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1.
Yang‐Heon Song 《合成通讯》2013,43(5):631-635
Selective oxidation of benzylic, allylic, and saturated secondary alcohols to the corresponding aldehydes or ketones by benzyldimethyltelluronium dichromate is described. 相似文献
2.
TIAN Mei * ZHANG Heng bin ** CAO Xue jingCollege of Chemistry Jilin University Changchun P.R. China 《高等学校化学研究》2002,18(3):330-333
IntroductionNicotinic acid,whose IUPAC name is 3-pyridine formic acid,also known as Vitamine B5,ismainly used as an additive in food,drink andforage industry[1— 3 ] .In medical practice,it is usedto cure pellagra and other relative vitaminedeficiency illness. It is also an intermediate for thesynthesis of important medicines and chemicalmaterials[1,4] . In China,the demand of nicotinicacid is very big. However,there are manyproblems in the current preparation methods ofnicotinic acid,such… 相似文献
3.
With a view to investigate the oxidation behaviors of cetyltrimethylammonium dichromate on multifunctional groups, some arylthioureas were subjected to oxidation, both in neutral and in acidic conditions. In neutral conditions, the products were found to be a mixture of corresponding urea and isonitrile. In acidic conditions, the products were corresponding ureas only. A probable mechanism was proposed for the formation of the product, wherein the first step involves coupling of –NH2 and –SH of one molecule to the –NH2 and –SH of another molecule, respectively, which is followed by removal of nitrogen and sulfur. The microwave irradiation resulted in great yield of isonitrile than urea in neutral conditions. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
4.
An efficient and straightforward method for oxidation of the benzylic alcohols to the corresponding aldehydes and ketones has been accomplished using triphenylmethylphosphonium dichromate (MTPPD) under solvent-free conditions with high chemoselectivity. The reaction is fast with good yields and straightforward workup. 相似文献
5.
Aldoxime is converted into corresponding nitrile derivative on treatment with cetyltrimethylammonium dichromate. 相似文献
6.
HASSANI H. 《中国化学》2009,27(5):1012-1014
Various types of sulfides were converted to sulfoxide by zinc dichromate trihydrate in high yields and rates under solvent-free conditions. 相似文献
7.
Summary. Quinoxalinium dichromate (QxDC) oxidizes benzyl alcohol and substituted benzyl alcohols smoothly in dimethyl sulfoxide (DMSO) and in the presence of acid to the corresponding aldehydes. The reaction has unit dependence on each of the alcohol, QxDC, and acid concentrations. Electron-releasing substituents accelerate the reaction, whereas electron-withdrawing groups retard the reaction, and the rate data obey Hammetts relationship. The reaction constant was –1.09±0.01 at 303K. Oxidation of ,-dideuteriobenzyl alcohol indicated the presence of a substantial primary kinetic isotope effect (kH/kD=6.78 at 303K). The reaction failed to induce the polymerization of acrylonitrile. The rates of oxidation were determined at different temperatures and the activation parameters were evaluated. The analysis of the dependence of the kinetic isotope effect on temperature indicated that the reaction involves a symmetrical cyclic transition state. A suitable mechanism is proposed. 相似文献
8.
《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2441-2446
This article describes an efficient and easy method for oxidation of sulfides 1 to their corresponding sulfoxides 2 with 1-butyl-4-aza-1-azoniabicyclo[2.2.2]octane dichromate (BAAOD) under nonaqueous conditions in high yields. 相似文献
9.
Lotfi Shiri Arash Ghorbani-Choghamarani 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):492-498
A simple, efficient, and chemoselective oxidation of benzylic alcohols to the corresponding aldehydes and ketones and also hydroquinones to the benzoquinones using bis-(2,4,6-trimethylpyridinium) dichromate (BTMPDC) in acetonitrile is described. A good range of primary and secondary benzylic alcohols and a limited range of hydroquinones were selectively oxidized under reflux conditions in reasonable yields. 相似文献
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11.
LI Li-jun~ 《高等学校化学研究》2001,17(3):253-258
In a sulfuric acid medium, oxalate exhibits a strong catalytic effect on the oxidation of p-chloride aniline(ClBN) by dichromate, and the red oxidation product of ClBN has a maximum absorhancy at 520 nm. Based on this founding, a new FI method for determining oxalate was developed. A calibration curve of oxalate in the range of 0.40—17.0μg/mL was obtained. The detection limit was 0.10μg/mL. Sampling rate was 103-samples/h. The possible interference by the co-existing substances or ions was examined. This new method was applied to the determination of micro amounts of oxalate in real samples with satisfactory results. 相似文献
12.
Quinaldinium Fluorochromate and Quinaldinium Dichromate: Two New and Efficient Reagents for the Oxidation of Alcohols 总被引:1,自引:0,他引:1
Summary. Two new mild oxidizing agents, quinaldinium fluorochromate and quinaldinium dichromate, were prepared and characterized. These reagents are suitable to oxidize various primary and secondary alcohols to the corresponding carbonyl compounds and anthracene to antraquinone in good yields. 相似文献
13.
Mamta Yadav Vellaichamy Ganesan Biswajit Maiti Rupali Gupta Piyush Kumar Sonkar Dharmendra Kumar Yadav Alain Walcarius 《Electroanalysis》2019,31(12):2472-2479
Single‐walled carbon nanotubes (SWCNTs) were immobilized on glassy carbon (GC) electrode by drop casting The resulting modified electrode (represented as GC/SWCNTs) efficiently oxidizes acetaminophen (AC), dopamine (DA) and pyridoxine (PY) by decreasing the respective oxidation potentials and increasing peak currents in comparison to bare GC electrode. The extent of lowering of overpotentials is in the order of AC>PY>DA, in agreement with the order of decrease in the HOMO‐LUMO energy gap (ΔE) of these analytes, as determined from Density Functional Theory (DFT) calculations. DFT calculations further reveal that due to the interaction of the analytes on the SWCNT(10,10) there is a negative charge density transfer (higher probability of electron transfer, lower ΔE value) to the frontier molecular orbitals of the analytes, which eases their oxidation. Since AC, DA and PY oxidize distinctly at distinct potential values, the present SWCNTs modified electrodes could be used to simultaneously determine them. Cyclic voltammetry, differential pulse voltammetry and amperometry techniques are utilized to understand the electrochemical characteristics of the analytes (AC, DA and PY) and subsequent sensing of them at the GC/SWCNTs electrode. The electrode is then applied to the determination of AC as a case study. Sensitivity, detection limit and linear calibration range for the AC are found to be 7.9 μA μM?1 cm?2, 1.1 μM and 2.0–100.0 μM, respectively. The increased electroactive surface area of the GC/SWCNTs increases the oxidation peak currents and hence increases the sensitivity of the determination. 相似文献
14.
Nebahat Değirmenbaşı Beytiye Özgün 《Monatshefte für Chemie / Chemical Monthly》2002,133(11):1417-1421
Summary. A new chromium(VI) reagent, quinoxalinium dichromate ([C8H6N2H]2Cr2O7, QxDC), was prepared by reacting quinoxaline with CrO3 in water. QxDC oxidizes primary and secondary alcohols and oximes to the corresponding carbonyl compounds, and anthracene to anthraquinone.
Corresponding author. E-mail: beytiyeozgun@hotmail.com
Received February 2, 2002; accepted April 3, 2002 相似文献
15.
Standardised methods are used to characterise the pulp or cellulosic material for its alkali resistance and alkali solubility. Today, pulp is usually characterised by its solubility in sodium hydroxide. The characterisation test was based on the treatment of pulp with sodium hydroxide solution of a defined concentration, according to a specified procedure. The dissolved organic matter was then determined by dichromate oxidation. The results obtained by size exclusion chromatography showed that both the amount and the molecular weight of the dissolved carbohydrates vary when investigating solubility and α-cellulose content of pulps. The results show further that S18 values obtained by dichromate oxidation are overestimated when characterising pulps containing higher amounts of hemicellulose and/ or short chain cellulose, compared with results obtained by the SEC method. On the contrary, S10 values are overestimated when determined by dichromate oxidation in higher alpha pulps. 相似文献
16.
Elisabeth C. L. Gautier Norman J. Lewis Alexander McKillop Richard J.K. Taylor 《合成通讯》2013,43(20):2989-3008
Anodic oxidation of a series of 1-substituted-2,5-dimethoxybenzenes gives 2-substituted-1,1,4,4-tetramethoxycyclohexa-2,5-dienes in almost quantitative crude yield. Selective monohydrolysis of these bis-ketals is possible in many cases, and gives 3-substituted-4,4-dimethoxycyclohexa-2,5-dienones in good to excellent overall yield. 相似文献
17.
Monica Bhatt Seema Kothari Kalyan K. Banerji 《Reaction Kinetics and Catalysis Letters》2001,72(1):101-105
The oxidation of thioglycollic, thiolactic and thiomalic acids bybenzyltrimethylammonium tribromide proceeds through the formation of asulfenium cation in the slow step. 相似文献
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A new method for the efficient synthesis of aldehydes, ketones, and oxophosphonates from various types of amines (primary and secondary) and aminophosphonates via oxidative deamination by nicotinium dichromate (=3‐carboxypyridinium dichromate; NDC) is described. 相似文献
20.
This paper reports on the results attained in the determination of the mechanism of oxidation of molybdenum sulphide under
non-isothermal conditions in an air atmosphere. The mechanism of the process was determined by simultaneous DTA-TG-DTG, and
the kinetic parameters of the reactions involved were obtained according to the methods of Kissinger and Ozawa.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献