C2对称双(口恶)唑啉的新合成方法

在脱水剂PCl3的存在下,噻吩-2,5-二甲酸与乙醇胺反应直接生成噻吩-2,5-双(口恶)唑啉及未环化产物1和2.副产物1和2碱性关环生成噻吩-2 ,5-双(口恶)唑啉,总收率达63%.此方法的优点是合成路线短,操作简单.     

双-2-噁唑啉化合物对PET的改性作用研究

用挤出机熔融共混法,比较了2,2′-双(2-噁唑啉),1,4-双(2-噁唑啉)苯和1,3-双(2-噁唑啉)苯3种双噁唑啉化合物与PET端羧基进行偶联反应和封端反应的程度和差别;并考查双噁唑啉助剂加入量,挤出温度与时间,后热处理对扩链效果的影响,以及研究扩链后PET的热失重、水解稳定性,力学性能及~(13)C～NMR分析。结果表明,经噁唑啉化合物扩链的PET增进了热稳定性和耐水解性,提高玻纤增强PET的力学性能。     

一步合成C_2型轴对称手性双唑啉的方法

报道了一步合成C2型轴对称手性双噁唑啉的方法。二甘醇酸与手性2-氨基-1-丁醇或L-苯丙氨醇在甲苯中回流脱水23 h,一步反应合成了(R)-或(S)-1,5-双-[2-′(4′-乙基噁唑啉)]甲醚和(S)-1,5-双-[2-′(4′-苄基噁唑啉)]甲醚,产率为91.8%~98.4%。     

2，2-双（2-噁唑啉）改性回收PET的研究

以扩链剂2，2-双(2-噁唑啉)对回收PET进行扩链增粘，从特性粘度和羧值的变化考察了其扩链效果，并用DSC法研究了不同添加量噁唑啉对PET热性能的影响。结果表明：双噁唑啉对PET有一定的扩链效果，且影响PET的冷结晶行为。     

2,2-(2,2'-4(S)-苯基-4,5-二氢(噁)唑啉基)丙烷金属络合物对硝酮环加成反应的催化作用

研究了手性双噁唑啉配体2,2-（2,2’-4（S）-苯基-4,5-二氢噁唑啉基）丙烷（5）与铜或锌的配合物对二苯基硝酮（8）与3-（（E）-2-丁烯酰基）-1,3-噁唑烷-2-酮（6）和2,3-二氢呋喃（7）两种烯烃的环加成反应的催化效果。研究结果表明,双噁唑啉金属络合物对硝酮的环加成反应有较好的催化作用,表现在反应速度的提高和立体选择性的改变。比较而言,（5）与铜的配合物具有更好的催化作用。使用二氯亚砜作为氯化试剂对双噁唑啉（5）的合成方法进行了合理的改进,使产率由69．7％提高到89％。     

反应挤出中PET相对分子质量的研究

用反应挤出机研究了聚对苯二甲酸乙二醇酯(PET)在熔融挤出过程中工艺条件和扩链剂用量对PET相对分子质量的影响。试验结果表明：降低反应段温度、提高真空度和增加螺杆转速可以有效地降低PET分子链的断裂。使用反应挤出机。在反应段温度为260C、真空度-0．1MPa、螺杆转速45r/min、扩链剂2．2′-双(2-噁唑啉)(简称双噁唑啉)用量为o．4％时效果最好．町以使PET相对分子质量由挤出前的25800g/mol提高到32000g/mol。对噁唑啉的结构和热谱研究表明．PET相对分子质量的提高是由于噁唑啉与PFT的端基发生了偶联反应。     

一步合成C2型轴对称手性双(噁)唑啉的方法

报道了一步合成C2型轴对称手性双噁唑啉的方法。二甘醇酸与手性2-氮基-1-丁醇或L-苯丙氨醇在甲苯中回流脱水23h，一步反应合成了（R）-或（S）-1，5-双-[2′-（4′-乙基嗯唑啉）]甲醚和（S）-1，5-双-[2′-（4′-苄基噼唑啉）]甲醚，产率为91．8％-98．4％。     

铜络合物手性催化羰基ene反应的密度泛函研究

应用密度泛函理论在M06/6-31G(d,p)(对铜应用LANL2DZ(f)基组)水平下细研究了手性噁唑啉铜(Ⅱ)催化二酮酯与烯烃的不对称羰基ene反应。该反应有四条可能反应通道,主要经历了噁唑啉铜(Ⅱ)与二酮酯配位生成络合物m1,络合物m2a1、m2a2、m2b1、m2b2,噁唑啉铜-α-羟基-β-酮酯络合物m3a、m3b。烯烃进攻噁唑啉铜-二酮酯络合物m1是手性噁唑啉铜(Ⅱ)催化二酮酯与烯烃的不对称羰基ene反应的速率决定步骤,也是该反应的手性决定步骤。因此该反应的主要反应通道为:m1→TS_(m1-m2a1)→m2a1→TS_(m2a1-m3a)→m3a,主要产物为(S)-α-羟基-β-酮酯,这与M.P.Doyle课题组的实验研究一致。     

PVF热稳定剂

用N-苯并噁唑啉酮衍生物可减少PVF加工过程中的氧化热降解。用N-苯并噁唑啉酮钾盐、N-苯并恶唑啉酮-β-丙腈和双苯并噁唑啉酮稳定的PVF在513°K6小时的重量损失比未稳定的PVF,分别从13%的降到     

2-苯基-3,5-二(4-吡啶基)异噁唑啉的合成及生物活性的研究

以硝基苯为起始原料,经还原生成苯基羟胺、再与4-吡啶甲醛反应生成硝酮、与4-乙烯基吡啶发生1,3-偶极环加成反应等3个步骤合成得到未见文献报道的新型四氢异噁唑啉化合物2-苯基-3,5-二(4-吡啶基)异噁唑啉。通过IR、1 HNMR、13 CNMR、HRMS等对该化合物的结构进行了表征。确定优化的1,3-偶极环加成反应条件为:反应温度75℃、溶剂为DMF。并对合成的新型四氢异噁唑啉化合物进行了生物活性测试,发现该化合物对10种病菌均有不同程度的抑制作用,尤其是对苹果轮纹的防效最高,达到了72.9%。表明,2-苯基-3,5-二(4-吡啶基)异啉啉具有一定的生物活性。     

噻吩-2,5 -二羧酸合成方法的研究

简要叙述了噻吩-2,5-二羧酸的性质和用途。综述了噻吩-2,5-二羧酸的4大类合成路线：以己二酸、糖、噻吩和氯乙酸分别为原料的合成方法。并对其合成方法的特点进行了分析。     

Catalytic Asymmetric Heterogeneous Aziridination Using CuHY/bis(oxazoline): Effect of Reaction Conditions on Enantioselectivity

The copper-catalyzed aziridination of styrene with copper-exchanged zeolite HY (CuHY) and copper(II) triflate (trifluoromethanesulfonate) (Cu(OTf)₂) as catalysts is described using N-(p-tolylsulfonyl)imino]phenyliodinane (PhI=NTs) as the nitrene donor. The effects on the ee and yield of the aziridine when the catalyst is modified by the presence of a chiral bis(oxazoline) are investigated in detail. The heterogeneously catalyzed reaction under these conditions shows a slight, but significant, enhancement in ee with increasing conversion at 25 °C. This is not observed in the more rapid homogeneously catalyzed reaction under identical reaction conditions using PhINTs as the nitrene donor. The enhancement in ee is proposed to result from the preferential reaction of the (S)-aziridine with the Cu²⁺:bis(oxazoline) complex in the presence of PhI=NTs, leading to an enhancement of the (R)-aziridine in the remaining aziridine product.     

Nanostructured biomimetic catalysts for asymmetric hydrogenation of enamides using molecular imprinting technology

A new class of heterogeneous catalysts for asymmetric hydrogenation of enamides was synthesized using molecular imprinting technology. These new catalysts are molecularly imprinted polymers (MIPs) made from rhodium (I) and copper (II) complexes with the bis(oxazoline) chiral ligands. One of the Rh-MIPs showed 87% ee toward L-enantiomeric product while the Cu-MIP showed 82% ee toward D-enantiomeric product. Both MIPs are easy to separate and reusable.     

Reaction of phenol‐ and thiophenol‐terminated compounds with bisoxazolines

Bulk reactions of phenolic compounds (bisphenol‐A and α,ω‐diphenol oligosulfone) or thiols (thiophenol and bis(4‐mercaptophenyl)sulfide) with bisoxazoline coupling agents, namely 2,2'‐(1,3‐phenylene)bis(2‐oxazoline) ( mbox ), 2,2'‐(1,4‐phenylene)bis(2‐oxazoline) ( pbox ), and 2,2'‐(2,6‐pyridylene)bis(2‐oxazoline) ( pybox ), were carried out in the bulk at 140–240°C. The reactions were followed by viscosimetry, size exclusion chromatography, and ¹H‐ and ¹³C‐NMR spectroscopy. The phenol/bisoxazoline bulk reactions at 240°C required the presence of sodium methoxide catalyst. Bisoxazoline pybox gave the best results in this case. Thiol and dithiol/bisoxazoline reactions were faster and did not require any catalyst. High‐molar‐mass polymers were obtained within 5 min at 200°C while using bis(4‐mercaptophenyl)sulfide (BMPS) and any of the bisoxazolines. The NMR spectra of model compounds and polymers were fully assigned, showing that the oxazoline/phenol and oxazoline/thiophenol (tph) polyaddition reactions proceed in the expected way, without any noticeable side reaction. All polymers were amorphous and displayed good thermal stability. Bisoxazolines were also used as coupling agents for the preparation of copolymers of BMPS and α,ω‐dicarboxy polyamide‐12 and for the preparation of polysulfone‐polyamide‐12 block copolymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Heterogeneous Enantioselective Synthesis of a Dihydropyran Using Cu-Exchanged Microporous and Mesoporous Materials Modified by Bis(oxazoline)

The formation of dihydropyran from the Diels–Alder reaction between E-ethyl-2-oxo-3-pentenonate and vinyl ethyl ether is investigated using copper (II) bis(oxazoline) as catalyst. The homogeneously and heterogeneously catalyzed reactions are contrasted. Immobilization using mesoporous materials (Cu-MCM-41, Cu-AlSBA-15, Cu-MSU-2) and zeolite Y is found to produce an effective heterogeneous catalyst. Although the level of enantioselection is not high in this initial study, the CuH-zeolite Y/bis(oxazoline) catalyst gives the highest ee (41% ee), which is significantly higher than that observed for the Cu(OTf)₂ homogeneous catalyst (20% ee) under comparable conditions. In addition, with the heterogeneously catalyzed reaction, the enantioselection changes from the initial 2R,4S product to the 2S,4R diastereoisomer. This behavior is not observed with the homogeneously catalyzed reaction, which always yields the 2R,4S product. These results are discussed in terms of the confinement of the catalyst complex within the pores of the heterogeneous catalyst.     

Catalytic Asymmetric Heterogeneous Aziridination of Styrene Using CuHY/bis(oxazoline): Comments on the Factors Controlling Enantioselectivity

The copper-catalyzed aziridination of styrene is described using both heterogeneous, copper-exchanged zeolite HY, and homogeneous, copper (II) triflate catalysts using both [N-(p-tolylsulfonyl)imino]phenyliodinane (PhI=NTs) and [N-(p-nosylsulfonyl)imino]phenyliodinane (PhI=NNs) as nitrene donors. The key differences observed for the two catalysts when modified by chiral bis(oxazoline) ligands are discussed in detail. In particular, the heterogeneously catalyzed asymmetric reaction can give much higher enantioselection than the comparable homogeneously catalyzed reaction. The structure of the bis(oxazoline) ligand is the critical factor, and bis(oxazoline) ligands that are ineffective with the homogeneous catalysts are highly effective for the Cu²⁺ cation constrained within the zeolite micropores. The consequences of this observation for the design of chiral ligands for asymmetric heterogeneous catalysis are discussed. The effect of the degree of styrene conversion on the enantioselectivity is described in detail using PhI=NNs as a nitrene donor. The reaction shows a significant enhancement in ee with conversion at 25°C, and the possible origin of this effect is discussed.     

Ionic Liquid Effect on the Reversal of Configuration for the Magnesium(II) and Copper(II) Bis(oxazoline)‐Catalysed Enantioselective Diels–Alder Reaction

Ionic liquids have been used to support a range of magnesium‐ and copper‐based bis(oxazoline) complexes for the enantioselective Diels–Alder reaction between N‐acryloyloxazolidinone and cyclopentadiene. Compared with reaction performed in dichloromethane or diethyl ether, an enhancement in ee is observed with a large increase in reaction rate. In addition, for non‐sterically hindered bis(oxazoline) ligands, that is, phenyl functionalised ligands, a reversal in configuration is found in the ionic liquid, 1‐ethyl‐3‐methylimidazolium bis[(trifluoromethanesulfonyl)imide], compared with molecular solvents. Supported ionic liquid phase catalysts have also been developed using surface‐modified silica which show good reactivity and enantioselectivity for the case of the magnesium‐based bis(oxazoline) complexes. Poor ees and conversion were observed for the analogous copper‐based systems. Some drop in ee was found on supporting the catalyst due a drop in the rate of reaction and, therefore, an increase in the contribution from the uncatalysed achiral reaction.     

Enantioselective cyclopropanation reactions promoted by immobilized bis(oxazoline)–copper complexes

Bis(oxazoline)–copper complexes can be immobilized by cationic exchange or a covalent bond to the support. In the first strategy the co-ordination properties of the solid counterion influence the results obtained, as is the case in the homogeneous phase. However, the solid counterions also lead to steric interactions with the chiral ligand and so the bis(oxazoline) behaves differently depending on its substituents and the nature of the anionic support. The best overall results are obtained with nanocomposite Nafion–silica as a support and the bis(oxazoline) with phenyl groups. In the second strategy the covalent bond between the ligand and an organic support can be achieved using a preformed polymer or by synthesis of the support using a functionalized chiral ligand. The best results are obtained with the latter system but the copolymerization conditions are critical for the activity and enantioselectivity of the catalyst. This revised version was published online in June 2006 with corrections to the Cover Date.     

Heterogeneous Catalytic Sulfimidation using Immobilized Cu(acac)2

The heterogeneous sulfimidation of various sulfides by microencapsulated copper(II) acetylacetonate, [MC‐Cu(acac)₂], and Cu(acac)₂ immobilized in ionic liquids using [N‐(p‐tolylsulfonyl)imino]phenyliodinane (PhINTs) as nitrene donor has been developed to afford the corresponding sulfimides in good to excellent yields. In the presence of a chiral bis(oxazoline) as ligand, asymmetric induction occurs to afford the chiral sulfimides (up to 50% ee). The ionic liquid containing the immobilized bis(oxazoline)‐copper catalyst can be reused for several cycles with consistent activity and enantioselectivity.