Noncatalytic C-amidoalkylation of acetylacetone and chromium acetylacetonate with N-sulfonyl polychloroacetaldehyde imines

N-(2,2,2-Trichloroethylidene)- and N-(2,2-dichloro-2-phenylethylidene)arenesulfonamides reacted with acetylacetone and chromium(III) acetylacetonate in the absence of a catalyst to give previously unknown β-aminoketone derivatives, N-(3-acetyl-1-polychloro-4-oxopentan-2-yl)arenesulfonamides.     

Design,synthesis, characterization and biological studies of copper(II) complexes with 2‐aminobenzimidazole derivatives as biomimetic agents

Four novel copper(II) complexes of 2‐aminobenzimidazole derivatives (obtained from the Knoevenagel condensation of acetylacetone (obtained from acetylacetone and halogen‐substituted benzaldehydes) and 2‐aminobenzimidazole) were synthesized. They were characterized using elemental analysis, molar conductance measurements, and fast atom bombardment mass, Fourier transform infrared, NMR, UV–visible and electron paramagnetic resonance spectroscopies. On the basis of the spectral studies, a distorted square planar geometry was assigned for all the complexes. The antibacterial screening of the ligands and their complexes revealed that all the complexes had higher activities than the free ligands. Superoxide dismutase and antioxidant activities of the copper complexes were also studied. The shifts in ΔE _p, E _1/2, I _pc and I _pa values were explored for the interaction of the complexes with calf thymus DNA using the electrochemical technique.     

Divalent nickel,cobalt and copper complexes of a tetradentate N6 macrocyclic ligand

Summary Divalent nickel, cobalt and copper salts react with 2,6-diaminopyridine and acetylacetone to form complexes containing a 16-membered N₆ tetradentate macrocyclic ligand. The complexes are characterised as distorted octahedra of the M(TML)X₂ type where M=nickel(II), cobalt(II) and copper(II); TML=tetradentate macrocyclic ligand and X=Cl, Br, NO₃ or NCS. The ligand coordinates through all the four azomethine nitrogen atoms which are bridged by acetylacetone moieties. Pyridine nitrogen does not participate in coordination, a fact supported by far i.r. studies. The magnetic, electronic and i.r. spectral studies indicate that the complexes have lower symmetries and the amounts of distortion calculated in terms of DT/DQ applying normalised spherical harmonic Hamiltonian theory indicate that these complexes are moderately distored.     

2,2,2-Trinitroethyl ethers of 2,2-dinitroalcohols

2,2,2-Trinitroethyl ethers of 2,2-dinitroalcohols and some of their derivatives have been obtained for the first time by nitration of oximes of 2,2,2-trinitroethyl ethers of hydroxy ketones and aldehydes with a HNO₃-Ac₂O mixture, followed by oxidation with H₂O₂. Starting carbonyl derivatives were prepared by oxidation and hydrolysis of the propargylic and allylic ethers, respectively, of 2,2,2-trinitroethanol followed by further reactions of these compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2797–2802, December, 1991.     

Thermal studies of some purine compounds and their metal complexes

The mechanism of the decomposition of the entitled compounds and their complexes is studied. Adenine, its Schiff base of salicylaldehyde, and its azo resorcinol derivatives are ended with carbon. However, oxalonitrile compound is appeared as a final product for adenine acetylacetone and an intermediate for adenine. The thermodynamic parameters of the decomposition reaction were evaluated and discussed. The change of entropy values, ΔS ^#, showed that the transition states are more ordered than the reacting complexes. The thermal processes proceed in complicated mechanisms where the bond between the central metal ion and the ligands dissociates after losing small molecules such as H₂O, NH₃, or HCl. In most cases, the free radical species of the ligands are assigned to exist through decomposition mechanisms. The copper adenine and nickel salicylaldehyde complexes are ended with the metal as a final product. However, the cobalt adenine, its acetylacetone, its salicylaldehyde, cadmium and mercury guanine complexes are ended with metal oxides.     

Synthesis,spectral and magnetic studies of some mixed ligand complexes of spin-free cobalt(II)

The reactions of acetylacetone, methyl acetoacetate and ethyl acetoacetate derivatives of cobalt(II) with diamines and hydroxyquinoline have resulted in the isolation of hexacoordinated complexes of the stoichiometry Co(L)₂(L′); where L = acetylacetone (AA), methyl acetoacetate (MeAA) or ethyl acetoacetate (EtAA) and L′ = ethylenediamine (En), propylenediamine (Pn) or 8-hydroxyquinoline. Their magnetic, IR and electronic spectral properties have been used to establish the stereochemistry. The values of the Racah interelectronic repulsion parameter (B) and crystal field splitting energy (10Dq) have been calculated using numerical as well as graphical procedures.     

Kinetic study of electrochemically induced Michael reaction of1,4-dihydroxyanthraquinone with acetylacetone and benzoylacetone

The electrochemical oxidation of 1,4-dihydroxyanthraquinone has been studied in the presence of acetylacetone and benzoylacetone as nucleophiles in a mixture of ethanol/water by means of cyclic voltammetry as a diagnostic technique.The results indicate the participation of electrochemically produced anthraquinone in the Michael addition reaction with acetylacetone and benzoylacetone to form the corresponding new anthraquinone derivatives.On the basis of the EC mechanism,the observed homogeneous rate constants（kobs）of the reaction of anthraquinone with acetylacetone and benzoylacetone were estimated by comparing the experimental cyclic voltammograms with the digitally simulated results.     

Structure-stability relationship of copper(II)-indol carboxylic acid derivative complexes from spectrophotometric,thermogravimetric and potentiometric studies

Some copper(II) complexes of N-methyl indol carboxylic acid derivatives have been isolated and characterized. These complexes were subjected to elemental and thermogravimetric analyses together with UV, visible and IR spectral studies. Based on these physicochemical studies, the suggested formula for the complexes obtained is CuL₂ where L = N-methyl indol carboxylic acid derivatives L₁-₄.Thermogravimetric analyses of the isolated complexes have already indicated different modes of interaction between the ligands and the central copper(II) metal ions. UV, visible and IR spectral studies have indicated that coordination of the ligands to the central metal ion is via carboxylic-, hydroxyl- and/or nitrogen-containing groups.The stability constants of some of these metal chelates were determined from potentiometric measurements and found to be in the order Cu(L₃)₂ < Cu(L₂)₂ < Cu(L₄)₂, which essentially depends on the acid dissociation constants of the ligands, determined under the same conditions.     

Novel one-pot synthesis of new derivatives of dihydropyrimidinones, unusual multisubstituted imidazoline-2-ones: X-ray crystallography structure

Three-component condensation of phenylglyoxal, alkyl acetoacetates or acetylacetone and urea proceeds smoothly, catalyzed by ZnCl₂, to afford the corresponding new 3,4- dihydropyrimidinones. This reaction is also catalyzed by AlCl₃:ZnCl₂ (3:1) under microwave irradiation in solvent-free conditions. One-pot three-component condensation of dimethyl urea, acetylacetone or alkyl acetoacetate and phenylglyoxal catalyzed by ZnCl₂ or AlCl₃:ZnCl₂ (3:1) yields new multisubstituted imidazoline-2-ones derivatives. Structures of products were studied by X-ray crystallographic data. The reaction of phenylglyoxal, urea and β-ketoesters in the presence of hydrochloric acid produces only 5-phenylhydantoins.     

Synthesis,characterization and catalytic studies of iron(III), cobalt(II), nickel(II) and copper(II) complexes containing triphenylphosphine and β-diketones

A series of new β-diketonato complexes have been synthesized from the reactions of iron(III), cobalt(II), nickel(II) and copper(II) Ph₃P complexes with β-diketones (acetylacetone, benzoylacetone and dibenzoylmethane). All the complexes have been characterized by elemental analyses, spectral studies (i.r., electronic., magnetic., e.p.r., ¹H-n.m.r.) and cyclic voltammetry. The new complexes have been used as catalysts for aromatic coupling and oxidation reactions. Higher catalytic activity has been observed for the nickel(II) complexes compared to the other complexes.     

Isotropic NMR Shifts in Imidazole, 2-Methyl Imidazole and n-Methyl Imidazole Complexed with Copper (II) β-Diketonates

Isotropic nuclear magnetic resonance shifts have been measured for imidazole (Im), 2-methyl imidazole (2MeIm) and N-methyl imidazole (NMeIm) adducts with Cu(AA)₂, Cu(TFA), and Cu(HFA)₂, where AA, TFA and HFA are anion of acetylacetone, trifluoroacetylacetone and hexafluoroacetylacetone, respectively, in deuteriochloroform solution. The pseudocontact contribution to the isotropic shifts are negligibly small and Ferrmi contact interaction is dominant in these copper complexes. The normal temperature effect and appreciable spin delocalization suggest that the imidazole and substituted imidazole adducts with Cu(chelate)₂ are all six-coordinated octahedral complexes, and consistent with our results of spectrophotometric study. In these imidazole complexes, the magnitude of the contact shifts lie in the order Cu(HFA)₂>Cu(TFA)₂>Cu(AA)₂, which is the same as that of the stability constants for the pyridine type adduct formation found from spectrophotometric studies. For a given Cu(chelate)₂, the basicity of ligand for adduct formation is in the order NMeIm>Im>2MeIm.     

Copper Salt‐Controlled Divergent Reactivity of [Cu]CF2PO(OEt)2 with α‐Diazocarbonyl Derivatives

Herein, we report a copper salt‐controlled divergent reactivity toward α‐diazocarbonyl compounds. By a simple change of the copper counteranion under identical reaction conditions, the reported method allowed an easy access to either (Z)‐α‐fluorovinylphosphonate or alkyl‐SCF₂PO(OEt)₂ derivatives in good yields. Mechanistic studies were performed and suggested two different pathways to explain the formation of these products.     

Synthesis,structure elucidation,DNA binding and molecular docking studies of novel copper(II) complexes of two 1,3,4-thiadiazolethiosemicarbazone derivatives

Four novel Cu(II) chelates were synthesized by reacting hydrated CuCl₂ and Cu(CH₃COO)₂ with two derivatives of 1,3,4-thiadiazolethiosemicarbazone. The structures and geometries of the synthesized complexes were deduced applying the alternative analytical and spectral tools confirming the complexes to have the formulae [(LH)Cu(Cl)]•0.5H₂O, [(LH)Cu(OAc)(H₂O)₂]•0.5H₂O, [(LCl)Cu(Cl)(H₂O)₂]•H₂O and [(LCl)Cu(OAc)]; where LH and LCl are phenyl and p-chlorophenyl derivatives of 1,3,4-thiadiazolethiosemicarbazone ligands, respectively (deprotonated form). IR spectral data confirmed the coordination of the ligands to the copper center as monobasic tridentate in the thiol form. Thermal analysis, UV–Vis spectra and magnetic moment assured the geometry around the copper center to be square planar, trigonal bipyramid and octahedral which have been confirmed by the computational studies. The two ligand derivatives and their copper complexes were applied to evaluate their binding modes with SS-DNA via UV–Vis spectral titration and viscosity measurements. The DNA-binding constant (k_b) values of the investigated derivatives were calculated and compared with ethidium bromide in order to assess their mode of binding with DNA. Moreover, docking study of these complexes was carried out to recognize the drug–DNA interactions and to calculate their binding energies.     

Five coordinated complexes of divalent nickel and copper with ligands derived from acid hydrazides and acetylacetone

Summary Picolinic acid hydrazide (PH) and isonicotinic acid hydrazide (INH) react with acetylacetone to form complexes, containing open chain tetradentate ligands, through anin situ process in the presence of nickel and copper salts. The complexes were isolated and characterised as five-coordinate with the aid of analyses, magnetic, e.s.r., electronic and i.r. spectral studies.Attempts to obtain the free ligand were unsuccessful, but its solid complexes can be isolated. Acetylacetonebispicolinoyl hydrazone Ac(PH)₂ coordinates through azomethine and pyridine nitrogen atoms while acetylacetonebisisonicotinoyl hydrazone Ac(INH)₂ does so through azomethine nitrogens and amido oxygen atoms, giving rise to complexes of the MAc(PH)₂X or MAc(INH)₂X type where X=Cl, Br, NO₃ or NCS and M=nickel(II) and copper(II). Magnetic, e.s.r. and electronic spectra are consistent with five coordinate geometries incorporating one anion on the axial positions. Various ligand field parameters have been calculated and the amount of distortion assessed in terms of DT/DQ. The metal-ligand vibrations in the far i.r. are discussed.     

Copper(ll) Complexes of Diamino Diamide and Diamino Diamine in Aqueous Solution

In order to study the difference on the equilibrium, spectral properties of copper(II) complexes of diamino diamide and diamino diamine, new tetradentate ligands, 4,7‐dimethyl‐4,7‐diazadecanediamide (4,7‐N,N′‐Me₂‐L‐2,2,2) and 1,10‐diamino‐4,7‐dimethyl‐4,7‐diazadecane (4,7‐N,N′‐Me₂‐3,2,3‐tet), have been synthesized. Synthetic procedures for these new ligands are described. Their protonation constants have been determined potentiometrically in 0.10 MKC1 at 25.0°C. The formation of their copper(II) complexes have been investigated quantitatively by the potentiometric technique and by the measurement of their electronic spectra.     

Dediazoniations of Arene Diazonium Ions in Homogeneous Solution. Part III: Heterolytic arylations in 2,2,2-trifluoroethanol - an SN1-or an SN2-reaction?

Benzenediazonium tetrafluoroborate in 2,2,2-trifluoroethanol decomposes to give fluorobenzene and phenyl 2,2,2-trifluoroethyl ether. In the presence of benzene, toluene, trifluoromethyl-benzene or anisole, the respective biphenyl derivatives are formed in addition to fluorobenzene and the ether. The distribution of the isomeric substituted biphenyls is consistent with an electrophilic substitution. No homolytic products (diazo tars, benzene) are formed. The reaction kinetics clearly show that ether formation and aryl-dediazoniations are of second-order type, i.e. that trifluoroethanol and the benzene derivatives mentioned above are rate-determining factors. It is shown that these results exclude the S_N1-mechanism which is usually assumed for heterolytic dediazoniations; free aryl cations are therefore not involved in these reactions. An S_N2-like mechanism seems to be the most likely, but one involving an encounter complex containing the dissociated benzenediazonium ion is also consistent with the experimental data.     

Synthesis,rearrangements, and fragmentation of ketene mercaptals derived from ketones or β-diketones and carbon disulphide

By use of the ion pair extraction technique, tetrabutylammonium salts of acetylacetone, benzoylacetone, and dibenzoylmethane were reacted with carbon disulphide to give salts of dithioacids. Alkylation gave dithioesters and ketene mercaptals. A simple procedure for the preparation of 2-diacylmethylene-1,3-dithietanes

was found. Cyclisation reactions of some acetylacetone derivatives gave a 1,3-dithiolane, a mercaptothiophene, and a [2.3-b] thienothiophene. Allylic ketene mercaptals derived from acetone, cyclohexanone, acetylacetone, benzoylacetone, and dibenzoylmethane rearranged to α-allyl-dithioesters. Inversion of the migrating allyl group was observed when the ketene mercaptal had a vinylic hydrogen; otherwise retention was found. 3-[(Crotylthio-, methylthio-)methylene] acetylacetone underwent decomposition at 170° to methyl, 1-methyl-allyl sulphide and the “desaurin”: 2,4-bis-(diacetyl-methylene)-1, 3-dithietane. By-products in syntheses of the dithioesters and ketene mercaptals included trithiocarbonates, alkylated β-diketones, and compounds formed by reactions of the solvent (CH₂Cl₂) with β-diketones or their carbon disulphide adducts (1,3-di-thietanes).     

ReBr(CO)5-catalyzed sequential addition-cyclization of 1,3-dicarbonyl compounds with electron-deficient internal alkynes affording trisubstituted 2H-pyran-2-ones

The reaction of 1,3-dicarbonyl compounds such as acetoacetate, acetylacetone, dibenzoylmethane, and benzoylacetate with electron-deficient internal alkynes in the presence of catalytic amount of ReBr(CO)₅ in toluene under neutral conditions resulted in the formation of 4,5,6-trisubstituted 2H-pyran-2-ones in moderate to high yield. The reaction took place via a two-step sequence including the rhenium(I)-catalyzed addition of the activated methylenes to alkynes to give enolic 2-alkenyl derivatives, and subsequently dealcoholic cyclization to form 2H-pyran-2-one derivatives.     

Porphyrins. 13. Reaction of meso-dimethylaminomethyletioporphyrin I with nucleophiles in the presence of zinc acetate

When meso-dimethylaminomethyletioporphyrin I (I) is heated in CCl₄ or tetrahydrofuran (THF) in the presence of zinc acetate, it reacts with alcohols to give the corresponding meso-alkoxy-methylporphyrins. Under similar conditions CH acids (acetone, acetylacetone, nitromethane, and others) form the corresponding meso-substituted derivatives with the formation of a C-C bond. Ethers are formed when the copper and nickel complexes of I are heated in ethylene glycol.See [1] for Communication 12.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 943–948, July, 1980.     

New ferro-and antiferromagnetic complexes of tridentate azomethines with copper

Tridentate azomethine ligands with N₂O₄ and N₃donor atoms and their copper complexes were synthesized and characterized. The dimeric structure of copper(II) chelates was confirmed by EXAFS studies. Complexes based on 2-tosylaminobenzaldehyde azomethines tend to undergo ferromagnetic exchange, whereas similar salicylaldehyde derivatives have antiferromagnetic exchange.