Presence Of CuCl Research Articles

New Procedure for One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones by Biginelli Reaction

Abstract A practical green chemistry procedure for synthesis of 3,4‐dihydropyrimidin‐2(1H);‐ones in good yields was successfully carried out in micellar systems according to the Biginelli reaction using β‐ketoester, urea and appropriate aromatic aldehyde in the presence of CuCl2 · H2O as catalyst. The advantages of this method involved the broader application scope of substrates, the more environmental friendly process and the low‐cost of the Lewis acid catalyst.

CuCl 2 induced reactions of 6-ethynyl- and 6-cyano-5-aryl-2,2′-bipyridines with various N- and O-nucleophiles in comparison with the reactions of relative 1,2,4-triazines

Meanwhile 5-aryl-6-cyano-2,2′-bipyridines are very stable towards various nucleophiles, addition copper(II) chloride to the reactional mixture facilitates nucleophilic addition to the cyano group dramatically. The cyanobipyridines react easily with water, methanol, ethanolamine in the presence of CuCl 2 yielding well-crystallized complexes containing carboxylates, carboximidates or carboxamidines as ligands. 5-Cyano-1,2,4-triazines are more active in the reactions due to higher electron-withdrawing properties of this heterocycle. Due to the same reason acetylene moiety of 5-ethynyl-3-pyridyl-1,2,4-triazine adds water quite easily but in the presence of copper chloride as well.

Direct C–H bond arylation of arenes with aryltin reagents catalysed by palladium complexes

Direct C-H bond arylation of simple arenes with aryltin reagents has been successfully catalysed by PdCl2 in the presence of CuCl2. CuCl2 proved to be an activator for a palladium intermediate as well as an oxidant.

Copper(II) Inhibits In vitro Conformational Conversion of Ovine Prion Protein Triggered by Low pH

To gain insight into the conformational conversion of ovine prion protein (OvPrP(C)) at different pH values and/or in the presence of CuCl(2), the secondary structure of OvPrP(C) was analysed by circular dichroism (CD) spectroscopy. Copper treatment of OvPrP(C) under moderately acidic conditions (pH approximately 5.0-6.0) as well as physiological conditions (pH 7.4) also makes OvPrP(C) adopt protease-resistant and beta-sheet-rich conformation. However, under lower pH conditions (2.0-4.5) with copper treatment, OvPrP(C) gained higher alpha-helix structure. This study demonstrated that Cu(2+) can significantly modulate conformational conversion triggered by acidic pH, and this will provide therapeutic intervention approaches for prion diseases.

Novel and Convenient Synthesis of Substituted Quinolines by Copper- or Palladium-Catalyzed Cyclodehydration of 1-(2-Aminoaryl)-2-yn-1-ols

A general and convenient synthesis of substituted quinolines by regioselective copper- or palladium-catalyzed 6-endo-dig cyclization-dehydration of 1-(2-aminoaryl)-2-yn-1-ols is reported. The crude substrates were easily obtained by the Grignard reaction between the appropriate alkynylmagnesium bromide and 2-aminoaryl ketones and could be used without further purification for the subsequent cyclization step. Heteroannulation reactions were carried out in MeOH or DME as the solvent at 60 or 100 degrees C in the presence of CuCl(2) or PdX(2) (in conjunction with 10 equiv of KX, X = Cl, I) as the catalyst to afford the quinoline derivatives in good to excellent isolated yields based on starting 1-(2-aminoaryl)-2-yn-1-ols (66-90%).

CuCl‐Catalyzed Regio‐ and Stereoselective Aminohalogenation of α,β‐Unsaturated Nitriles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Metallophosphination of Alkynes: Efficient Synthesis of β‐Functionalized Alkenylphosphines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

CuCl‐Catalyzed Regio‐ and Stereoselective Aminohalogenation of α,β‐Unsaturated Nitriles

Abstractα,β‐Unsaturated nitriles were found to be suitable substrates for aminochlorination with N,N‐dichloro‐p‐toluenesulfonamide (4‐TsNCl2) in the presence of CuCl as the catalyst (10 mol‐%) and 4 Å molecular sieves. The reaction is very convenient to carry out at room temperature without the protection of inert gases, and this method provides an easy route to vicinal haloamino nitriles with excellent regio‐ and stereoselectivities and in good chemical yields. The stereochemistry has been unambiguously confirmed by X‐ray structural analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Self-initiated atom transfer radical polymerization of methyl methacrylate in cyclohexanone

The self-initiated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in cyclohexanone (CHO) in the presence of CuCl 2/ N, N, N′, N″, N″-pentamethyldiethylenetriamine (PMDETA) is reported. The linear semilogarithmic plot of ln([ M] 0/[ M]) vs time, the linear increase of number-average molecular weight ( M n) with conversion, and rather narrow molecular weight distributions (MWDs) have been observed, which are in agreement of the characteristics of living/controlled polymerization. The NMR spectrum revealed the existence of terminal chlorine. The chain extension further proved the living characteristic. The polymerization can only be successful using CHO as the solvent, and is well controlled at the temperature as low as 50 °C. The effects of ligand, solvent, temperature and monomer to catalyst ratio are all discussed.

Metallophosphination of Alkynes: Efficient Synthesis of β-Functionalized Alkenylphosphines

Reactions of alkynes with [Cp2Zr(1-butene)(DMAP)] (DMAP = 4-(dimethylamino)pyridine) and chlorophosphines afforded zirconoalkenylphosphines in good to high yields, and their molecular structures were determined by single-crystal X-ray diffraction. The zirconoalkenylphosphines could be transformed into β-functionalized alkenylphosphines through coupling reactions with various electrophiles in the presence of CuCl.

Bidirectional racemic synthesis of the biologically active quinone cardinalin 3

Readily available 2,2',6,6'-tetramethoxy-1,1'-biphenyl was transformed in 14 synthetic steps into the natural product cardinalin 3 using a bidirectional approach. One of the key steps was the formation of the cis-1,3-dimethylnaphtho[2,3-c]pyran ring. (+/-)-1,1'-[6,6'-Diallyl-5,5'-bis(benzyloxy)-1,1',3,3'-tetramethoxy-2,2'-binaphthalene-7,7'-diyl]diethanol was treated with O(2) in the presence of CuCl(2) and catalytic PdCl(2) to afford 5,5'-bis(benzyloxy)-7,7',9,9'-tetramethoxy-1,1',3,3'-tetramethyl-1H,1'H-8,8'-bibenzo[g]isochromene. Hydrogenation of this compound afforded 7,7',9,9'-tetramethoxy-cis-1,3-cis-1',3'-tetramethyl-3,3',4,4'-tetrahydro-1H,1'H-8,8'-bibenzo[g]isochromene-5,5'-diol in quantitative yield, which was converted in 3 steps to cardinalin 3.

Monophosphine and diphosphine ligands for diplatinum polyynediyl complexes: Efficient syntheses of new functionality-containing systems and model compounds

Br(CH 2) 4Br and NaO(CH 2) 2CH CH 2 react under suitable conditions to give Br(CH 2) 4O(CH 2) 2CH CH 2 (55%), which is treated with KPPh 2 to yield the ether-containing phosphine Ph 2P(CH 2) 4O(CH 2) 2CH CH 2 (83%). The reaction of CH 3CH 2OC(O)CH C(CH 3) 2 and BrMg(CH 2) 3CH CH 2 in the presence of CuCl (cat.) and ClSiMe 3 yields CH 3CH 2OC(O)CH 2C(CH 3) 2(CH 2) 3CH CH 2 (67%), which is reduced to an alcohol that is brominated, reacted with Grubbs’ catalyst, hydrogenated, and treated with KPPh 2 to give the bis(geminally dimethylated) diphosphine Ph 2P(CH 2) 2C(CH 3) 2(CH 2) 8C(CH 3) 2(CH 2) 2PPh 2 (47% overall). The photochemical reaction of I(CF 2) 8I and H 2C CHCH 2SnBu 3 yields H 2C CHCH 2(CF 2) 8CH 2CH CH 2 (52%), which is converted with 9-BBN to a diol (92%) that is brominated and treated with LiPR 2 to give the fluorinated diphosphines R 2P(CH 2) 3(CF 2) 8(CH 2) 3PR 2 (R = a, p-tol, 67%; b, t-Bu, 69%; c, o-tol, 86%). Reactions of Br(CH 2) m Br and LiPR 2 similarly yield R 2P(CH 2) m PR 2 ( m/R = 8/ a, 95%; 14/ a, 96%; 14/ p-C 6H 4- t-Bu, 98%). Reactions of KPPh 2 with Br(CH 2) m′ CH CH 2and Br(CH 2) 7CH 3 give the corresponding monophosphines Ph 2P(CH 2) m′ CH CH 2 ( m′ = 7, 82%; 10, 84%) and Ph 2P(CH 2) 7CH 3 (85%). When the former is combined with [Pt(μ-Cl)(C 6F 5)(tht)] 2 (tht = tetrahydrothiophene), trans-(C 6F 5)(Ph 2P(CH 2) m′ CH CH 2) 2PtCl (77–70%) is isolated. When the latter (excess) is combined with trans, trans-(C 6F 5)( p-tol 3P) 2Pt(C C) 4Pt(P p-tol 3) 2(C 6F 5) (RT, 65 °C), trans, trans-(C 6F 5)(Ph 2P(CH 2) 7CH 3) 2Pt(C C) 4Pt(Ph 2P(CH 2) 7CH 3) 2(C 6F 5) (53%) is isolated.

One‐Pot Transformation of Trichloroacetamide into Readily Deprotectable Carbamates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Formation and Cleavage of P−C, Mo−C, and C−H Bonds Involving Arylphosphinidene and Cyclopentadienyl Ligands at Dimolybdenum Centers

The phosphinidene-bridged complex [Mo2Cp2(μ-PR*)(CO)4] (R = 2,4,6- C6H2tBu3) experiences an intramolecular C−H bond cleavage from a tBu group to give the phosphide-hydride derivative [Mo2Cp2(μ-H){μ-P(CH2CMe2)C6H2tBu2}(CO)4] in refluxing diglyme (ca. 438 K) or under exposure to near-UV−visible light. In contrast, its exposure to UV light yields two different dicarbonyl derivatives depending on the reaction conditions, either the triply bonded [Mo2Cp2(μ-PR*)(μ-CO)2] (Mo−Mo = 2.5322(3) Å) or its isomer [Mo2Cp2(μ-κ1:κ1,η6-PR*)(CO)2], in which the phosphinidene ligand bridges asymmetrically the metal centers while binding its aryl group to one of the molybdenum atoms in a η6-fashion. The latter complex experiences a proton-catalyzed tautomerization to yield the cyclopentadienylidene−phosphinidene derivative [Mo2Cp(μ-κ1:κ1,η5-PC5H4)(η6-R*H)(CO)2]. Carbonylation of the η6-phosphinidene complex proceeds stepwise through the η4-tricarbonyl complex [Mo2Cp2(μ-κ1:κ1,η4-PR*)(CO)3] and then to the starting tetracarbonyl compound, whereas its reaction with CNtBu yields only the η4-complex [Mo2Cp2(μ-κ1:κ1,η4-PR*)(CNtBu)(CO)2], which was characterized through an X-ray study. The η4-tricarbonyl species reacts with CNtBu in tetrahydrofuran to give the metal−metal bonded derivative [Mo2Cp2(μ-PR*)(CNtBu)(CO)3]. In petroleum ether, however, this reaction yields the bis(isocyanide) derivative [Mo2Cp2(μ-PR*)(CNtBu)2(CO)3], which has an asymmetric trigonal phosphinidene bridge and no metal−metal bond. All the above results can be explained by assuming the operation of two primary processes in the photolysis of [Mo2Cp2(μ-PR*)(CO)4], one of them involving a valence tautomerization of the phosphinidene ligand, from the trigonal (four-electron donor) to the pyramidal (two-electron donor) coordination mode. The carbonylation reaction of the η6-complex is accelerated by the presence of CuCl, due to the formation of the trimetal species [CuMo2(Cl)Cp2(μ-κ1:κ1:κ1,η6-PR*)(CO)2] and [CuMo2(Cl)Cp2(μ-κ1:κ1:κ1,η4-PR*)(CO)3]. The latter complexes were also characterized by single-crystal X-ray studies.

A copper(II)-catalyzed protocol for modified Friedländer quinoline synthesis

2-Aminobenzyl alcohol reacts with an array of ketones in dioxane at 100 °C in the presence of a catalytic amount of CuCl 2 along with KOH under O 2 atmosphere to afford the corresponding quinolines in good yields. 2-Aminobenzyl alcohol is also oxidatively coupled and cyclized with various aldehydes by step-by-step procedure, an initial treatment of 2-aminobenzyl alcohol in the presence of CuCl 2 and KOH in dioxane under O 2 atmosphere and subsequent addition of aldehyde to the mixture followed by stirring under argon atmosphere, to give 3-substituted quinolines in moderate to good yields.

Vicarious Nucleophilic C‐Amination of Nitrobenzene and 5‐ and 6‐Nitro‐1‐methylbenzimidazoles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Ionic Liquid-promoted Ring-closure Reactions between 1,4-Dihydroxyanthraquinone and Diamines

The reaction of 1,4-Dihydroxyanthraquinone with diamines was carried out in the presence of CuCl(2), CuCl in the ionic liquid [Bmim]PF(6), [Bmim]BF(4) or [Bmim]Cl x CuCl.

One-Pot Transformation of Trichloroacetamide into Readily Deprotectable Carbamates

[Structure: see text] A trichloroacetamide group was converted to an isocyanate, which was in situ captured by a variety of alcohols in the presence of CuCl and n-BuN4Cl to afford the corresponding carbamates. The scope and limitation of this transformation are also described.

Generation of Benzocyclobutadiene Derivatives from Zirconaindene Derivatives

Zirconaindene derivatives produced benzocyclobutadiene derivatives in situ in the presence of CuCl and 1,4-naphthoquinone, which afforded their dimers, 6a,10b-dihydrobenzo[a]biphenylenes and dibenzosemibullvalenes or dibenzo[a,e]cycloctenes.

Design and synthesis of structurally well-defined functional polypropylenes via transition metal-mediated olefin polymerization chemistry

Functionalization of polyolefins is an industrially important yet scientifically challenging research subject. This paper summarizes our recent effort to access structurally well-defined functional polypropylenes via transition metal-mediated olefin polymerization. In one approach, polypropylenes containing side chain functional groups of controlled concentrations were obtained by Ziegler-Natta-catalyzed copolymerization of propylene in combination with either living anionic or controlled radical polymerization of polar monomers. The copolymerization of propylene with 1,4-divinylbenzene using an isospecific MgCl2-supported TiCl4 catalyst yielded polypropylenes containing pendant styrene moieties. Both metalation reaction with n-butyllithium and hydrochlorination reaction with dry hydrogen chloride selectively and quantitatively occurred at the pendant reactive sites, generating polymeric benzyllithium and 1-chloroethylbenzene species. These species initiated living anionic polymerization of styrene (S) and atom transfer radical polymerization (in the presence of CuCl and pentamethyldiethylenetriamine) of methyl methacrylate (MMA), respectively, resulting in functional polypropylene graft copolymers (PP-g-PS and PP-g-PMMA) with controllable graft lengths. In another approach, chain end-functionalized polypropylenes containing a terminal OH-group with controlled molecular weights were directly prepared by propylene polymerization with a metallocene catalyst through a selective aluminum chain transfer reaction. Both approaches proved to be desirable polyolefin functionalization routes in terms of efficiency and polymer structure controllability.