Cu(Ⅱ)-catalyzed aerobic oxidative amidation of azoarenes with amides

A method for Cu(Ⅱ)-catalyzed dehydrogenative amidation of azoarene using air as the terminal oxidant was developed. Various amides, such as arylamides, alkylamides, lactams, and imides, are all effective amidation reagents and provide the desired products in moderate to excellent yields. Notably, good yields can also be obtained on a gram-scale with this amidation reaction.In this protocol of azoarene amidation, the catalyst(Cu(OAc)_2) and oxidant(air) are inexpensive and readily available, and the process is highly efficient and atom economical.     

Cu(I)- and Cu(II)-catalyzed cyclo- and Michael addition reactions of unsaturated β-ketoesters

The α-alkylidene β-ketoesters 2-carbethoxycyclopentenone (1a) and ethyl 2-benzoylacrylate (1b) react with 1,2-dimethylbutadiene (2) (Diels-Alder), N-benzyl-N-(cyclohexylethynyl)-4-methylbenzenesulfonamide (3) (Ficini reaction), ethynyl(phenyl)sulfane (4) ([2 + 2] cycloaddition), and 1,2,5-trimethyl-1H-pyrrole (5) (Michael addition) in the presence of copper(I) (6) or copper(II) triflate (7) (1-2 mol %) in dichloromethane. This convenient protocol converts 1a and 1b to the corresponding cycloaddition (8-10) or Michael addition (11) products in good yields after reaction times of 0.5-3 h without requiring purified solvents or inert gas atmosphere.     

SbCl3-catalyzed solvent-free Friedel–Crafts reaction of phenols with mandelic acids to 3-aryl benzofuran-2(3H)-ones: Synthesis of spirocyclic 2,3-dihydrobenzofuran-2-ones

A facile, SbCl₃-catalyzed, one-pot, tandem Friedel–Crafts/lactonization reaction of phenols and mandelic acids has been developed under solvent-free conditions to afford 3-aryl benzofuran-2(3H)-ones in good to high yields (52–90%). Additionally, the utility of 3-aryl benzofuran-2(3H)-ones is demonstrated by using them as precursors in the synthesis of a new class of spirocyclic benzofuran-2-ones using classical synthetic methodologies.     

Crystal Structures of Cu(Ⅰ) and Cu(Ⅱ) Complexes of Tris(N-n-propylbenzimidazol-2-ylmethyl)amine

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Synthesis and Properties of u-Oxamido Heterobinuclear Cu(Ⅱ)-Co(Ⅱ) Complexes

Three heterobinuclear complexes were synthesized, namely [Cu (oxpn) Co (L)2] (ClO4)2·xH2O(L= 2,2'-bipyridyl(bpy), 1,10-phenanthroline(phen) , and 5-nitro-1, 10-phenanthroline (NO2-phen)), where oxpn represents N, N'-bis(3-aminopropyl) oxam-ido. Based on 1R, elemental analysis, conductivity measurement and electronic spectra, these complexes were characterized by an extended oxamido-bridged structure with Cu(Ⅱ) in a planar environment and Co(Ⅱ) in a octahedral environment. The symmetry of the cation is very close to C2v.The complexes were also characterized with variable temperature (4~300K) magnetic susceptibility, and the data were fit for the susceptibility equation derived from spin Hamilton, H= -2JS1.S2-DSx12 by least square strategy. The exchange integral, J, was found to be -22.36 cm-1 (for bpy);-15.45 cm-1 (for phen); -19. 10cm-1(for NO2-phen), indicating that there is a weak antiferromagnetic spin-exchange interaction between the metal ions.     

Synthesis and Magnetic Studies of Oxamido-Bridged Cu(Ⅱ)-Fe(Ⅱ) Heterobinuclear Complexes

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Synthesis and properties of one-dimensional Ni(Ⅱ) and Ni(Ⅱ)Cu(Ⅱ) complexes linked by hydrogen bond

Four dithiooxalato (Dto) bridged one-dimensional Ni(ll) and Ni(ll)Cu(ll) complexes (Me6[14]dieneN4)Ni2(Dto)2) (1), (Me6[14]dieneN4)CuNi(Dto)2 (2), (Me6[14]aneN4)Ni2(Dto)2 (3), and (Me6[14]aneN4)CuNi(Dto)2(4), were synthesized. These complexes have been characterized by elemental analysis, IR, UV and ESR spectra. The crystal structure of complex 3 was determined. It crystallizes in the monoclinic system, space group C2/c with a = 2.2425(4) nm, b = 1.0088(2) nm, c=1.4665(3) nm, β= 125.32(3)° ;Z=4; R = 0.076, Rw = 0.079. In the complex, Ni(1) coordinates four sulphur atoms of two Dto ligands in plane square environment. Ni(2) lies in the center of mac-rocyclic ligand. For Dto ligand, two sulphur atoms coordinate Ni(1), and O(1) coordinates Ni(2) and forms weak coordination bond. O(2) is linked to N(2) of macrocyclic ligand through hydrogen bond.     

W(II)-catalyzed hydroarylation of bicyclo[2.2.1]hept-2-ene by simple arenes

The tungsten(II) carbonyl compound (CO)₄W(μ-Cl)₃W(SnCl₃)(CO)₃ has been found to be a very effective catalyst for the hydroarylation of bicyclo[2.2.1]hept-2-ene (norbornene) conducted in arene solution at room temperature. Norbornene adducts with benzene, toluene, para-xylene, and mesitylene have been isolated and their structures have been unambiguously established by means of ¹H and ¹³C NMR spectroscopy. On the basis of ¹H NMR monitoring of several catalytic reactions, a possible mechanism involving coordination of norbornene to the W(II) atom and its activation has been proposed.     

Nickel(II)-catalyzed carbon-carbon bond formation reaction of functionalized organozinc reagents with aromatic aldehydes

In the presence of a silylating reagent and catalytic amount of Ni(acac)₂, organozinc halides reacted with aromatic aldehydes to give the corresponding dialkylation products in good to excellent yields under mild conditions.     

经由Domino脱HCl/Pd（OAc）2催化的Heck反应合成查尔酮

通过Domino脱HCl/Pd(OAc)2催化的Heck反应实现了β-氯代烷基芳基酮、酯和酰胺与卤代芳烃的交叉偶联反应,高效合成了查尔酮类化合物。利用原位生成烯酮为中间体进行反应的策略,减少副反应的发生,从而提高反应的效率。该方法对各种官能团的容忍性好,为从氯代烷烃出发直接合成查尔酮类化合物提供了一条新途径。     

Efficient palladium(II)-catalyzed homocoupling of thiazole-4-carboxylic or oxazole-4-carboxylic derivatives

An efficient Pd(OAc)₂-catalyzed homocoupling of thiazole-4-carboxylic or oxazole-4-carboxylic derivatives is described. It represents a facile and practical methodology to prepare bis-5,5′-thiazole (oxazole)-4,4′-dicarboxylic derivatives in good to excellent yields. This protocol tolerates a series of substitutions on the thiazole (oxazole) rings, including alkyl, carbonyl, and electron-withdrawing/donating group substituted phenyl groups.     

Copper-catalyzed domino reaction between 1-(2-halophenyl)methanamines and amidines or imidates for the synthesis of 2-substituted quinazolines

The CuI-catalyzed domino reaction between 1-(2-bromophenyl)methanamines and amidines using K₃PO₄ as the base, pivalic acid as the additive, and aerial oxygen as the oxidant gives access to substituted quinazolines in a single step with yields in the range between 43 and 90%. It is assumed that the reaction proceeds as a Cu(I)-catalyzed intermolecular N-arylation followed by an intramolecular nucleophilic substitution and a Cu(II)-catalyzed oxidation. The amidines can be replaced with imidates and the reaction can also be run with 1-(2-iodophenyl)methanamine.     

Synthesis and DNA cleavage properties of ternary Cu(II) complexes containing histamine and amino acids

The ternary complexes of [Cu^II(Hist)(Tyr)]⁺1 and [Cu^II(Hist)(Trp)]⁺2 have been synthesized, structurally characterized and their DNA binding and cleavage abilities probed. The intrinsic binding constants (K_b) for complexes/CT-DNA were also determined (K_b = 2.7 × 10² for complex 1 and K_b = 2.2 × 10² for complex 2). These complexes exhibit their nuclease activity on plasmid DNA, which seems to depend on the nature of the aromatic moiety. The DNA hydrolytic cleavage rate constants were also determined for complexes 1 and 2, which are 0.91 and 0.79 h⁻¹, respectively.     

Synthesis and spectral studies of macrocyclic Cu(II) complexes by reaction of various diamines,copper(II) perchlorate and 1,4-bis(2-carboxyaldehyde phenoxy)butane

Six macrocyclic complexes, were synthesized by reaction of 1,4-bis(2-carboxyaldehyde phenoxy)butane and various amines and their copper(II) perchlorate complexes were synthesized by template effect reaction of 1,4-bis(2-carboxyaldehyde phenoxy)butane, Cu(ClO₄)₂?·?6H₂O and amines. The metal-to-ligand ratios were found to be 1?:?1. Cu(II) metal complexes are 1?:?2 electrolytes as shown by their molar conductivities (Λ_M) in DMF (dimethyl formamide) at 10^?3?M. The Cu(II) complexes are proposed to be square planar based on elemental analysis, FT–IR, UV–Vis, magnetic susceptibility measurements, molar conductivity measurements, and mass spectra.     

Complexes of Co(II), Ni(II) and Cu(II) with lapachol

Complexes of naturally occurring hydroxynaphtho-quinone, lapachol (2-hydroxy-3(3-methyl-2-buthenyl)-1,4-naphthoquinone = HL) with Co(II), Ni(II) and Cu(II) have been prepared by reaction of the corresponding acetates with the ligand (HL) in ethanol. The molecular and crystal structures were determined for [CoL₂(EtOH)₂] (1), [NiL₂(EtOH)₂] (2), and [CuL₂(py)₂] (3). In all cases the deprotonated lapachol behaves as chelating bidentate ligand. The complexes were also characterized by elemental analyses, cyclic voltammetry, and FAB-MS.     

Ligation properties of 2-acetyl-2-thiazoline semicarbazone (ATsc): Isolation, spectroscopic and X-ray study of ATsc and its Cu(II) and Ni(II) complexes

A new ligand, 2-acetyl-2-thiazoline semicarbazone (ATsc), has been prepared and characterized by a variety of physico-chemical techniques. Likewise, the metal complexes [CuCl₂(ATsc)] and [Ni(ATsc)₂](NO₃)₂ · H₂O have been isolated and characterized through elemental analysis, IR, UV–Vis–NIR diffuse reflectance and magnetic susceptibility, as well as, in the case of the copper complex, by means of EPR. Moreover, the structures have been determined by X-ray diffraction. In both complexes the Schiff base acts as a tridentate ligand through N(1), N(2) and O atoms, making two five-membered chelate rings. The copper complex consists of monomeric molecules in which the copper atom is five coordinated in a distorted square-pyramidal geometry, with one ATsc and two chlorine ligands. The complex cation of nickel possesses approximately a non-crystallographic C₂ symmetry. The environment around the nickel atom may be described as a distorted octahedral geometry with the metallic atom coordinated to two ATsc ligands.     

Separation of Ga(III) from Cu(II), Ni(II) and Zn(II) in aqueous solution using synthetic polymeric resins

Poly (acrylamide-acrylic acid-dimethylaminoethylmethacrylate), p(AM-AA-DMAEM) and Poly(acrylamide-acrylic acid)-ethylenediaminetetracetic acid disodium, p(AM-AA)-EDTANa₂ were prepared by gamma radiation-induced template polymerization technique and used for the separation of Ga (III) from Cu (II), Ni (II), and Zn (II) in aqueous media. The effect of pH and contact time on the separation process was studied. The optimum pH value for the separation process is 3–3.5. The result shows that Ga (III) is first extracted while Cu (II), Ni (II) and Zn(II) are slightly extracted at this pH value. The recovery of metals using HCl, HNO₃ and H₂SO₄ has been studied. The resins may be regenerated using 2M HCl solutions.