Stereoselective titanium-mediated aldol reactions of (S)-2-tert-butyldimethylsilyloxy-3-pentanone

Titanium-mediated aldol reactions based on (S)-2-tert-butyldimethylsilyloxy-3-pentanone, a lactate-derived chiral ketone, provide the corresponding 2,4-syn-4,5-syn adducts in high yields and diastereomeric ratios with a wide array of achiral and chiral aldehydes. Furthermore, spectroscopic studies of intermediates involved in the process have permitted to propose a mechanism that accounts for the experimental results.     

ω-氟砜基氟烷基格氏试剂的制备及其反应

合成氟烷基酮的通用方法是将全氟烷基金属试剂与羰基类化合物反应。但对于ω位带有官能团的全氟烷基金属试剂的研究,唯一的例子是:     

苯腙基乙酰基二取代乙酸乙酯的合成和晶体结构

报道了标题化合物C12H14N2O3(Mr=234.25)的合成和晶体结构.晶体属单斜晶系,P21/c空间群.晶胞参数:浕=0.84589(17)nm,b=1.7597(4)nm,c=0.82599(17)nm,α=90°,β=91.21(3)°,γ=90°,V=1.2292(4)nm3,Z=4,Dc=1.266g/cm3,μ=0.092mm-1,F(000)=496;偏离因子R=0.0760,Rw=0.1932.     

聚醚酮酮（PEKK）／4，4′-二苯氧基二苯砜（DPODPS）多嵌段共聚物的合成与性能

采用溶液缩聚法由酰氯端基聚醚酮酮(PEKK)齐聚物和4，4′-二苯氧基二苯砜(DPODPS)制备了PEKK／DPODPS多嵌段共聚物，用DSC、TGA等方法对共聚物进行了表征和性能测试。结果表明，随着共聚物中DPODPS含量的增加，共聚物的熔融温度逐渐降低，而其玻璃化转变温度则逐渐升高。当DPODPS质量分数在32．63％～40．73％范围内时，所得共聚物的Tg为185～193℃，比纯PEKK的Tg高出20～28℃；其Tm为322～346℃，比纯PEKK的Tm降低35～59℃，这既保持了纯PEKK的耐热性，又改善了熔融加工性能。该组成范围内的共聚物的拉伸强度(σi)为86．6～84．2MPa，拉伸模量(M)为3．1～3．4GPa，断裂伸长率(ε)为18．5％～20．3％。     

The formation of cation-ligand complexes of tributylammonium cation with diethyl carbonate,ethylene carbonate,propylene carbonate, 4-butyrolactone,ethyl acetate,and cyclopentanone ino-dichlorobenzene at 25°C

The effects of adding millimolar quantities of a series of compounds containing the carbonyl function on the conductances of solutions (0.2 mM) of tri-n-butylammonium picrate ino-dichlorobenzene solvent at 25°C have been measured. Values of the complex formation constants K ₁ ⁺ for 1:1 cation-ligand complexes are derived from these data. The corresponding values of –G ₁ ⁰ at 25°C are (in kcal-mole ^–1 ): 4-butyrolactone, 4.29; propylene carbonate, 3.87; ethylene carbonate, 3.59; cyclopentanone, 3.42; ethyl acetate, 2.84; and diethyl carbonate, 2.78. These results together with earlier results from this laboratory are discussed in terms of the effects of structure on cation-ligand affinity.     

小分子胺直接有效催化合成α-苯硒基酮

用有机小分子胺, 如辛可尼啶, L-脯胺酸和N-取代的手性1,2-环己二胺等直接催化酮与苯硒基氯反应, 通过这一简单有效的方法, 高收率合成了一些α-苯硒基酮.     

Brnsted酸性离子液体催化醛(酮)与二元醇的缩合反应

研究了以Bro¨nsted酸性离子液体1-正丁基-3-甲基咪唑磷酸二氢盐(BMImH2PO4)为催化剂,在不使用其它有机溶剂且无需脱水的条件下,于室温下进行醛(酮)与二元醇的缩合反应,得到了由中至高的转化率和高选择性.产物1,3-二口恶戊烷可以和反应物自动分层,后处理操作简单.过量的醇与离子液体可以多次重复使用,且醛(酮)的转化率无明显降低.     

Simple route to secondary amides of phosphorylacetic acids and their use for extraction and sorption of actinides from nitric acid solutions

An efficient method for the synthesis of secondary alkylamides of phosphorylacetic acids (APA) was proposed. The method involves amidation of ethyl phosphorylacetates with primary aliphatic amines. The scope of reaction was determined. Reactions with ethylenediamine and 1,4-diaminobutane yield the corresponding bisamides; in the case of 1,3-diaminopropane, N-(3-aminopropyl)diphenylphosphorylacetamide or N,N-propylenebis(diphenylphosphorylacetamide) was obtained, depending on the reaction conditions. The extraction of americium(III) complexes and the sorption of uranium(VI) by sorbents with physically sorbed APA from nitric acid solutions were studied. There is no correlation between the partition coefficient of americium(III) and the structure of APA; in the sorption of uranium(VI), the degree of extraction depends on the complexone structure.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2394–2402, November, 2004.     

Synthesis and Characterization of Novel Organosoluble Methyl Substituted Poly(aryl Ether Ketone)s Containing Sulfone Linkage

Several new methyl substituted poly(aryl ether ketone)s containing sulfone linkage with inherent viscosities of 0.62–0.84 dL/g have been prepared from 4,4′‐bis(2‐methylphenoxy)diphenylsulfone and 4,4′‐bis(3‐methylphenoxy)diphenylsulfone with terephthaloyl chloride and isophthaloyl chloride by electrophilic Friedel‐Crafts acylation in the presence of DMF with anhydrous AlCl₃ as a catalyst in 1,2‐dichloroethane, respectively. These polymers having weight‐average molecular weight in the range of 71,000–49,000 are all amorphous and show high glass transition temperatures ranging from 167 °C to 191 °C, excellent thermal stability at temperatures over 400 °C in air or nitrogen, high char yields of 51–58% in nitrogen and good solubility in CHCl₃ and polar solvents such as DMF, DMSO and NMP at room temperature.     

铜催化下格氏试剂与酰卤的选择性偶合: 直链酮化合物的合成

在一般情况下,格氏试剂与酰卤偶合反应难以控制在酮阶段,往往得到叔醇。在较低温度下有机铜试剂与酰卤偶合可高产率地得到酮,所以用固体铜盐CuX(X=Cl、Br、I)作为格氏试剂与酰卤偶合的催化剂,可以提高反应的选择性,从而提高酮的产率。但固体铜盐的催化反应仅适合于空间位阻较大的脂肪酮和某些芳香酮的制备,对于直链脂肪酮的制备则产率很低。我们采用可溶性铜络合物Li_2Cucl_4(四氯合铜酸锂)等作催化剂,在均相溶液中反应,有效地提高了催化效果及反应的选择性,从而使格氏试剂与酰卤的偶合反应成功地用于直链脂肪酮的制备,产率良好。