Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• microscopic observation. Enzyme-linked lectin assays: 96-well microtiter Nunc-Immuno plates (Maxi-Sorp) were coated with PAA-GlcNAc (100 μL per well, diluted from a stock solution of 5 μg mL−1 in 50 mM carbonate buffer pH 9.6) for 1 h at 37 °C. The wells were then washed with T-PBS (3 × 100 μL per well, PBS

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• -Acetoxymethyl-substituted pyrimidine derivatives offer many options for the introduction of new substituents. For example the removal of the acetyl group by treatment with potassium carbonate in methanol and oxidation with Dess–Martin periodinane (DMP) converted PM61 and PM63 into aldehydes PM69 and PM71 in

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• trifluoride etherate (0.4 mL, 3.12 mmol) were injected by syringe. The mixture was stirred at 25 °C for 2 d. Thereafter, saturated aqueous sodium hydrogen carbonate (10 mL) was added and the mixture was extracted five times with 15 mL portions of dichloromethane. The combined organic layers were washed with

Cyclopropene derivatives of aminosugars for metabolic glycoengineering

• Jessica Hassenrück and
• Valentin Wittmann

Beilstein J. Org. Chem. 2019, 15, 584–601, doi:10.3762/bjoc.15.54

• Scheme 3. Alcohol 4 was activated with 4-nitrophenyl chloroformate, and the obtained carbonate 5 reacted with neutralized mannosamine and peracetylated as described above to give Ac4ManNCyoc(H2) in a yield of 57%. Deacetylation with N,N-ethyldimethylamine in methanol and further aldolase reaction and DMB

• for C19H27NO10, 452.1527; found, 452.1522. (2-Methylcyclopropyl)methyl (4-nitrophenyl) carbonate (5): 2-Methylcyclopropanemethanol (4, 0.57 mL, 5.81 mmol) was dissolved under nitrogen atmosphere in dry dichloromethane (80 mL) and dry pyridine (2.8 mL). The solution was cooled to 4 °C and 4-nitrophenyl

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• rather on the respective thermodynamic stability of the dihydro derivatives. Application of the dithionite reduction to the synthesis of 2,3,5-tri-O-acetyl- and 2,3,5-tri-O-benzoyl-D-β-1,4-dihydronicotinamide ribosides [19][31][35], their tripropionate, tri-n-butyrate, triisobutyrate, triethyl carbonate

Study on the regioselectivity of the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide

• Pedro N. Batalha,
• Luana da S. M. Forezi,
• Maria Clara R. Freitas,
• Nathalia M. de C. Tolentino,
• Ednilsom Orestes,
• José Walkimar de M. Carneiro,
• Fernanda da C. S. Boechat and
• Maria Cecília B. V. de Souza

Beilstein J. Org. Chem. 2019, 15, 388–400, doi:10.3762/bjoc.15.35

• treated with potassium carbonate followed by a dropwise addition of bromoethane, as the alkylating agent. This synthetic strategy provided exclusively the 1-ethylated product 7 with a good overall yield (80%, Scheme 1). Previous treatment of 5 with potassium carbonate promotes the establishment of an acid

• for the deprotonation reaction using potassium carbonate as a base. These results are in agreement with the analysis of the stability of the conjugate bases due to structural electronic effects. The oxoquinoline conjugate base presents a great stability, since it promotes a greater dispersion of the

• . Procedure for the preparation of N-benzyl-1-ethyl-4-oxo-1,4-dihydroquinoline-3-carboxamide (7) In a round bottom flask, 1.0 g (3,6 mmol) of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide (5), 1.4 g (10.1 mmol) of potassium carbonate and 10.0 mL of dimethyl sulfoxide (DMSO) were added and stirred at room

Chemical structure of cichorinotoxin, a cyclic lipodepsipeptide that is produced by Pseudomonas cichorii and causes varnish spots on lettuce

• Hidekazu Komatsu,
• Takashi Shirakawa,
• Takeo Uchiyama and
• Tsutomu Hoshino

Beilstein J. Org. Chem. 2019, 15, 299–309, doi:10.3762/bjoc.15.27

• : 181–184 °C. Preparation of the monoacetate and the tetraacetate This toxin (6.0 mg) was dissolved in 5 mL of a mixture (1:1) of CH3CN and 0.01 M carbonate buffer solution (pH 9.7), and then 1.5 mL of Ac2O was added. The reaction was carried out at room temperature for 6 h. Almost all of the toxin had

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• (cyclohexene carbonate)s was carried out by the β-diiminate (BDI) zinc-catalyzed block copolymerization of functionalized epoxides and CO2 with a norbornenyl-containing initiator (Scheme 5) [68]. The subsequent “grafting through” by ROMP of norbornene resulted in the synthesis of multiblock copolymer brushes

First synthesis of cryptands with sucrose scaffold

• Patrycja Sokołowska,
• Michał Kowalski and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2019, 15, 210–217, doi:10.3762/bjoc.15.20

• , 19.84; found: C, 58.12; H, 5.67; I, 19.79. Cryptand 11: To a solution of 10 (258 mg, 0.20 mmol) in acetonitrile (7 mL), powdered potassium carbonate (342 mg, 3.227 mmol, 16 equiv) was added, followed by aza-crown 8 (53 mg, 0.20 mmol, 1 equiv), and the mixture was stirred and boiled under reflux for 24 h

• , 27.32. Synthesis of cryptand 23: To a solution of 22 (118 mg, 0.09 mmol) in acetonitrile (15 mL), powdered potassium carbonate (270 mg, 2.55 mmol, 30 equiv) was added, followed by amine 15 (40 mg, 0.09 mmol, 1.1 equiv), and the mixture was stirred and boiled under reflux for 24 h (TLC monitoring

Systematic synthetic study of four diastereomerically distinct limonene-1,2-diols and their corresponding cyclic carbonates

• Hiroshi Morikawa,
• Jun-ichi Yamaguchi,
• Shun-ichi Sugimura,
• Masato Minamoto,
• Yuuta Gorou,
• Hisatoyo Morinaga and
• Suguru Motokucho

Beilstein J. Org. Chem. 2019, 15, 130–136, doi:10.3762/bjoc.15.13

• )-limonene-derived diol and its corresponding five-membered cyclic carbonate were prepared. The diol (cyclic carbonate) comprises four diastereomers based on the stereochemical configuration of the diol (and cyclic carbonate) moiety. By choosing the appropriate starting compounds (trans- and cis-limonene

• their characteristic signals. Keywords: cyclic carbonate; diastereomer; diol; limonene; NMR; Introduction (R)-Limonene (LM) is a naturally occurring terpene, and therefore a very attractive and renewable resource [1]. Its derivatives have versatilely and widely been studied [1][2][3][4]. Otherwise

• with triphosgene. Neither of the desired products 1b and 1c have been synthesised until now. When 2c was used, the carbonation proceeded smoothly to afford the corresponding carbonate 1c exclusively. The isolated yield after purification was moderate (58%). Conversely, the reaction of 2b was

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

• Anne Schnell,
• J. Alexander Willms,
• S. Nozinovic and
• Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

• shield. Then potassium carbonate (412 mg, 3.31 mmol, 2 equiv) was added and the mixture was refluxed for another 24 h. Hydrazine (587 µL, 9.93 mmol, 6 equiv) was added again and the mixture was refluxed for 1 h. When the mixture had cooled to room temperature 10 mL of dichloromethane were added. The

• . The mixture was stirred for another 3 h, after the solution of sodium nitrite had been added. 55 mL dichloromethane were added and the organic layer was washed twice with saturated sodium hydrogen carbonate solution and dried over magnesium sulfate. The solvents were evaporated and 340 mg of a pink

• , ingredients see below) in 186 mL deionized water was added dropwise to a 0 °C cold stirred solution of cyanuric acid (2.00 g, 15.50 mmol, 1 equiv), sodium hydroxide (1.86 g, 46.49 mmol, 3 equiv), sodium carbonate (2.46 g, 23.24 mmol, 1.5 equiv) and potassium bromide (5.53 g, 46.49 mmol, 3 equiv) in 223 mL

A simple and effective preparation of quercetin pentamethyl ether from quercetin

• Jin Tatsuzaki,
• Tomohiko Ohwada,
• Yuko Otani,
• Reiko Inagi and
• Tsutomu Ishikawa

Beilstein J. Org. Chem. 2018, 14, 3112–3121, doi:10.3762/bjoc.14.291

• potassium carbonate (K2CO3) are generally selected as the solvent and base, acetone can be replaced with dimethylformamide (DMF) if the starting phenol is poorly soluble in acetone. To our knowledge four reactions [37][38][39][40] were found in the literature as successful per-O-methylations of quercetin (2

Stereodivergent approach in the protected glycal synthesis of L-vancosamine, L-saccharosamine, L-daunosamine and L-ristosamine involving a ring-closing metathesis step

• Pierre-Antoine Nocquet,
• Aurélie Macé,
• Frédéric Legros,
• Jacques Lebreton,
• Gilles Dujardin,
• Sylvain Collet,
• Arnaud Martel,
• Bertrand Carboni and
• François Carreaux

Beilstein J. Org. Chem. 2018, 14, 2949–2955, doi:10.3762/bjoc.14.274

• configuration of the stereogenic center bearing the hydroxy group (Scheme 5). With this in mind, the secondary alcohol 23 was engaged in a Mitsunobu reaction using p-nitrobenzoic acid as nucleophile to afford the expected compound 25. Hydrolysis of the ester was achieved using potassium carbonate in methanol to

Green synthesis of new chiral 1-(arylamino)imidazo[2,1-a]isoindole-2,5-diones from the corresponding α-amino acid arylhydrazides in aqueous medium

• Nadia Bouzayani,
• Jamil Kraїem,
• Sylvain Marque,
• Yakdhane Kacem,
• Abel Carlin-Sinclair,
• Jérôme Marrot and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2018, 14, 2923–2930, doi:10.3762/bjoc.14.271

• conditions, we investigated the reaction in nontoxic solvents such as water and dimethyl carbonate (DMC). Indeed, DMC is well-known as safe reagent and solvent that has been used for many green applications [31][32][33]. On the other hand, water is a simply and environmentally benign solvent and interest has

Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate

• Eloi P. Coutant,
• Vincent Hervin,
• Glwadys Gagnot,
• Candice Ford,
• Racha Baatallah and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2853–2860, doi:10.3762/bjoc.14.264

• -hydroxyimino esters [23][24][25][26] and then extensively used to prepare a wide range of amino acids [3][27]. This proceeds via a [2 + 4] cycloaddition between ethyl nitrosoacrylate, generated in situ from the reaction of sodium carbonate and furan 48, to give the cycloadduct 49. Then, upon heating, a

• ) as a model substrate. It turned out that this [2 + 4] cycloaddition can proceed under a wide range of conditions. The original conditions stirring compound 47, an excess of 2-methylfuran (48af) and solid sodium carbonate in dichloromethane for 24 hours gave the expected cycloadduct 49af but we found

• phase transfer catalyst. For instance, (note b in Table 2), stirring a 1:1.1 proportion of compounds 47 and 48af, sodium carbonate, and 0.01 equiv tetrabutylammonium bromide in toluene for 1.5 hours led to a 42% yield of the α-hydroxyimino ester 2af. On the other hand, such catalysis was not required

DABCO- and DBU-promoted one-pot reaction of N-sulfonyl ketimines with Morita–Baylis–Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives

• Soumitra Guin,
• Raman Gupta,
• Debashis Majee and
• Sampak Samanta

Beilstein J. Org. Chem. 2018, 14, 2771–2778, doi:10.3762/bjoc.14.254

• useful synthons [72][73] in the presence of open atmosphere (Scheme 1b). Results and Discussion We have commenced the model reaction between cyclic N-sulfonyl imine 1a as interesting C,N-binucleophiles [74] and MBH carbonate of acrylate 2a using 20 mol % of DABCO in toluene at room temperature for 14 h

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• vacuum. The resulting brown solid material was named as graphene oxide (GO, 142). In continuation, a solution of 5% sodium carbonate was added to the sonicated GO (142) in deionized water so that the pH was increased up to 9–10. 64% hydrazine hydrate was added as well. Then, the reaction mixture was

Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid

• Jacqueline Pollini,
• Valentina Bragoni and
• Lukas J. Gooßen

Beilstein J. Org. Chem. 2018, 14, 2737–2744, doi:10.3762/bjoc.14.252

• including sustainable solvents like dimethyl carbonate and p-cymene. Unfortunately, this led to a decreased conversion and just 44–47% yield of the desired product. The use of the halogenated solvent dichloromethane was still most efficient. Comparative tests with varying amounts of 1-hexene revealed that

Assembly of fully substituted triazolochromenes via a novel multicomponent reaction or mechanochemical synthesis

• Robby Vroemans,
• Yenthel Verhaegen,
• My Tran Thi Dieu and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2689–2697, doi:10.3762/bjoc.14.246

• furnished both regioisomers in poor yields since the chromanones 7 and 8 are known to be unstable under the triazolization conditions [36]. Hence, no further attempts were made to improve these yields. Additionally, NH-triazole 9 could be alkylated using benzyl bromide and potassium carbonate in acetone

Quinolines from the cyclocondensation of isatoic anhydride with ethyl acetoacetate: preparation of ethyl 4-hydroxy-2-methylquinoline-3-carboxylate and derivatives

• Nicholas G. Jentsch,
• Jared D. Hume,
• Emily B. Crull,
• Samer M. Beauti,
• Amy H. Pham,
• Julie A. Pigza,
• Jacques J. Kessl and
• Matthew G. Donahue

Beilstein J. Org. Chem. 2018, 14, 2529–2536, doi:10.3762/bjoc.14.229

• ]. Isatoic anhydrides 9 are readily prepared from inexpensive, commercially available 2-aminobenzoic acid derivatives (anthranilic acids) with a variety of carbonyl transfer reagents such as phosgene, triphosgene, carbonyldiimidazole, or diethyl carbonate. We therefore employed a modified Coppola quinoline

Selective formation of a zwitterion adduct and bicarbonate salt in the efficient CO₂ fixation by N-benzyl cyclic guanidine under dry and wet conditions

• Yoshiaki Yoshida,
• Naoto Aoyagi and
• Takeshi Endo

Beilstein J. Org. Chem. 2018, 14, 2204–2211, doi:10.3762/bjoc.14.194

• fixation of CO2 such as cycloaddition of CO2 to various epoxides and synthesis of carbonate derivatives from CO2 and alcohols [6][7][8][9][10][11][12][13]. However, these kinds of catalysts often need high temperatures and pressure to completely achieve the CO2 fixation [6]. On the other hand, amidine and

Studies towards the synthesis of hyperireflexolide A

• G. Hari Mangeswara Rao

Beilstein J. Org. Chem. 2018, 14, 2106–2111, doi:10.3762/bjoc.14.185

• 13C NMR spectra were recorded at 100 MHz (125 MHz) on a JEOL spectrometer. Samples for NMR were made in CDCl3. Tetramethylsilane was used as the internal standard. Commercial grade solvents were distilled before use. Ethyl acetate was distilled over anhydrous sodium carbonate. Dichloromethane and

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• ) using atmospheric oxygen as the stoichiometric oxidant, TBA-Eosin Y photocatalysis and carbonate as the base at room temperature (Scheme 23) [68]. The group also reported that this transformation is possible using sunlight as the source of photons, with a yield comparable to that obtained when blue LEDs

• for application to LSF. Leonori et al. have demonstrated the coupling of amide derivatives to aromatics using aryloxy amides, under Eosin Y photocatalysis with green LEDs and potassium carbonate (Scheme 30) [74]. The reaction is well suited for LSF, as is demonstrated by the authors in the

Defining the hydrophobic interactions that drive competence stimulating peptide (CSP)-ComD binding in Streptococcus pneumoniae

• Bimal Koirala,
• Robert A. Hillman,
• Erin K. Tiwold,
• Michael A. Bertucci and
• Yftah Tal-Gan

Beilstein J. Org. Chem. 2018, 14, 1769–1777, doi:10.3762/bjoc.14.151

• -galactopyranoside (ONPG) at a final concentration of 0.4 mg/mL was added, followed by 100 µL of lysate, and the plate was incubated for 3 hours at 37 ºC. The reaction was stopped by adding 50 µL of 1 M sodium carbonate solution, and the OD420nm and OD550nm were measured using a plate reader. The final results were

An amine protecting group deprotectable under nearly neutral oxidative conditions

• Shahien Shahsavari,
• Chase McNamara,
• Mark Sylvester,
• Emily Bromley,
• Savannah Joslin,
• Bao-Yuan Lu and
• Shiyue Fang

Beilstein J. Org. Chem. 2018, 14, 1750–1757, doi:10.3762/bjoc.14.149

• base potassium carbonate at room temperature. The products were then purified with flash column chromatography. As shown in Table 1, the yields of the deprotection ranged from 48% to 88%. Among them, 3a and 3d, which are aliphatic amines, gave better yields (Table 1, entries 1 and 4). Compounds 3b and

• conditions (Table 1, entry 9). In the β-elimination step, when methanol was used as the solvent as in the general deprotection procedure, no reaction occurred even after stirring overnight. This might be caused by the more favoured deprotonation of the carboxylic acid group by potassium carbonate, which made

• diamine 10 in 75% isolated yield (Scheme 2). The basic conditions involving potassium carbonate used to induce β-elimination of oxidized dM-Dmoc did not cause any loss of Fmoc protection. Conclusion In summary, we have demonstrated that dM-Dmoc could serve as a new protecting group for aliphatic and