Synthesis of 2(1H)-pyrazinone phosphonates via an Arbuzov-type reaction

A simple and catalyst-free method for the synthesis of phosphonated 2(1H)-pyrazinones is described starting from 3,5-dichloropyrazinones. The method also works for 3-bromo- and 3-iodopyrazinones. Classical heating conditions as well as microwave-enhanced reaction conditions were tested.     

Asymmetric multicomponent copper catalyzed synthesis of chiral propargylamines

A three-component stereoselective reaction between an aldehyde, an amine and phenylacetylene to afford optically active propargyl amines in good yields was developed. The reaction is catalysed by copper complexes of enantiomerically pure bis-imines. The best results were obtained with imines readily prepared in very high yields from the commercially available binaphtyl diamine.

A very simple experimental procedure at room temperature allowed to obtain optically active propargyl amines in very good yields and enantioselectivity up to 75%. The extremely simple methodology and the mild reaction conditions, as well as the possibility of a modular approach for developing new and more efficient bis-imine-based chiral ligands make the present methodology very attractive.     

2,6—二异丙苯异氰酸酯的新的简便合成

报道了用Ｐｂ（ＯＡｃ）４氧化草酸单酰胺制得异氰酸酯的一种新方法，合成反应改在非水溶液中进行，该法反应条件简单，试剂低毒和价格便宜，并且产率高，适用于工业生产。     

Oscillations in non-mass action kinetics models of biochemical reaction networks arising from pairs of subnetworks

It is well known that oscillations in models of biochemical reaction networks can arise as a result of a single negative cycle. On the other hand, methods for finding general network conditions for potential oscillations in large biochemical reaction networks containing many cycles are not well developed. A biochemical reaction network with any number of species is represented by a simple digraph and is modeled by an ordinary differential equation (ODE) system with non-mass action kinetics. The obtained graph-theoretic condition generalizes the negative cycle condition for oscillations in ODE models to the existence of a pair of subnetworks, where each subnetwork contains an even number of positive cycles. The technique is illustrated with a model of genetic regulation.     

Expeditious and efficient synthesis of Strecker’s α-aminonitriles catalyzed by sulfated polyborate

A straightforward, mild, efficient, and environmentally benign protocol for a three-component Strecker reaction of aldehydes or ketones, amines, and trimethylsilyl cyanide catalyzed by sulfated polyborate has been described to afford α-aminonitriles under solvent-free reaction conditions. The major advantages of the present method are excellent yields, shorter reaction time, simple experimental procedure, easy workup procedure, recyclability of the catalyst, solvent-free reaction conditions and ability to tolerate a variety of functional groups which gives economical as well as ecological rewards.     

Gold-catalyzed direct oxidative coupling reactions of non-activated arenes

A general gold-catalyzed oxidative homo- and hetero-coupling of arenes in mild conditions is described. This reaction gives moderate to excellent yield using PhI(OAc)₂ as an oxidant. The effects of temperature, solvent, oxidant and concentration of substrate in this process have also been studied in detail. The product identity and distribution as well as the substrate limitation give us insights into this type of gold catalysts. Depending upon the reaction conditions, the gold catalyst behaves as a simple Lewis acid, which produces amines from arenes using DIAD as an aminating reagent.     

Immobilization of Iridium Triazolylidene Complexes into Polymer Scaffolds and Their Application in Water Oxidation

A triazolylidene irdium complex was postmodified with simple methods to introduce two alcohol groups in the triazolylidene backbone. The reaction of this difunctionalized iridium triazolylidene unit with terephthalic acid chloride allowed for integrating these iridium complexes into a polymeric assembly. Both the monomeric complexes as well as the polymerized systems showed activity in water oxidation driven by cerium ammonium nitrate as a chemical oxidant with comparable catalytic performance. Post-reaction analysis of the aqueous reaction solution by ICP MS showed a partial loss of iridium from the polymer into the aqueous phase under catalytic conditions, indicating a need for more robust polymer supports for this type of application.     

颜色指示法高通量筛选多相催化材料

介绍一种简单的组合化学技术, 用来筛选或优化多相催化反应中的催化剂. 在酯化反应中, 用甲基橙指示剂指示酯化反应的进程并对沸石的类型, 不同碳链的醇和酸的催化活性进行研究. 在光催化反应中, 选择甲基橙、罗丹明B作为反应物. 通过颜色变化, 对不同方法制备的TiO2进行高通量筛选.     

Immobilization and Continuous Recycling of Photoredox Catalysts in Ionic Liquids for Applications in Batch Reactions and Flow Systems: Catalytic Alkene Isomerization by Using Visible Light

A catalytic (E)‐ to (Z)‐isomerization of olefins using a photoredox catalyst under mild reaction conditions is presented. A variety of (Z)‐alkenes can be prepared in the presence of visible light. A new reaction system allows an easy and efficient scale‐up, as well as a continuous flow process in which the photocatalyst is immobilized in an ionic liquid and continuously recycled by simple phase separation.     

Rhenium-Catalyzed Construction of Polycyclic Hydrocarbon Frameworks by a Unique Cyclization of 1,n-Diynes Initiated by 1,1-Difunctionalization with Carbon Nucleophiles

A regioselective cyclization of 1,n-diynes under rhenium catalysis was developed on the basis of a rare type of 1,1-difunctionalization of terminal alkynes with carbon nucleophiles, followed by sequential addition reactions of the resulting alkenylrhenium species. The reaction provides an efficient approach to the synthesis of complex cyclopentane-fused bi- and tricycles and spirocycles, which are useful building blocks for the construction of essential frameworks of biologically active compounds as well as functional materials, from simple starting materials by the formation of up to six new carbon–carbon bonds in a single step. The reaction proceeds under neutral conditions and does not require external ligands or additives. The key to this reactivity is the unique activation mode of the rhenium carbonyl complex, which prefers to interact with heteroatoms in polar carbon–heteroatom bonds as well as nonpolar carbon–carbon unsaturated π bonds.     

Diisopropylethylammonium acetate (DIPEAc): An efficient and recyclable catalyst for the rapid synthesis of 5-substituted-1H-tetrazoles

A simple and efficient protocol developed for the synthesis of 5-substituted 1H-tetrazole derivatives through [2+3] cycloaddition reaction between benzonitriles and sodium azide using diisopropylethylammonium acetate as a recyclable reaction medium is described. The reactions proceed well at 80?°C and provide the corresponding tetrazoles in good to excellent yields (up to 94% yield). Developed method has notable advantages, such as simple and mild conditions, easy workup, reusability with consistent catalytic activity, and safer alternative to hazardous, corrosive conventional Lewis acid catalysts.     

Copper-catalyzed aerobic oxidation of hydroxamic acids leads to a mild and versatile acylnitroso ene reaction

A mild formation of transient acylnitroso intermediates using a copper chloride catalyst and 1 atm of air as the terminal oxidant is described. The mild reaction conditions enable the inter- and intramolecular acylnitroso ene reaction with a wide range of functionalized alkene partners, as well as the first asymmetric variant. Notably, this transformation provides a practical and operationally simple method for effecting allylic amidation using an environmentally benign oxidant and a readily abundant transition metal.     

Amines made easily: a highly selective hydroaminomethylation of olefins

A highly chemo- and regioselective hydroaminomethylation of simple as well as functionalized alpha-olefins using a cationic rhodium precatalyst together with Xantphos as ligand is reported. Studies of the influence of ligands and reaction conditions led to an unprecedented selective hydroaminomethylation procedure. The novel procedure constitutes an economically attractive and environmentally favorable synthesis of secondary and tertiary aliphatic amines.     

NBS-mediated practical cyclization of N-acyl amidines to 1,2,4-oxadiazoles via oxidative N‒O bond formation

A reaction involving an efficient NBS-mediated oxidative N?O bond formation has been established for the synthesis of 1,2,4-oxadiazoles from readily accessible N-acyl amidines. The features of this synthetic method include simplicity of operation, mild reaction conditions, short reaction times, high yields, and eco-friendliness. The reaction also works well with crude N-acyl amidines obtained by amidation of simple benzoic acids and amidines to produce biologically relevant 1,2,4-oxadiazoles in a scalable fashion.     

A facile preparation of imidazolinium chlorides

A process for the preparation of symmetric and unsymmetric imidazolinium chlorides that involves reaction of a formamidine with dichloroethane and a base (a) is described. This method makes it possible to obtain numerous imidazolinium chlorides under solvent-free reaction conditions and in excellent yields with purification by simple filtration. Alternatively, symmetric imidazolinium chlorides can be prepared directly in moderate yields from substituted anilines by utilizing half of the formamidine intermediate as sacrificial base (b).     

Macromolecular reaction and interdiffusion in a compatible polymer blend

A theory describing slow macromolecular reaction and interdiffuion in a compatible polymer blend is suggested based on the linear non-equilibrium thermodynamic principles. A simple model system is considered. In a blend consisting initially of homopolymers A and B, the transformation A → B proceeds with the B units accelerating the reaction. A system of diffusive-reaction equations for relevant macroscopic variables is derived. The randomness of the reacting chains' structure gives rise to a new interdiffusion mode in addition to the reacting polymer-homopolymer B interdiffusion. Numerical calculations reveal that the diffusive intermixing of reacting chains of different composition may significantly affect the reaction rate and the local compositional heterogeneity as well. It is possible to discriminate the fast- and the slow-mode theories of interdiffusion using reaction kinetics data. Under certain conditions, the reaction may proceed in a non-trivial autowave-like regime.     

Copper-catalyzed three-component reaction of ethynylstibanes,organic azides,and selenium: A simple and efficient synthesis of novel selenides and diselenides having 1,2,3-triazole rings

A simple method for the synthesis of monoselenides and diselenides having 1,2,3-triazole ring is described herein. The three component reaction of ethynylstibanes, organic azides, and selenium powder is catalyzed by CuI (10?mol%) using 1,10-phenanthroline as the ligand (10?mol%) under aerobic conditions. Either selenides or diselenides can be synthesized by selecting the appropriate amount of selenium powder for otherwise identical reaction conditions. The obtained selenides and diselenides having a 1,2,3-triazole ring are all novel compounds. By using an antimony reagent, this one-pot reaction provides regioselective double Se-arylation under simple reaction conditions.     

Metal-free synthesis of benzimidazo[1,2-c]quinazolin-6-ones with indole and benzenediamine oxidized by I2/TBHP

A variety of benzimidazo[1,2-c]quinazolin-6-ones derivatives can be accessed in moderate to good yields under simple and metal-free reaction conditions using indoles and o-benzenediamines oxidized by iodine and TBHP. This procedure works in reasonable yields for different indoles as well as o-benzenediamines thus may provide a good synthesis of quinazolinones. A TBHP oxidized ring expansion reaction mechanism that explains the synthesis of benzimidazo[1,2-c]quinazolin-6-ones were reported.     

Simple and efficient protocol for the synthesis of functionalized styrenes from 1,2-dibromoethane and arylboronic acids

[reaction: see text] A simple and efficient protocol for the preparation of functionalized styrenes is disclosed that employs the palladium-catalyzed cross-coupling reaction of arylboronic acids with vinyl bromide, generated in situ from 1,2-dibromoethane. The reaction is carried out under mild reaction conditions. Compared with the cross-coupling reactions usually employed to obtain vinylarenes, this protocol is very simple, overcomes the inconvenience of using of ethylene under pressure, and uses air-stable and widely available arylboronic acids instead of vinyl organometallic reagents.     

Tetramethylguanidium Lactate Ionic Liquid： Catalyst-free Medium for Michael Addition Reaction

A catalyst-free, facile and efficient Michael addition reaction of active methylene compounds as well as nitromethane with chalcones catalyzed by guanidinium lactate ionic liquid was done. A series of chalcones, nitromethane, and active methylene compounds were converted smoothly to the corresponding products in high yields. The simple procedure, very mild conditions, high yields, and reuse of the IL without any loss of catalytic activity make this protocol considerably attractive for academic researches and practical applications.