Synthesis of 3-keto-quinolines from enaminones,anilines and DMSO: Transition metal free one pot cascade

An efficient and transition metal-free approach for the synthesis of functionalized 3-ketoquinolines from readily available anilines, enaminones and DMSO in the presence of K₂S₂O₈ has been conducted. This one pot tandem reaction proceeds through [3+2+1] cycloaddition reaction involving DMSO, enaminones and amines. In this environmental benign approach, DMSO acts as both a one carbon source and the solvent. A broad range of variously substituted amines and enaminones are successfully employed in this one pot tandem process to access a broad range of substituted 3-ketoquinolines.     

Regioselective Synthesis of Natural 6‐Prenylpolyhydroxyisoflavone (Lupisoflavone) and Lupisoflavone Hydrate with Hypervalent Iodine Reagents

The Pd(0)‐catalyzed coupling reaction of 6‐iodotetraalkoxyisoflavone, which was obtained from the oxidative rearrangement of 3′‐iodotetraalkoxychalcones, with 2‐methyl‐3‐butyn‐2‐ol in heating condition affords 6‐alkynylisoflavone. Hydrogenation of 6‐iodotetraalkoxyisoflavone followed by acid‐catalyzed dehydration with p‐TsOH·H₂O gave lupisoflavone.     

Control of site selectivity in trifluoromethylation of alkenes bearing a pendant indolyl group: Synthesis of CF3-containing tetrahydrocarbazoles

We present a tetrahydrocarbozole-forming carbo-trifluoromethylation of indoles bearing an alkenyl group at the C3 position. The reaction proceeded selectively with the combination of TsOH·H₂O as a catalyst and CH₂Cl₂ as a solvent. The site-selectivity could be altered by changing the reaction solvent; the use of THF instead of CH₂Cl₂ increased the formation of aromatic trifluoromethylation products.     

Synthesis of a phloroacetophenon[4]arene consisting of four isomers via the one-pot,acid-catalysed condensation of phloroacetophenone with benzaldehyde

A phloroacetophenon[4]arene (3) consisting of four isomers was synthesised for the first time via the condensation of phloroacetophenone and benzaldehyde in a one-pot reaction with refluxing toluene in the presence of catalytic amounts of TsOH·H₂O for a maximum yield of 64%. The conformational elucidation of four isomers (3a–d) by ¹H NMR spectroscopy and X-ray crystal structure analysis showed them to be cone, partial cone, 1,3-alternate and 1,2-alternate types of conformations, respectively.     

The association in mixtures of dimethylsulphoxide and water as studied by Raman spectroscopy

In mixtures of dimethylsulphoxide (DMSO) and water, formation of a complex (DMSO) · (H₂O)₂ is indicated by wavenumber shifts and linewidth variations of the v SO Raman band. Higher temperatures interfere with this complex formation.     

The origin of the radiobiological damage in cells stored in cryostatic conditions

The radiation induced free radical damage in Chinese hamster lung fibroblast V-79 cells stored in DMEM culture medium containing 10% DMSO has been investigated by matrix EPR spectroscopy in connection with the H₂O/DMSO binary phase diagram. A major part of the indirect effect is due to radicals from the DMSO·3H₂O phase in the freezing medium, which are released on warming in the temperature range between 130 K and 160 K, that is, far below the eutectic melting temperature (210 K). The radicals trapped in the DMSO·3H₂O phase react with oxygen above 160 K giving reactive oxygen species (ROS) of the type of peroxyl radicals. A lower limit yield of 10–15% was calculated for this conversion. Scavenging experiments with a stable nitroxyl radical (tempol) have demonstrated that part of the DMSO·3H₂O radicals escape by mutual recombination on melting and are therefore available for inducing indirect cell damage. The same experiments performed with pure frozen water have shown that OH radicals are not available for inducing cell damage. The EPR measurements performed on H₂O/DMSO frozen mixtures suggest that the radiation induced radical forming process does not change when passing to the low dose range below 1 Gy, in agreement with the linear model.     

Cluster glass-like behavior in a 2D bimetallic molecule-based magnet

The compound of formula Na₂[Co₂{Cu(opba)}₃]·2DMSO·6H₂O has been synthesized where opba stands for ortho-phenylenebis(oxamato) and DMSO is dimethylsulfoxide. Magnetic properties have been investigated in the 2–300 K temperature range. The compound presents a large coercive field, around 3.5 kOe at 4.2 K, and the A.C. susceptibility measurements has revealed a cluster glass-like behavior.     

Tartrate der TypenLn 2(H2 T)3·xH2O undLnH5 T 2·xH2O einiger Seltenerdmetalle

The following compounds were isolated and more closely studied by means of thermal analysis, X-ray scattering and IR absorption spectra and determination of solubilities: Pr₂(H₂ T)₃ · 6 H₂O, Nd₂(H₂ T)₃ · 6 H₂O, Sm₂(H₂ T)₃ · 5 H₂O, Gd₂(H₂ T)₃ · 5 H₂O, Tb₂(H₂ T)₃ · 5 H₂O, Dy₂(H₂ T)₃ · 5 H₂O, Ho₂(H₂ T)₃ · 5 H₂O, Er₂(H₂ T)₃ · 5 H₂O, PrH₅ T ₂ · 2 H₂O, NdH₅ T ₂ · 2 H₂O, SmH₅ T ₂ · 2 H₂O, GdH₅ T ₂ · 3 H₂O, TbH₅ T ₂ · 3 H₂O, DyH₅ T ₂ · 3 H₂O, HoH₅ T ₂ · 3 H₂O, ErH₅ T ₂ · 3 H₂O.     

New crystal forms of tris(2-aminoethanolato-O,N)cobalt(III): Structures and properties

Crystal forms of cobalt(III) tris(2-aminoethanolate) hydrates, i.e., red cubic crystals of the composition fac-[Co(NH₂CH₂CH₂O)₃] · 5.44H₂O (fac-I · 5.44H₂O) and blue prismatic crystals of the composition mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) were studied by the ⁵⁹Co, ¹³C NMR and X-ray diffraction methods. It was found that mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) is a new pseudopolymorphic modification of fac-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (fac-I · 3H₂O), while fac-I · 3H₂O represents a new polymorphic modification of the complex mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) described previously. The comparative analysis of the spectra revealed dynamic equilibrium between these geometric isomers; the fac-isomer is stable in aqueous solutions.     

Synthesis,crystal structure,and density functional theory study of a zinc(II) complex containing terpyridine and pyridine-2,6-dicarboxylic acid ligands: Analysis of the interactions with amoxicillin

An octahedral zinc(II) complex of 2,2′:6′,2″-terpyridine (Tpy) and pyridine-2,6-dicarboxylate (Pydc), [Zn(II)(Tpy)(Pydc)·4H₂O] was synthesized and its structure was determined by a single-crystal X-ray diffraction. The ligand pyridine-2,6-dicarboxylate coordinated to the zinc(II) ion via two pairs of carboxylate oxygens and one nitrogen atom, whereas 2,2′:6′,2″-terpyridine also contributed three coordination bonds through its nitrogen atoms. [Zn(II)(Tpy)(Pydc)·4H₂O] showed luminescence properties between 412 and 435 nm in DMSO. The solid-state octahedral geometry of [Zn(II)(Tpy)(Pydc)·4H₂O] was also preserved in solution as confirmed by the observed UV λ_ex = 346. Experimental and theoretical studies indicated that [Zn(II)(Tpy)(Pydc)·4H₂O] interacted with amoxicillin. Density functional theory calculations at B3LYP/LanL2dz level of theory suggested that [Zn(II)(Tpy)(pydc)·4H₂O] dimer interacts with (2S,5R,6R)-6-{[(2R)-2-amino-2-(4-hydroxyphenyl)-acetyl]amino}-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-24-carboxylic acid (amoxicillin) via highest occupied molecular orbital and lowest unoccupied molecular orbital, π–π interaction, hydrogen bond interaction, and van der Waals forces, thus influencing [Zn(II)(Tpy)(Pydc)·4H₂O] properties.     

Synthesis of zinc and copper borates in a single technological cycle

A zero-waste technology was developed for obtaining in a single technological cycle four valuable products: combustion retarder Zn₃B₁₀O₁₈ · 14H₂O, microfertilizer 2ZnO · 3B₂O₃ · 7H₂O, copper borate 3CuO · 2B₂O₃ · nH₂O · mNa₂SO₄, and wood antiseptic “Mebor.”     

A simple one pot synthesis of novel tricyclic quinazolinones

Synthesis of a series of tricyclic quinazolinones have been accomplished starting from anthranilamide and 1,3-cyclic dione promoted by TsOH·H₂O The protocol presented herein based on retro-Dieckmann type reaction, leading to incorporation of dione as an acyclic unit into the product. Simple reaction conditions, broad scope, excellent yields are the advantages of this protocol. Further, this methodology is extended to the synthesis of pyridopyrimidinones and benzimidazopyridines.     

Coordination compounds of cobalt, nickel, copper and zinc with thiosemicarbazone and 3-phenylpropenal semicarbazone

Hydrates of 3-phenylpropenal thiosemicarbazone (HL·H₂O) and semicarbazone (HL′·H₂O) react in methanol with cobalt, nickel, copper, and zinc chlorides, nitrates, and acetates to form coordination compounds MX₂·2HL·nSolv [M = Co, Ni, Cu, Zn; X = Cl, NO₃; HL = C₆H₅CH=CH-CH=N-NHC(O)NH₂; n = 0–3; Solv = H₂O, CH₃OH], CuX₂·HL·nH₂O [M = Ni, Cu; n = 0, 1], ML₂·nH₂O and ML′·nH₂O [M = Co, Ni, Zn; HL′ = C₆H₅CH=CH-CH=N-NHC(O)NH₂; n = 0–3]. In the presence of amines (A = C₅H₅N, 2-CH₃C₅H₄N, 3-CH₃C₅H₄N, and 4-CH₃C₅H₄N) these reactions yield the complexes Cu(A)LCl·CH₃OH and M(A)LX·nH₂O [M = Cu, Ni; X = Cl, NO₃; n = 0–2]. The copper complexes with the amine ligands are of polynuclear structure, and other complexes are monomeric. Carbazones (HL and HL′) are included in the complexes as bidentate N,S-and N,O-ligands. The thermolysis of the complexes involves the stages of removing solvent crystallization molecules (70–90°C), deaquation (150–170°C), and full thermal decomposition (500–580°C).     

A novel binuclear uranyl(VI) complex of bis(N,N′-3-carboxysalicylidene)-1,3-diaminopropan-2-ol: Synthesis, structure, and properties

A binuclear uranyl(VI) Schiff base complex of general formula [(UO₂)₂(H₂L)(OH)(DMSO)₂] · 2DMSO (I) (H₂L = trianion of bis(N,N??-3-carboxysalicylidene)-1,3-diaminopropan-2-ol) was synthesized and studied by ¹H NMR, UV-Vis, IR spectroscopy and X-ray crystallography.     

Thermal and calorimetric investigations of M(IO3)2·2H2O forM 2+=Ni2+ and Zn2+ and their deuterated analogues

The thermal dehydration and decomposition of M(IO₃)₂·2H₂O (M ²⁺=Ni²⁺ and Zn²⁺) and their deuterates were investigated by DTA and DSC methods. The data obtained confirm their onestage dehydration and their decomposition to the respective oxides. Ni(IO₃)₂·2H₂O and Ni(IO₃)₂·2D₂O, were more stable than Zn(IO₃)₂·2H₂O and Zn(IO₃)₂·2D₂O. A considerable isotope effect was observed in relation toT _deh for Ni(IO₃)₂·2H₂O and Ni(IO₃)₂·2D₂O, which was explained by the presence of structural changes well differentiated from the dehydration process for the deuterate. The data obtained for both pairs of dihydrates were used to determine ΔH _f ^o for Ni(IO₃)₂·2H₂O and Ni(IO₃)₂·2D₂O.     

Synthesis,Characterization, and Crystal Structure of new Macromolecule Iron(III) Complex Containing Dimethyl Phosphate,Acetate, and Dimethyl sulfoxide

The reaction between a solution of [Fe₃O(μ‐OAc)₆(H₂O)₃]Cl·6H₂O ( 1 ) (OAc = acetate) and TMP (TMP = trimethyl phosphate) in absolute ethanol and DMSO (DMSO = dimethyl sulfoxide), led to the coordination macromolecule ‐[Fe₁₆(μ₃O)₈(μ₃‐OH)₄(μ‐OH)₄(μ‐DMP)₁₂(μ‐OAc)₁₂(DMSO)₄]·2DMSO·1.5H₂O ( 2 ) (DMP = dimethyl phosphate). This complex was characterized by elemental analysis, IR spectroscopy, and single‐crystal structure. Crystal data for 2 at ?153 °C: triclinic, space group , a = 18.185(2), b = 18.349(2), c = 21.976(3) Å, α = 91.633(3)°, ß = 103.833(3)° γ = 96.486(3)°, Z = 2 and R1 = 0.0655.     

A new approach to the preparation of lanthanide catalysts for the synthesis of 2-propyl-3-ethylquinoline based on the reactions of LnCl3 · 6H2O crystalline hydrates with triisobutylaluminum

A new approach to the preparation of lanthanide catalysts for the synthesis of nitrogen heterocycles (exemplified by 2-propyl-3-ethylquinoline) was developed based on the reactions of LnCl₃ · 6H₂O crystalline hydrates with alkylaluminums. It was found that the interaction of LnCl₃ · 6H₂O (Ln = Ce, Pr, Tb, and Eu) with iso-Bu₃Al in aromatic solvents (20°C) resulted in the formation of soluble (isobutane and the alumoxane (iso-Bu₂Al)₂O) and insoluble products (with the empirical formula LnCl₃ · xH₂O · y(iso-Bu₂Al)₂O (x = 0.4–0.7; y = 0.04–0.07)). The physiochemical properties of LnCl₃ · xH₂O · y(iso-Bu₂Al)₂O were studied, and these compounds were found to be highly efficient catalysts for the reaction of aniline condensation with butyraldehyde to form 2-propyl-3-ethylquinoline.     

Ruthenium(II,III,III) μ<Subscript>3</Subscript>-oxotrifluoroacetate with dimethyl sulfoxide: Synthesis,structure, and DTF quantum-chemical calculations

The reaction of [Ru ₃ ^III (μ₃-O)(μ-O₂CCF₃)₆(H₂O)₃](O₂CCF₃) in methanol gives two solvates, [Ru₃O(O₂CCF₃)₆(DMSO)₃] · 1/2H₂O (I) and [Ru₃O(O₂CCF₃)₆(DMSO)₃] · H₂O (II), of a novel trinuclear mixedvalence Ru(II,III,III) trifluoroacetate complex, where two DMSO molecules are coordinated to the Ru atoms through the O atom, while the third DMSO molecule is coordinated through the S atom. According to the X-ray diffraction data, the complex can crystallize in two crystal systems: triclinic (I) (space group P \(\overline 1 \)) and monoclinic (II) (space group P2₁/m). The unit cell parameters for I are: a = 9.354, b = 11.005, c = 20.846 Å, α = 99.10, β = 96.38, γ = 92.17, Z = 2; R = 7.27%; for I are: a = 9.186, b = 17.044, c = 13.091 Å, β = 101.10, Z = 2; R = 14.18%.     

Studies on ion association. Calorimetric study of the formation of monoazido complexes of Ni(II), Zn(II) and Cd(II)

From rehydration experiments the hydrates Ba(OH)₂ · 8 H₂O, Ba(OH)₂ · 3 H₂O β-Ba(OH)₂, · 1 H₂O, and γ-Ba(OH)₂ · 1 H₂O have been found in the system Ba(OH)₂-H₂O. Thermoanalytical measurements (DTA, TG, DTG, high temperature X-ray diffraction, high temperature Raman scattering) on these hydrates are reported. Thermal decomposition of Ba(OH)₂ · 8 H₂O and Ba(OH)₂ · 3 H₂O always results in the formation of β-Ba(OH)₂ · 1 H₂O, the stable form of the monohydrates at ambient temperature. Dehydration of β- and γ-Ba(OH)₂ · 1 H₂O, both of which form anhydrous β-Ba(OH)₂ as the first product of decomposition, starts at 105 and 115°C, respectively. Single crystals of Ba(OH)₂ · 3 H₂O and γ-Ba(OH)₂ · 1 H₂O were prepared from Ba(OH)₂ · 8 H₂O meltings and from ethanolic solutions of Ba(OH)₂ , respectively. The crystal data are: Ba(OH)₂ · 3 H₂O (orthorhombic, Pnma): a = 764.0(2), b = 1140,3(5), c = 596.5(1) pm, Z = 4; γ-Ba(OH)₂ · 1 H₂O (monoclinic, P2₁/m or P2₁): a = 704.9(2), b = 418.4(1), c = 633.3(1) pm, β = 111.45(2)°, Z = 2.     

Synthesis,crystal structure and properties of a novel 1D chain organic–inorganic rare earth coordination polymer: Gd0.5H0.5{[Gd(H2O)6] [Gd(H2O)2(DMSO)] [α-SiW11O39]}·7H2O

A 1D chain organic–inorganic rare earth coordination polymer Gd_0.5H_0.5{[Gd(H₂O)₆] [Gd(H₂O)₂(DMSO)][α-SiW₁₁O₃₉]}·7H₂O has been synthesized by reaction of α-K₈SiW₁₁O₃₉·13H₂O, HClO₄, Gd₂O₃ with dimethyl sulfoxide (DMSO) and characterized by elemental analysis, IR, UV, ESR spectra and X-ray diffraction. The title compound crystallizes in a monoclinic lattice, P2₁/c space group, with a?=?23.544(5), b?=?11.527(2), c?=?23.297(5)?Å, β?=?109.05(3)°, V?=?35976(2)?ų, Z?=?4, R ₁?=?0.0838, wR ₂?=?0.1300. The neighboring polyanion units {[Gd(H₂O)₆][Gd(H₂O)₂(DMSO)][α-SiW₁₁O₃₉]}^2? are bridged together forming a 1D chain structure by means of [Gd(H₂O)₂(DMSO)]³⁺ ions. The ESR spectra of the title compound at room temperature are composed of eight lines, indicating the strong effect of the crystal field generated by the nearest surrounding ligands of the Gd^III cation.