A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates

• András György Németh,
• György Miklós Keserű and
• Péter Ábrányi-Balogh

Beilstein J. Org. Chem. 2019, 15, 1523–1533, doi:10.3762/bjoc.15.155

• isocyanide component under air. In the case of using other bases, such as caesium carbonate (Cs2CO3), diisopropylethylamine (DIPEA) or sodium ethoxide (NaOEt), only the isothiocyanate intermediate of the reaction was isolated (Table 1, entries 17, 18, and 20). However, using diazabicycloundecene (DBU) as the

Synthesis of aryl cyclopropyl sulfides through copper-promoted S-cyclopropylation of thiophenols using cyclopropylboronic acid

• Emeline Benoit,
• Ahmed Fnaiche and
• Alexandre Gagnon

Beilstein J. Org. Chem. 2019, 15, 1162–1171, doi:10.3762/bjoc.15.113

• equivalent of copper(II) acetate, 1.0 equivalent of bipyridine, and 2.0 equivalents of sodium carbonate in dichloroethane at 70 °C for 16 hours provided the desired S-cyclopropylated compound 1a in 86% yield accompanied by only 4% of the diaryl disulfide side-product 26a (Table 1, entry 1, "standard

• only viable alternative to bipyridine (Table 1, entry 7), with other ligands commonly used in copper-catalyzed reactions such as proline and 2,2,6,6-tetramethyl-3,5-heptanedione giving yields under 15%. Reducing the number of equivalents of boronic acid 25 and sodium carbonate was found to be well

• tolerated, giving a comparable yield as the "standard conditions" (Table 1, entry 8). While changing the inorganic base to potassium phosphate tribasic or potassium carbonate gave yields below 75%, we found that cesium carbonate provided a net increase in the yield of the reaction (Table 1, entry 9

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

• Shahien Shahsavari,
• Dhananjani N. A. M. Eriyagama,
• Bhaskar Halami,
• Vagarshak Begoyan,
• Marina Tanasova,
• Jinsen Chen and
• Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

• ). Due to the steric hindrance of the side product 2 from deprotection, we found that a nucleophilic scavenger was no longer needed during deprotection, and the β-elimination step could be achieved using the non-nucleophilic weak base potassium carbonate. Results and Discussion To develop the dM-Dmoc

• the overall results of the deprotection and cleavage procedure. Removal of the oxidized dM-Dmoc protection groups and cleavage of the oxidized Dmoc linker were achieved with a solution of the weak non-nucleophilic base potassium carbonate at pH 8 at room temperature giving the fully deprotected 5

• ammonium hydroxide deprotection and cleavage conditions. We have demonstrated that the so called UltraMild deprotection and cleavage conditions involving potassium carbonate in anhydrous methanol are incompatible with α-chloroacetamide and thioester [40]. These findings are easily understandable because

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• of 9, followed by an intramolecular cyclic amide formation, would produce isoindolinone derivatives 4. Employing benzoic acids 10 ortho-substituted with iodine along with alkynylcarboxylic acids 11 and ammonium acetate (12), in the presence of caesium carbonate and copper iodide as catalyst (10%), a

• reaction of propiolic acid and aryl halides [78]. Furthermore, the authors have been able to carry out the reaction in a sequential manner starting from propiolic acid and aryl iodides in the presence of caesium carbonate and a palladium catalyst. Next, addition of 2-iodobenzoic acid and ammonium acetate

Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration

• Sora Park and
• Jeung Gon Kim

Beilstein J. Org. Chem. 2019, 15, 963–970, doi:10.3762/bjoc.15.93

• from low reactivity. The solvent-free mechanochemical polymerization of trimethylene carbonate using the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) are examined herein. The polymerizations under ball-milling conditions exhibited significant

• carbonate); Introduction Nowadays mechanochemical syntheses are widespread in many areas of chemistry [1][2][3][4]. The efficient mixing and energy input induced by mechanical motions have promoted many chemical reactions with superior efficiencies [5]. Sometimes, unexpected outcomes that cannot be

• mechanochemical ball milling. The organocatalytic polymerization of trimethylene carbonate to form aliphatic polycarbonates was found to be more efficient when using a mechanical ball-milling reaction than a solution polymerization (Scheme 1). The detailed findings are disclosed in this article. Results and

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