Reductive Amination of Aldehydes and Ketones with Primary Amines by Using Lithium Amidoborane as Reducing Reagent

A variety of secondary amines were obtained in high isolated yields in the reductive amination of aldehydes and ketones by using lithium amidoborane as reducing agent. Compared to ammonia borane, lithium amidoborane has higher reducibility, and thus, exhibits faster reaction rate.     

Mechanochemical Reaction of Aromatic Ketones and Aldehydes in the Presence of Zn-ZnCl2

The solvent-free reactions of aromatic ketones and aldehydes in the presence of Zn-ZnCl2 were performed with the aid of high-speed vibration mill, Retsch MM200 mixer mill and Retsch RM100 mortar grinder to give pinacol coupling and reduction products in varying yields.     

Rh-Catalyzed Coupling of Aldehydes with Allylboronates Enables Facile Access to Ketones

We present herein a novel strategy for the preparation of ketones from aldehydes and allylic boronic esters. This reaction involves the allylation of aldehydes with allylic boronic esters and the Rh-catalyzed chain-walking of homoallylic alcohols. The key to this successful development is the protodeboronation of alkenyl borylether intermediate via a tetravalent borate anion species in the presence of KHF₂ and MeOH. This approach features mild reaction conditions, broad substrate scope, and excellent functional group tolerance. Mechanistic studies also supported that the tandem allylation and chain-walking process were involved.     

微波干法催化醛酮与胺的缩合反应

利用微波辐射和固体中性Al2 O3 载体催化醛酮与胺的缩合反应的方法合成了十六种亚胺 ,研究了微波功率、作用时间、产物提取方式等因素对反应的影响 ;与无微波作用的一般合成方法相比 ,该法明显地提高反应速度及产率 ;文中用低极性熔点递变物质灌装毛细管的方法观测微波作用下反应温度 ,探讨微波作用化学反应的机理 ,其机理除与微波加热作用有关外还与分子间氢键及分子的缔合性有关。     

A Novel Lu Index to QSPR Studies of Aldehydes and Ketones

A novel index based on the hyper-Wiener index, named Lu, was proposed. The relative bond length between two adjacent vertices in a molecular graph was taken into account in the definition of the Lu index. The usefulness of the new index in QSPR study was verified by its correlation with a number of organic compounds including aliphatic aldehydes and ketones. For each of the physical properties (the normal boiling points, molar refractions and gas heat capacities at 25°C), high quality QSPR models were obtained. The final models were validated to be statistically reliable using the leave-one-out cross validation and/or an external test set. The correlation coefficients (> 0.99) of all constructed models indicate the necessity of such an index, and show the potential of the Lu index for QSAR/QSPR studies.     

气相色谱辅助傅里叶红外光谱用于固定污染源大气醛酮毒物的监测

获得了９种大气中常见的醛、酮及甲醇毒物的ＦＴＩＲ系列标准光谱图，建立了用衍生化气相色谱法和非衍生化气相色谱法辅助获得了ＦＴＩＲ标准谱图的技术，详细讨论了用人工干预ＦＴＩＲ光谱自动差减法定量分析上述常见醛、酮污染物的可行性问题。     

A Novel Environmentally Benign Method for the Selective Oxidation of Alcohols to Aldehydes and Ketones

In the presence of [Ru(terpyridine)(2,6‐pyridinedicarboxylate)], aliphatic and benzylic alcohols are oxidized to the corresponding aldehydes or ketones with high selectivity by using hydrogen peroxide as the oxidant. There is no need for the addition of co‐catalysts or organic solvents. By applying an optimized reaction protocol, high catalyst productivity (turnover number>10 000) and activity (turnover frequency up to 14 800 h^?1) has been achieved.     

Triphenylmethylphosphonium Dichromate: An Effective and Chemoselective Reagent for Oxidation of Benzylic Alcohols to the Corresponding Aldehydes and Ketones

An efficient and straightforward method for oxidation of the benzylic alcohols to the corresponding aldehydes and ketones has been accomplished using triphenylmethylphosphonium dichromate (MTPPD) under solvent-free conditions with high chemoselectivity. The reaction is fast with good yields and straightforward workup.     

General Reductive Amination of Aldehydes and Ketones with Amines and Nitroaromatics under H2 by Recyclable Iridium Catalysts

Heterogeneous iridium catalysts were prepared and applied for the reductive amination of aldehydes and ketones with nitroaromatics and amines using H₂ . The iridium catalysts were prepared by pyrolysis of ionic liquid 1‐methyl‐3‐cyanomethylimidazoulium chloride ([MCNI ]Cl) with iridium chloride (IrCl₃ ) in activated carbons. Iridium particles were well dispersed and stable in the N‐doped carbon materials from [MCNI ]Cl with activated carbon. The Ir@NC (600‐2h) catalyst was found to be highly active and selective for the reductive amination of aldehydes and ketones using H₂ and a variety of nitrobenzenes and amines were selectively converted into the corresponding secondary and tertiary amines. The Ir@NC (600‐2h) catalyst can be reusable several times without evident deactivation.     

Ruthenium‐Catalyzed Direct Asymmetric Reductive Amination of Diaryl and Sterically Hindered Ketones with Ammonium Salts and H2

A Ru‐catalyzed direct asymmetric reductive amination of ortho‐OH‐substituted diaryl and sterically hindered ketones with ammonium salts is reported. This method represents a straightforward route toward the synthesis of synthetically useful chiral primary diarylmethylamines and sterically hindered benzylamines (up to 97 % yield, 93–>99 % ee). Elaborations of the chiral amine products into bioactive compounds and a chiral ligand were demonstrated through manipulation of the removable and convertible ‐OH group.     

KF‐Melamine Formaldehyde Resin (KF‐MFR) as a Versatile and Efficient Heterogeneous Reagent for Aldol Condensation of Aldehydes and Ketones under Microwave Irradiation

KF‐Melamine formaldehyde resin (KF‐MFR) was demonstrated to be a highly efficient heterogenious catalyst for cross‐aldol condensation under microwave irradiation. In this synthesis, various aldehydes and ketones were condensed together in the presence of supported KF on melamine‐formaldehyde resin to afford different chalcone derivatives in good to excellent yields. KF‐MFR proved to have unique termal and chemical resistance and can be reused for many consecutive runs without remarkable loss in catalytic activity.     

Copper‐Catalyzed Reductive N‐Alkylation of Amides with N‐Tosylhydrazones Derived from Ketones

A CuI‐catalyzed reductive coupling of ketone‐derived N‐tosylhydrazones with amides is presented. Under the optimized conditions, an array of N‐tosylhydrazones derived from aryl–alkyl and diaryl ketones could couple effectively with a wide variety of (hetero)aryl as well as aliphatic amides to afford the N‐alkylated amides in high yields. The method represents the very few examples for reliably accessing secondary and tertiary amides through a reductive N‐alkylation protocol.     

Stereogenic Phosphorus‐Induced Diastereoselective Formation of Chiral Carbon during Nucleophilic Addition of Chiral HP Species to Aldehydes or Ketones

P,C‐Stereogenic α‐hydroxyl phosphinates or phosphine oxides were prepared from the additions of (R_P)‐phosphinate to ketones or (R_P)‐phosphine oxide to aldehydes, respectively, catalyzed by bases at room temperature in up to >99:1 diasteromeric ratio (d.r._P/d.r._C) and 99 % yields. The diastereoselectivity was induced by reversible equilibrium and different stabilities between two diastereomers of adduct, which was caused by the spatial interaction between menthoxyl or menthyl to alkyl groups of aldehydes or ketones.     

Chemoselective Oxidation of Benzyl,Amino, and Propargyl Alcohols to Aldehydes and Ketones under Mild Reaction Conditions

Catalytic oxidation reactions often suffer from drawbacks such as low yields and poor selectivity. Particularly, selective oxidation of alcohols becomes more difficult when a compound contains more than one oxidizable functional group. In order to deliver a methodology that addresses these issues, herein we report an efficient, aerobic, chemoselective and simplified approach to oxidize a broad range of benzyl and propargyl alcohols containing diverse functional groups to their corresponding aldehydes and ketones in excellent yields under mild reaction conditions. Optimal yields were obtained at room temperature using 1 mmol substrate, 10 mol % copper(I) iodide, 10 mol % 4-dimethylaminopyridine (DMAP), and 1 mol % 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) in acetonitrile, under an oxygen balloon. The catalytic system can be applied even when sensitive and oxidizable groups such as alkynes, amines, and phenols are present; starting materials and products containing such groups were found to be stable under the developed conditions.     

高效液相色谱法测定卷烟滤嘴对主流烟气中低分子醛酮化合物的截留效率

用高效液相色谱法测定了用过的烟嘴中8种低分子醛酮化合物,据此对烟嘴从主流烟气中截留8种化合物的效率。烟嘴样品用衍生试剂溶液与甲醇(10+90)混合液30 mL萃取10min,分取适量萃取液供高效液相色谱分析。以DIONEX Explosives色谱柱为分离柱,用乙腈和水以不同比例混合的溶液为流动相进行梯度洗脱,在检测波长365nm处进行测定。8种低分子醛酮化合物在一定质量浓度范围内与其峰面积呈线性关系,方法的检出限(3s)在0.07~0.15mg·L-1之间。加标回收率在85.1%~102%之间,测定值的相对标准偏差(n=5)小于6.8%。