Improved and Practical Synthesis of [2,4,5‐Tris(trimethylsilyl)‐ phenyl](phenyl)iodonium Triflate and Utilization as a 1,4‐Benzdiyne Synthon

An efficient and improved method for preparing [2,4,5‐tris(trimethylsilyl)phenyl](phenyl)iodonium triflate as a 1,4‐benzdiyne synthon was developed by using phenyiodonium diacetate/boron triflouride⋅diethyl etherate [PhI(OAc)₂/BF₃⋅OEt₂] reagent. The iodonium triflate generated 3,4‐bis(trimethylsilyl)benzyne quantitatively to give cycloadducts with tetraphenylcyclopentadienone, furan and anthracene in high yields. These cycloadducts bearing two trimethylsilyl groups were transformed into the corresponding aryne precursors, which underwent subsequent cycloaddition reactions to afford polycyclic aromatic compounds such as 1,4‐dihydro‐1,4‐epoxyanthracene, naphthotriazole, triptycene, and anthratriazole derivatives in good to high yields. The total reactions are formally considered as double cycloaddition reactions of 1,4‐benzdiyne. This practical and useful formal benzdiyne strategy is described.

     

Cooperative Indium(III)/Silver(I) System for Oxidative Coupling/Annulation of 1,3‐Dicarbonyls and Styrenes: Construction of Five‐Membered Heterocycles

A cooperative indium(III)/silver(I) system for the synthesis of various five‐membered heterocycles, including dihydrofurans, pyrroles, spirolactones, and spiroiminolactones, through the sequential oxidative coupling/annulation reaction of 1,3‐dicarbonyl compounds with styrenes has been developed. Four different heterocyclic systems were successfully synthesized depending on the substitution pattern of the substrates using readily available starting materials. This system has the advantages of a broad substrate scope, moderate to good chemical yields, an operationally easy and simple procedure, and short reaction times.

     

Catalytic Synthesis of Peptide‐Derived Thiazolines and Oxazolines using Bis(quinolinolato)dioxomolybdenum(VI) Complexes

Bis(2‐ethyl‐8‐quinolinolato)dioxomolybdenum(VI) ( 9 ) (1 mol %) shows remarkable catalytic activity for the dehydrative cyclization of cysteine‐containing dipeptides 1 to give the corresponding thiazolines 2 with less than 6 % epimerization at the C2‐exomethine position. For the dehydrative cyclization of threonine‐containing dipeptides 4 , 1 mol % of bis(2‐phenyl‐8‐quinolinolato)dioxomolybdenum(VI) ( 10 ) gives the corresponding oxazolines 5 with retention of configuration at the 5‐position.     

An Efficient Catalytic Aerobic Oxidation of Alcohols in Water Using Hypervalent Iodine(V)

A transition metal‐free aerobic oxidation of alcohols to the corresponding aldehydes or ketones can be effectively catalysed by iodoxybenzene (PhIO₂)/Br₂/NaNO₂ in water.     

Laccase/2,2,6,6‐Tetramethylpiperidinoxyl Radical (TEMPO): An Efficient Catalytic System for Selective Oxidations of Primary Hydroxy and Amino Groups in Aqueous and Biphasic Media

Copper salts/2,2,6,6‐tetramethylpiperidinoxyl radical (TEMPO) catalytic systems enable efficient aerobic oxidations of primary alcohols but they generally show a reduced reactivity in aqueous medium. Herein, we report an oxidative catalytic system composed of Trametes versicolor laccase and TEMPO, which is able to work in buffer solutions at room temperature using ambient air. Although this catalytic system displays great efficiency in aqueous systems, the addition of methyl tert‐butyl ether allows the reduction of TEMPO loading, also enhancing the solubility of hydrophobic compounds. This practical methodology promotes the chemoselective aerobic oxidation of hydroxy or amino groups, leading to interesting organic derivatives such as aldehydes, lactones, hemiaminals or lactams.

     

Rhodium‐Catalyzed Oxidative Cycloaddition of N‐tert‐Butoxycarbonylhydrazones with Alkynes for the Synthesis of Functionalized Pyrroles via C(sp3)–H Bond Functionalization

A rhodium(III)‐catalyzed cycloaddition of N‐tert‐butoxycarbonylhydrazones with internal alkynes was developed. The reaction features a regioselective α‐imino alkyl C(sp³)−H bond functionalization resulting in selective formation of highly functionalized NH‐free pyrroles. Our studies showed that utilizing the N‐tert‐butoxycarbonyl (N‐Boc) as the oxidizing directing group is critical for achieving the observed pyrrole formation versus the isoquinoline formation. To account for the pyrrole formation, we hypothesized that a prior tautomerization of the N‐Boc‐hydrazones to enamines should occur, followed by regioselective C(sp²)–H cleavage to form a putative five‐membered rhodacycle. Subsequent coupling of the rhodacycle with the alkynes would afford the pyrrole products.

     

Catalytic oxidation of alcohols using molecular oxygen mediated by poly(ethylene glycol)-supported nitroxyl radicals

The selective catalytic oxidation of alcohols over a mixture of copper(I) chloride and a number of linear ‘linker-less’ or ‘branched’ poly(ethylene glycol)-supported nitroxyl radicals of the 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) family as a catalyst system has been investigated in the presence of molecular oxygen in a batch reactor. It is found that the activity profile of the polymer-supported nitroxyl radicals is in good agreement with that of low-molecular weight nitroxyl catalysts, for example, allylic and benzylic alcohols are oxidised faster than aliphatic alcohols. The oxidations can be tuned to be highly selective such that aldehydes are the only oxidation products observed in the oxidation of primary alcohols and the oxidations of secondary alcohols yield the corresponding ketones. A strong structural effect of the polymeric nitroxyl species on catalytic activity that is dependent upon their spatial orientation of the nitroxyl radicals is particularly noted. The new soluble macromolecular catalysts can be recovered readily from the reaction mixture by solvent precipitation and filtration. In addition, the recycled catalysts demonstrate a similar selectivity with only a small decrease in activity compared to the fresh catalyst even after five repetitive cycles.     

Impact of Frying on Changes in Clam (Ruditapes philippinarum) Lipids and Frying Oils: Compositional Changes and Oxidative Deterioration

The current study shows the compositional changes and oxidation development of clam (Ruditapes philippinarum, R. philippinarum) lipids and frying oils when subjected to different processing conditions. Parameters measured include acid value, peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), total oxidation (TOTOX), lipid classes, fatty acid composition, phosphatidylcholine (PC), and phosphatidylethanolamine (PE) contents together with major glycerophospholipid (GP) molecular species. Deep-fat frying increased triacylglycerol (TAG) content and decreased the contents of PC, PE, and GP molecular species in clam in a time-dependent manner. Meanwhile, minor amounts of free fatty acids, diacylglycerols, monoacylglycerols, and polar lipids were detected in frying oils, indicating lipid migration between the clam and frying oils. The time-dependent increase of POV, TBARS, and TOTOX in fried clams and frying oils with concurrent reduction of docosahexenoic acid and eicosapentaenoic acid indicates extensive oxidative degradation of clam lipids. Moreover, the moisture-rich clam aggravated the deterioration of frying oils. Consequently, deep-fat frying significantly altered the lipid profile and decreased the nutritional value of clams.     

硝酸催化氧化法制备氯化亚铜的研究

用硝酸为催化剂制备氯化亚铜 ,大大地提高了生产效率。制得的氯化亚铜纯度可达 98%以上     

催化氧化动力学法测定电镀废液中的铬（Ⅵ）

研究并确定了Ｃｒ（Ⅵ）对过氧化氢氧化５号专利蓝退色反应的催化作用及动力学条件。建立了痕量Ｃｒ（Ⅵ）的分光光度分析法,其检出限为１．９ １０＾－８ｇ／ｍＬ,废液中铬（Ⅵ）的回收率达９０％以上。     

Synthesis and properties of poly(aryl ether ketone ketone)/poly(aryl ether ether ketone ketone) copolymers with pendant cyano groups

2,6‐Diphenoxybenzonitrile (DPOBN) was synthesized by reaction of phenol with 2,6‐difluorobenzonitrile in N‐methyl‐2‐pyrrolidone in the presence of KOH and K₂CO₃. Poly(aryl ether ketone ketone)/poly(aryl ether ether ketone ketone) copolymers with pendant cyano groups were prepared by the Friedel–Crafts electrophilic substitution reaction of terephthaloyl chloride with varying mole proportions of diphenyl ether and DPOBN using 1,2‐dichloroethane as solvent and N‐methyl‐2‐pyrrolidone as Lewis base in the presence of anhydrous AlCl₃. The resulting polymers were characterized by various analytical techniques, such as FT‐IR, differential scanning calorimeter, thermal gravimetric analysis, and wide‐angle X‐ray diffraction. The crystallinity and melting temperature of the polymers were found to decrease with increase in concentration of the DPOBN units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 514°C in N₂ atmosphere. The glass transition temperature was found to increase with increase in concentration of the DPOBN units in the polymer when the molar ratios of DPOBN to DPE ranged from 10/90 to 30/70. The copolymers containing 30–40 mol % of the DPOBN units exhibit excellent thermostability at (350 ± 10)°C and have good resistance to acidity, alkali, and organic solvents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3601–3606, 2007     

Heterogeneously Catalyzed Oxidative Cyanation of Tertiary Amines with Sodium Cyanide/Hydrogen Peroxide using Polymer‐Supported Iron(II) Phthalocyanines as Catalyst

The first report on heterogeneously catalyzed oxidative cyanation of various tertiary amines to the corresponding α‐amino nitriles with high yields and selectivity by using hydrogen peroxide oxidant in presence of sodium cyanide and Fe(II) phthalocyanine supported on a polymer as catalyst is described. The present method has the added benefits of facile recovery of the catalyst from the reaction mixture and its subsequent use without further activation. Consistent catalytic activity with no metal leaching was observed during this course.     

Synthesis and characterization of poly(aryl ether sulfone)s with metallophthalocyanine pendant unit

A series of novel poly(aryl ether sulfone) copolymers containing dicyanophenyl group were prepared by the reaction of bis(4‐chlorophenyl)sulfone with (3,4‐dicyano) phenylhydroquinone and 4,4′‐isopropylidenediphenol. On this basis, a series of poly(aryl ether sulfone)s containing metallophthalocyanine units were synthesized by the reaction of poly(aryl ether sulfone)s containing dicyanophenyl group with excessive amounts of 1,2‐dicyanobenzene and the corresponding metal salt in quinoline. All these copolymers were found to have high glass transition temperature and thermal stability. These copolymers were found to be soluble in common solvents, and capable of forming transparent films by solution casting. The copolymers containing metallophthalocyanine units showed strong optical absorption in the visible region, and exhibited blue photoluminescence in solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3457–3461, 2006     

不同形貌的纳米Mg(OH)2催化臭氧化降解甲硝唑

采用化学沉淀法分别以六水合氯化镁和取自察尔汗盐湖的天然水氯镁石为原料制备了不同形貌的纳米 Mg(OH)₂催化剂,通过扫描电子显微镜、X射线衍射、傅里叶变换红外光谱等手段对所合成的催化剂的表面形貌、晶体结构和表面官能团等性质进行了表征。将两种不同形貌的纳米Mg(OH)₂材料首次应用于催化臭氧化过程,研究了两种不同形貌的纳米Mg(OH)₂[Mg(OH)₂-1和Mg(OH)₂-2]催化剂对甲硝唑的降解和矿化能力。结果表明,在单独臭氧化过程中,反应10min时甲硝唑的降解和矿化效率均较低,分别为51.9%和17.4%,而在臭氧化系统中分别加入Mg(OH)₂-1和Mg(OH)₂-2,甲硝唑的去除效率和矿化效率均明显提高,且Mg(OH)₂-2的催化臭氧化性能要优于Mg(OH)₂-1。另外,单独臭氧化过程、Mg(OH)₂-1催化臭氧化以及Mg(OH)₂-2催化臭氧化过程中甲硝唑的降解均较好地符合伪一级动力学反应模型（R²>0.97）。除此之外,对这两种不同形貌的纳米Mg(OH)₂催化剂的稳定性进行了考察,结果表明,催化剂在循环使用六次后对甲硝唑仍有较高的催化臭氧化去除效率。因此,所合成的两种形貌的纳米Mg(OH)₂催化剂将是一种很有前景的、能用于去除抗生素的臭氧化催化剂。     

Preparation of poly(styrene‐b‐2‐hydroxyethyl acrylate) block copolymer using reverse iodine transfer polymerization

Reverse iodine transfer polymerizations (RITP) of 2‐h‐ydroxyethyl acrylate (HEA) were performed in N,N‐dimethylformamide at 75°C using AIBN as initiator. Poly(2‐hydroxyethyl acrylate) (PHEA) with M_n = 3300 g mol^?1 and M_w/M_n <1.5 were obtained. Homopolymerization of styrene in RITP was also carried out under similar conditions using toluene as solvent. The resulting iodo‐polystyrene (PS‐I) with (M_{n, SEC} = 607 g mol^?1, polydispersity index (PDI) = 1.31) was used as a macroinitiator for the synthesis of amphiphilic block copolymers based on HEA with controlled well‐defined structure. Poly(styrene‐b‐2‐hydroxyethyl acrylate) (PS‐b‐PHEA) with M_n = 13,000 g mol^?1 and polydispersity index (M_w/M_n) = 1.4 was obtained, copolymer composition was characterized using ¹H‐NMR and FTIR, whereas SEC and gradient HPLC were used to confirm the formation of block copolymer and the living character of polymer chains. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Catalytic Asymmetric Inverse‐Electron‐Demand (IED) [4+2] Cycloaddition of Salicylaldimines: Preparation of Optically Active 4‐Aminobenzopyran Derivatives

The catalytic asymmetric inverse‐electron‐demand (IED) [4+2] cycloaddition of various salicylaldehyde‐derived N‐arylimines with electron‐rich alkenes in the presence of chiral BINOL‐derived phosphoric acid catalysts has been studied with the aim of obtaining optically active 4‐aminobenzopyran derivatives. Dienophiles such as 2,3‐dihydro‐2H‐furan, benzyl N‐vinylcarbamate and 2‐vinylindole have been employed.     

Destruction of aniline by mediated electrochemical oxidation with Ce(IV) and Co(III) as mediators

Mediated electrochemical oxidation has been employed to test the feasibility of treating soluble organic wastes. We report Ce(IV)- and Co(III)-mediated electrochemical oxidation of aniline at various electrodes in acidic media as an example of organic waste. Aniline was oxidized by an electrogenerated electron transfer mediator, Ce⁴⁺ or Co³⁺, in the anolyte and carbon dioxide was produced as a final oxidation product. Carbon dioxide was collected by bubbling through a barium hydroxide solution. When a powerful oxidizing agent, Ce(IV) or Co(III), was used as an electron shuttling mediator, parameters affecting the coulombic efficiency for aniline oxidation were the standard oxidation potentials of the mediators, their concentrations and the reaction temperature. Intermediate species produced during the oxidation of aniline were identified by cyclic voltammetric and absorption spectroscopic measurements.     

Catalytic Use of a Soluble Organoindium(III) Species for Allylation and Crotylation of Ketones with Boronates

The unprecedented use of a soluble organoindium species, indium(III) hexamethyldisilazide [In(III)(hmds)₃], for catalytic carbon carbon bond formations between ketones and boronates, is reported. Various functionalized tertiary homoallyl alcohols were generated easily in high yields. Remarkably, free hydroxy and primary amine functionalities proved to be tolerated. A rate acceleration and markedly improved diastereoselectivities were observed in the presence of methanol. Based on preliminary NMR experiments and the α‐selectivity with an α‐substituted boronate, we assume the in situ generation of reactive allylindium(III) species through catalytic boron‐to‐indium transmetalation.