氨基取代苯并咪唑衍生物的合成及在酮的氢转移反应中的应用

以α-氨基酸与邻苯二胺在微波辐射下反应合成了α-氨基取代苯并咪唑(1～5).1-(1H-苯并[d]咪唑-2-基)乙胺(1)与溴丁烷反应可形成单丁基、二丁基、三丁基取代产物1a～1d,1的氨基经Boc保护,N-烷基化后制备咪唑环上的N-烷基化产物1i～1g.制备的氨基取代咪唑与Ru(II)化合物原位组成催化体系,考察了其在取代苯乙酮的氢转移反应中的催化活性.结果表明RuCl2(PPh3)3与各配体组成的催化剂均有较好的催化活性,含有NH2基团的α-氨基取代苯并咪唑化合物参与的催化体系催化活性最好,TOF(Turnover frequency)可达到40200 h-1.     

4-(6-甲氧基-2-萘基)-2-(2-羟苄亚氨基)噻唑合成与表征

6-甲氧基-2-(2-溴酰基)萘与硫脲反应环合得4-(6-甲氧基-2-萘基)-2-氨基噻唑;后者与水杨醛反应制备了新化合物4-(6-甲氧基-2-萘基)-2-(2-羟苄亚氨基)噻唑,收率为72.1%～94.8%.目标物采用核磁共振、红外光谱和元素分析测试技术进行了表征;分析目标物和中间体中萘环质子偶合分裂情况.并且确定了萘环上各质子的归属.     

(S)-4-氨基-5-巯基戊酸的简便合成方法

(S)-4-氨基-5-巯基戊酸(Glutamate thiol,Glu SH)是谷氨酸α-羧基被亚甲基巯基取代的衍生物,也可被视为半胱氨酸的衍生物.该氨基酸是海洋抗肿瘤环酯肽Apratoxin E及其结构优化物的重要组成片段.报道(S)-4-氨基-5-巯基戊酸两种简便合成方法.第一种方法是以巯基和氨基均被保护的D-半胱氨酸为原料,先与米氏酸缩合生成β-酮酯,然后还原消除酮羰基、脱羧形成内酰胺,最后去除巯基和氨基上的保护基以及将内酰胺环打开,以4步76.0%的总收率得到所需产物.第二种方法以氨基和γ-羧基被保护的谷氨酸为原料,先将α-羧基还原为伯醇,然后借助Mitsunobu反应引入巯基,最后一锅脱除氨基、巯基和羧基上的保护基得到(S)-4-氨基-5-巯基戊酸.     

聚乙二醇(400)中的不对称Baylis-Hillman反应

从易得的L-脯氨酸出发, 方便地合成了氨基醇1. 以聚乙二醇(400)为溶剂, 考察了手性氨基醇1 (30 mol%)在聚乙二醇(400)中催化不对称的Baylis-Hillman反应, 有较好的催化活性和立体选择性, 产率最高达95.4%, ee值最高达54.3%. 手性氨基醇1-聚乙二醇(400)催化体系可方便回收并重复利用, 在前三次循环中, 未发现反应产率和选择性有明显变化.     

氨功能化陶瓷膜支撑体担载钯纳米颗粒及其增强的催化性能(英文)

采用双氨基硅烷偶联剂N-β-(氨乙基)-γ-氨丙基三甲氧基硅烷(AAPTS)对陶瓷膜表面接枝功能化并负载钯纳米颗粒,制得一种有效的可重复使用的催化剂.利用X射线衍射、扫描电镜、电子能谱、感应耦合等离子体、X射线光电子能谱和高分辨透射电镜对催化剂进行了物性表征,并将其用于催化对硝基苯酚加氢制对氨基苯酚反应.和单氨基硅烷γ-氨丙基三乙氧基硅烷(3-APTS)功能化改性相比,担载在AAPTS功能化陶瓷膜上的钯纳米颗粒具有更高的催化活性和稳定性.相比于3-APTS,AAPTS分子中含有两个氨基,具有更强的供电子效应,因此钯纳米颗粒可更多更稳定地负载在AAPTS功能化陶瓷膜上,从而具有更高的催化活性和稳定性.     

新型氨基功能化碱性离子液体1-(2-氨基乙基)-3-甲基咪唑咪唑盐催化四类取代2-氨基-4H-色烯衍生物的合成

设计合成了阴阳离子均具有碱性位点的新型氨基功能化碱性离子液体1-(2-氨基乙基)-3-甲基咪唑咪唑盐([2-aemim]im,3),经ESIMS和1H NMR确定了结构.[2-aemim]im的碱性与氨基功能化的阳离子([2-amim]+)有关,但主要取决于咪唑阴离子(im-).TG-DSC分析显示[2-aemim]im具有高的热稳定性.将[2-aemim]im用于催化水相介质中芳香醛、丙二腈和酚的三组分一锅法反应制备2-氨基-4H-色烯衍生物,阴阳离子之间表现出协同促进催化作用.该催化剂具有高效和底物作用范围广的特点,应用不同的酚类及类似物,如1-萘酚、2-萘酚、间苯二酚和环己二酮,以高产率得到了相应的不同官能团取代的2-氨基-4H-苯并[h]色烯(4a～4e),2-氨基-4H-苯并[f]色烯(5a～se),2-氨基-4H-色烯(6a～6e)和2-氨基-4H-四氢色烯(7a～7e)四类2-氨基-4H-色烯衍生物.离子液体至少可以循环使用5次,催化活性无显著降低.     

氨基醇杂多酸类离子液体催化环酮的Baeyer-Villiger氧化反应

合成了一系列氨基醇杂多酸类离子液体, 并将其用于催化环酮的Baeyer-Villiger氧化反应. 以2-庚基环戊酮为模板底物, H₂O₂为氧化剂, 探究了此类氨基醇杂多酸类离子液体的催化活性, 筛选出催化活性最高的催化剂为[Pro-ps]H₂PW₁₂O₄₀, 最佳反应条件: n(2-庚基环戊酮)∶n(催化剂)∶n(H₂O₂)=1∶0.03∶4, 反应温度40 ℃, 反应时间8 h, 无溶剂. 在最佳条件下, 2-庚基环戊酮的转化率为98.19%, 产物δ-十二内酯的选择性可达82.84%. 水相中的离子液体[Pro-ps]H₂PW₁₂O₄₀经干燥后可以重复使用. 经过5次循环使用后催化活性未见明显下降. [Pro-ps]H₂PW₁₂O₄₀还可用于催化其它多种环酮的Baeyer-Villiger氧化反应, 结果表明, 该催化剂具有良好的重复使用性和底物普适性.     

介孔硅负载Keggin型钨磷酸催化环己烯环氧化(英文)

采用共合成法制备了一系列不同硅氨基含量的介孔氧化硅SBA-15,在其孔道中引入Keggin型钨磷酸,且其含量随硅氨基含量的增加而增加. 考察了不同处理温度下杂多酸的热稳定性,发现焙烧后钨物种能在SBA-15孔道内高度分散. 以H2O2为氧化剂,研究了该催化剂在环己烯环氧化反应中的催化活性,考察了杂多酸负载量和焙烧温度对催化活性的影响. 结果表明,400 C处理后的钨磷酸催化剂具有高的反应活性和重复使用性能.     

负载型金基催化剂Au/Fe(OH)3催化苯乙烯环氧化反应

用共沉淀法制备了Au/Fe(OH)3催化剂, 以叔丁基过氧化氢为氧化剂, 考察焙烧温度和金担载量等对苯乙烯环氧化反应的影响. 结果表明, 催化剂的焙烧温度、金担载量对苯乙烯环氧化反应有较大影响. 在室温下直接合成的质量分数为4.67%的Au/Fe(OH)3催化剂对苯乙烯环氧化反应显示了很好的催化活性, 于80 ℃反应3 h苯乙烯的转化率达到84.1%, 环氧苯乙烷的选择性达到71.5%. 通过X射线粉末衍射(XRD)、X射线光电子能谱(XPS)和Mössbauer分析, 发现催化剂的催化活性与金的价态及铁的化学存在状态有很大关系. 离子态Au3+与载体Fe(OH)3的协同作用对苯乙烯环氧化反应显示出很好的催化活性.     

一锅法合成2-(2-氨基苯甲酰胺基)苯甲酸类化合物

报道了一种一锅法高效合成2-(2-氨基苯甲酰胺基)苯甲酸类化合物的新方法.以取代2-氨基苯甲酸为原料,合成了20个2-(2-氨基苯甲酰胺基)苯甲酸类化合物,其中有9个新化合物,收率达84%～99%.该方法操作简单,反应条件温和,对环境友好,产率高,并且底物普适性好.探讨了电子效应和空间位阻因素对反应的影响,为2-(2-氨基苯甲酰胺基)苯甲酸类化合物的合成提供了一种新途径.并且,2-(2-氨基苯甲酰胺基)苯甲酸(3a)经一步反应可高效生成大环内酯4和喹唑啉酮5.     

Monodisperse crosslinked pHEMA particle‐supported chiral Mn(III)salen catalyst for asymmetric epoxidation of olefin

Monodisperse crosslinked poly(hydroxyethyl methacrylate) particles (pHEMA) were synthesized for immobilization of the chiral Mn(III)salen homogeneous catalyst by axial coordination. The pHEMA‐Mn(III)salen catalyst was subsequently characterized by FT‐IR, UV and scanning electron microscopy. The results showed that, the heterogeneous Mn(III)salen catalysts also exhibited high activity and enantioselectivity compared to the homogeneous catalyst for the disubstituted cyclic indene and 6‐cyano‐2,2‐dimethylchromene. Moreover, the catalysts were easily separated from the reaction systems and could be renewed several times without significant loss of catalytic activity. Meanwhile, the enantiomeric excess (ee) value remained at 80% in the eighth cycle. The pHEMA support, immobilized by Mn(III)salen, probably acted as a mediator of the reaction between the substrate and the oxidant, and enhanced the stability of the Mn(III)salen compound. Copyright © 2012 John Wiley & Sons, Ltd.     

A new heterogeneous chiral (salen)manganese(III) system for enantioselective epoxidation of non‐functionalized olefins

This communication describes the design and application of a novel catalytic epoxidation system derived from the initial immobilization of a homogeneous sulfonato (salen)Mn(III) complex on two solid carriers (silica gel and siliceous earth) and subsequent dispersion of the supported manganese complexes into ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMImPF₆) and 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMImBF₄) for recycling. The performance of chiral (salen)Mn(III) system in enantioselective epoxidation of olefins was investigated systematically. Even higher enantioselectivity than that of the homogeneous counterpart was obtained with similar catalytic activity. In particular, the best catalytic result is that the combination of the silica gel‐supported (salen)Mn(III) catalyst and BMImPF₆ affords 97–100% ee for epoxidation of α‐methylstyrene, and high ee values were retained even after three cycles. Copyright © 2010 John Wiley & Sons, Ltd.     

A Homogeneous Chiral Manganese(III)–Salphe Catalyst for Enantioselective Epoxidation of Olefins

A new chiral Mn(III)–Salphe catalyst was synthesized from natural amino acid (R)-phenylalanine and 3,5-di-tert-butyl-hydroxybenzaldehyde and applied to the asymmetric epoxidations of unfunctionalized olefins in ionic liquids. Satisfactory enantioselectivities (79% < ee < 93%) and good yields were achieved when NaClO was used as oxidant. We found that both the pH value (11.3) and reaction temperature (15 °C) were crucial for the epoxidation reactions. In our reaction system, NH₄OAc was unnecessary. We proposed that alcoholic hydroxyls in the Mn(III)–Salphe compound played the role of axial ligand. However, the reaction time was longer than when using Jacobsen's catalyst because of the structure of the Mn(III)–Salphe compound, in which coordination geometries by the two alcoholic hydroxyls with certain angles affected the substrate approaching the Mn(V) = 0 center. The chiral ligand was characterized by the combination of infrared, ultraviolet, and visible spectra and ¹H NMR.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

大位阻手性吡咯烷(salen)Mn(III)配合物在烯烃不对称环氧化反应中的应用

设计合成了具有大位阻的手性吡咯烷(salen)Mn(III)配合物Mn3,并研究了其在NaClO水/有机两相氧化体系中催化烯烃的不对称环氧化反应性能。 具有叔胺基团的配合物Mn3具有比Jacobsen催化剂更高的反应活性、以及近似的产率和略高的对映选择性。 尤其是过量CH₃I的加入可以极大地缩短环氧化反应的时间,而高产率和高对映选择性依然保持。     

Enhanced enantioselective oxidation of olefins catalyzed by Mn-porphyrin immobilized on graphene oxide

An efficient enantioselective heterogeneous catalyst, GO-[Mn(TPyP)tart], was prepared by covalent attachment of Mn(III) complex of H₂TPyP via the propyl linkage to graphene oxide (GO) nanosheet and using chiral tartrate counter ion. The catalyst was characterized by Fourier transform infrared (FT-IR), diffuse reflectance ultraviolet–visible (DR UV–Vis) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and thermogravimetric analysis (TGA). The graphene-supported Mn-porphyrin showed higher activity for the enantioselective epoxidation of unfunctionalized olefins with molecular oxygen in the presence of isobutyraldehyde. It could be recovered easily and reused in asymmetric oxidation of styrene precursor in a five-step sequence without any considerable loss of its catalytic activity and selectivity. The obtained optically epoxide selectivities were achieved in 86% to 100%.     

Asymmetric iodocyclization catalyzed by salen-CrIIICl: its synthetic application to swainsonine

The previously developed enantioselective iodocyclization of gamma-hydroxy-cis-alkenes required 30 mol% of (R,R)-salen-Co(II) complex as chiral catalyst and 0.75 equivalent of N-chlorosuccinimide (NCS) as activator to produce 2-substituted tetrahydrofurans with 61 to 90% ee. Due to the considerable loading amount of the Co(II) complex, another more effective catalyst was pursued by screening (R,R)-salen-transition metal complexes. When 10 mol% of the catalysts were applied with 0.5 equivalent of NCS, a higher level of stereoselectivity was attained with the corresponding Cr(III)Cl (84% ee), Mn(II)Cl (52% ee) and Co(II) complexes (66% ee). Refinement of the conditions established a novel catalytic enantioselective iodocyclization protocol using iodine in the presence of 7 mol% of (R,R)-salen-Cr(III)Cl complex activated by 0.7 equivalent of NCS in toluene to induce 74 to 93% ee.     

Enantioselective epoxidation of non-functionalised alkenes using a urea–hydrogen peroxide oxidant and a dimeric homochiral Mn(III)-Schiff base complex catalyst

The catalytic enantioselective epoxidation of chromenes, indene and styrene using a urea–hydrogen peroxide adduct as an oxidising agent and the novel dimeric homochiral Mn(III)-Schiff base catalyst 1 has been investigated in the presence of carboxylate salts and nitrogen and oxygen coordinating co-catalysts. Conversions of more than 99% were obtained with all alkenes except styrene. Absolute chiral induction, as determined by ¹H NMR using the chiral shift reagent (+)-Eu(hfc)₃, was obtained in the case of nitro- and cyanochromene. The catalyst could be re-used for up to five cycles with some loss of activity due to degradation of the catalyst under epoxidation condition with retention of e.e.'s.     

Chiral Jacobsen's catalyst immobilized on zinc poly(styrene‐phenylvinylphosphonate)‐phosphate functionalized by diamine as highly efficient and reusable catalyst for alkene epoxidation

Chiral Jacobsen's catalyst anchored on zinc poly(styrene‐phenylvinylphosphonate)‐phosphate (ZnPS‐PVPA) functionalized by diamines shows superior catalytic activities (conversion up to 99%; enantiomeric excess up to 99%) in the enantioselective epoxidations of unfunctional olefins with m ‐chloroperoxybenzoic acid and NaIO₄ as oxidants. The whole chiral salen Mn(III) catalyst, including the ZnPS‐PVPA support and the linker as well as chiral salen Mn ligand together contribute to the chirality of products. The heterogeneous catalyst has the potential for use in industry owing to superior stability (recycling nine times) and activity in large‐scale reactions (such as 200 times).     

Chiral Mn(III) salen complex immobilized on imidazole-modified mesoporous material via co-condensation method as an effective catalyst for olefin epoxidation

An imidazole modified mesoporous material has been prepared through a co-condensation procedure and adopted to covalently anchor chiral Mn(III) salen complex. The active centers in the as-synthesized catalyst were presented in the form of ionic species. The results of XRD, FTIR, DRUV-Vis, and N₂ sorption confirmed the successful immobilization of chiral Mn(III) salen complex inside the channels of the modified support and the maintenance of the mesoporous structure of parent support in the immobilized catalyst. This heterogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to those of the homogeneous counterpart in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, notably high turnover frequencies have been obtained over this heterogeneous catalyst for the relatively short reaction time and low catalyst amount, due in part to the ionic property as well as the uniform distribution of the active centers.     

离子液体功能化手性salen Mn(Ⅲ)配合物不对称催化仲醇氧化动力学拆分反应

采用共价键联法,将亲水性咪唑类离子液体结构引入手性salen Mn(Ⅲ)配合物的C5位,制备了离子液体功能化手性salen Mn(Ⅲ)配合物.傅里叶变换红外光谱、紫外光谱和旋光分析等结果表明,咪唑类离子液体结构已嫁接到手性salen Mn(Ⅲ)配合物结构中,且嫁接过程未破坏催化活性中心.在以PhI(OAc)2为氧化剂,H2O/CH2Cl2为溶剂的(+/-)-α-甲基苯甲醇不对称氧化动力学拆分反应中,该催化剂表现出比传统手性salen Mn(Ⅲ)催化剂更高的催化活性,仲醇的转化率达到63%以上,对映选择性为99%,拆分效率为18.3%.可通过调变溶剂实现催化剂的分离并重复使用3次以上.实验结果表明,亲水性咪唑离子液体可改善水相反应传质问题且有利于稳定催化活性中间体,从而提高催化活性及稳定性.