MIL-101(Cr)-SO_3H催化2-取代喹啉衍生物转移氢化反应的研究

2-取代-1,2,3,4-四氢喹啉骨架广泛存在于天然产物中,具有抗疟、抗氧化等生物活性.报道了MIL-101(Cr)-SO3H催化以汉奇酯为氢供体的2-取代喹啉衍生物的转移氢化反应.该方法反应条件温和,适用于2位具有不同取代基的喹啉衍生物,催化剂易于回收和循环利用,为2-取代-1,2,3,4-四氢喹啉衍生物的合成提供了新途径.     

基于喹啉选择加氢反应的多相金属催化剂研究进展

喹啉选择加氢制备1,2,3,4-四氢喹啉是最为简便和可行的方法,后者是一种重要的精细化工中间体.本文综述了近10年基于喹啉及其衍生物选择加氢反应的多相金属催化剂研究进展,探讨了活性金属组分和载体对催化性能的影响.最后对该领域存在的问题和发展前景进行了总结和展望.     

金属有机框架与Pt粒子复合材料催化喹啉选择性加氢性能研究※

喹啉选择性加氢制备1,2,3,4-四氢喹啉在药物、农药和精细化学品等的生产中表现出巨大的应用潜力, 引起了广泛关注. 该反应通常要在高温、高压等苛刻条件下进行, 温和条件下对其选择性加氢仍具有很大挑战. 本工作以氯化锆为金属盐和2,2'-联吡啶-5,5'-二羧酸为配体制备金属有机框架材料UiO-67N, 以Pt纳米粒子为活性组分, 可控制备出具有三明治结构的UiO-67N@Pt@UiO-67N复合催化剂, 同时可调控其壳层厚度为11, 28和42 nm. 利用X射线衍射分析、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、电感耦合等离子发射光谱仪、傅里叶变换红外光谱仪和氮气吸脱附测试对催化剂进行了系统表征. 研究发现, 相比于UiO-67而言, UiO-67N可以显著提高Pt纳米粒子催化喹啉选择性加氢的性能, 且UiO-67N@Pt@UiO-67N在常温下实现了高转化率(>99%)和高选择性(>99%)催化喹啉加氢制备1,2,3,4-四氢喹啉; 随着壳层厚度的增加, 其催化活性会显著降低, 但选择性保持不变. 以喹啉的衍生物作为底物, 三明治结构催化剂也可展现出优异的活性和选择性加氢性能. 相比于负载型催化剂, 三明治结构复合催化剂具有优异的循环稳定性. X射线光电子能谱和红外光谱分析表明, UiO-67N与Pt纳米粒子间的电子转移, 以及与喹啉间的强界面相互作用有助于提高催化剂的性能.     

纳米Ru催化剂催化喹啉加氢反应

制备了高分散性负载型5%Ru/C催化剂,采用X射线衍射、X射线光电子能谱和高分辨透射电镜对催化剂进行了表征.结果表明,所制得的5%Ru/C催化剂分散度高,金属钌的平均粒径小于5nm.在喹啉加氢反应中,催化剂显示出很高的催化活性和生成1,2,3,4-四氢喹啉的选择性,但未检测到十氢喹啉生成.补加新鲜催化剂后,1,2,3,4-四氢喹啉可全部转化为十氢喹啉.对喹啉加氢机理进行了探讨.     

(S)-N-取代-1,2,3,4-四氢异喹啉-3-甲酰胺催化直接不对称Aldol反应研究

本文研究了以(S) -N-取代-1,2,3,4-四氢异喹啉-3-甲酰胺衍生物的有机小分子催化剂催化不对称Aldol反应,得到高达92%收率和57%的ee值.     

6-羟基-3,4-二氢喹啉-1(2H)-羧酸叔丁基酯的合成研究

以6-羟基喹啉为原料,使用钯碳催化加氢和硼氢化钠还原两种方法合成了6-羟基-1,2,3,4-四氢喹啉化合物,考察反应温度与碱性条件对6-羟基-3,4-二氢喹啉-1(2H)-羧酸叔丁基酯合成收率的影响,10℃反应温度下,以碳酸氢钠作碱是合成的最佳反应条件。     

多孔SiO_2·xH_2O负载RuB纳米粒子催化喹啉加氢反应

通过水解,聚乙烯吡咯烷酮(PVP)保护,NaOH刻蚀等方法制备了多孔及富含表面羟基的SiO2·xH2O负载的RuB催化剂RuB/SiO2·xH2O,并用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、傅里叶变换红外(FT-IR)光谱和BET(Brunauer-Emmett-Teller)等手段对该催化剂进行了表征.结果表明该催化剂具有良好的抗中毒能力,在3.0MPa的H2压力和80℃的温和反应条件下,喹啉的转化率高于95%,生成1,2,3,4-四氢喹啉的选择性高于97%.并系统研究了表面羟基和溶剂对催化剂性能的影响,发现以水为溶剂时,RuB/SiO2·xH2O对喹啉加氢反应展示出较高的活性和对1,2,3,4-四氢喹啉较高的选择性,催化剂能够多次循环使用.这一体系的优异催化性能归属于载体表面羟基和水的协同作用.     

高分散 Ru/MMT 催化剂的制备及其催化喹啉加氢性能

 通过简单的离子交换法制备出高分散的蒙脱土 (MMT) 负载 Ru 催化剂, 采用 X 射线衍射、X 射线光电子能谱、程序升温还原和高分辨透射电子显微镜等手段对催化剂进行了表征. 结果表明, 金属 Ru 在蒙脱土层间高度分散, Ru 的平均粒径约 2 nm. 在喹啉加氢反应中, 该催化剂显示出很高的反应活性和选择性. 在 2 MPa 和 60 °C 的温和条件下, 以水为溶剂时, Ru/MMT 催化喹啉加氢生成 1,2,3,4-四氢喹啉的选择性高于 96.4%, 喹啉转化率达 99.2%. 当温度升高到 140 °C、压力增加到 3 MPa 时, 不需要补加催化剂就可以将喹啉一步加氢生成十氢喹啉, 选择性高达 98.1%.     

Ru/ZrO2·xH2O催化喹啉加氢反应

制备了负载型催化剂Ru/ZrO2·xH2O,并用XRD、XPS和TEM对催化剂进行了表征,所制得的催化剂金属钌的平均粒径约为3.8 nm.在2MPa和40℃的温和条件下,以水为溶剂时,Ru/ZrO2·rH2O催化喹啉加氢生成1,2,3,4-四氢喹啉的选择性达98.0%,而且表现出较强的抗氮中毒能力,催化剂循环使用性能稳定.对喹啉加氢反应中的催化反应机理进行了探讨.     

Ru/ZrO2·xH2O催化喹啉加氢反应

制备了负载型催化剂Ru/ZrO2·xH2O, 并用XRD、XPS和TEM对催化剂进行了表征, 所制得的催化剂金属钌的平均粒径约为3.8 nm. 在2 MPa和40 ℃的温和条件下, 以水为溶剂时, Ru/ZrO2·xH2O催化喹啉加氢生成1,2,3,4-四氢喹啉的选择性达98.0%, 而且表现出较强的抗氮中毒能力, 催化剂循环使用性能稳定. 对喹啉加氢反应中的催化反应机理进行了探讨.     

Chemoselective hydrogenation method catalyzed by Pd/C using diphenylsulfide as a reasonable catalyst poison

While Pd/C is one of the most useful catalysts for hydrogenation, the high catalyst activity of Pd/C causes difficulty in its application to chemoselective hydrogenation between different types of reducible functionalities. In order to achieve chemoselective hydrogenation using Pd/C, we investigated catalyst poison as a controller of the catalyst activity. We found that the addition of Ph₂S (diphenylsulfide) to the Pd/C-catalyzed hydrogenation reaction mixture led to reasonable deactivation of Pd/C. By the use of the Pd/C-Ph₂S catalytic system, olefins, acetylenes, and azides can be selectively reduced in the coexistence of aromatic carbonyls, aromatic halides, cyano groups, benzyl esters, and N-Cbz (benzyloxycarbonyl) protecting groups. The present method is promising as a general and practical chemoselective hydrogenation process in synthetic organic chemistry.     

Adaptive Catalysts for the Selective Hydrogenation of Bicyclic Heteroaromatics using Ruthenium Nanoparticles on a CO2-Responsive Support

Ruthenium nanoparticles (NPs) immobilized on an amine-functionalized polymer-grafted silica support act as adaptive catalysts for the hydrogenation of bicyclic heteroaromatics. Whereas full hydrogenation of benzofuran and quinoline derivatives is achieved under pure H₂, introducing CO₂ into the H₂ gas phase leads to an effective shutdown of the arene hydrogenation while preserving the activity for the hydrogenation of the heteroaromatic part. The selectivity switch originates from the generation of ammonium formate species on the surface of the materials by catalytic hydrogenation of CO₂. The CO₂ hydrogenation is fully reversible, resulting in a robust and rapid switch between the two states of the catalyst adapting its performance in response to the feed gas composition. A variety of benzofuran and quinoline derivatives were hydrogenated to fully or partially saturated products in high selectivity and yields simply by altering the composition of the feed gas from H₂ to H₂/CO₂. The adaptive catalytic system thus provides controlled access to valuable products using a single catalyst rather than two specific and distinct catalysts with static reactivity.     

Solid supported Pd(0): an efficient recyclable heterogeneous catalyst for chemoselective reduction of nitroarenes

Solid supported palladium(0) (SS-Pd) catalyzed highly chemoselective reduction of nitroarenes to the corresponding anilines was accomplished under a milder reaction condition. This catalyst showed high compatibility with various reducing agents (NaBH₄, Et₃SiH, and NH₂NH₂·H₂O) and a large number of reducible functional groups such as sulfonamide, amides, carboxylic acid, ester, alcohol, halide, hetero cycle, nitrile, alkene, carbonyl, O-benzyl, and N-benzyl were tolerated. Most of the reactions were clean and high yielding. The SS-Pd catalyst could be recycled up to seven runs without significant loss of activity.     

Solid‐Supported Green Synthesis of Substituted Hydrocinnamic Esters by Focused Microwave Irradiation

An efficient chemoselective hydrogenation protocol for substituted cinnamic esters is developed for the synthesis in quantitative yield of corresponding bioactive dihydrocinnamic esters with solid‐supported palladium chloride/ammonium formate (cat.) in HCOOH/H₂O 1 : 2 as a hydrogenating agent under focused‐microwave irradiation for 10 min.     

Characterization of a Polymer-Bound Palladium Acetate Catalyst and Studies on the Selective Hydrogenation of Dienes and Alkynes

Abstract

Palladium(II) acetate has been anchored onto a copolymer support containing pyridyl and carboxyl groups. XPS studies showed the Pd 3d binding energies for the recovered catalyst to be less by 1 eV after being used in hydrogenation studies. However, x-ray studies and a chemical test based on KCN treatment failed to reveal any palladium oxide or palladium metal formation in the recovered catalyst. It is presumed that an acetate ligand is lost during hydrogenation, which could be the reason for the lowering of the palladium 3d binding energies in the recovered catalyst. Results of investigations of the hydrogenation of olefins and selectivity of the catalyst toward the hydrogenation of dienes and alkynes are presented. The loss of palladium due to leaching under the reaction conditions employed was found to be very low (<1%/cycle).     

Selective hydrogenation of aromatic compounds using modified iridium nanoparticles

Till now, Ionic liquid‐stabilized metal nanoparticles were investigated as catalytic materials, mostly in the hydrogenation of simple substrates like olefins or arenes. The adjustable hydrogenation products of aromatic compounds, including quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes, are always of special interest, since they provide more choices for additional derivatization. Iridium nanoparticles (Ir NPs) were synthesized by the H₂ reduction in imidazolium ionic liquid. TEM indicated that the Ir NPs is worm‐like shape with the diameter around 12.2 nm and IR confirmed the modification of phosphine‐functionalized ionic liquids (PFILs) to the Ir NPs. With the variation of the modifier, solvent and reaction temperature, substrate like quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes could be hydrogenated by Ir NPs with interesting adjustable catalytic activity and chemoselectivity. Ir NPs modified by PFILs are simple and efficient catalysts in challenging chemoselective hydrogenation of quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes. The activity and chemoselectivity of the Ir NPs could be obviously impacted or adjusted by altering the modifier, solvent and reaction temperature.     

Catalytic Generation and Chemoselective Transfer of Nucleophilic Hydrides from Dihydrogen

Copper(I)–N-heterocyclic-carbene (NHC) complexes enabled the catalytic generation of nucleophilic hydrides from dihydrogen (H₂) and their subsequent transfer to allylic chlorides. The highly chemoselective catalyst displayed no concomitant hydrogenation reactivity; in fact, the terminal double bond formed in the hydride transfer remained intact. Switching to deuterium gas (D₂) allowed for regioselective monodeuteration with excellent isotope incorporation.     

Celite‐Polyaniline supported palladium catalyst for chemoselective hydrogenation reactions

Polyaniline coated on particles of celite is used as support to load palladium catalyst. This heterogenized Celite?PANI?Pd system, is used as an efficient catalyst for chemoselective hydrogenation reactions. The catalyst is characterized by usual spectral, analytical techniques and studied for hydrogenation reactions at ambient conditions. The mild reaction conditions allow the control over the reactions and excellent selectivity is achieved in number of conversions. Hydrogenation of a carbon–carbon double bond was favored over other polar π‐bond systems, while labile functional groups such as benzyl ether, benzyl esters, cyano, nitro and halogen remained unaffected. Primary amines were converted to N,N‐dimethyl amines with formaldehyde, the double bond of coumarin was selectively hydrogenated without opening of the lactone functionality.     

Development of a Practical and Scalable Preparation using Sonication of Pd/Fibroin Catalyst for Chemoselective Hydrogenation

A practical and efficient preparation method of palladium‐fibroin (Pd/Fib), silk‐fibroin‐supported Pd(0) by means of sonication, has been developed. The Pd/Fib catalyst could be prepared within 12 h at room temperature starting from commercial silk‐fibroin and Pd(OAc)₂ in MeOH, whereas our previous preparation method required at least 4 days. The present improved process is applicable to a large‐scale preparation of Pd/Fib. The Pd/Fib prepared by the present method also catalyzed chemoselective hydrogenation of acetylenes, olefins, and azides in the presence of aromatic ketones, aldehydes, and halides; N‐Cbz protective groups; and benzyl esters, which are readily hydrogenated under the Pd/C‐ or Pd/C(en)‐catalyzed hydrogenation conditions.