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.     

Inside Cover: Biomimetic Chiral Pyridoxal and Pyridoxamine Catalysts (Chin. J. Chem. 2/2019)

The inside cover picture shows the development of chiral pyridoxal and pyridoxamine catalysts by mimicking vitamin B₆‐dependent enzymes. These chiral pyridoxals and pyridoxamines displayed extraordinary catalytic performances in asymmetric biomimetic transamination and Mannich reaction, to give various chiral α‐amino acids and α,β‐diamino acid esters in good yields with excellent diastero‐ and/or enantioselectivities. The research has provided some useful information for further applications of the catalytic power of vitamin B6 in the area of asymmetric cayalysis. More details are discussed in the article by Zhao et al. on page 103–112.

     

Reductive Amination of Aldehydes and Ketones with 2-(Tributylamino)-ethoxyborohydride

Summary. A new ionic liquid is presented as a medium and reducing agent for the reductive amination of aldehydes and ketones.     

Reductive Amination of Aldehydes and Ketones with 2-(Tributylamino)-ethoxyborohydride

A new ionic liquid is presented as a medium and reducing agent for the reductive amination of aldehydes and ketones.     

Reductive Amination of Aldehydes and Ketones with Sodium Triacetoxyborohydride. Studies on Direct and Indirect Reductive Amination Procedures(1)

Sodium triacetoxyborohydride is presented as a general reducing agent for the reductive amination of aldehydes and ketones. Procedures for using this mild and selective reagent have been developed for a wide variety of substrates. The scope of the reaction includes aliphatic acyclic and cyclic ketones, aliphatic and aromatic aldehydes, and primary and secondary amines including a variety of weakly basic and nonbasic amines. Limitations include reactions with aromatic and unsaturated ketones and some sterically hindered ketones and amines. 1,2-Dichloroethane (DCE) is the preferred reaction solvent, but reactions can also be carried out in tetrahydrofuran (THF) and occasionally in acetonitrile. Acetic acid may be used as catalyst with ketone reactions, but it is generally not needed with aldehydes. The procedure is carried out effectively in the presence of acid sensitive functional groups such as acetals and ketals; it can also be carried out in the presence of reducible functional groups such as C-C multiple bonds and cyano and nitro groups. Reactions are generally faster in DCE than in THF, and in both solvents, reactions are faster in the presence of AcOH. In comparison with other reductive amination procedures such as NaBH(3)CN/MeOH, borane-pyridine, and catalytic hydrogenation, NaBH(OAc)(3) gave consistently higher yields and fewer side products. In the reductive amination of some aldehydes with primary amines where dialkylation is a problem we adopted a stepwise procedure involving imine formation in MeOH followed by reduction with NaBH(4).     

Inside Back Cover: Allosteric Modulation of Human Serum Albumin Induced by Peptide Ligand (Chin. J. Chem. 8/2017)

The inside back cover picture shows the allosteric modulation of human serum albumin (HSA) induced by the Peptide SA06 ligand. Peptide SA06 is a reported peptide ligand comprising 20 amino acids, and is known to non‐covalently bind with HSA to extend the lifetime and improve the pharmacokinetic performance of drug molecules. The structural evidence on the allosteric interaction between peptide ligand and HSA, and the structure‐affinity relations of the binding mechanism have been revealed in this work, which can also shed light on optimization of therapeutic properties in the affinity‐controlled delivery systems. More details are discussed in the article by Wang et al. on page 1270–1277.

     

Reductive Amination of Aldehydes and Ketones to Their Corresponding Amines with NaBH4 in Micellar Media

A variety of aliphatic and aromatic aldehydes and ketones were efficiently reduced to their corresponding amines when treated with primary and secondary amines and NaBH₄ in micellar media at room temperature under neutral conditions.     

Inside Cover: Structural Designs for Accommodating Volume Expansion in Sodium Ion Batteries (Chin. J. Chem. 9/2018)

The inside cover picture shows that four effective routes are applied to the anode material to help it keep fit, which is out of shape due to the intake of sodium ions. As a result, the sodium ion batteries (SIBs) with this anode exhibit high electrochemical performances, so that they tend to meet the demand for large‐scale energy storage devices. In this review, four strategies based on structural designs are summarized in order to accommodate volume changes of anode materials in SIBs, including nanoarchitecture configuration, buffer matrix protection, cavity volume reservation, and interlayer spacing regulation. More details are discussed in the review by Fu et al. on page 866–874.

     

Inside Back Cover: Cu(II)‐Catalyzed Ligand‐Free Oxidation of Diarylmethanes and Second Alcohols in Water (Chin. J. Chem. 9/2017)

The inside back cover picture shows a simple and efficient Cu(II )‐catalyzed ligand‐free oxidation of diarylmethanes and secondary alcohols using 70% TBHP in water. A series of diarylmethanes were directly oxidized into diaryl ketones in 67%–98% yields. Additionally, various secondary alcohols were also transformed into the desired products in 48%–98% yields. Importantly, the catalytic system in the absence of any organic solvent, surfactant, or phase transfer agent, had a wide substrate scope and a high tolerance for various functional groups. More details are discussed in the article by Liu et al. on page 1391–1395.

     

Efficient Protocol for Reductive Amination of Aldehydes and Ketones with Sodium Borohydride in an Ionic Liquid/H2O System

The imines were generated in situ from carbonyl compounds and amines, which undergo smooth reduction with sodium borohydride in an ionic liquid/H₂O solvent system. The reaction conditions were very mild and neutral to afford the corresponding highly functionalized amines in excellent yields.     

Inside Cover: Construction of Highly Emissive Pt(II) Metallacycles upon Irradiation (Chin. J. Chem. 4/2019)

The inside cover picture shows  in situ construction of highly emissive Pt(II) metallacycles upon irradiation. The self‐assembled diarylethene‐containing metallacycles can realize supramolecular transform from the open‐ring isomers to their closed‐ring ones under UV irradiation. Moreover, the closed‐ring isomers featured a relatively high fluorescence quantum yield. This property of “turn‐on” fluorescence switching provides a new method to construct highly emissive supramolecular fluorescent materials by light stimulus. More details are discussed in the article by Yang et al. on page 323–329.

     

Cover Picture: Highly Stable Molecular Borromean Rings (Chin. J. Chem. 2/2018)

The cover picture shows a series of Cp*Rh‐based molecular Borromean rings (BRs), which consist of three chemically independent rings that are locked in such a way that no two of the three rings are linked with each other. Interestingly, the structure of BRs is very similar to Kong Ming Lock (孔明锁), a kind of Chinese traditional six‐piece burr puzzle. In this work, some of as‐synthesized BRs display high stability in solution. The reason is related to the length ratio of the long‐arm linker and short‐arm linker, where smaller aspect ratios of the metallarectangles promote improved stability of the BRs in solution. Increasing the width of the metallaligand or pyridyl ligand hinders the formation of BRs and leads to unoccupied monomeric rectangles, which were further used as catalysts. More details are discussed in the article by Jin et al. on page 106–111.