Silica‐Gel‐Supported Ceric Ammonium Nitrate (CAN): A Simple and Efficient Solid‐Supported Reagent for Oxidation of Oxygenated Aromatic Compounds to Quinones

A silica‐gel‐supported heterogeneous ceric ammonium nitrate (CAN) reagent has been developed for oxidizing oxygenated aromatics to quinones in nonaqueous media. The advantages of this procedure include excellent yields, mild reaction conditions, nonaqueous media, short reaction times, and easy product isolation.     

Synthesis of β-Ketoiminato Copper(II) Complexes and Their Use in Copper Deposition

The template synthesis of ethylenediamine ( 1 ) with 2-acetylcyclopentanone ( 2 ) and [Cu(OAc)₂ · H₂O] ( 5 ) produced [Cu(1-(2-cC₅H₆(O))C(Me)NCH₂)₂)] ( 6 ) in 82 % yield. Reaction of 5 with bis(benzoylacetone)diethylenetriamine ( 7 , = L H)^[1] gave [Cu(μ-OAc)( L )(H₂O)]₂ ( 8 ). The solid-state structures of 6 and 8 were determined confirming that 8 possesses intra- and intermolecular hydrogen bonds resulting in a dimer formation. The thermal behavior of 6 – 8 was studied by TG and TG-MS. Under oxygen CuO was formed, whereas under Ar Cu/Cu₂O ( 6 ) or Cu ( 8 ) was obtained. Complex 6 was used as CVD precursor for Cu and Cu-oxide deposition (substrate temp., 400–500 °C, N₂, 60 mL · min^–1; O₂, 60 mL · min^–1; pressure, 0.87–1.5 mbar). The as-obtained deposits show separated particles of different appearance at the substrate surface as evidenced by SEM. Non-volatile 8 was applied as spin-coating precursor for Cu and CuO formation [conc. 0.25 mol · L^–1; volume 0.2 mL; 3000 rpm; depos. time 2 min; heating rate 50 K · min^–1; holding time 60 min (Ar), 120 min (air) at 800 °C]. The samples on silicon consist of granulated particles (Ar) or are non-dense with a grainy topography (air). EDX and XPS measurements confirmed the formation of Cu (Ar) or CuO (O₂) with up to 13 mol-% C impurity.     

Montmorillonite K10 Clay: An Effective Solid Catalyst for One‐Pot Synthesis of Polyhydroquinoline Derivatives

An efficient one‐pot four‐component coupling process for the synthesis of polyhydroquinoline derivatives catalyzed by montmorillonite K10 clay is described. This procedure has such advantages as short reaction time, high yields, and simple workup. The catalyst could be reused several times and keeps its initial activity in the recycle reactions.     

Silica‐Gel‐Supported Aluminium Chloride: A Stable,Efficient, Selective,and Reusable Catalyst for Tetrahydropyranylation of Alcohols and Phenols

A simple, effective, and highly chemoselective method to form 2‐tetrahydropyranyl ethers of alcohols and phenols in the presence of silica‐gel‐supported aluminium chloride as a heterogeneous Lewis acid catalyst is described. The catalyst can be easily recovered and reused without appreciable change in its efficiency.     

Lanthanum(III) Nitrate Hexahydrate: A Versatile Reagent for the Synthesis of Bis(indolyl) Methanes under Solvent‐Free Conditions

A mild and efficient synthesis of bis(indolyl) methanes by the reaction of indoles with various aldehydes at room temperature in the presence of a catalytic amount of a La(NO₃)₃ · 6H₂O afforded the corresponding bis(indolyl) methanes in excellent yields under solvent‐free conditions.     

Simple and Efficient Synthesis of 4,7‐Dimethoxy‐1(H)‐indene

Stirring 4,7‐dimethoxy‐1‐indanol in chloroform at room temperature in the presence of a catalytic amount of p‐toluenesulfonic acid gave 4,7‐dimethoxy‐1(H)‐indene in quantitative yield. Other solvents, including benzene, which was the most frequently used one for this reaction, gave mostly polymeric materials. The new method was also effective for dehydration of other electron‐rich benzylic alcohols.     

Sodium Borohydride–Solid LiClO4: An Effective Reagent for Reducing Aldehydes and Ketones in Aprotic Solvent

An efficient and simple method for the reduction of aldehydes, ketones and acid chlorides has been accomplished by using NaBH₄–solid LiClO₄ in mild conditions at ambient temperature with complete chemoselectivity in reduction of α,β‐unsaturated aldehydes and ketones. The reaction is fast with high yield and simple workup.     

A Simple and Efficient Copper(Ⅱ) Complex as a Catalyst for N-Arylation of Imidazoles

Four inexpensive and air‐/moisture‐stable pyrrolecarbaldiminato‐Cu complexes 1 – 4 were synthesized and evaluated to be a novel class of catalysts for the N‐arylation of imidazoles with aryl halides. A variety of aryl iodides, bromides and activated aryl chlorides underwent the coupling with imidazoles, promoted by the catalyst 4 , in moderate to good yields without the protection by an inert gas.     

Solid‐Solid Phase and Solvent‐Free Oxidative Removal of N‐(4‐Alkoxyphenyl) Groups of Monocyclic β‐Lactams with Ceric Ammonium Nitrate as a Cheap,Simple, and Efficient Method

Five N‐(4‐methoxyphenyl)‐ and five N‐(4‐ethoxyphenyl)‐β‐lactams were prepared by ketene‐imine [2+2] cycloaddition (Staudinger reaction). Then these 2‐azetidinones were N‐dearylated by grinding together with ceric ammonium nitrate without hazardous solvents in good to excellent yields. The solid‐solid phase N‐dearylation is easier, simpler, and more efficient than the general method in solution. The pure N‐unsubstituted β‐lactams obtained by a nontedious workup and without further purification.     

Sulphamic Acid—A Mild,Efficient, and Cost‐Effective Solid Acid Catalyst for the Synthesis of Bis(1H‐indol‐3‐yl)methanes

Sulphamic acid (SA) is found to efficiently catalyze the electrophilic substitution reactions of indoles with aldehydes and ketones in ethanol to afford the corresponding bis(indolyl)methanes. The method is simple and cost effective, and gives good yields in short reaction times. The catalyst is found to be recyclable.     

Preparation of a Cu(II)‐Immobilized Co‐polymer(CIC) for Effective Removal of Urea

The study describes the preparation of Cu(II)‐immobilized copolymer(CIC) under optimum conditions for the effective removal of urea. The copolymeric hydrogels, synthesized by free‐radical aqueous copolymerization of monomers acrylamide and sodium acrylate, have been analyzed for their Cu(II) uptake behavior. The sorption of Cu(II) into polymer follows a Langmuir–type pattern and amount sorbed depends upon the composition of copolymeric gels, presence of other co‐ions in the solution, pH of the solution, initial concentration of sorbate, degree of crosslinking of the copolymeric hydrogel, temperature of the solution etc. In the preliminary study, the Cu(II) immobilized co‐polymer(CIC) sorbent demonstrated a fair tendency to remove urea from aqueous solutions.     

NaHSO4·H2O as a Heterogeneous Acidic Reagent for Mild and Convenient Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones and Their Sulfur Derivatives

One-pot cyclocondensation reaction of aromatic aldehydes, 1,3-dicarbonyl compounds and urea/thiourea in the presence of NaHSO₄·H₂O produced 4-aryl substituted 3,4-dihydropyrimidin-2(1H)-ones and their sulfur analogs in high to excellent yields. The reactions were carried out in refluxing n-hexane and were completed within 2.5–11 h.     

Synthesis of Poly(Ethylene Glycol)–Supported (R)-BINOL Derivatives and Their First Application in Enantioselective Mukaiyama Aldol Reactions

The Mukaiyama aldol reaction of 2-styryl-oxazole-4-carbaldehyde (1) as model substrate with S-ketene silyl acetal 2 catalyzed by poly(ethylene glycol)-supported binaphthyl-derived chiral titanium(IV) complexes afforded the corresponding aldol product in good to excellent yields and enantioselectivities up to 94% ee. The chemical yields and/or the enantioselectivities are enhanced by generating the active catalyst from Ti(OiPr)₄, polymer-supported ligands (R)-6 or (R)-8, and chiral or achiral promoters. Pyrrolidine derivative (S)-13 and trifluoromethyl-substituted phenol 12 are the most efficient additives found.     

Electrochemical Synthesis of Fe–Cu Composites Based on Copper(II) Ferrite and Their Electrocatalytic Properties

Russian Journal of Electrochemistry - Copper(II) ferrite is synthesized by the co-precipitation method in the absence and in the presence of polyvinyl alcohol which is followed by thermally...     

Tris(dimethylsilyl)methyllithium: A Reagent for the Synthesis of Vinylbis(silanes) Containing Si–H Functional Groups

Reactions between a series of nonenolisable aldehydes and tris(dimethylsilyl)methyllithium, (HMe₂Si)₃CLi, are described. The Peterson reaction takes place readily to give vinylbis(silanes). Moreover, styrene and butyl acrylate 1:1 copolymer (P), prepared by use of α,α′-azobis(isobutyronitrile) (AIBN) as an initiator in toluene at 70 ± 1°C, was formylated via direct electophilic substitution by methyl dichloromethyl ether (Cl₂CHOMe) in the presence of tin(IV) chloride (SnCl₄) in nitrobenzene (PhNO₂) as solvent. The reaction of (HMe₂Si)₃CLi with formyl groups on the side chains of the copolymer led to new macromolecules bearing vinylbis(silane) functional groups.     

Carrier‐Mediated Transport of Hg(II) through Bulk and Supported Liquid Membranes

The transport of Hg (II) ions from an aqueous solution into an aqueous receiving solution through bulk and supported liquid membranes containing a calix[4]arene derivative 1 as a carrier was examined. The kinetic parameters of bulk liquid membrane studies were analyzed assuming two consecutive, irreversible first‐order reactions. The influence of temperature, stirring rate, carrier concentration and solvent on the kinetic parameters (k₁, k₂, R_m ^max, t_max, J_d ^max, J_a ^max) has also been investigated. The membrane entrance rate, k₁, and the membrane exit rate, k₂, increased with increasing temperature and stirring rate. The activation energy values are calculated as 4.87 and 48.63 kj mol^?1 for extraction and reextraction, respectively. The values of calculated activation energy indicate that the process is diffusionally controlled by species. Also, the transport behavior of Hg²⁺ from aqueous solution through a flat‐sheet supported liquid membrane has been investigated by the use of calix[4]arene derivative 1 as carrier and Celgard 2500 as the solid support. A Danesi mass transfer model was used to calculate the permeability coefficients for each parameter studied. The highest values of permeability were obtained with 2‐nitrophenyloctyl‐ether (NPOE) solvent and the influence was found to be in the order of NPOE>chloroform>xylene.     

The Ternary Coppersilver Selenide—A New Homogeneous Solid State Ion-Selective Electrode for Copper (II)

Abstract

The performance characteristics of a copper (II) ion-selective electrode, based on pressed-pellet membrane of ternary CuAgSe, are reported. The sensing material is isostructural with the natural mineral β -eucairite and shows high corrosion resistivity which results in stable and reproducible electrode performance upon ageing. The electrodes exhibit a linear Nernstian response dawn to 5.10^?8 M in non buffered medium and down to 10^?13M in copper-glycine ion buffer. Data on the electrode stability for a period of two and a half years, on the electrode response time, pH-dependence, selectivity etc. are also presented.     

Silica–PSCl3: A Mild and Efficient Reagent for Deoxygenation of Sulfoxides

A new solid supported reagent, silica–PSCl₃, has been developed for deoxygenation of sulfoxides. With this reagent, conversion of sulfoxides to sulfides occurred cleanly and efficiently at room temperature. Facile isolation of the product was achieved by simple filtration of the by‐products without any extensive workup.     

Solvent‐Free Williamson Synthesis: An Efficient,Simple, and Convenient Method for Chemoselective Etherification of Phenols and Bisphenols

Etherification of phenols with dimethyl‐ and diethylsulfates and benzyl chloride was performed efficiently in the presence of a suitable solid base, NaHCO₃ or K₂CO₃, under solvent‐free conditions. The reaction proceeded rapidly at low temperature, and the corresponding ethers were obtained with high purity and excellent yield. Selective etherification of electron‐poor phenols in the presence of electron‐rich ones and also selective mono‐etherification of bisphenols are the noteworthy advantages of this method. This method is environmentally friendly.     

Silica‐Supported bis (Trimethylsilyl) Chromate: Oxidation of Thiols to Their Corresponding Disulfides

An efficient and convenient method for the oxidation of thiols mediated by silica‐supported bis (trimethylsilyl) chromate (BTSC) in acetonitrile is reported.