Academic literature on the topic 'Phenol(alkyl-2 methoxy-4)|fin'
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Journal articles on the topic "Phenol(alkyl-2 methoxy-4)|fin"
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Jirovetz, Leopold, Gerhard Buchbauer, Andrea Wobus, Mohamed P. Shafi, and Beena Jose. "Medicinal used plants from lndia: analysis of the essential oil of air-dried Biophvtum sensitivum (L.) DC." Scientia Pharmaceutica 72, no. 1 (March 17, 2004): 87–96. http://dx.doi.org/10.3797/scipharm.aut-04-08.
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The essential oil of the air-dried plant Biophytum sensitivum (L.) DC. (Oxalidaceae) from Southern lndia was investigated by gas chromatographic-spectroscopic (GC-FID and GC-MS) and olfactoric methods to identify compounds responsible for the characteristic odor as well as partly for the folk medicinal use of this plant. Especially benzene derivatives, such as 1,4-dimethoxy benzene (24.9%), 1,2-dimethoxy benzene (10.6%) and 2-methoxy-4-methyl phenol (3.5%), the monoterpenes (Z)-linalool oxide (8.1%), (E)-linalool oxide (5.2%) and linalyl acetate (3.4%) as well as l-octen-3-ol (9.5%) and isophorone (3.1%) were found to be main constituents (concentrations higher than 3%, calculated as relative %-peak area of GC-FID analysis using an apolar column) of this essential oil, with totally 69 compounds identified. In addition, the odor impression of the sample is described and the possible biological activity of single volatiles discussed.
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Joshi, Rajesh K. "Chemical Composition of the Essential oil ofChromolaena odorata(L.) R. M. King & H. Rob. Roots from India." Journal of Chemistry 2013 (2013): 1–4. http://dx.doi.org/10.1155/2013/195057.
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The hydrodistilled essential oil of the roots ofChromolaena odorata(L.) R. M. King & H. Rob. was analysed by gas chromatography equipped with flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS). A total of twenty-nine compounds have been identified, accounting 97.6% of the total oil. The main constituents were himachalol (24.2%), 7-isopropyl-1,4-dimethyl-2-azulenol (17.6%), androencecalinol (14.1%), and 2-methoxy-6-(1-methoxy-2-propenyl) naphthalene (5.6%). The essential oil consists mainly of phenyl derivatives (41.6%), followed by oxygenated sesquiterpenes ((26.6%), long-chain hydrocarbons (18.9%), sesquiterpene hydrocarbons (6.8%), oxygenated monoterpenes (2.8%), and monoterpene hydrocarbons (0.9%). This study revealed that the roots ofC. odorataproduced different chemotypes other than leaves oil. This is the first report on the essential oil composition of the roots ofC. odorata.
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Pincock, A. L., and J. A. Pincock. "The structure, photochemical reactivity, and photophysical properties of adamantyl X-substituted aryl ethers and a comparison with the alkyl groups, methyl, tert-butyl, and allyl." Canadian Journal of Chemistry 83, no. 9 (September 1, 2005): 1237–52. http://dx.doi.org/10.1139/v05-117.
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The structure, photophysical properties, and photochemistry of the adamantyl aryl ethers 1 in both methanol and cyclohexane have been examined. UV absorption spectra, 13C NMR chemical shifts, X-ray structures, and Gaussian calculations (B3LYP/6-31G(d)) indicate that these ethers adopt a 90° conformer in the ground state. In contrast, fluorescence spectra, excited singlet state lifetimes, and calculations (TDDFT) indicated a 0° conformer is preferred in the first excited singlet state S1. Irradiation in either solvent results in the formation of adamantane and the corresponding phenol as the major products, both derived from radical intermediates generated by homolytic cleavage of the ether bond. The 4-cyano substituted ether 1j was the only one to form the ion-derived product, 1-methoxyadamantane (16% yield), on irradiation in methanol. Rate constants of bond cleavage for these ethers from S1 were estimated by two different methods by comparison with the unreactive anisoles 2, but the effect of substituents was too small to determine structurereactivity correlations. The temperature dependence of the quantum yields of the fluorescence of the unsub stituted, 4-methoxy and 4-cyano derivatives of 1 and 2 were also determined. These results indicated that the activated process for 1 was mainly bond cleavage for the 4-cyano substrate whereas for 2, it was internal conversion and intersystem crossing. Key words: aryl ether photochemistry, fluorescence, excited-state rate constants, excited-state temperature effects.
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Lu, Andy Z., Thomas Q. Hu, David A. Osmond, Brian O. Patrick, and Brian R. James. "Tetrazole ethers from lignin model phenols: synthesis, crystal structures, and photostability." Canadian Journal of Chemistry 79, no. 8 (August 1, 2001): 1201–6. http://dx.doi.org/10.1139/v01-110.
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The phenolic OH moiety in lignin is one of the key functional groups responsible for the photo-induced yellowing of mechanical wood pulps and papers. To evaluate new protective groups for the stabilization of lignin phenols, the model compounds, 2-methoxy-4-propylphenol (1) and 4-hydroxy-3-methoxyacetophenone (2) were reacted with 5-chloro-1-phenyl-1H-tetrazole to give the corresponding tetrazole ethers 1' and 2', respectively, that were then studied for their photostability. The synthesis of these ethers was more efficient than that of alkyl ethers because of less hydrolysis of the alkylating agent under the reaction conditions. Compounds 1' and 2' were fully characterized, including X-ray crystal structure analyses. Crystals of 1' and 2' were monoclinic of space groups P21/c and P21/a, respectively. For 1': a = 9.8679(6), b = 16.708(1), c = 10.2841(6) Å, β = 109.732(5)°, Z = 4. For 2': a = 7.7212(2), b = 27.350(5), c = 14.569(3) Å, β = 101.30(2)°, Z = 8. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.039 (Rw = 0.046) for 2029 reflections with I [Formula: see text] 3σ(I) (for 1'), and to R = 0.055 (Rw = 0.073) for 3634 reflections with I [Formula: see text] 3σ(I) (for 2'). Compound 2' was much more photostable than the precursor phenol on exposure to strong fluorescent light, while 1' was only slightly more stable than the precursor phenol.Key words: alkylation, ethers, lignin model compounds, methylation, phenols, yellowing inhibition.
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Journal, Baghdad Science. "Synthesis of some Schiff's bases derivatives from aminoazo compounds." Baghdad Science Journal 4, no. 3 (September 2, 2007): 416–19. http://dx.doi.org/10.21123/bsj.4.3.416-419.
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Reaction of,2- [( 4- amio phenyl ) diazenyl] 1,3,4- thiadiazole -5- thiol (S1) with p- chlorobenzeldehyde,3,4 – dimethoxy benzaldehyde and pyrrol-2- carbonxaldehyde gave -5- [{4-(4-chlorobenzylidene amino) phenyl} diezenyl]-1,3,4- thiadiazole-2- thiol (S2),5-[{ 4-[(3,4- dimethoxybenzyldene )amino phenyl ] diazenyl)-1,3,4- thiadiazole-2-thiol,(S3) and -5- [4-(1,H – pyrrol -2- yl- methylene)amino phenyl] diazenyl)-1,3,4- thiadiazole-2- thiol (S4) respectively as schiff's bases compounds. On the same route-2-[(4-amino-1- naphthyl ) diazenyl] -1,3,4- thiadiazole -5- thiol (S5) reacts with –p- chloro benzaldehyde and –m- nitrobenzaldehyde to give the follwing schiff's bases -5-[{ 4-(4- chloro benzylidene ) amino -1- naphthyl} diazenyl] -1,3,4- thiadiazole -2- thiol (S6) and -5- ({ 4- [3- nitrobenzylidene) amino] -1- naphthyl({ diazenyl) -1,3,4 – thiadiazole-2- thiol (S7). Sn2 reaction was carried out by the reaction of compound (S6,S7) with bromo ethyl acetate to get ethyl[5{4-(4- chlorobenzylidene amino)-1- naphthyl} diazenyl] -1- 1,3,4- thiadiazole-2- yl- thio] acetate (S8) and ethyl [5-{4- (2- nitrobenzylidene amino)-1- naphthyl diazenyl] -1,3,4- thiadiazole -2-yl-acetate (S9).(Fig.1).
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Ceesay, Abdoulie, Mariana Nor Shamsudin, Mohammed Aliyu-Paiko, Intan Safinar Ismail, Muhammad Farhan Nazarudin, and Norfarrah Mohamed Alipiah. "Extraction and Characterization of Organ Components of the Malaysian Sea Cucumber Holothuria leucospilota Yielded Bioactives Exhibiting Diverse Properties." BioMed Research International 2019 (April 15, 2019): 1–16. http://dx.doi.org/10.1155/2019/2640684.
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The aim of the present study was to extract and characterize bioactive components from separate body organs of Holothuria leucospilota. Preliminary qualitative assessment of the crude extracts was positive for phenols, terpenoids, carbohydrates, flavonoids, saponins, glycosides, cardiac glycosides, steroids, phlobatannins, and tannins in all body organs evaluated. Phenolics were the most abundant group of bioactives accounting for approximately 80%. The extraction solvent mixtures that yielded most compounds evaluated were methanol/acetone (3:1, v:v) and methanol/distilled water (3:1, v:v). In other analyses, GC-MS data revealed diverse metabolic and biologically active compounds, where those in high concentrations included 2-Pentanone, 4-hydroxy-4-methyl- among the ketones; phenol- 2,4-bis(1,1-dimethylethyl)-, a phenol group; and 2-Chlorooctane, a hydrocarbon. Among FA and their methyl/ethyl esters, n-hexadecanoic acid, 5,8,11,14-eicosatetraenoic acid ethyl ester (arachidonic acid), and 5,8,11,14,17-eicosapentaenoic acid methyl ester (EPA) were among the most abundant FAMEs accounting for approximately 50% of the subgroups measured. Data from GC-FID analysis revealed methyl laurate (C12:0), methyl myristate (C14:0), methyl palmitate (C16:0), and methyl stearate (18:0) methyl esters as the most abundant saturated FA, whereas cis-9-oleic methyl ester (C18:1) and methyl linoleate (C18:2) were found as the major monounsaturated FA and PUFA FAMEs, respectively, in the body wall of the species. Taken together, the extraction and characterization of different categories of metabolically and biologically active compounds in various organ extracts of H. leucospilota suggest that the species is potentially a rich source of cholesterol-lowering, antioxidant, antimicrobial, and anticancer agents. These substances are known to benefit human health and assist in disease prevention. These findings justify the use of sea cucumbers in traditional folklore medication and the current interest and attention focused on the species to mine for bioactives in new drugs research.
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Dinda Putri, Karina, Ni Luh Ari Yusasrini, and Komang Ayu Nocianitri. "Pengaruh Metode Pengolahan Terhadap Aktivitas Antioksidan Dan Karakteristik Teh Herbal Bubuk Daun Afrika (Vernonia amygdalina Delile)." Jurnal Ilmu dan Teknologi Pangan (ITEPA) 10, no. 1 (March 31, 2021): 77. http://dx.doi.org/10.24843/itepa.2021.v10.i01.p08.
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This study aims to determine the effect of processing methods on antioxidant activity and characteristics of African leaf herbal tea and find out the right processing method to get the highest antioxidant activity and the best characteristics. The Completely Randomized Design was used in this study with treatment methods which consisted of 4 levels, namely Method A (steam blanching and drying), Method B (withering and pan firing) Method C (withering and Drying) and Method D (steam blanching and pan firing). This study was repeated 4 times to obtain 16 experimental units. The data obtained were analyzed by analysis of variance and if the treatment had a significant effect it was followed by Duncan’s Multiple Range Test (DMRT). The parameters tested in this study include water content, ash content, total phenols, total flavonoids, color, antioxidant activity and sensory characteristics. The results showed that the methods of processing herbal tea powder of African leaves has a highly significant effect on water content, total phenol, total flavonoids, antioxidant activity, color, and sensory tests of color, taste, flavor and have a significant effect on overall reception and have no significant effect on ash content. Herbal tea powder of African leaves processed by method steaming and drying was the best treatment with a moisture content of 6.41%, ash content of 5.27%, total phenol of 2.4169 mgGAE/g, total flavonoids 2, 6563 mgQE/g, antioxidant activity 67.28%, color (L, a, b = 4.86; -49.07; 34.71), light green color, very distinctive aroma of African tea leaves, very bitter taste, and overall reception likes.
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Ouahrouch, Abdelaaziz, Moha Taourirte, Hassan Bihi Lazrek, Mohamed El Azhari, Joachim Engels, and Jan Bats. "Synthesis and structural characterization of four related α-phosphonates." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1019. http://dx.doi.org/10.1107/s2053273314089803.
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α-Aminophosphonates are structural analogues of natural amino acids. They have been the subject of considerable attention due to their potential biological activities. They may be applied as enzyme inhibitors , antibacterial agents , antitumour agents or antiviral agents [4]. α -Aminophosphonates can be synthesized via the Kabachnik–Fields reaction [5] by the coupling of a carbonyl, an amine and a dialkyl phosphite unit. We report here the synthesis and crystal structures of four diethyl [(arylamino)(4-ethynylphenyl) methyl] phosphonate derivatives, namely diethyl [(4-bromoanilino) (4-ethynyl-phenyl) methyl] phosphonate, (I), diethyl ((4-chloro-2-methyl-anilino) {4-[2-(trimethylsilyl) ethynyl] phenyl} methyl) -phosphonate, (II), diethyl ((4-fluoroanilino) {4-[2-(trimethyl-silyl) ethynyl] phenyl} methyl) phosphonate, (III), and diethyl [(4-ethynylphenyl) (naphthalen-2-ylamino) methyl] phosphonate, (IV). The X-ray analysis confirms the structures found (Fig. I-IV), the products was crystallized by slow evaporation of ethyl acetate/n-hexane solution [3].
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Yodsomnuk, Panadda, Kanya Junjeam, and Mutsee Termtanun. "Photoactivity of Fe and Zn-doped TiO2 in phenol degradation under visible light." MATEC Web of Conferences 192 (2018): 03047. http://dx.doi.org/10.1051/matecconf/201819203047.
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This study developed bandgap energy of TiO2 into the visible region for the photo-activation. The photocatalytic performance of TiO2 was improved when Fe-doping at 2% and 4% by weight, Zn-doping at 2% and 4% by weight, and doping Fe/Zn 1+1% and 2+2% by weight using flame spray pyrolysis as a synthesis method. Brunauer-Emmett-Teller (BET), ultraviolet-visible spectroscopy (UV-Vis), and x-ray diffraction (XRD) were used to characterize the properties of synthesized and all doped TiO2 photocatalysts. To prove the effectiveness, all the modified TiO2 were also compared with the pure synthesized TiO2 by performing photodegradation of phenol under 1hr visible light. The remaining phenol concentration was estimated using gas chromatography-flame ionization detector (GC-FID). Doped TiO2 enhances smaller grain size, larger specific surface area and narrower the bandgap energy after comparing with the pure synthesized TiO2. Zn-doped leads to large surface area that improved the photocatalytic activity of catalyst. However, there was no significant synergistic effect between Fe and Zn doping. The optimum condition for phenol photodegradation was at about 4%Fe doped TiO2.
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Drapak, Iryna, Borys Zimenkovsky, Lina Perekhoda, Мargarita Suleyman, Hanna Yeromina, Natalia Skaletska, Natalya Seredynska, and Anatoly Demchenko. "Search for angiotensin II receptor antagonists among 4-aryl-n-(aryl)-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imine derivatives." Pharmacia 66, no. 4 (December 31, 2019): 181–86. http://dx.doi.org/10.3897/pharmacia.66.e36808.
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The aim of study was to find potential antihypertensive and cardiotropic drugs among new 4-aryl-N-(aryl)-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imines. Materials and methods: The target compounds were synthesized by condensation asymmetrical substituted thioureas with α-bromo-4-R1-acetophenones in ethanol medium. The structure and purity of the compounds synthesized were confirmed by 1H, 13C NMR-spectroscopy and elemental analysis. Docking studies of synthesized compounds to the active site of angiotensin receptor ІІ (PDB ID: 3R8A) were performed in order to find its potential inhibitors and to select promising compounds for experimental screening. Pharmacological studies of the influence on the cardiovascular system were performed. Results: The results of docking studies indicate a high affinity of all tested substances to the selected biotarget. The thermodynamic probability of binding of synthesized substances to protein 3R8A was confirmed by negative values of scoring functions. Hydrobromide of 4-(4-methoxyphenyl)-N-phenyl-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imine 3(1) and hydrobrmide of 4-(4-methoxyphenyl)-N-(4-bromphenyl)-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imine 3(3), which have the highest negative values of scoring functions, are recommended for in vivo pharmacological studies. Based on a complete analysis of the geometric location of the synthesized compounds (ligands) in the active site of the angiotensin II receptor, it was found that the complexes are formed with the involvement of Nitrogen atom of imino group, the 1,3-thiazole ring, the phenyl and alkyl moieties of the molecule form hydrogen bonds, intermolecular electrostatic and donor-acceptor interactions. The conducted pharmacological studies of the influence on the cardiovascular system have allowed to confirm the presence of antihypertensive effect inherent in compounds of this series (except for compound 3(2)). The most effective antihypertensive effect, which is similar in duration and strength of the effect of valsartan, was the effect of compound 3(5). Conclusions: In order to expand the arsenal of biologically active substances of cardiotropic action a systematic series of new 4-aryl-N-(aryl)-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imine derivatives were synthesized. The structure and purity of the compounds synthesized were confirmed by 1H, 13C NMR-spectroscopy and elemental analysis. Based on the results of docking studies using Autodock 4.2.6 software, selected compounds with the best affinity for protein biomes (PDB codes: 3R8A) are promising for experimental studies of hypotensive and cardiotropic activity. The most effective antihypertensive effect, which is similar in duration and strength of the effect of valsartan, was the effect of compound 3(5). A comparative analysis of the results of molecular docking and in vivo results suggests that there is a positive correlation between scoring protein inhibition and experimental data.
Dissertations / Theses on the topic "Phenol(alkyl-2 methoxy-4)|fin"
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Wasser, Christian. "Synthese de derives phenoliques et etude de leur proprietes hypopigmentantes." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13191.
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Ce memoire presente les syntheses d'acyl-2 methoxy-4 phenols (a) d'alkyl-2 methoxy-4 phenols (b), d'alkyl-3 methoxy -4phenols (c), d'alkoxy-4 phenols (d) d'acide (hydroxy-4' phenyl)-3 methyl-2 propionique (e), d'acide (hydroxy-4' phenyl)-3 hydroxy-2 propionique, d'hydroxy-7 carboxy-3 tetrahydro-1,2,3,4 isoquinoleine et d'acide hydroxy-4 phenylpropargylique(f). L'etude "in vivo" (cobayes) et "in vitro" des proprietes hypopigmentantes des composes a, b, c, d, e et f. L'etude "in vivo" et "in vitro" des proprietes hypopigmentantes de substances naturelles : arbutine, luteoline, abscissine
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Reinaud, Olivia. "Nouvelles methodes d'alkylation regioselective d'orthoquinones originales : synthese de differentes classes de produits naturels quinoniques." Paris 6, 1987. http://www.theses.fr/1987PA066200.
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Ben, Tiba Younes. "Synthèse d'analogues iodés du practolol." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10269.
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Les etudes biologiques ont montre qu'un derive du practolol dans lequel le groupe acetamido en para a ete remplace par hncoch#2ch#2ch=chi (ami-9), possede les caracteristiques necessaires a un marqueur des recepteurs -adrenergiques. La synthese de l'enantiomere s (la seule forme active) et marque avec une haute activite specifique a constitue le premier objectif de ce travail. Pour verifier la purete enantiomere avec laquelle ami-9s a ete obtenu, nous avons mis au point une methode de determination de cette purete a l'aide d'un agent de derivation chiral, l'acide 2-fluoro-2-phenylacetique. Cette methode peut etre generalisee aux -bloquants du groupe b et etendue a la determination de la configuration des -aminoalcools. Le second objectif consistait a preparer de nouveaux analogues iodes du practolol en changeant les substituants soit sur l'azote de la fonction amine soit sur celui de la partie amide : - le groupe isopropyle par ch#2ch=chi et (ch#3)#2cch=chi, - le groupe nhcoch#3 par ich=chch#2ncoch#3 et hncooch#2ch=chi. Un dernier compose dans lequel la modification porte sur les deux azotes, en remplacant l'isopropyle par un groupe comportant la structure de la salicylamide et l'acetamido en para par hncoch#2ch#2ch=chi, a egalement ete synthetise.
Book chapters on the topic "Phenol(alkyl-2 methoxy-4)|fin"
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Taber, Douglass F. "Benzene Derivatives: The Tanino-Miyashita Synthesis of Zoanthenol." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0061.
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Yuqing Hou of Southern Illinois University found (J. Org. Chem. 2009, 74, 6362) that the peroxy ether 2 served effectively to directly transfer a methoxy group to the lithiated 1 to give 3. Wanzhi Chen of Zhejiang University, Xixi Campus, showed (J. Org. Chem. 2009, 74, 7203) that pyrimidines such as 4, readily prepared from the corresponding phenol, underwent smooth Pd-catalyzed ortho acetoxylation. Trond Vidar Hansen of the University of Oslo observed (Tetrahedron Lett. 2009, 50, 6339) that simple electrophilic formylation of phenols such as 6 also proceeded with high ortho selectivity. Kyung Woon Jung of the University of Southern California optimized (J. Org. Chem. 2009, 74, 6231) the Rh catalyst for ortho C-H insertion, converting 8 into 9. Jin-Quan Yu of Scripps/La Jolla devised (Science 2010, 327, 315) a protocol for carboxy-directed catalytic ortho palladation that allowed subsequent Heck coupling, transforming 10 into 11. Norikazu Miyoshi of the University of Tokushima established (Chem. Lett. 2009, 38, 996) that in situ generated strontium alkyls added 1,6 to benzoic acid 13, to give, after mild oxidative workup, the 4-alkyl benzoic acid 15. Amin Zarei of Islamic Azad University showed (Tetrahedron Lett. 2009, 50, 4443) that their previously developed protocol for preparing stable diazonium silica sulfates could be extended to the preparation of an aryl azide such as 17. Stephen L. Buchwald of MIT developed (J. Am. Chem. Soc. 2009, 131, 12898) a Pd-mediated protocol for the conversion of aryl chlorides to the corresponding nitro aromatics. Virgil Percec of the University of Pennsylvania has also reported (Organic Lett. 2009, 11, 4974) the conversion of an aryl chloride to the borane, and Guy C. Lloyd-Jones has described (Angew. Chem. Int. Ed. 2009, 48, 7612) the conversion of phenols to the corresponding thiols. Kwang Ho Song of Korea University and Sunwoo Lee of Chonnam National University demonstrated (J. Org. Chem. 2009, 74, 6358) that the Ni-mediated homologation of aryl halides worked with a variety of primary and secondary formamides. Kwangyong Park of Chung-Ang University observed (J. Org. Chem. 2009, 74, 9566) that Ni catalysts also mediated the coupling of Grignard reagents with the tosylate 22 not in the usual way but with the C-S bond to give 23.
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Taber, Douglass. "C-H Functionalization to Form C-O, C-N, and C-C Bonds." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0015.
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A classic example of C-H functionalization is the familiar NBS bromination of a benzylic site. Recent updates of this approach allow for direct alkoxylation (J. Am. Chem. Soc. 2008, 130, 7824) and net amination (Organic Lett. 2008, 10, 1863). For the amination of simple aliphatic H’s, Holger F. Bettinger of Ruhr-Universität Bochum developed (Angew. Chem. Int. Ed. 2008, 47, 4744) the boryl azide 2. The insertion with 1 proceeded to give a statistical mixture of the nitrene insertion products 3 and 4. The tethered C-H functionalization devised (J. Am. Chem. Soc. 2008, 130, 7247) by Phil S. Baran of Scripps-La Jolla is selective, as in the conversion to 5 to 6, but appears to be limited to tertiary and benzylic C-H sites. Michael P. Doyle of the University of Maryland established (J. Org. Chem. 2008, 73, 4317) an elegant protocol for the oxidation of an alkyne such as 7 to the ynone 8. Note that the oxidation did not move the alkyne. Marta Catellani of the Università di Parma reported (Adv. Synth. Cat. 2008, 350, 565) the intriguing Pd-catalyzed conversion of 9 to 10. Under mild conditions, it might likely be possible to hydrolyze the vinyl ether to reveal the phenol 11. Another way of looking at this overall transformation would be to consider the ether 10 to be a protected form of the aldehyde 12. C-H activation can also lead to C-C bond formation. Irena S. Akhrem of the Nesmeyanov Institute, Moscow, described (Tetrahedron Lett. 2008, 49, 1399) a hydride-abstraction protocol for three-component coupling of a hydrocarbon 13 , an amine 14 , and CO, leading to the homologated amide 15. Hua Fu of Tsinghua University, Beijing, showed (J. Org. Chem. 2008 , 73, 3961) that oxidation of an amine 16 led to an intermediate that could be coupled with an alkyne 17 to give the propargylic amine 18. Products 15 and 18 are the result of sp2 and sp coupling, respectively. C-H functionalization leading to sp3 -sp3 coupling is less common. Jin-Quan Yu of Scripps/La Jolla found (J. Am. Chem. Soc. 2008, 130, 7190) that activation of the N-methoxy amide 19 in the presence of the alkyl boronic acid 20 gave smooth coupling, to 21.
Conference papers on the topic "Phenol(alkyl-2 methoxy-4)|fin"
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Karis, T. E., and M. D. Carter. "Oxidation Chemistry of Primary and Secondary Antioxidants." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63592.
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Inhibition of oil oxidation is the key to long life of synthetic lubricants operating in thermal stress and boundary lubrication environments [1]. Bench-scale tests to screen oil formulations provide a rapid means for optimizing formulations prior to longer running verification tests done with the oil in the end-use application [2]. The ultimate goal of accelerated oil life tests is to link the sample combustion temperature, or induction time, at a given heating rate, or temperature, to the estimated lifetime under normal use temperatures. A first order reaction model has recently been employed to derive kinetic parameters from the heating rate dependence of the combustion temperature in the non-isothermal pressure DSC (NIPDSC) test by Adhvaryu et al. [3]. The first order reaction model [4] is also employed here, but we show that a more detailed scheme is needed to fit the heat flow during the combustion exotherm. The detailed kinetic model also provides the link between the NIPDSC test and the isothermal pressure DSC test, as well lifetime estimation at temperatures closer to the end-use conditions. Although isothermal PDSC is useful on grease [5], it does not provide a sharp exotherm for the unthickened base oil [6]. The NIPDSC test provides a reasonably sharp exotherm for formulated base oil in a relatively short amount of time. In the NIPDSC test, 10–12 mg of oil is placed in an open DSC pan. The sample chamber is pressurized with oxygen. The sample temperature is linearly increased with time until the occurrence of the combustion exotherm. The exotherm peak temperature and total heat flow did not exhibit any regular dependence on oxygen pressure between 0.55 and 3.4 MPa. The base oil was an (average) C7 ester of pentaerythritol. Primary antioxidants were hindered phenol and aromatic amines, and Zn-dialkyldithiocarbamate (ZDTC) and Zn-dialkyldithiophosphate (ZDDP) were used as secondary antioxidants. For some of the tests, soluble catalyst [2] was incorporated as iron (III) 2-ethylhexanoate. The reduced heat flow thermograms during the NIPDSC test on the base oil are shown in Fig. 1. The curves are normalized by the peak heat flow rate as Q/Qp, and the symbols denote curves from the first order reaction model, discussed below. The exotherm temperature increases and the exotherm sharpens with increased heating rate. At the 20 °C/min heating rates, the internal heating upon combustion noticeably skews the shape of the exotherm.