, 16, 2141–2150, doi:10.3762/bjoc.16.182

• derivatives is discussed, as well as that of the introduction of an isopropyl/cyclopropyl/oxetanyl group from 1-propanol and ethanol, which represents carbon extensions (volume increase). Results and Discussion Lipophilicity data and discussion The lipophilicities of the nonfluorinated E1 and F1 have not been

pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

• Goutam Ghosh and
• Gustavo Fernández

Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168

• thoroughly washed with DMF. Subsequently, a Kaiser test [23] was performed to monitor the deprotection step. A few resin beads were placed in a small vial and washed with ethanol, and then, two drops of each of the three solutions were added and heated to 100 °C for 4–6 min. The color change of the initially

A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates

• Olusesan K. Koleoso,
• Matthew Turner,
• Felix Plasser and
• Marc C. Kimber

Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165

• product was observed when ethanol was used as the nucleophile giving product 39 in 52% isolated yield. In contrast, isopropanol gave an inseparable mixture of the α- and γ-addition products, 40a/b in 33% isolated yield. As with the case for the formation of 19, all of the starting allenes were consumed in

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• pyridines via C–N, C–C, and C–S bond formations in a mixture of ethanol and H2O under ultrasound irradiation. The catalyst is characterized by XRD, FTIR, Raman spectroscopy, SEM, and EDAX analysis. The main advantages of this methodology include the wide substrate scope, cleaner reaction profile, short

• 1 and 2a in the presence of 5.0 wt % of the NDL in a mixture of ethanol and water 1:1 for 10 min under both conventional stirring and ultrasound irradiation. The obtained results are presented in Table 4. It was observed that the reaction proceeded with an improved yield of 3a (70–98%) by increasing

• . Conclusion An environmentally benign NDL catalyst was characterized and utilized as a heterogeneous catalyst for the synthesis of 2-aryl-1-arylmethyl-1H-benzo[d]imidazoles, dihydropyrimidinones/ -thiones, and 2-amino-4-(hetero)aryl-3,5-dicarbonitrile-6-sulfanylpyridines in a mixture of ethanol and H2O 1:1

Stereoselective Biginelli-like reaction catalyzed by a chiral phosphoric acid bearing two hydroxy groups

• Xiaoyun Hu,
• Jianxin Guo,
• Cui Wang,
• Rui Zhang and
• Victor Borovkov

Beilstein J. Org. Chem. 2020, 16, 1875–1880, doi:10.3762/bjoc.16.155

• set as a model reaction (Table 1). Screening of solvents indicated that chiral phosphoric acid 3 stereoselectively promoted this reaction in aprotic solvents (Table 1, entries 1–6), while in protic solvent, such as ethanol, the racemic product was obtained (Table 1, entry 7). To our pleasure, the

• prepared from ʟ-tartaric acid and ethanol. THF was freshly distilled after refluxing with Na, while SOCl2, pyridine, PCl3, and I2 were purchased and used directly. Commercially available starting materials were used without further purification if not specified otherwise. Chiral phosphoric acid 3 was

• the mixture after cooling to rt. The resulting solution was extracted with EA (20 mL × 3), dried, and concentrated. The residue was recrystallized from 80% ethanol (ethanol/H2O 4:1, v/v) to give 7.2 g of (2R,3R)-1. Yield 56%; mp 149–151 °C; [α]D25 +153.9 (c 0.5, CHCl3); 1H NMR (CDCl3, 400 MHz) δ 7.31

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• dissolved in anhydrous ethanol (8 mL), and pyridinium p-toluenesulfonate (PPTS, 286 mg, 1.14 mmol, 2 equiv) was added. The solution was stirred at 60 °C for 2.5 h. The reaction mixture (at rt) was poured into a separating funnel containing diethyl ether (40 mL) and brine (16 mL). The organic layer was dried

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

• Dalel El-Marrouki,
• Sabrina Touchet,
• Abderrahmen Abdelli,
• Hédi M’Rabet,
• Mohamed Lotfi Efrit and
• Philippe C. Gros

Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144

• reaction, using sodium ethoxide in ethanol, followed by the hydrolysis with concentrated sulfuric acid at a low temperature [56], leading to the corresponding new γ-diketones 5a–d in 61–87% yield (Scheme 2). Despite the efficiency of the Nef reaction, the diversity at the R1 position via this synthetic

• aprotic solvents, other than toluene (Table 1, entries 7 and 8), the reaction produced complex mixtures of degradation products, and using alcohols had a notable impact on the reaction contents. Indeed, going from ethanol to propanol, and thus increasing the refluxing temperature, led to the indolone 7b

• of the intermediately formed imine to the Michael acceptor (Scheme 3). We then investigated the synthesis of cinnoline derivatives by mixing the diketone 5a and hydrazine monohydrate under various conditions (Table 2). We first investigated the reactivity in ethanol, as a protic solvent, at room