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《合成通讯》2013,43(24):3817-3827
N-Cyanoimido-(O,O-dialkyl) phosphonyl/S-methyl thiocarbonates 2 were synthesized as facile, useful synthons for preparation of 1,3,5-triazine-, 1,2,4-triazole-, and 1,2,4-oxadiazole-phosphonates through cyclization reaction with various binucleophilic reagents. In addition, when 2a was treated with o-phenylenediamine, benzimidazole-2-yl phosphonate was obtained through addition–elimination reaction. 相似文献
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Sn对肉桂醛加氢催化剂Pt/Al2O3的修饰作用 总被引:8,自引:0,他引:8
研究了负载型Pt催化剂上肉桂醛加氢反应规律,并对Sn的修饰作用进行了考察.未修饰催化剂Pt/Al2O3上,主要以C=C加氢为主;加入少量Sn修饰剂,肉桂醛加氢活性大幅度提高,而且C=O加氢选择性有所提高.当Sn/Pt摩尔比大于0.8后,虽然C=O加氢选择性仍较高,但加氢活性明显降低.Sn/Pt摩尔比为1的催化剂上,肉桂醛转化率高于96%时,肉桂醇选择性可高达80%.结合XRD与化学吸附等表征结果,表明电子因素和立体因素的综合作用是影响肉桂醛加氢选择性的主要因素. 相似文献
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Abstract— From the theoretical analysis of the time variation of the change in absorbance of chicken iodopsin solution (at—195°C), the formation of a new intermediate during bleaching has been suggested. 相似文献
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Dwight W. Chasar 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):149-154
Abstract The reaction of 2,6-di-t-butyl-4-methylphenylphosphorodichloridite with α-diketones in the presence of magnesium metal affords modest yields of 1,3,2-dioxaphospholenes. This may be the first evidence for the existence of the monocoordinate aryloxyphosphinidene intermediate, ROP. 相似文献
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The possibility of substitution of the conventional pentanol as cosurfactant by butyl lactate, on the preparation of OAV microemulsions in a system with SDS as anionic surfactant, is investigated. Whereas a narrow region of OAV microemulsion is described for the system with pentanol for a critical ratio 85/15 between water and SDS, butyl lactate leads to wider regions of solubility for different water/surfactant proportions, making easy the preparation of these microemulsions. Besides this advantage, being butyl lactate obtained from renewable resources and considered as a safe and biodegradable product, the microemulsions prepared with this cosurfactant could be applied in technological fields as cosmetic and dermopharmaceutical, where the biological agressivity of pentanol could avoid any practical application. As a complementary study, the influence that 1,3-buryleneglycol as polar cosolvent exert on the microemulsion regions, was also considered. Although according to experimental data given in the paper 1,3-butyleneglycol affects only slightly the OAV region of microemulsions, it can be foreseen that its presence could provide emollient characteristics to the final compositions. 相似文献
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Mahmood Tajbakhsh Ardeshir Khazaei Majid Shabani Mahalli Ramin Ghorbani Vaghi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1159-1163
N,N-Dibromobenzenesulfonamide(dibromoamine-B), which is prepared easily in high yield, has been employed as effective brominating agent for carbanionic substrates under mild conditions. β-Diketones and β-ketoesters were brominated by this reagent without using any bases. The reagent can be recovered, rebrominated, and reused several times. 相似文献
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Konstantin Karaghiosoff Cornelia Cleve Alfred Schmidpeter 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):289-296
Abstract Only a limited number of heterophospholes are known. A general synthesis1 involves the [4 + 1]-cyclocondensation of a reactive phosphorus(III) compound with an appropriate four-membered chain, as in the synthesis of the 2H-1,2,3-diazaphospholes.2 The limiting factor in this case is the poor availability of four-membered chains with the necessary functionality at the ends. 相似文献
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Abstract— We have used a flashlamp driven tunable dye laser combined with angle tuned frequency doubling crystals for producing UV-B radiation for action spectra studies of various organisms. Optimum UV-B power generation is needed to provide biologically effective doses at wavelengths greater than 300 nm. Optimizing power will also serve to lengthen the lifetime of dyes and other laser components at shorter wavelengths where UV-B output is more than adequate. While much information is available on dyes and dye performance from manufacturers, little information is available on the use of dyes and dye mixtures for providing the continuous high power spectrum of wavelengths necessary for biological UV action spectroscopy. We have examined a number of dyes and dye mixtures for optimal laser performance at wavelengths from 260 to 330 nm. The dyes and dye mixtures discussed here provide adequate power output in the UV-B wavelength range and have allowed us to perform numerous UV-B action spectra studies using the tunable dye laser. 相似文献
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《Journal of carbohydrate chemistry》2013,32(9):813-819
Multigram preparation of strategically protected 2-azido-2-deoxy mannose 5 from pentaacetyl glucose 1 is described. This manno-derivative was obtained in a straightforward manner and in high overall yield and represents a flexible building-block for complex oligosaccharide synthesis. 相似文献
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J. L. Vučina M. B. Skakun-Todorović S. R. Albahari 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2)
Abstract 35-labelled organic compounds are widely used in different fields: medicine, chemistry, biochemistry, biology, etc. Some of these compounds are known as chemoprotectors and 35S-labelled forms are used in the investigation of such protective mechanism. Details of the chemical and biochemical syntheses of some 35S-labelled organic compounds are given in the paper: DL-cysteine hydrochloride-35S (1-amino-2-mercaptopropionic acid), vitamin B1-35S (thiamin hydrochloride), thiourea-35S, carbon disulphide-35S and L-methionine-35S (1-amino-4-methyl- thiobutyric acid). Products of high specific activities are obtained: 5–10 mCi/mM DL-cysteine hydrochloride-35S; 60–120 mCi/mM vitamin B1-35S; 100–200 mCi/mM thiourea-35S; 20–100 mCi/mM carbon disulphide- 35S and 1–10 Ci/mM L-methionine-35S. All the products are of high chemical and radiochemical purity, which were determined by thin layer chromatography. 相似文献
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研究了YBa2Cu3O6~7超导催化剂上CO加氢反应,反应主要产物是甲醇和二甲醚。利用原位FTIR、XPS和XRD技术对催化剂进行了表征。原位FTIR结果表明,反应中间物可能为醛基、甲氧基和甲酸根。CO吸附到YBa2Cu3O6~7上与晶格氧发生反应生成CO2,YBa2Cu3O6~7产生氧空位并由Orthorhombic相转变为Tetragonal相。 相似文献
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研究了YBa2Cu3O6~7超导催化剂上CO2的加氢反应。应用TPD、TPR、SEM和原位FTIR等技术对催化剂进行表征发现,CO2极易吸附到YBa2Cu3O6~7催化剂的氧空位上。反应过的催化剂易被还原。反应的中间物种是醛基和甲酸根。根据FTIR结果提出甲醇是CO2和H2反应的直接产物,CO2+H2→CH3OH+H2O和CO2+H2→CO+H2O是体系中存在的平行反应 相似文献
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Jan Michalski Jerzy Mikołajczak Marek Pakulski Aleksandra Skowronska 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):233-234
Abstract The oxidative addition of molecules X–Y to three-coordinated phosphorus compounds is of considerable general interest. If one of the groups attached to the phosphorus atom is an alkoxy, OR, the final product is almost always > P(O)Y with the formation of an alkyl halide RX. The above process is known as Arbuzov reaction, the mechanism of which can be represented, in the light of our present knowledge, as follows: mental mechanistic problem for the Arbuzov reaction. The R(?)phosphite (4) was prepared from R(+)2-octanol of 95% opt. purity, [α]20 D + 9.4° (neat) and the chlorophosphite (3) by standard condensation in the presence of tertiary amine and purified by distilla tion in vacuo, δ31P ?127.5 ppm, [α]D 20 ?25.6° (neat). Equimolar amounts of the phosphite (4) and the corresponding halogen in CH2 C12 solution were allowed 相似文献
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Heterocyclic ketene aminals 1 react with aryl azides 2 to give thetitled compounds 3, and in some cases also with the formation offused heterocycles 4. 相似文献
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稠杂环化合物的研究 Ⅵ.3—(3‘—吡啶基)—6—脂肪基/芳香基均三唑并[3,4—… 总被引:6,自引:1,他引:6
本文研究了3-(3'-吡啶基)-4-氨基-5-巯基-1,2,4-三唑在POCl3存在下与脂肪酸和芳香酸的缩合反应,制得24种新的3-(3'-吡啶基)-6-脂肪基/芳基均三唑并[3,4-b]-1,3,4-噻二唑,利用元素分析、IR、^1H NMR及MS方法确认了结构。部分化合物进行了抗菌和除草试验。 相似文献