Condensation Of Acetylacetone Research Articles

Half-Curcuminoids Encapsulated in Alginate-Glucosamine Hydrogel Matrices as Bioactive Delivery Systems.

The therapeutic effects of curcumin and its derivatives, based on research in recent years, are limited by their low bioavailability. To improve bioavailability and develop the medical field of application, different delivery systems have been developed that are adapted to certain environments or the proposed target type. This study presents some half-curcuminoids prepared by the condensation of acetylacetone with 4-hydroxybenzaldehyde (C1), 4-hydroxy-3-methoxybenzaldehyde (C2), 4-acetamidobenzaldehyde (C3), or 4-diethylaminobenzaldehyde (C4), at microwaves as a simple, solvent-free, and eco-friendly method. The four compounds obtained were characterized in terms of morphostructural and photophysical properties. Following the predictions of theoretical studies on the biological activities related to the molecular structure, in vitro tests were performed for compounds C1-C3 to evaluate the antitumor properties and for C4's possible applications in the treatment of neurological diseases. The four compounds were encapsulated in two types of hydrogel matrices. First, the alginate-glucosamine network was generated and then the curcumin analogs were loaded (G1, G3, G5-G7, and G9). The second type of hydrogels was obtained by loading the active compound together with the generation of the hydrogel carrier matrices, by simply dissolving (G4 and G10) or by chemically binding half-curcuminoid derivatives to glucosamine (G2 and G8). Thus, two types of curcumin analog delivery systems were obtained, which could be applied in various types of medical treatments.

Homogeneous Gold Catalysis Using Complexes Recovered from Waste Electronic Equipment.

Despite the greater awareness of elemental sustainability and the benefits of the circular economy concept, much waste electrical and electronic equipment (WEEE) is still destined for landfill. Effective methods for valorizing this waste within our society are therefore imperative. In this contribution, two gold(III) complexes obtained as recovery products from WEEE and their anion metathesis products were investigated as homogenous catalysts. These four recovery products were successfully applied as catalysts for the cyclization of propargylic amides and the condensation of acetylacetone with o-iodoaniline. Impressive activity was also observed in the gold-catalyzed reaction between electron-rich arenes (2-methylfuran, 1,3-dimethoxybenzene, and azulene) and α,β-unsaturated carbonyl compounds (methyl vinyl ketone and cyclohexenone). These recovered compounds were also shown to be effective catalysts for the oxidative cross-coupling reaction of aryl silanes and arenes. When employed as Lewis acid catalysts for carbonyl-containing substrates, the WEEE-derived gold complexes could also be recovered at the end of the reaction and reused without loss in catalytic activity, enhancing still further the sustainability of the process. This is the first direct application in homogeneous catalysis of gold recovery products sourced from e-waste.

Preparation and Some Characterization Analyses of Cobalt (II) Complex with Schiff Base Derived from Acetyleacetone and 2-Aminopyridine

A Schiff base has been prepared by condensation of acetylacetone and 2-aminopyridine. Metal complex of the Schiff base was prepared by the reaction of the Schiff base and cobalt(II) chloride in methanol. The complex was isolated, washed and dried. The Schiff base and the complex were yellow and purple colors respectively. They were characterized by solubility test, melting point and decomposition temperature, FT-IR., and molar conductivity analysis. Solubility test on the Schiff base and complex showed that they all soluble in DMF and DMSO but insoluble in CCl4 and ether. Also FT-IR. analysis showed a band at 1674cm-1 assigned to azomethine of the Schiff base which shifted to 1644cm-1 in the complex. The complex is high spin complex and electrolytic in nature.

Preparation and Some Characterization Analyses of Cobalt (II) Complex with Schiff Base Derived from Acetyleacetone and 2-Aminopyridine

A Schiff base has been prepared by condensation of acetylacetone and 2-aminopyridine. Metal complex of the Schiff base was prepared by the reaction of the Schiff base and cobalt(II) chloride in methanol. The complex was isolated, washed and dried. The Schiff base and the complex were yellow and purple colors respectively. They were characterized by solubility test, melting point and decomposition temperature, FT-IR., and molar conductivity analysis. Solubility test on the Schiff base and complex showed that they all soluble in DMF and DMSO but insoluble in CCl4 and ether. Also FT-IR. analysis showed a band at 1674cm-1 assigned to azomethine of the Schiff base which shifted to 1644cm-1 in the complex. The complex is high spin complex and electrolytic in nature.

Stable Bicyclic Functionalized Nitroxides: The Synthesis of Derivatives of Aza-nortropinone–5-Methyl-3-oxo-6,8-diazabicyclo[3.2.1]-6-octene 8-oxyls

In recent decades, bicyclic nitroxyl radicals have caught chemists’ attention as selective catalysts for the oxidation of alcohols and amines and as additives and mediators in directed C-H oxidative transformations. In this regard, the design and development of synthetic approaches to new functional bicyclic nitroxides is a relevant and important issue. It has been reported that imidazo[1,2-b]isoxazoles formed during the condensation of acetylacetone with 2-hydroxyaminooximes having a secondary hydroxyamino group are recyclized under mild basic catalyzed conditions to 8-hydroxy-5-methyl-3-oxo-6,8-diazabicyclo[3.2.1]-6-octenes. The latter, containing a sterically hindered cyclic N-hydroxy group, upon oxidation with lead dioxide in acetone, virtually quantitatively form stable nitroxyl bicyclic radicals of a new class, which are derivatives of both 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (TEMPON) and 3-imidazolines.

Nickel(II) Phosphane‐ and N‐heterocyclic Carbene Complexes with Tridentate, Dianionic [S,N,O]2– Ligands

Square‐planar dinuclear nickel(II) complexes containing [S,N,O]2– ligands formed by condensation of acetyl acetone or benzoyl acetone with cysteamine were prepared. These dimeric nickel(II) compounds undergo bridge‐cleavage reactions with the cage phosphine PTA (PTA = 1,3,5‐triaza‐7‐phosphaadamantane) or in situ generated N‐heterocyclic carbenes. The resulting diamagnetic, square planar NiII complexes were characterized by spectroscopic methods and X‐ray diffraction.

Synthesis, structural characterization, DFT calculations and biological properties of mono- and dinuclear nickel complexes with tetradentate transformed ligands by aerobic oxidative-coupling reactions

Reaction of nickel chloride with acetylacetone bis(salicylhydrazone) (L) (prepared in situ by condensation of acetylacetone with salicylhydrazide) in methanol results in the formation of air-sensitive nickel (II) complex of symmetrical tetradentate Schiff base [NiII(L)] (1). Air oxidation of 1 leads to the formation of dinuclear species [NiII(L-L)NiII] (2) where the ligand (L-L)4– is formed by oxidative C-C coupling at the central methylene group of the acetylacetone fragment of (L)2–. The same reaction in methanol/pyridine solution leads to oxidative C-N coupling forming a mesoionic [NiII(L-Py)](3). The use of Nickel acetylacetonate in methanol/pyridine or DMSO solution under aerobic conditions provide [NiII(L-O)(py)2](4), [NiII(L-O)(DMSO)2](5). In this case, the ligand (L)2– is partially oxidized to form (L-O) which is formed by oxidation of the central methylene group. The molecular structure of 1–5 have been determined by X-ray crystallography. The first three complexes 1, 2 and 3 have a square-planar geometry, while, 4 and 5 adopt octahedral geometry. In vitro antioxidant activities of compounds 1, 4 and 5 were evaluated against DPPH radical and hydrogen peroxide and were compared with standard antioxidant, ascorbic acid. Our results reveal that the three compounds exhibit excellent radical scavenging activities. DFT calculations have been performed on complexes 1–5 using the BP86 and B3LYP functionals to provide a complete rationalization of their structures and to describe their electronic structures elucidating the fundamental spin state and the Metal-Ligand interaction type.

Electropolymerizable IrIII Complexes with β-Ketoiminate Ancillary Ligands.

A series of electropolymerizable cyclometallated IrIII complexes were synthesized and their electrochemical and photophysical properties studied. The triphenylamine electropolymerizable fragment was introduced by using triphenylamine-2-phenylpyridine and, respectively, triphenylamine-benzothiazole as cyclometalated ligands. The coordination sphere was completed by two differently substituted β-ketoiminate ligands deriving from the condensation of acetylacetone or hexafluoroacetylacetone with para-bromoaniline. The influence of the -CH3 /-CF3 substitution to the electrochemical and photophysical properties was investigated. Both complexes with CH3 substituted β-ketoiminate were emissive in solution and in solid state. Highly stable films were electrodeposited onto ITO coated glass substrates. Their emission was quenched by electron trapping within the polymeric network as proven by electrochemical studies. The -CF3 substitution of the β-ketoiminate leads instead to the quenching of the emission and inhibits electropolymerization.

SYNTHESIS AND CHARACTERIZATION OF L=4-(2-AMINOPHENYLIMINO)-PENTEN-2-OL. AND ITS COMPLEXES [ML(H2O)] ; M= Zn(II), Cd(II), Ni(II), Cu(II) AND Co(II)

4-(2-amino-phenylimino)-pentene-2-ol (L) was obtained by condensation of acetylacetone and o-phenylenediamine in ethanolic medium. The reactions stoichiometries between the metal(II) ion and the ligand (L) in molar ratio of M:L (1:1) resulted in the formation of the complexes of types [ML(H2O)]. The ligand (L) and its complexes have been characterized with the help of melting point, molar conductance, electronic and infrared spectra. From the data, it is found that all the complexes of formula [ML(H2O)] ; M= Zn(II), Cd(II), Ni(II), Cu(II) and Co(II) posses tetragonal geometry.

A new tetranuclear copper(II) complex using a Schiff base ligand: Synthesis, structural, and magnetic studies

This paper reports on the synthesis, X-ray, and magnetic properties of tetranuclear CuII complex [CuL4] with square-like structure. A Schiff base ligand used for synthesis in this work derives from condensation of acetylacetone with DL-valine amino acid. The structure of the synthesized ligand was investigated by FTIR and NMR. Investigation of the crystal packing diagrams demonstrates extensive C–H⋯O interactions of hydrogen bonding, causing to the production of network structures. The complex exhibits exchange interaction among the CuII ions by a bridging carboxylate pathway. Analysis of the magnetic data through spin Hamiltonians of the form Ĥ=-2J(Ŝ1Ŝ4+Ŝ4Ŝ2+Ŝ2Ŝ3+Ŝ3Ŝ1)-2J′(Ŝ1Ŝ2+Ŝ3Ŝ4) (J has a positive value for a ferromagnetic interaction and negative value for an antiferromagnetic interaction) lead to the following parameters set of best-fit: J=3.04cm−1, J′=0cm−1, g=2.09, and ZJ=−0.109cm−1.

New Cu(II) coordination polymer by chiral tridentate Schiff base ligand

The present research reports the synthesis, X-ray, magnetic and electronic properties for novel coordination polymer based upon copper (II) with chiral tridentate Schiff base ligand synthesized at condensation of acetylacetone and l-leucine amino acid. The investigation was also conducted by quantum mechanical calculations. The large energy gap indicates a high kinetic stability. Magnetic measurement gives predominant antiferromagnetic interactions within the chain. Results reveals further insight into copper(II) chiral tridentate Schiff base complexes.

Nanosilica supported molybdenum catalyst for the epoxidation of olefins under thermal and ultrasonic irradiation conditions

The chemical modification of spherical sub-100 nm silica nanoparticles with 3-aminopropyltriethoxysilane and subsequent reaction with acacen (the Schiff base ligand derived from the condensation of acetylacetone and ethylenediamine) and MoO2(acac)2 precursor produced MoO2acacen@APTSNPs. The characterization of the obtained material was performed by Fourier transform infrared, inductively coupled plasma optical emission spectroscopy, nitrogen adsorption–desorption measurements, thermogravimetric analysis, and scanning electron microscopy, which indicated that the molybdenum complex is successfully supported on the SCMNPs support. The epoxidation of olefins with tert-butyl hydroperoxide in the presence of MoO2acacen@APTSNPs was carried out with good activities and selectivities under reflux and ultrasonic irradiation conditions.

ChemInform Abstract: Synthesis of Tetrasubstituted Furan Derivatives by Condensation of 1,3‐Diketones with Cyclic α‐Hydroxy‐β‐oxo Esters.

Tetrasubstituted 3-acylfuran derivatives were obtained by condensation of acetylacetone with alicyclic and heterocyclic α-hydroxy-β-oxo esters under acidic conditions [0.1 equiv. cerium(III) salt in AcOH]. With [b]-annulated 4-acyl-3-hydroxy-5-methylfuran-2-carboxylates as common intermediates, the reaction proceeded along different pathways depending on the starting materials used: Alicyclic α-hydroxy-β-oxo esters gave cycloalkane-annulated furans as products. The ester group was lost after saponification and decarboxylation at elevated temperature. A thiopyrano[3,4-b]-annulated 2H-furan was obtained when starting from a tetrahydrothiopyranone derivative. With piperidones or a tetrahydropyranone as starting materials, the heterocyclic six-membered ring was cleaved in a retro-Mannich type reaction and one carbon atom was lost. 4-Acetyl-5-methylfuran-2-carboxylates with a 2-amino or 2-hydroxyethyl substituent in the 3-position are obtained in these cases.

Synthesis, characterization and structure of nickel and copper compounds containing ligands derived from keto-enehydrazines and their catalytic application for aerobic oxidation of alcohols.

Ligand precursors HL(R,Ph) (R = Me, Ph) were synthesised by condensation of acetylacetone and the corresponding N,N-substituted hydrazines and were characterised spectroscopically and structurally. Both in the solid state and in solution they behave as (Z)-keto-enehydrazines and this was confirmed by DFT calculations which showed that this form was the most stable of their possible tautomers. The reaction of HL(R,Ph) compounds with copper acetate and nickel acetate in EtOH afforded the corresponding complexes [M(L(R,Ph))2] (M = Cu, Ni; R = Me, Ph). The methyl-substituted derivatives were structurally characterised by X-ray methods. A four-coordinate environment around the metal centre, where the two L(Me,Ph) ligands act as bidentate N,O-chelators and lie in a pseudo-trans conformation, was found for both compounds. The dihedral angle between the two six-membered metallacycles M(L(Me,Ph)) was 0° for nickel, a typical square planar coordination, meanwhile it was 23° for copper, a square planar slightly distorted to pseudotetrahedral coordination. Copper complexes [Cu(L(R,Ph))2] were tested as catalysts, in combination with TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl radical), for the aerobic oxidation of 4-nitrobenzyl alcohol as the model reaction. An almost complete conversion to the corresponding aldehyde was observed after 1 h at 60 °C and 1 bar of dioxygen, in toluene as the solvent. Importantly, air at atmospheric pressure was also observed to be appropriate for the oxidation, although longer reaction times were required. After the optimization of the reaction conditions, the study was extended to other alcohol substrates and good catalytic activity was found for benzylic-type alcohols, while low yield was found for 1-octanol.

Synthesis of Tetrasubstituted Furan Derivatives by Condensation of 1,3‐Diketones with Cyclic α‐Hydroxy‐β‐oxo Esters

AbstractTetrasubstituted 3‐acylfuran derivatives were obtained by condensation of acetylacetone with alicyclic and heterocyclic α‐hydroxy‐β‐oxo esters under acidic conditions [0.1 equiv. cerium(III) salt in AcOH]. With [b]‐annulated 4‐acyl‐3‐hydroxy‐5‐methylfuran‐2‐carboxylates as common intermediates, the reaction proceeded along different pathways depending on the starting materials used: Alicyclic α‐hydroxy‐β‐oxo esters gave cycloalkane‐annulated furans as products. The ester group was lost after saponification and decarboxylation at elevated temperature. A thiopyrano[3,4‐b]‐annulated 2H‐furan was obtained when starting from a tetrahydrothiopyranone derivative. With piperidones or a tetrahydropyranone as starting materials, the heterocyclic six‐membered ring was cleaved in a retro‐Mannich type reaction and one carbon atom was lost. 4‐Acetyl‐5‐methylfuran‐2‐carboxylates with a 2‐amino or 2‐hydroxyethyl substituent in the 3‐position are obtained in these cases.

ChemInform Abstract: Condensation of Acetylacetone with Formaldehyde and Thiols.

Acetylacetone reacted with formaldehyde and thiols in aqueous medium or in the presence of 0.1 equiv of sodium hydroxide to give the corresponding 3-[(alkylsulfanyl)methyl]pentane-2,4-diones which exist in solution as mixtures of diketone and enol tautomers. Four-component condensation of acetylacetone with formaldehyde, methanethiol, and sodium sulfide, depending on the reaction time, led to the formation of a mixture of 1,1-bis(methylsulfanylmethyl)propan-2-one with 1,1′-{3-[(methylsulfanyl)methyl]tetrahydro-2H-thiopyran-3,5-diyl}diethanone or with 8-methyl-5-(methylsulfanylmethyl)-3-thiabicyclo[3.3.1]non-7-en-6-one.

1-Cyanoacetyl-3,5-dimethylpyrazole

1-Cyanoacetyl-3,5-dimethylpyrazole (1) is a white crystalline solid with a melting point of 118–121 °C,[1] stable at room temperature in air. In the 1950s, Ried and Meyer[1] were the first to describe it as a mild cyanoacetylating reagent, being more reactive than ethyl cyanoacetate. Pyrazole 1 is a cheap, handy, and non-toxic reagent that proved to be superior to cyanoacetyl chloride and cyanoacetyl azide in terms of stability and convenience. It is commercially available and can be prepared in about 90% yield by condensation of acetylacetone (2) with cyanoacetohydrazide (3) in aqueous hydrochloric acid (Scheme [1]).[2]

Influence of Reactant 4-Aminobenzonitrile Inclusion on the Crystal Structure of (Z)-4-(4-oxopent-2-en-2-ylamino)benzonitrile

The title compound (Z)-4-(4-oxopent-2-en-2-ylamino)benzonitrile, C12H12N2O, was synthesized by the condensation of acetylacetone and 4-aminobenzonitrile in methanol, with a few drops of formic acid as catalyst. Crystallization of the reaction product solution yielded both pure crystals of the title compound, as well as an inclusion product with a strict 1:1 stoichiometry with one of the reactants, 4-aminobenzonitrile. Crystals of the reactant-inclusion compound, C12H12N2O–C7H6N2 (I), and pure C12H12N2O (II) have been determined at 143(2) and 88(2) K, respectively. The mixed-form crystals crystallized in the monoclinic system, whereas pure-form crystals crystallized in the triclinic system. Intramolecular hydrogen bonds of the type N–H···O were observed in both the mixed and pure-form crystals. However, in the mixed-form, the two components are connected by a N3–H3···N2 intermolecular hydrogen bond, which gives rise to a planar structure and parallel packing of adjacent molecules. In contrast, the structure of the pure compound without any reactant molecule interactions is not planar and exhibits a more complicated stacking array for adjacent molecules. The title compound (Z)-4-(4-oxopent-2-en-2-ylamino)benzonitrile, C12H12N2O, was synthesized by the condensation of acetylacetone and 4-aminobenzonitrile in methanol. Crystallization of the reaction product solution yielded both pure crystals of the title compound, as well as an inclusion product with a strict 1:1 stoichiometry with one of the reactants, 4-aminobenzonitrile. The mixed-form crystals crystallized in the monoclinic system, whereas pure-form crystals crystallized in the triclinic system. Intramolecular hydrogen bonds of the type N–H···O were observed in both the mixed and pure-form crystals. However, in the mixed-form, the two components are connected by a N3–H3···N2 intermolecular hydrogen bond, which gives rise to a planar structure and parallel packing of adjacent molecules. In contrast, the structure of the pure compound without any reactant molecule interactions is not planar and exhibits a more complicated stacking array for adjacent molecules.

Oligomerization of organochlorosilanes in the acetylacetone—carbamide system

Condensation of acetylacetone with carbamide in nonpolar media (benzene, toluene) is initiated by organochlorosilanes. The reaction rapidly occurs under mild conditions to give oligosiloxanes and 4,6-dimethylpyrimidin-2(1H)-one hydrochloride. The conversion of chlorosilanes and the yields of oligosiloxanes are nearly ∼100%.

ChemInform Abstract: Novel Synthesis of Some New Fluorescent 2‐Amino‐3‐cyanopyridines

Abstractvia one‐pot three‐component condensation of acetylacetone, malononitrile, and different amines in the presence of N‐hydroxybenzamide or p‐toluenesulfonic acid