- Spectrophotometric determination of cobalt(II) and cyanocobalamin with vanillilfluorone and its applications
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Spectrophotometric determination of cobalt(II) was accomplished with vanillilfluorone (VF) in the presence of dimethylbenzyltetradecylammonium chloride (Zephiramine, Zep). In the determination of cobalt(II), Beer's law was obeyed in the range of 24-470 ng/ml, with an effective molar absorption coefficient (at 575 nm) and relative standard deviation of 1.35×105 l mol-1 cm-1 and 0.66% (n=5), respectively. The composition ratio of the colored complex was determined by the mole ratio and continuous variation methods, and it was found to be Co(II) :VF: Zep=1 : 2 : 4. Analysis of cyanocobalamin by the same procedure showed that cyanocobalamin could be determined in the concentration range of 0.5-0.11 μg/ml using the proposed method.
- Hoshino, Mitsuru,Matsushita, Momoka,Samma, Megumi,Asano, Mamiko,Yamaguchi, Takako,Fujita, Yoshikazu
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Read Online
- Spectrophotometric determination of hydrogen peroxide with osmium(VIII) and m-carboxyphenylfluorone
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Spectrophotometric determination of hydrogen peroxide was accomplished with osmium(VIII) and m-carboxyphenylfluorone (MCPF) in the presence of cetyltrimethylammonium chloride (CTAC). In the determination of hydrogen peroxide based on the fading of the color of osmium(VIII)-MCPF complex, Beer's law was obeyed in the range 20-406 ng mL-1, with an effective molar absorption coefficient (at 580 nm) of 5.21 × 104 L mol -1 cm-1 and a relative standard deviation of 0.33% (n = 6). Further, we performed the characterization of MCPF and obtained the crystal structure.
- Hoshino, Mitsuru,Kamino, Shinichiro,Doi, Mitsunobu,Takada, Shingo,Mitani, Shota,Yanagihara, Rika,Asano, Mamiko,Yamaguchi, Takako,Fujita, Yoshikazu
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Read Online
- Direct Acetoxylation of Arenes
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Acetoxylation of arenes is an important reaction and an unmet need in chemistry. We report a metal-free, direct acetoxylation reaction using sodium nitrate under an anhydrous environment of trifluoroacetic acid, acetic acid, and acetic anhydride. Arenes (31 examples), with oxidation potentials (Eox, in V vs SCE) lower than benzene (2.48 V), were acetoxylated with good yields and regioselectivity. A stepwise, single electron-transfer mechanism is proposed.
- Hong Nguyen, Thi Anh,Hou, Duen-Ren
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supporting information
p. 8127 - 8131
(2021/08/23)
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- Synthetic method of medical intermediate 1,2,4-triacetoxybenzene
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The invention discloses a synthetic method of a medical intermediate 1,2,4-triacetoxybenzene. The synthetic method comprises the following steps: adopting acetic anhydride, concentrated sulfuric acid,p-benzoquinone, Co(NO3)2.6H2O, DMF, 2-methylimidazole and zinc oxide as main raw materials, adopting cobalt nitrate hexahydrate Co(NO3)2.6H2O and 2-methylimidazole to ultrasonically synthesize a nanocatalyst, and using the nano catalyst to catalyze the reaction of acetic anhydride and p-benzoquinon, so that a generated skeleton carrier ZIF material is uniform in particle size and small in crystal grain size; by loading metal ions Zn, the activity of reactants can be improved, and the activation time of the reactants can be greatly reduced; and the raw materials are mixed in the followingratios: a weight ratio of acetic anhydride to p-benzoquinone is 11:3; a weight ratio of the catalyst to active carbon is 4:3; the weight ratio of cobalt nitrate hexahydrate to 2-methylimidazole is 5:4; a weight ratio of ZnO powder to ZIF-67 is 1:2. By adopting the synthetic method, the heat release rate is effectively controlled, the synthetic process is performed under a mild condition, the generation of the side reaction and the waste of raw materials can be reduced, the conversion rate of a target product is increased, and an excellent catalytic effect for the synthetic reaction of 1,2,4-triacetoxybenzene can be achieved.
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Page/Page column 3-7
(2018/09/08)
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- CONCERTED PROCESSES FOR FORMING 1,2,4-TRIHYDROXYBENZENE FROM HYDROQUINONE
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Flow batteries incorporating an active material with one or more catecholate ligands can have a number of desirable operating features. Commercial syntheses of catechol produce significant quantities of hydroquinone as a byproduct, which presently has limited value in the battery industry and can represent a significant waste disposal issue at industrial production scales. Using a concerted, high-yield process, low-value hydroquinone can be transformed into high-value 1,2,4-trihydroxybenzene, which can be a desirable ligand for active materials of relevance in the flow battery industry. Methods for forming 1,2,4-trihydroxybenzene can include: oxidizing hydroquinone in a first reaction to form p-benzoquinone, converting the p-benzoquinone in a second reaction to form 1,2,4-triacetoxybenzene, deacetylating the 1,2,4-triacetoxybenzene in a third reaction to form 1,2,4-trihydroxybenzene, and isolating the 1,2,4-trihydroxybenzene after performing the first reaction, the second reaction and the third reaction consecutively.
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Paragraph 0094
(2018/04/26)
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- 9. 9 '- (4, 4' - biphenyl) double-phenylfluorone bromo reagent preparation method and application of
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The invention belongs to the technical field of phenylfluorone compounds, and provides a 9,9'-(4,4'-biphenyl)bisfluorone bromination reagent, and a preparation method and an application thereof in order to solve the problem of unsatisfactory sensitivity and selectivity of reagents for detection of heavy metal ions in the prior art. 4,4'-Biphenyldicarboxaldehyde with a large conjugated system reacts with 1,2,4-trihydroxybenzene triacetate to synthesize the novel bisfluorone reagent with a larger conjugated system, so the sensitivity and the fluorescence characteristic of the reagent are enhanced. The 9,9'-(4,4'-biphenyl)bisfluorone bromination reagent can be used in detection of Mo (VI) ions under alkaline conditions and fluorescence detection of Mn (II). The reagent is a highly-selective and highly-selective fluorescence analysis reagent for detecting Mo (VI) and Mn (II), and is a luminosity analysis developer with a good analysis performance.
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Paragraph 0028; 0032; 0034
(2017/11/24)
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- 9. 9 '- (3, 3' - dihydroxy - 4, 4' - b phenylate base) double-phenylfluorone reagent and its preparation method and application
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The invention belongs to the technical field of phenylfluorone compounds and provides a 9,9'-(3,3'-dihydroxy-4,4'-diphenylether)bifluorone reagent and a preparation method and application thereof to solve the problem that an existing phenylfluorone compound having non-ideal sensitivity and selectivity is unable to serve as a fluorescent reagent in the fluorescent detection of metal ions.Two pyranoid ring structural units are introduced in molecules, the quantity of metal ion coordination sites is increased by one time, the ability of the reagent to coordinate with metal ions is enhanced, and the fluorescent reagent good in sensitivity and selectivity is obtained.The preparation method is simple, the cost is low, properties are stable, a detection limit in nickel determination by fluorophotometric quenching process in a basic medium in the presence of a surfactant is lower that of other reagent quenching processes, cobalt determination by spectrophotometry is higher than other fluorone reagent processes in sensitivity, and a detection limit in cobalt determination by discoloring spectrophotometry is lower than that of a process using other fluorone reagents.This reagent has high detection speed for nickel and cobalt ions and is good in selectivity, high in sensitivity and high in complex stability.
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Paragraph 0020; 0023
(2017/11/16)
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- Synthesis method of 1,2,4-triacetoxybenzene serving as catalin drug intermediate
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A synthesis method of 1,2,4-triacetoxybenzene serving as a catalin drug intermediate comprises steps as follows: 2.9-3.1 mol of 4'-methyl-acetoacetanilide and 200 ml of a phosphoric acid solution with certain concentration are added to a reaction container provided with a stirrer and a thermometer, the stirring speed is controlled in the range from 200 rpm to 260 rpm, 0.9 mol of p-benzoquinone is added several times, the temperature of the solution is controlled in the range of 60-65 DEG C, the temperature of the reaction solution is naturally reduced in the stirring process, solids are separated out after the solution is cooled, the temperature of the solution is reduced to 15-19 DEG C, 2L of a potassium chloride solution with certain concentration is added, white crystals are separated out, the temperature of the solution is reduced to 11-13 DEG C, filtration is performed, a product is recrystallized with an acetone solution with the mass percentage being 90% and dried in the vacuum, and the white granular crystal product 1,2,4-triacetoxybenzene is obtained.
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Paragraph 0008; 0016; 0017
(2016/11/24)
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- Synthesis of 5-Antipyriylazosalicylfluorone and its colour reaction with molybdenum
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The synthesis of a new reagent, 5-antipyriylazosalicylfluorone was reported. The colour reaction between 5-antipyriylazosalicylfluorone and molybdenum(VI) was studied. In weak acid medium and in the presence of surfactant cetyltrimethylammonium bromide, Mo(VI) reacted with 5-antipyriylazosalicylfluorone to form a complex with the maximum absorption wavelength at 530 nm. Beer's law was obeyed in the range of 0-1.4 μlg mL -1 for Mo(VI). The value of Mo(VI) content in food samples determined by this method was accordant with that measured by atomic absorption spectrophotometry. The relative standard deviation was 1.3-2.1 % for 7 replicate determinations. The recovery of the standard addition was 99.8-103.0 %.
- Liu, Ying-Hong,Ma, Wei-Xing,Li, Yan-Hui,Liu, Juan
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experimental part
p. 1735 - 1738
(2012/01/13)
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- Transformation of quercitols into 4-methylenecyclohex-5-ene-1,2,3-triol derivatives, precursors for the chemical chaperones N-octyl-4-epi-β- valienamine (NOEV) and N-octyl-β-valienamine (NOV)
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(+)-proto-Quercitol (1) and (-)-vibo-quercitol (2), both of which could be readily prepared by the bioconversion of myo-inositol, were successfully converted into the corresponding 4-methylenecyclohex-5-ene-1,2,3-triol derivatives. These compounds were demonstrated to be suitable precursors, preserving their configurations, for bioactive carba-aminosugars such as the potent chemical chaperone drug candidates, N-octyl-4-epi-β-valienamine (NOEV, 3) and N-octyl-β-valienamine (NOV, 4).
- Kuno, Shinichi,Takahashi, Atsushi,Ogawa, Seiichiro
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body text
p. 7189 - 7192
(2012/02/02)
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- Biaryl crosslinkers. I. Crosslinking of a bisazidobiaryl with poly(3-hexylthiophene)
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A new biaryl-based bisazide has been used to crosslink poly(3- hexylthiophene), a conducting polymer useful for organic electronics. Crosslinking was monitored using infrared spectroscopy and film morphology was studied using scanning electron microscopy. Hole mobility studies of the devices prepared from pristine and crosslinked polymer show an increase in hole mobility of one order of magnitude for the latter devices.
- Lohani, Jaya,Balakrishnan,Gaur, Manoj,Raghunathan,Eswaran
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body text
p. 549 - 554
(2011/10/03)
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- Hydroxycoumarin derivatives: Novel and potent α-glucosidase inhibitors
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A novel class of hydroxycoumarin derivatives were found to be potent α-glucosidase inhibitors. Their syntheses were reported and the structure-activity relationship was established. Kinetic enzymatic assays indicated that compound 10 was a slow-binding and noncompetitive inhibitor with a Ki value of 589 nM, while compound 11 was a competitive inhibitor with a Ki value of 4.810 μM. Among all hydroxycoumarin derivatives studied, compounds 10 and 11 exhibited the highest activities, were specific inhibitors of α-glucosidase, and could be exploited as the lead compounds for the development of potent α-glucosidase inhibitors. Compounds 10 and 11 were also selected for further discussion for the mechanism of enzymatic inhibition.
- Shen, Qiong,Shao, Jialiang,Peng, Quan,Zhang, Wanjin,Ma, Lin,Chan, Albert S. C.,Gu, Lianquan
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scheme or table
p. 8252 - 8259
(2011/02/23)
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- Efficient acylation and one-pot synthesis of dehydroandrographolide succinate on a large scale assisted with microwave radiation
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A rapid and convenient method for acylation and large-scale synthesis of dehydroandrographolide succinate has been developed under microwave irradiation. It is a one-pot condensation and is compatible with dehydration and rearrangement of double bond in mild reaction conditions with good yield, high purity (up to 99.8%), time-savings, few pollutants and low cost. In addition, a number of acylation derivatives were synthesized under microwave irradiation.
- Luo, Xin-Feng,He, Ling,Yin, Hai-Bin,Zheng, Hu,Bei, Di,Deng, Jin-Jin,Huang, Wen-Cai
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experimental part
p. 3444 - 3452
(2009/12/05)
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- Bi(OTf)3-catalyzed acylation of p-quinones: A facile synthesis of acylated hydroquinones
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p-Quinones undergo smooth acylation with acetic anhydride in the presence of 2mol% of bismuth triflate under mild conditions to afford the corresponding 1,4-diacylated-2-acetoxylated hydroquinones in excellent yields with high selectivity.
- Yadav,Reddy, B. V. Subba,Swamy,Rao, K. Raghavender
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p. 6037 - 6039
(2007/10/03)
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- 2,3-Dioxabicyclo[2.2.2]oct-7-en-5-one: Synthesis and Reactions of the Keto Endoperoxide of Phenol
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The photooxygenation of 1,4-cyclohexadiene (3) affords the diastereomeric hydroperoxy endoperoxides exo-4 and endo-4 and the diastereomeric hydroperoxides trans-5 and cis-5 in a ratio of 87: 9:3.5:0.5. Selective reduction of hydroperoxide group in the endoperoxides exo-4 and endo-4 in the presence of titanium tetraisopropoxide-diethyl sulfide gave the corresponding hydroxy endoperoxides exo-7 and endo-7, which on PCC oxidation leads to the phenol-derived keto endoperoxide 2. The triphenylphosphine deoxygenation of the keto endoperoxide 2 produces a 9:1 mixture of 1,2-and 1,4-dihydroxybenzenes 10 and 11, while the CoTPP-catalyzed rearrangement affords the bisepoxide 12, malealdehyde (13), and β-lactone 14. The mechanisms of these transformations are presented.
- Adam, Waldemar,Balci, Metin,Kilic, Hamdullah
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p. 5926 - 5931
(2007/10/03)
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- An expeditious chemo-enzymatic route from glucose to catechol by theuse of 2-deoxy-scyllo-inosose synthase
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A potential two-step process to catechol from D-glucose comprising one- pot incubation of D-glucose with recombinant 2-deoxy-scyllo-inosose synthase (BtrC) and hexokinase, togther with chemical reductive dehydration of the resulting 2-deoxy-scyllo-inosose with Hl, was developed. (C) 2000 Elsevier Science Ltd.
- Kakinuma, Katsumi,Nango, Eriko,Kudo, Fumitaka,Matsushima, Yoshitaka,Eguchi, Tadashi
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p. 1935 - 1938
(2007/10/03)
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- Triflic acid an efficient catalyst for the Thiele-Winter reaction
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Triflic acid is a convenient and non hazardous acid for the Thiele-Winter reaction of quinones. The synthetic scope of the Thiele-Winter reaction was increased by the use of triflic acid.
- Villemin, Didier,Bar, Nathalie,Hammadi, Mohamed
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p. 4777 - 4778
(2007/10/03)
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- SYNTHESIS OF 2-ACYL-4-HYDROXYCYCLOHEXANE-1,3-DIONES - KAIROMONES AND PROTECTIVE SUBSTANCES OF SOME INSECTS
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The synthesis of some derivatives of β-triketones based on a new synthon - 4-hydroxycyclohexane-1,3-dione - is described.Using the proposed scheme, 4-hydroxy-2-(octadec-9Z,12Z-dienoyl)cyclohexane-1,3-dione, a kairomone of some species of Lepidoptera, has been obtained.
- Zaitsev, V.G.,Polozov, G.I.,Lakhvich, F.A.
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p. 180 - 185
(2007/10/02)
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- Synthesis of 2-acyl-4-hydroxycyclohexane-1,3-diones, kairomones and defensive compounds of some insects
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The synthesis of some natural β-triketones starting from a new synthon, 4-hydroxycyclohexane-1,3-dione, is described including the first preparation of /Z,Z/-2-octadec-9,12-dienoyl-4-hydroxycyclohexane-1,3-dione, kairomone of some species of Lepidoptera.
- Zaitsev, Vladimir G.,Polosov, Genrich I.,Lakhvich, Fyodor A.
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p. 6377 - 6386
(2007/10/02)
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