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Relevant bibliographies by topics / Quinone. Carbenes (Methylene compounds)

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Academic literature on the topic 'Quinone. Carbenes (Methylene compounds)'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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Journal articles on the topic "Quinone. Carbenes (Methylene compounds)"

1

Dong, Ying, Dong Liang, Jianjin Huang, and Peng Zhang. "Sesquiterpenes with Quinone Reductase-Inducing Activity from Liriodendron Chinense." Natural Product Communications 4, no. 4 (April 2009): 1934578X0900400. http://dx.doi.org/10.1177/1934578x0900400403.

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Bioassay-directed separation of the methylene chloride extracts from the wood of Liriodendron chinense led to the isolation of six sesquiterpenes, tulipinolide (1), α-liriodenolide (2), β-liriodenolide (3), lipiferolide (4), 11,13-dehydrolanuginolide (5), and tulipinolide diepoxide (6). Compounds 1-6 have not been found previously in L. chinense. The structures of the compounds were established on the basis of NMR spectroscopic data. All the compounds exhibited quinone reductase (QR)- inducing activity in Hepa lclc7 cells.

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2

Mbuvi, Harun M., Erik R. Klobukowski, Gina M. Roberts, and L. Keith Woo. "O-H insertion and tandem N-H insertion/cyclization reactions using an iron porphyrin as catalyst with diazo compounds as carbene sources." Journal of Porphyrins and Phthalocyanines 14, no. 03 (March 2010): 284–92. http://dx.doi.org/10.1142/s1088424610001982.

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Iron(III) tetraphenylporphyrin chloride, Fe(TPP)Cl , efficiently catalyzed the insertion of carbenes derived from methyl 2-phenyldiazoacetates into O-H bonds of aliphatic and aromatic alcohols, with yields generally above 80%. Although the analogous N-H insertions are rapid at room temperature, the O-H insertion reactions are slower and required heating in refluxing methylene chloride for about 8 hours using 1.0 mol.% catalyst. Fe(TPP)Cl was also found to be effective for tandem N-H insertion/cyclization reactions when 1,2-diamines and 1,2-alcoholamines were treated with diazo reagents to give piperazinones and morpholinones and related analogs such as quinoxalinones and benzoxazin-2-ones. This approach provides a new one-pot route for synthesizing these classes of heterocyclic compounds.

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3

Kidonakis, Marios, and Manolis Stratakis. "Reduction of the Diazo Functionality of α-Diazocarbonyl Compounds into a Methylene Group by NH3BH3 or NaBH4 Catalyzed by Au Nanoparticles." Nanomaterials 11, no. 1 (January 18, 2021): 248. http://dx.doi.org/10.3390/nano11010248.

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Supported Au nanoparticles on TiO2 (1 mol%) are capable of catalyzing the reduction of the carbene-like diazo functionality of α-diazocarbonyl compounds into a methylene group [C=(N2) → CH2] by NH3BH3 or NaBH4 in methanol as solvent. The Au-catalyzed reduction that occurs within a few minutes at room temperature formally requires one hydride equivalent (B-H) and one proton that originates from the protic solvent. This pathway is in contrast to the Pt/CeO2-catalyzed reaction of α-diazocarbonyl compounds with NH3BH3 in methanol, which leads to the corresponding hydrazones instead. Under our stoichiometric Au-catalyzed reaction conditions, the ketone-type carbonyls remain intact, which is in contrast to the uncatalyzed conditions where they are selectively reduced by the boron hydride reagent. It is proposed that the transformation occurs via the formation of chemisorbed carbenes on Au nanoparticles, having proximally activated the boron hydride reagent. This protocol is the first general example of catalytic transfer hydrogenation of the carbene-like α -ketodiazo functionality.

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4

Polonik, Sergey, Galina Likhatskaya, Yuri Sabutski, Dmitry Pelageev, Vladimir Denisenko, Evgeny Pislyagin, Ekaterina Chingizova, Ekaterina Menchinskaya, and Dmitry Aminin. "Synthesis, Cytotoxic Activity Evaluation and Quantitative Structure-ActivityAnalysis of Substituted 5,8-Dihydroxy-1,4-naphthoquinones and Their O- and S-Glycoside Derivatives Tested against Neuro-2a Cancer Cells." Marine Drugs 18, no. 12 (November 29, 2020): 602. http://dx.doi.org/10.3390/md18120602.

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Based on 6,7-substituted 2,5,8-trihydroxy-1,4-naphtoquinones (1,4-NQs) derived from sea urchins, five new acetyl-O-glucosides of NQs were prepared. A new method of conjugation of per-O-acetylated 1-mercaptosaccharides with 2-hydroxy-1,4-NQs through a methylene spacer was developed. Methylation of 2-hydroxy group of quinone core of acetylthiomethylglycosides by diazomethane and deacetylation of sugar moiety led to 28 new thiomethylglycosidesof 2-hydroxy- and 2-methoxy-1,4-NQs. The cytotoxic activity of starting 1,4-NQs (13 compounds) and their O- and S-glycoside derivatives (37 compounds) was determined by the MTT method against Neuro-2a mouse neuroblastoma cells. Cytotoxic compounds with EC50 = 2.7–87.0 μM and nontoxic compounds with EC50 > 100 μM were found. Acetylated O- and S-glycosides 1,4-NQs were the most potent, with EC50 = 2.7–16.4 μM. Methylation of the 2-OH group innaphthoquinone core led to a sharp increase in the cytotoxic activity of acetylated thioglycosidesof NQs, which was partially retained for their deacetylated derivatives. Thiomethylglycosides of 2-hydroxy-1,4-NQs with OH and MeO groups in quinone core at positions 6 and 7, resprectively formed a nontoxic set of compounds with EC50 > 100 μM. A quantitative structure-activity relationship (QSAR) model of cytotoxic activity of 22 1,4-NQ derivatives was constructed and tested. Descriptors related to the cytotoxic activity of new 1,4-NQ derivatives were determined. The QSAR model is good at predicting the activity of 1,4-NQ derivatives which are unused for QSAR models and nontoxic derivatives.

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5

Lopes, Andrey P., Bianca S. Bagatela, Paulo C. P. Rosa, Dhammika N. P. Nanayakkara, José Carlos Tavares Carvalho, Edson L. Maistro, Jairo K. Bastos, and Fábio F. Perazzo. "Antioxidant and Cytotoxic Effects of Crude Extract, Fractions and 4-Nerolidylcathecol from Aerial Parts ofPothomorphe umbellataL. (Piperaceae)." BioMed Research International 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/206581.

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The crude ethanolic extract from aerial parts ofPothomorphe umbellataL. (Piperaceae) and fractions obtained by partitions sequentially among water-methanol, methylene chloride, and ethyl acetate, as well as the major constituent, 4-nerolidylcatechol, were, respectively, evaluated and evidenced for antioxidant and cytotoxic effects through fluorometric microplate and microculture tetrazolium assays in HL-60 cells. The crude ethanolic extract demonstrated the preeminent antioxidant activity (IC50=1.2 μg/mL) against exogenous cytoplasmic reactive oxygen species, followed by the water-methanolic (IC50=4.5 μg/mL), methylene chloride (IC50=5.9 μg/mL), ethyl acetate (IC50=8.0 μg/mL), 4-nerolidylcatechol (IC50=8.6 μg/mL), and the sterol fractions (IC50>12.5 μg/mL). Vitamin C, the positive control used in this assay, presented IC50value equivalent to 1.7 μg/mL. 4-Nerolidylcatechol (IC50=0.4 μg/mL) and methylene chloride fraction (IC50=2.3 μg/mL) presented considerable cytotoxicity probably because of the presence of ano-quinone, an auto-oxidation by product of the catechol. Polar compounds, present in the ethanol extract, appear to increase the solubility and stability of the major active constituent, acting synergistically with 4-nerolidylcatechol, improving its pharmacokinetic parameters and increasing significantly its antioxidant activity which, in turn, suggests that the aqueous-ethanolic extract, used in folklore medicine, is safe and effective.

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6

Kysilka, Ondřej, Markéta Rybáčková, Martin Skalický, Magdalena Kvíčalová, Josef Cvačka, and Jaroslav Kvíčala. "HFPO Trimer-Based Alkyl Triflate, a Novel Building Block for Fluorous Chemistry. Preparation, Reactions and 19F gCOSY Analysis." Collection of Czechoslovak Chemical Communications 73, no. 12 (2008): 1799–813. http://dx.doi.org/10.1135/cccc20081799.

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Triflate 4, CF3(CF2)2O-CF(CF3)CF2O-CF(CF3)CH2-OTf (RFOCH2OTf), of the HFPO trimer-based alcohol 3 (RFOCH2OH) is a novel highly fluorinated building block for fluorous chemistry. In analogy to similar polyfluorinated triflates with methylene spacer, its reactivity is limited to strong and soft nucleophiles. Whereas reactions with cyanide anion, phenolate anion, enolate of diethyl malonate or lithium salt of benzaldehyde bis(phenylsulfanyl)acetal were unsuccessful, the corresponding imidazole 5, iodide 6 or azide 7 were prepared in good yields. Reaction of imidazole 5 with (perfluorohexyl)methyl triflate (9) afforded highly fluorinated non-crystalline imidazolium salt 8, TfO-RFOCH2-(C3H3N2)+-CH2C6F13-n, which could be employed as fluorous ionic liquid or intermediate for fluorous carbenes. Complete assignment of complex 19F NMR spectra of all compounds employed was accomplished using 19F gCOSY NMR method.

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7

Hopper, David J., and Lisa Cottrell. "Alkylphenol Biotransformations Catalyzed by 4-Ethylphenol Methylenehydroxylase." Applied and Environmental Microbiology 69, no. 6 (June 2003): 3650–52. http://dx.doi.org/10.1128/aem.69.6.3650-3652.2003.

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ABSTRACT 4-Ethylphenol methylenehydroxylase from Pseudomonas putida JD1 acts by dehydrogenation of its substrate to give a quinone methide, which is then hydrated to an alcohol. It was shown to be active with a range of 4-alkylphenols as substrates. 4-n-Propylphenol, 4-n-butylphenol, chavicol, and 4-hydroxydiphenylmethane were hydroxylated on the methylene group next to the benzene ring and produced the corresponding chiral alcohol as the major product. The alcohols 1-(4′-hydroxyphenyl)propanol and 1-(4′-hydroxyphenyl)-2-propen-1-ol, produced by the biotransformation of 4-n-propylphenol and chavicol, respectively, were shown to be R(+) enantiomers. 5-Indanol, 6-hydroxytetralin, 4-isopropylphenol, and cyclohexylphenol, with cyclic or branched alkyl groups, gave the corresponding vinyl compounds as their major products.

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8

Nicolaides, Demetrios N., R. Wajih Awad, Georgios K. Papageorgiou, Efthalia Kojanni, and Constantinos A. Tsoleridis. "Reactions ofO-methylo-quinone monoximes with methyl-, methylene- and methine- substituted aromatic compounds. Synthesis of benzo[d]oxazole and 1,4-benzoxazine derivatives." Journal of Heterocyclic Chemistry 34, no. 6 (November 1997): 1651–56. http://dx.doi.org/10.1002/jhet.5570340602.

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9

Padilla-Montaño, Nayely, Leandro de León Guerra, and Laila Moujir. "Antimicrobial Activity and Mode of Action of Celastrol, a Nortriterpen Quinone Isolated from Natural Sources." Foods 10, no. 3 (March 11, 2021): 591. http://dx.doi.org/10.3390/foods10030591.

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Species of the Celastraceae family are traditionally consumed in different world regions for their stimulating properties. Celastrol, a triterpene methylene quinone isolated from plants of celastraceas, specifically activates satiety centers in the brain that play an important role in controlling body weight. In this work, the antimicrobial activity and mechanism of action of celastrol and a natural derivative, pristimerin, were investigated in Bacillus subtilis. Celastrol showed a higher antimicrobial activity compared with pristimerin, being active against Gram-positive bacteria with minimum inhibitory concentrations (MICs) that ranged between 0.16 and 2.5 µg/mL. Killing curves displayed a bactericidal effect that was dependent on the inoculum size. Monitoring of macromolecular synthesis in bacterial populations treated with these compounds revealed inhibition in the incorporation of all radiolabeled precursors, but not simultaneously. Celastrol at 3 µg/mL and pristimerin at 10 µg/mL affected DNA and RNA synthesis first, followed by protein synthesis, although the inhibitory action on the uptake of radiolabeled precursors was more dramatic with celastrol. This compound also caused cytoplasmic membrane disruption observed by potassium leakage and formation of mesosome-like structures. The inhibition of oxygen consumption of whole and disrupted cells after treatments with both quinones indicates damage in the cellular structure, suggesting the cytoplasmic membrane as a potential target. These findings indicate that celastrol could be considered as an interesting alternative to control outbreaks caused by spore-forming bacteria.

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10

Slabko, O. Yu, O. N. Shandova, and V. A. Kaminskii. "Reactions of p-quinone diimines of the 1,2,3,4,4a,5-hexahydro-10H-benzimidazo[2,1-j]quinolin-10-imines with some compounds having an activated methylene group." Russian Journal of Organic Chemistry 45, no. 3 (March 2009): 425–29. http://dx.doi.org/10.1134/s1070428009030130.

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Dissertations / Theses on the topic "Quinone. Carbenes (Methylene compounds)"

1

Moeng, Mmushi Moses. "Terthienyl carbene complexes." Diss., Pretoria : [s.n.], 2001. http://upetd.up.ac.za/thesis/available/etd-02092006-153600/.

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2

Lu, Xiaosong. "Generation and reactions of aryloxy and diaryloxycarbenes /." *McMaster only, 2001.

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3

Frankowski, Kevin J. "Carbenes and carbenoids as powerful tools in organic synthesis." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 2.18 Mb., 94 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3205422.

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4

Merkley, Nadine. "Carbenes and radicals from benzyloxy [delta]3-1,3,4-oxadiazolines /." *McMaster only, 2001.

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Thesis (Ph.D.) -- McMaster University, 2001.
[Delta] in title is a Greek letter. The number 3 in title is superscript. Includes bibliographical references (leaves 147-162). Also available via World Wide Web.

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5

El-Saidi, Manal M. T. "Synthesis and thermolysis of 2,2-dioxy-5,5-dimethyl-[delta three]-1,3,4-oxadiazolines : dioxycarbenes and their reactions /." *McMaster only, 1996.

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6

Couture, Philippe. "Syntheses and reactions of aminooxycarbenes from thermolysis of [Delta3]-1,3,4-oxadiazolines /." *McMaster only, 1997.

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7

Asay, Matt J. "Ylides stabilization of novel, low valent carbon-based ligands with applications in catalysis /." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3350076.

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Thesis (Ph. D.)--University of California, Riverside, 2009.
Includes abstract. Title from first page of PDF file (viewed Mar. 8, 2010). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.

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8

Lian, Yiqian. "Chromium and iron organometallics in organic synthesis synthetic studies toward total synthesis of taxol and chromium to iron transfer processes /." Diss., Connect to online resource - MSU authorized users, 2006.

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9

Rafael, Christopher Carlos Ferreira. "Synthesis of chromium carbene scaffolds for use in medicinal chemistry." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1010863.

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This study involves using methyllithium to synthesize Fischer carbene complexes as precursors for metal templated α,β-unsaturated complexes with potential as acceptors in the Baylis Hillman reaction as well as in Dötz benzannulation. Fischer carbene complexes contain low oxidation state metal centers, are electrophilic in nature and are stabilized by π-donating substituents such as alkoxy and amino groups. The increased electron withdrawing nature of the metal carbonyl moiety was expected to improve the rates of reaction compared to organic carbonyls. Four Fischer carbenes were synthesized via nucleophilic addition of MeLi to chromium and tungsten hexacarbonyl at low temperatures followed by alkylation using either a Meerwein salt (Me₃OBF₄) to give the desired Fischer metal methyl methoxy carbenes or Et₄NBr/alkylhalide to make the corresponding ethoxy and allyloxy carbenes. Characterization was by means of ¹³C NMR, ¹H NMR, and IR. In silico studies were carried out looking at the effect of substituents on the carbene bond. Synthesis of α,β-unsaturated complexes was effected via the aldol condensation route and found to be unfavorable using enolizable aldehydes, although the use of two aryl aldehydes resulted in successful preparation of two α,β-unsaturated complexes. Difficulty in the purification of these complexes hindered their full characterization. Computational studies looked at the effect of substituents on the system as well as variation of the metal from Cr to Mo and W. Synthesis of Baylis Hillman adducts using α,β-unsaturated complexes as acceptors was unsuccessful due to the ease of product oxidization. One potential product was obtained in its crude form although purification was not possible due to oxidation. Computational studies suggested that the oxygen on the ligand negatively impacts the stability of these Fischer carbene derived Baylis Hillman adducts promoting intramolecular oxidation of the metal. The α,β-unsaturated complexes and Baylis Hillman adducts were considered to be candidates to undergo Dötz benzannulation methodology. The use of the α,β-unsaturated complexes in this reaction was generally unsuccessful, both in the microwave and in conventional reflux conditions. Computational studies of these compounds were carried out to facilitate understanding of their stability and configuration.

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10

Wang, Jian. "Heteroaryl(trifluoromethyl)carbenes and related strained cumulenes under matrix isolation conditions." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3289461.

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Books on the topic "Quinone. Carbenes (Methylene compounds)"

1

Metal carbenes in organic synthesis. Weinheim: Wiley-VCH, 1999.

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Nefedov, O. M. Khimii͡a︡ karbenov. Moskva: Khimii͡a︡, 1990.

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3

V, Kazimirchik I., Lukin K. A, and Nefedov O. M, eds. T͡S︡ikloprisoedinenie dikhlorkarbena k olefinam. Moskva: "Nauka", 1985.

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4

U, Schubert, ed. Advances in metal carbene chemistry. Dordrecht, Netherlands: Kluwer Academic Publishers, 1989.

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5

N-heterocyclic carbenes: From laboratory curiosities to efficient synthetic tools. Cambridge: Royal Society of Chemistry, 2011.

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Cazin, Catherine Suzanne Julienne. N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis. Dordrecht: Springer Science+Business Media B.V., 2011.

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7

G, Bertrand, ed. Carbene chemistry: From fleeting intermediates to powerful reagents. New York: Marcel Dekker, 2002.

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8

Bertrand, Guy. Carbene Chemistry: From Fleeting Intermediates to Powerful Reagents. CRC, 2002.

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9

Dötz, K. H. Metal Carbenes in Organic Synthesis. Springer, 2004.

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10

Nolan, Steven P. N-Heterocyclic Carbenes in Synthesis. Wiley-VCH, 2006.

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