Novel Stereoselective Synthesis of (E)- α，β-Unsaturated Esters by the Tandem Reaction of Deprotonation-Oxidation-Wittig Reaction from Phosphonium and Arsonium Salt

Phosphonium or arsonium salt 1 can undergo the tandem reaction of deprotonation -oxidation-Wittig reaction with alcohol 2 in the presence of sodium hydroxide and manganese dioxide,which affords a general simplified method for the stereoselective synthesis of (E)- α-β-unsaturated esters 3.     

Indium (III) Tribromide : An Excellent Catalyst for Biginelli Reaction

A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy- carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of β-keto ester, aldehydes and urea through improved Biginelli reaction.     

Study on the effects of fluorine and oxygen deficiency on YBa2Cu307 byab initio method

The calculations of clusters modeling the fluorine-doping and oxygen deficiency of YBa₂Cu₃0₇ have been performed by the method of all-electronab initio Hartree-Fock with self-consistent crystal field. Results show that in CuO planes electric charge significantly increases, the chemical valence of Cu decreases and the covalent bonding of Cu-O greatly weakens owing to oxygen deficiency, while the effect of F restores the local electronic structure of YBa₂Cu₃O₇. The reported opinion that F occupied the oxygen vacancy in Cu-O chains seems disputable according to the calculated bonding characteristics Project supported by the National Natural Science Foundation of China.     

General and practical catalytic enantioselective Strecker reaction of ketoimines: significant improvement through catalyst tuning by protic additives

Significant improvement in enantioselectivity and catalyst activity was achieved for the catalytic enantioselective Strecker reaction. Using a catalyst (1-2.5 mol %) prepared from Gd(OⁱPr)₃ and d-glucose derived ligand 1, and in the presence of 2,6-dimethylphenol as an additive, high enantioselectivity was obtained from a wide range of ketoimines, including heteroaromatic and cyclic ketoimines. The new method was applied to an efficient catalytic asymmetric synthesis of sorbinil, a therapeutic agent for diabetic complications.     

稀土铜硫化合物TbCuS2的合成和晶体结构

Terbium copper disulfide, TbCuS₂, has been synthesized in the reaction of the elements in a KI flux at 850 ℃. The compound crystallizes in space group P2₁/c of the monoclinic system with four formula units in a cell of dimensions of a= 0.639 3(1) nm, b=0.702 5(1) nm, c=0.670 8(1) nm, β=98.097(4)°, and V=0.298 3(1) nm³ at 153 K. The structure comprises two-dimensional ²_∞[CuS₂] layers along [100] separated by the Tb atoms. In the structure, each Tb and Cu atoms are coordinated to seven and four S atoms, respectively. CSD: 415490.     

New aspects in the reaction of azomethines with cyclic CH-acidic compounds

Summary Treatment of substituted benzylidene anilines1 a – df with cyclic CH-acidic compounds2a–m in ethanol at room temperature yields in additon/elimination reactions the corresponding arylidene derivatives4 and the 2:1 adducts5. The addition products3, which are formed as intermediates, could not be isolated in any case. The donor/acceptor effect of the substituents on the benzylidene moiety influences to a significant extent the reactivity towards the azomethine carbon.

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Neue Aspekte der Reaktion von Azomethinen mit cyclischen CH-aciden Verbindungen

Zusammenfassung Bei der Umsetzung der substituierten Benzylidenaniline1 a – f mit den cyclischen CH-aciden Verbindungen2 a – m in Ethanol bei Raumtemperatur erhält man in Additions/Eliminierungsreaktionen die Arylidenderivate4 und die 2:1-Addukte5. Die als Intermediat gebildeten Additionsprodukte3 konnten in keinem Fall isoliert werden. Die Donor-bzw. Acceptorwirkung der Substituenten am Benzylidenrest beeinflußt maßgebend die Reaktivität am Azomethinkohlenstoff.

     

水煤气变换反应的微观动力学分析──Cu基催化剂上H_2S中毒失活原因的 Monte Carlo 模拟研究

用ＢＯＣＭＰ方法及ＭｏｎｔｅＣａｒｌｏ模拟技术，对Ｈ２Ｓ导致Ｃｕ基催化剂失活的原因进行了计算分析。研究结果表明，当原料气中存在Ｈ２Ｓ时，ＷＧＳ反应的活化能明显高于无Ｈ２Ｓ时的活化能，随着表面Ｈ２Ｓ浓度的增大（θ＝０，０．１０，０．２５），反应的活化能也逐渐变大（其大小比为１∶１．３４∶３．３），究其原因可归结为Ｈ２Ｓ的存在使得反应物分子的吸附热减小，从而使Ｈ２Ｏ的解离吸附（ＷＧＳ反应的速控步骤）活化能增大。     

芳酸及其衍生物的三氯甲基化反应的研究

首次报道了以四氯苯膦为转化剂或采用二氯苯膦与五氯化磷相结合, 将芳酸或芳酰氯转化为三氯甲基芳烃. 同时, 对影响反应的因素进行了研究, 发现连有推电子基的二氯苯膦有促进反应的作用, 而连有吸电子基团则减缓反应的进行, 而反应底物(芳酸或芳酰氯)的结构效应则相反: 连有吸电子基的芳酸有利于反应, 而连有推电子基团则减缓反应的进行. 此外, 发现反应中生成的苯膦酰二氯可作为催化剂重复使用, 并对转化反应的条件进行了改进与优化, 合成出9个三氯甲基芳烃, 其中2个是未见文献报道的新化合物.     

Solid-state synthesis and properties of SmCoO3

In this paper, perovskite oxide SmCoO₃ was prepared by the solid-state reaction method using Co₂O₃ and Sm₂O₃ as raw materials. The structure and properties of the samples were investigated by XRD, Raman spectral techniques, and DC measurements and so on. The results of XRD and Raman spectra showed that the mixtures of Co₂O₃ and Sm₂O₃ can react to produce a single phase perovskite oxide SmCoO₃ around 1353 K. The single-phase SmCoO₃ changes from an insulator to a semi-conductor and transition occurs around 470 K. The thermal expansion coefficient (2.17 × 10⁻⁵ K⁻¹) of the single-phase SmCoO₃ is approximately equal to that of doped LaGaO₃, but much bigger than that of SDC(Ce_0.85Sm_0.15O₂) above 873 K.     

An Efficient Deselenenylation Reaction to the Synthesis of 3, 5-Disubstituted Isoxazoline and Isoxazole

The development of organoselenium chemistry1 has been expanding rapidly during the last decades. Among them, organic selenides are key intermediates, for that they can be efficiently introduced, manipulated, and removed through selenoxide syn-elimination2. Our research group3 has been interested in the application of selenium in organic synthesis for several years. Isoxazolinyl substituted phenyl selenide 13a, although a β-H exists in the molecule, did not undergo selenoxide syn-elimination e…