Search results

Search for "carbonate" in Full Text gives 479 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

  • Jonas Holste,
  • Paul Weldon,
  • Donald Boyer and
  • Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

Graphical Abstract
  • shaken for 15 min and then placed in an oven at 100 °C until the silica gel was completely dried. The impregnated silica gel was stored in the dark until use. Syntheses 1-(1-Propen-1-yl)piperidine (2): In a manner analogous to [27], potassium carbonate (2 g, 15 mmol), piperidine (10 mL, 0.1 mol), and
PDF
Album
Supp Info
Full Research Paper
Published 18 Oct 2024

Synthesis and cytotoxicity studies of novel N-arylbenzo[h]quinazolin-2-amines

  • Battini Veeraiah,
  • Kishore Ramineni,
  • Dabbugoddu Brahmaiah,
  • Nangunoori Sampath Kumar,
  • Hélène Solhi,
  • Rémy Le Guevel,
  • Chada Raji Reddy,
  • Frédéric Justaud and
  • René Grée

Beilstein J. Org. Chem. 2024, 20, 2592–2598, doi:10.3762/bjoc.20.218

Graphical Abstract
  • afforded the known aldehyde 2 in 65% yield [13]. Then, reaction with guanidinium carbonate in DMA at high temperature [12], gave the desired intermediate 2-aminobenzo[h]quinazoline (3). In a final step, classical Buchwald–Hartwig coupling [14][15][16][17] with bromobenzene under the conditions described
  • ]quinazolin-2-amine (3): To a stirred solution of guanidinium carbonate (2.0 g, 0.011 mol) in DMA (15 mL) was added compound 2 (1.5 g, 0.008 mol). Then the reaction mixture was heated to stir at 150 °C for 16 h. After completion of the reaction (TLC), the mixture was poured into ice water, a solid was formed
  • bromobenzene (0.384 mmol, 1.5 equiv), Xanthphos (0.051 mmol, 0.2 equiv) and cesium carbonate (0.769 mmol, 3 equiv). This mixture was degassed for 15 minutes under N2 atmosphere. Pd2(dba)3 (0.0256 mmol, 0.1 equiv) was added and the reaction mixture was stirred for 16 h at 100 °C. After cooling to room
PDF
Album
Supp Info
Full Research Paper
Published 14 Oct 2024

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

  • Nian Li,
  • Ruzal Sitdikov,
  • Ajit Prabhakar Kale,
  • Joost Steverlynck,
  • Bo Li and
  • Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

Graphical Abstract
PDF
Album
Review
Published 09 Oct 2024

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

  • Hisanori Senboku and
  • Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

Graphical Abstract
  • ][9][10][11], yielding phenylacetic acids. For example, Troupel et al. successfully performed electrochemical reduction of benzyl ethers and several esters such as acetate, trifluoroacetate, benzoate, and dibenzyl carbonate derived from benzyl alcohols, including 1-phenylethanol compounds, in the
  • [13], plausible reaction pathways are proposed as seen in Scheme 6. At the cathode, one-electron reduction of the hydroxy group in diarylmethanol 1 generates H2 and the corresponding alkoxide ion A, which captures carbon dioxide to form carbonate ion B. Although it is currently unclear whether this
  • proceeds in a stepwise or concerted manner, two-electron reduction of carbonate ion B generates the corresponding diphenylmethyl anion C, which reacts with carbon dioxide to produce a carbon–carbon bond that results in the formation of diphenyl acetate ion D. Electrochemical reduction of carbon dioxide
PDF
Album
Supp Info
Full Research Paper
Published 20 Sep 2024

Asymmetric organocatalytic synthesis of chiral homoallylic amines

  • Nikolay S. Kondratyev and
  • Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

Graphical Abstract
  • -trifluoromethylamine derivatives of high molecular complexity (Scheme 28). The process involves a highly enantioselective reaction of the isatin-derived Morita–Baylis–Hillman carbonate 137 with a novel α-CF3-substituted imine 136, derived from inexpensive benzothiophene-2,3-dione. A C2-symmetrical cinchona-derived
  • equiv of isatin with a 50% excess of the α-CF3-substituted imine in toluene at room temperature in the presence of 10 mol % of organocatalyst 138 for times between 1 and 80 h. The reaction exhibited a broad scope in the isatin carbonate derivatives with high to excellent enantioselectivities (89–99
  • corresponding free amines by hydrolysis with aqueous HCl. The reaction proceeded in good yields and with complete retention of stereointegrity. In a proposed mechanism, isatin carbonate 137 reacts with a quinuclidine unit of the catalyst 138 by an SN2’ attack to form cationic intermediate 142. The t-BuO− anion
PDF
Album
Review
Published 16 Sep 2024

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

  • Ignaz Betcke,
  • Alissa C. Götzinger,
  • Maryna M. Kornet and
  • Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

Graphical Abstract
  • give 1,5-diacyl-5-hydroxypyrazolines 131. Cleavage of the protecting group with potassium carbonate in methanol finally provides the corresponding 5-acyl NH-pyrazoles 132 (Scheme 46) [149]. A novel approach to synthesizing pyrazoles via the initial formation of isoxazoles 138 through (3 + 2
PDF
Album
Review
Published 16 Aug 2024

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

  • Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

Graphical Abstract
  • electrolyte with potassium carbonate as a base and two platinum electrodes. Mechanistically, condensation of the two reactants formed isatin-derived acylhydrazone 37. Hydrolysis of the latter in the presence of the inorganic base gave rise to potassium carboxylate 39. Meanwhile, two consecutive SET oxidations
PDF
Album
Review
Published 14 Aug 2024

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

  • Pengcheng Lu,
  • Luis Juarez,
  • Paul A. Wiget,
  • Weihe Zhang,
  • Krishnan Raman and
  • Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

Graphical Abstract
  • -substituted indazole analogs in 44% and 40% yields, respectively, by treating compound 6 with methyl iodide and potassium carbonate in dimethylformamide (DMF) at room temperature for 17 h [40]. Other works have shown poor selectivity when 6 and other isomers similar to 6 were reacted with isopropyl iodide and
  • potassium carbonate, isopropyl bromide and cesium carbonate, and bromocyclohexane with potassium carbonate, and only afforded yields not higher than 52% in various solvents [41][42][43]. Recently, Alam and Keeting [37] explored the regioselectivity in the alkylation of variously substituted indazoles
  • cesium carbonate (766 mg, 2.352 mmol) followed by the necessary tosylate (1.5 equiv). The resulting mixture was stirred for 2 hours at 90 °C. The mixture was poured into EtOAc (500 mL) and washed with water (100 mL) and brine. The organic layer was dried and concentrated, the obtained residue was
PDF
Album
Supp Info
Full Research Paper
Published 09 Aug 2024

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

  • Cristina Martini,
  • Muhammad Idham Darussalam Mardjan and
  • Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

Graphical Abstract
  • potassium carbonate was almost quantitative (97–99% yield). It is worth mentioning that the GBB reaction starting from the deacetylated substrate also leads to good results (83–91% of yield), but the overall yield is lowered due to a sluggish deacetylation reaction of 29. Sugar-based aldehydes were employed
PDF
Album
Review
Published 01 Aug 2024

Chiral bifunctional sulfide-catalyzed enantioselective bromolactonizations of α- and β-substituted 5-hexenoic acids

  • Sao Sumida,
  • Ken Okuno,
  • Taiki Mori,
  • Yasuaki Furuya and
  • Seiji Shirakawa

Beilstein J. Org. Chem. 2024, 20, 1794–1799, doi:10.3762/bjoc.20.158

Graphical Abstract
  • -valerolactones 7 and 8, which are functionalized with sulfur and nitrogen, in high yields. Additionally, optically active δ-valerolactone 3a was converted to optically active epoxy-ester 9 upon treatment with potassium carbonate in methanol. Notably, the transformed products were obtained without any loss of
PDF
Album
Supp Info
Full Research Paper
Published 30 Jul 2024

Harnessing unprotected deactivated amines and arylglyoxals in the Ugi reaction for the synthesis of fused complex nitrogen heterocycles

  • Javier Gómez-Ayuso,
  • Pablo Pertejo,
  • Tomás Hermosilla,
  • Israel Carreira-Barral,
  • Roberto Quesada and
  • María García-Valverde

Beilstein J. Org. Chem. 2024, 20, 1758–1766, doi:10.3762/bjoc.20.154

Graphical Abstract
  • benzodiazepine with different bases (caesium carbonate, sodium hydroxide). However, the complete cyclisation to the pyrrolobenzodiazepinone was not achieved, so the described three-step strategy starting from 2-nitrobenzoic acid (Ugi reaction/cyclization to pyrrolidine/reduction sequence) remains as a better
  • after the Ugi/cyclization sequence, yielded the corresponding piperazinoquinazoline 14 with a high global yield (Scheme 10). Moreover, the treatment of piperazinones 9c–e,k derived from 3-bromopropanamine with caesium carbonate in boiling acetonitrile for 1 h afforded the corresponding
  • , without purification, was treated with caesium carbonate (1 equiv) and heated to reflux for an hour. Gratefully, the dipyrrolopiperazinone derivatives 12 were obtained with high yields and complete diastereoselectivity in an efficient and simple way (Scheme 11, Table 6). The structure of these systems was
PDF
Album
Supp Info
Full Research Paper
Published 25 Jul 2024

Syntheses and medicinal chemistry of spiro heterocyclic steroids

  • Laura L. Romero-Hernández,
  • Ana Isabel Ahuja-Casarín,
  • Penélope Merino-Montiel,
  • Sara Montiel-Smith,
  • José Luis Vega-Báez and
  • Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

Graphical Abstract
  • out, resulting in the corresponding N-tosylhydrazones 51a–c. Afterwards, the compounds were subjected to microwave irradiation in the presence of (3-azidopropyl)boronic acid and potassium or cesium carbonate, yielding 3-spiropyrrolidines 52a–c in high overall yields as 1:1 mixture of diastereomers
  • diol 141 with chloroacetyl chloride, followed by cyclization induced by formation of the alcoholate. On the other hand, amino diol 141b was N-alkylated with methyl bromoacetate and then microwaved in the presence of potassium carbonate to obtain morpholinone 144 (Scheme 38). Romero-Hernández and Merino
PDF
Album
Review
Published 24 Jul 2024

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

  • Koichi Mitsudo,
  • Atsushi Osaki,
  • Haruka Inoue,
  • Eisuke Sato,
  • Naoki Shida,
  • Mahito Atobe and
  • Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

Graphical Abstract
  • 1,1,2,2-tetrachloroethane as an internal standard. aPerformed in 1,4-dioxane/H2O (7:1), and the yield was determined by 1H NMR analysis using ethylene carbonate as an internal standard. Effect of cathode catalyst for the electrochemical reduction of 1a using a PEM reactora. Electrochemical reduction of 1a
PDF
Album
Supp Info
Full Research Paper
Published 11 Jul 2024

Benzylic C(sp3)–H fluorination

  • Alexander P. Atkins,
  • Alice C. Dean and
  • Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

Graphical Abstract
  • for the heterobenzylic position, as shown by compound 4. In 2018, a subsequent publication by the same group detailed the use of increased lithium carbonate and NFSI loadings (conditions [B]) to access the difluorinated products [37]. This report also demonstrated a single example of 18F
PDF
Album
Review
Published 10 Jul 2024

Synthesis of substituted triazole–pyrazole hybrids using triazenylpyrazole precursors

  • Simone Gräßle,
  • Laura Holzhauer,
  • Nicolai Wippert,
  • Olaf Fuhr,
  • Martin Nieger,
  • Nicole Jung and
  • Stefan Bräse

Beilstein J. Org. Chem. 2024, 20, 1396–1404, doi:10.3762/bjoc.20.121

Graphical Abstract
  • followed by the addition of diisopropylamine, either in a one-pot synthesis or in two consecutive steps (Table 1). Subsequently, different aliphatic and aromatic substituents were attached to the pyrazole nitrogen by nucleophilic substitution with suitable organohalides 16 and cesium carbonate [3]. Due to
PDF
Album
Supp Info
Full Research Paper
Published 20 Jun 2024

Domino reactions of chromones with activated carbonyl compounds

  • Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

Graphical Abstract
  • attack of the sulfur to the bromide (intermediate AC) and subsequent ring-cleavage. In most reactions, DBU was employed as the base. In case of products derived from N-unsubstititued 3H-indole-2-thiones (R3 = H), employment of potassium carbonate proved to be advantageous. Similarly to the formation of
PDF
Album
Review
Published 29 May 2024

Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics

  • Luca Julianna Tóth,
  • Kateřina Krejčová,
  • Milan Dejmek,
  • Eva Žilecká,
  • Blanka Klepetářová,
  • Lenka Poštová Slavětínská,
  • Evžen Bouřa and
  • Radim Nencka

Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91

Graphical Abstract
  • , DCM, rt, overnight, b) BnBr, NaH, DMF, 0 °C to rt, 1 h, c) (R = Et) diethyl carbonate, LiHMDS, THF, −78 to 0 °C, 1 h, d) (R = allyl) allyl chloroformate, LiHMDS, THF, −78 to 0 °C, 1 h, e) POCl3, DMF, 90 °C, 30 min, f) (BnCO)2O, 100 °C, 1.5 h, g) methanesulfonic acid, DCM, 0 °C to rt, 4 h, h) CyOH
PDF
Album
Supp Info
Full Research Paper
Published 06 May 2024

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

  • Arnaldo G. de Oliveira Jr.,
  • Martí F. Wang,
  • Rafaela C. Carmona,
  • Danilo M. Lustosa,
  • Sergei A. Gorbatov and
  • Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

Graphical Abstract
  • the palladium source in combination with the pyrazinebisoxazoline ligand, (S)-PyraBox (L1), zinc carbonate as base, and methanol as solvent at 40 °C. These initial conditions furnished 2-methoxypyrrolidines arylated at the 4-position, compound 3, as Heck products as illustrated in Scheme 3. The
PDF
Album
Supp Info
Full Research Paper
Published 29 Apr 2024

Methodology for awakening the potential secondary metabolic capacity in actinomycetes

  • Shun Saito and
  • Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

Graphical Abstract
  • carbonate and terminal olefin functionalities [50]. Thus, artificial methods of genetic engineering and chemistry also play an important role in the identification of novel secondary metabolites. Culture conditions Medium composition, pH, oxygen supply, light Simply modifying the culture conditions is an
PDF
Album
Review
Published 10 Apr 2024

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

  • Geng-Xin Liu,
  • Xiao-Ting Jie,
  • Ge-Jun Niu,
  • Li-Sheng Yang,
  • Xing-Lin Li,
  • Jian Luo and
  • Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

Graphical Abstract
  • (Table 1, entry 7), whereas only low yields of 4a were observed with Pd(0) catalysts Pd(PPh3)4 and Pd2(dba)3 (Table 1, entries 8 and 9). Moreover, adding potassium carbonate as additive failed to furnish 4a, demonstrating that the trace amount of acid from the Pd(II) catalyst may facilitate the formation
PDF
Album
Supp Info
Full Research Paper
Published 27 Mar 2024

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

  • Alexander S. Hampton,
  • David R. W. Hodgson,
  • Graham McDougald,
  • Linhua Wang and
  • Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

Graphical Abstract
  • , but the second fluorination step occurs only after reaction for several days. In the solid phase, mechanical milling of the diketone substrate with solid Selectfluor in the presence of sodium carbonate [13][14], and reaction of ketones with a strong base and an N–F reagent give rise to the
  • ) gave only relatively low conversions to 2a and 3a. Other organic nitrogen bases were tested, and we found that quinuclidine (entries 8 and 9, Table 1) gave high conversion to difluorinated product 3a, with very little monofluorinated product 2a being observed. Suspensions of caesium carbonate or sodium
  • effective base to facilitate the formation of 1a-enolate from 1a-enol and thus facilitate the initial monofluorination step by either fluorine or N-fluoroammonium ion 6. Carbonate ions are also expected to be highly basic in MeCN, however, their limited solubility is likely to inhibit their ability to act
PDF
Album
Supp Info
Full Research Paper
Published 28 Feb 2024

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

  • Carlos R. Azpilcueta-Nicolas and
  • Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

Graphical Abstract
  • co-workers reported that the combination of NHPI esters and cesium carbonate (Cs2CO3) gave rise to a new absorption band in the visible region, suggesting the formation of a photoactive charge-transfer complex [70]. This activation mode was initially employed in a decarboxylative coupling reaction
  • (Scheme 30B). Then, cesium carbonate deprotonates the enol OH in 145, to provide the enolate form of Breslow’s intermediate 146, which is a suitable reducing agent to trigger the fragmentation of NHPI ester 58 (E°ox = −0.97 V vs SCE in MeCN). Hence, it is proposed that enolate 146 induces the single
PDF
Album
Perspective
Published 21 Feb 2024

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

  • Nils Clamor,
  • Mattis Damrath,
  • Thomas J. Kuczmera,
  • Daniel Duvinage and
  • Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

Graphical Abstract
  • mol % raised yields to synthetically useful 74% (Table 1, entry 7). The excess amount of 1a was still necessary as a significant amount of iodobiphenyl is formed under the reaction conditions as a result of an undesired heterolytic iodine–carbon bond cleavage. Other carbonate bases and changing the Cu
PDF
Album
Supp Info
Letter
Published 04 Jan 2024

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

  • Nedra Touj,
  • François Mazars,
  • Guillermo Zaragoza and
  • Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

Graphical Abstract
  • . Yet, we did not try to purify them any further. Before closing this section, it should be stressed that we were not able to isolate any dithiocarboxylate betaines when aldiminium salt 3b or triazolium salt 5a were treated with cesium carbonate and carbon disulfide in acetonitrile in the presence of
PDF
Album
Supp Info
Full Research Paper
Published 20 Dec 2023

Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

  • Xing Liu,
  • Wenjing Shi,
  • Jing Sun and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1923–1932, doi:10.3762/bjoc.19.143

Graphical Abstract
  • features a broad substrate scope, simple reaction conditions, and high molecular convergence. Keywords: acylhydrazone; annulation; azepine; MBH carbonate; spirooxindole; Introduction Among the various N-containing heterocyclic compounds, 1,2-diazepine represents one of the important privileged structural
PDF
Album
Supp Info
Full Research Paper
Published 18 Dec 2023
Other Beilstein-Institut Open Science Activities