Efficient synthesis of functionalized spiro-2,5-dihydro-1,2-λ-oxaphospholes

The reaction of ethyl propiolate with triphenylphosphine (Ph₃P) in the presence of N-alkylisatins led to ethyl 2,2,2-triphenyl-2,5-dihydro-1,2-λ⁵-oxaphosphole-4-carboxylate-spiro-1-alkyl-1,3-dihydro-2H-indol-2-ones in good yield. The reaction of dialkyl acetylenedicarboxylates with Ph₃P in the presence of N-alkylisatins led to dialkyl 2,2,2-triphenyl-2,5-dihydro-1,2-λ⁵-oxaphosphole-3,4-dicarboxylate-spiro-1-alkyl-1,3-dihydro-2H-indol-2-ones and alkyl 4-(alkoxy)-5-oxo-2,5-dihydro-3-furancarboxylate-spiro-1-alkyl-1,3-dihydro-2H-indol-2-ones.     

Alkylation of 1,2,3-benzotriazole with iodomethyl ketones

Solvent-free reactions of 1,2,3-benzotriazole with 1-iodopropan-2-one and 1,3-diiodopropan-2-one in the absence of a catalyst involved alkylation of the heteroring at the N¹ atom and subsequent quaternization at the N³ atom with formation of 1,3-bis(2-oxopropyl)-1H-1,2,3-benzotriazolium triiodide which is a new conducting ionic liquid. The reaction of 1,2,3-benzotriazole with 1,3-diiodopropan-2-one was accompanied by reductive deiodination of the iodomethyl groups in the initial ketone with hydrogen iodide liberated by N¹-alkylation. Triiodide ion readily exchanges for nitrate ion by the action of AgNO₃ to produce 1,3-bis(2-oxopropyl)-1H-1,2,3-benzotriazolium nitrate. The reaction of 1,2,3-benzotriazole with 2-iodo-1-phenylethan-1-one in melt resulted in the formation of 1,3-bis(2-oxo-2-phenylethyl)-1H-1,2,3-benzotriazolium triiodide.     

Hetero-Diels–Alder reactions of perfluoroalkyl thioamides with electron-rich 1,3-dienes: synthesis of new 2-aminosubstituted-3,6-dihydro-2H-thiopyrans and related compounds

Hetero-Diels–Alder reactions of perfluoroalkyl thioamides with electron-rich 1,3-dienes such as 2,3-dimethylbutadiene, isoprene or penta-1,3-diene gave a simple and efficient access to new 2-aminosubstituted-3,6-dihydro-2H-thiopyrans. Three different procedures were used depending on the nature of the polyfluoroalkyl chains (R_F=CF₃, (CF₂)_nCF₃, (CF₂)₄H) and on the nitrogen substituents of the thioamides (R¹, R²=H, p-Tol, morpholino, Ac). Moreover, cycloadditions of silyloxydienes (1- or 2-trimethylsilyloxy-1,3-butadiene and Danishefsky's diene) with N-acyl,N-tolyl trifluoromethylthioamides afforded in almost all cases the corresponding 3,6-dihydro-2H-thiopyrans or 3-oxo-tetrahydrothiopyrans. For non-symmetrical 1,3-dienes, the regio- and stereochemistry of the reactions were studied (especially using X-ray diffraction analysis) indicating a strong similarity with those reported for fluorinated thiocarboxyl derivatives. Finally, two silylated 3,6-dihydro-2H-thiopyrans underwent an unexpected base-induced ring contraction to give new 1,3-thiazolidin-4-ones.     

13C NMR spectra of some 1,2-disubstitutedN-vinyl-1H-1,2,4-triazoles

¹³C NMR spectra (20 and 75 MHz, in DMSO-d₆) of a series of 1,3-diaryl-3-(1H-1,2,4-triazol-1-yl)- and 1,3-diaryl-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones were registered. It was shown that the chemical shifts of both the carbon atom of the alkene group and C(3) reflect regio- and stereoisomerism of these compounds. Taking this into account the isomeric structures of several 1,3-diaryl-3-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones were identified and the configurations relative to the double bond of a number of 1,3-diaryl-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones were determined.     

Zur Synthese und Pyrolyse von Organoelement-benzasolderivaten des Phosphors,Arsens, Siliciums und Zinns

3-Organo-1,3-benzazaphospholes and -benzazarsoles as well as 3,3-disubstituted 1,3-benzazasiloles and -benzazastannoles are prepared from o-LiC₆H₆NC(Li)Bu^t and the relevant organoelement dichlorides. The heterocycles obtained are converted by flash vacuum pyrolysis into the aromatic 1H-1,3-benzazaphospholes and benzazarsoles, respectively.     

π-Olefin-iridium-komplexe : II. Synthese und dynamisches verhalten von bis(η4-Cyclodien)-hydrido-iridium(I)-komplexen

By reaction of [Ir(COD)Cl]₂ (COD = 1,5-cyclooctadiene) with i-C₃H₇MgBr in the presence of cyclic dienes, complexes of the type [IrH(COD)L] (L = 1,3-cyclohexadiene, 2-methyl-],3-cyclohexadiene, 5-ethyl-1,3-cyclohexadiene, 1,3-cycloheptadiene) are obtained. The system IrCl₃/i-C₃H₇MgBr/1,3-C₆H₈ yields [IrH(1,3-C₆H₈)₂]. According to NMR spectroscopic investigations the pure hydrido forms exist in solution only at low temperatures while at room temperature dynamic H-addition—elimination equilibria of the type [IrH(η⁴-diene)(COD)] ? [Ir(η³-enyl)(COD)] and [IrH(η⁴-1,3-C₆H₈)₂] ? [Ir(η³-C₆H₉)-(η⁴-1,3-C₆H₈)], respectively, are observed; the hydrogen at the iridium atom is thereby transferred to the endo positions of the diene ligands.     

Reactions of alkylcobalt complexes containing a tetradentate nitrogen-donating ligand

The reactions of RCo(BDM1,3pn)(H₂O) with light, heat, acids, electrophiles and nucleophiles were studied. (HBDM1,3pn is a mononegative, tetradentate dioxime-diimine ligand formed by condensing 2,3-butanedionemonoxime with 1,3-propanediamine in a 2/1 molar ratio; R = CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, and C₆H₃CH_2-) Pyrolysis and photolysis of the alkyl complexes result in a cobalt(II) complex (anaerobic conditions) along with alkenes and alkanes. The major organic products from solid state pyrolysis at 200°C or photolysis in water are CH₄ (R = CH₃), C₂H₄ (R = C₂H₅), C₃H₆ (R = n-C₃H₇), C₄H₈ (R = n-C₄H₉) and (C₆H₅CH₂)₂ (R = C₆H₅CH₂). No alkyl—cobalt bond cleavage occurs with acids or bases in most cases. Two exceptions are the reactions with 3 M HNO₃ at 25°C and with 1 M NaOH at 52°C. Electrophiles like I₂ cleave the alkyl—cobalt bond forming RI and Co^III (BDM1,3pn)I₂. Nucleophilic reagents (N^-) displace the H₂O trans to the alkyl group to form RCo(BDM1,3pn)(N), but do not dealkylate the alkyl complex under the reaction conditions studied.     

Preparation and structural characterization of hetero-dinuclear Schiff base copper(II)-zinc(II) complexes and their inhibition studies on Helicobacter pylori urease

A series of hetero-dinuclear Cu^II-Zn^II complexes, [CuZnCl₂L¹] (1), [CuZnCl₂L²] (2), [CuZnBr₂L³] (3), [CuZnBr₂L⁴(DMF)] (4), [CuZnCl₂L⁴] (5), [CuZnCl₂L⁵] (6), [CuZnCl₂L³] (7) and [CuZnBr₂L¹] (8), where L¹, L², L³, L⁴ and L⁵ are the deprotonated forms of N,N′-bis(3-ethoxysalicylidene)-1,3-propanediamine (H₂L¹), N,N′-bis(2-hydroxynaphthylmethylidene)-1,3-propanediamine (H₂L²), N,N′-bis(3-methoxysalicylidene)-1,3-propanediamine (H₂L³), N,N′-bis(salicylidene)-1,3-propanediamine (H₂L⁴) and N,N′-bis(salicylidene)-1,4-butanediamine (H₂L⁵), respectively, have been synthesized and characterized by physico-chemical methods and single-crystal X-ray diffraction. The complexes were tested for their urease inhibitory activity. Complexes 1 and 8 show effective urease inhibitory activity with IC₅₀ values of 2.2 and 10.7 μM. The molecular docking study of the complexes with the Helicobacter pylori urease was performed.     

Spectral characterization and biological evaluation of Schiff bases and their mixed ligand metal complexes derived from 4,6-diacetylresorcinol

In the present study two new series of Copper(II), Nickel(II) and Cobalt(II) complexes with two newly synthesized Schiff base ligands 4,6-bis(1-(4-bromophenylimino)ethyl)benzene-1,3-diol (H₂L¹), 4,6-bis(1-(4-methoxyphenylimino) ethyl)benzene-1,3-diol (H₂L²) and organic ligands 8-hydroxy quinoline, 1,10-phenanthroline have been prepared. The Schiff bases H₂L¹ and H₂L² ligands were synthesized by the condensation of 4,6-diacetyl resorcinol with 4-bromo aniline and 4-methoxy aniline. The ligands and their metal complexes have been characterized by FT-IR, Mass, ¹H NMR, UV–Vis., elemental analysis, ESR and Thermal gravimetric analysis. The Schiff base and their metal complexes were tested for antimicrobial activity against gram positive bacteria Staphylococcus aureus, Streptococcus pyogenes and gram negative bacteria Escherichia coli, Pseudomonas aeruginosa and fungus Candida albicans, Aspergillus niger and Aspergillus clavatus using Broth Dilution Method.     

(1,3-Diformylindenyl)cyclopentadienyl ruthenium derivatives

The reaction of [CpRu(CH₃CN)₃][PF₆], [Cp*RuCl] _n , and [Cp^FRuCl]n with 1,3-diformylindene results in the predominant formation of zwitter-ionic arene-cyclopentadienyl complexes {η⁶-1,3-(CHO)₂C₉H₅}RuCp (Cp = C₅H₅), {η⁶-1,3-(CHO)₂C₉H₅}RuCp* (Cp* = C₅Me₅), and {η⁶-1,3-(CHO)₂C₉H₅}RuCp^F (Cp^F = C₅Me₄CF₃), respectively. The ruthenocenes {η⁵-1,3-(CHO)₂C₉H₅}RuCp, {η⁵-1,3-(CHO)₂C₉H₅}RuCp*, and {η⁵-1,3-(CHO)₂C₉H₅}RuCpF were synthesized by the reaction of 1,3-diformylindenyl potassium with [CpRu(CH₃CN)₃][PF₆], [Cp*RuCl] _n , and [Cp^FRuCl] _n .     

Some reactions of Ni-Mo and Ni-W propargylic cations with nucleophiles

Preliminary reactions of the metal stabilized carbocationic species [(η-C₅H₅)Ni(μ-η²(Ni),η³(Mo)-HC₂CMe₂)Mo(CO)₂(η-C₅H₄Me)]⁺ BF₄⁻ (Ni-Mo) with nucleophiles are reported. The Ni-Mo cationic propargylic complex undergoes nucleophilic attack by sodium methoxide to regenerate the neutral μ-alkyne complex [(η-C₅H₅)Ni{μ-η²,η²-HC₂CMe₂(OMe)}Mo(CO)₂(η-C₅H₄Me)] (Ni-Mo), from which the stabilized carbocation was originally derived by protonation. The new complexes [(η-C₅H₅)Ni{μ-η²,η²-HC₂CMe₂(C₅H₅)}Mo(CO)₂(η-C₅H₄Me)] (Ni-Mo), which exist as an inseparable mixture of 1(c)-1,3- and 2(c)-1,3-cyclopentadienyl isomers, were also obtained. When the Ni-Mo cations were treated with potassium t-butoxide, the alkyne isomers with pendant 1(c)-1,3- and 2(c)-1,3-cyclopentadienyl groups are also formed. The μ-hydroxyalkyne complex [(η-C₅H₅)Ni{μ-η²,η²-HC₂CMe₂(OH)}-Mo(CO)(η-C₅H₄Me)] (Ni-Mo) was also isolated concurrently, and presumably arises from nucleophilic attack of fortuitously present hydroxide ions in the BuO⁻ reagent on the Ni-Mo cation. When NaBH₄ was added to the Ni-Mo propargylic, nucleophilic attack by hydride resulted and the μ-ⁱPrC₂H heterobimetallic complex [(η-C₅H₅)Ni{μ-η²,η²-HC₂Prⁱ}Mo(CO)₂(η-C₅H₄Me)] (Ni-Mo) was recovered in good yield. Small quantities of other side-products were isolated and characterized spectroscopically. Some tantalizing differences in reactivity were observed when the corresponding Ni-W stabilized carbocation was reacted with methoxide ions. When the not fully characterized solid formed by protonating [(η-C₅H₅)Ni(μ-η²,η²-{HC₂CMe₂)(OMe)}W(CO)₂(η-C₅H₄Me)] (Ni-W) was treated with methoxide ions, regioisomers (1(c)-1,3- and 2(c)-1,3-cyclopentadienyl species) of composition [(η-C₅H₅)Ni{μ-η²,η²-HC₂CMe₂(C₅H₅)}W(CO)₂(η-C₅H₄Me)] (Ni-W) were formed. Direct reaction of the pure cation [(η-C₅H₅Niμ-η²,η³-HC₂CMe₂)W(CO)₂(η-C₅H₄Me)]⁺ (Ni-W) with methoxide also generated the same 1(c)-1,3- and 2(c)-1,3-cyclopentadiene-substituted alkyne complexes. Unlike the case with the Ni-Mo complexes, the initial μ-HC₂CMe₂(OMe) species was not regenerated.     

Intricate 3D lanthanide-organic frameworks with mixed nodes nets

Three lanthanide-organic frameworks formulated as [Yb₂(1,3-pda)₃(H₂O)]_n·nH₂O (1) [La₂(2,5-pydc)₃(H₂O)₂]_n (2) and [La(2,5-pydc)(2,5-Hpydc)(H₂O)₂]_n·nH₂O (3) (H₂1,3-pda=1,3-phenylenediacetic acid, H₂2,5-pydc=pyridine-2,5-dicarboxylic acid) have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. Both the frameworks of compounds 1 and 2 exhibit intricate 3D architectures which can be simplified as nets with mixed nodes. Compound 1 presents a very complicated net with five types of nodes comprising intersecting (3,4)-connected and CdSO₄ nets. Compound 2 possesses a (4,4,6)-connected net with (4²8⁴)(4⁴6²)₂(4⁹6⁶)₂ circuit symbol. While compound 3 is a 2D layer based upon carboxyl-bridged La^III chains.     

A Cu(II) coordination polymer: Crystal structure and therapeutic effect on sepsis

Unique thiocyanate-connected 1-dimensional chain Cu(II) coordination polymer (CP), namely, [Cu₂L¹(μ_1,3-SCN) (η¹SCN)]_n (1), was produced in the existence of KSCN and Cu(NO₃)₂·3H₂O utilizing an underlying multisite N,O donor Schiff base ligand (L¹H₂). [N,N′-bis(3-methoxysalicylidenimino)-1,3-daminopropane] (L¹H₂), the Schiff base ligand is a 1:2 M ratio condensation product of 1,3-diaminopropane and O-vaniline in the methanol medium. The as-created CP 1 has been investigated with various characterization approaches like powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), -thermogravimetric analysis (TGA) and single crystal X-ray diffraction (SCXRD) analyses. And the mechanism and therapeutic effect of this CP on sepsis was discussed and its specific mechanism was also assessed. First of all, for the infected animals, their survival rate was recorded after the bacterial infection and treatment of complex. Besides this, utilizing the enzyme linked immunosorbent assay (ELISA) assay, the inflammatory cytokines levels that released into plasma were determined after the exposure of compound.     

Molecular and polymeric uranyl and thorium hybrid materials featuring methyl substituted pyrazole dicarboxylates and heterocyclic 1,3-diketones

A series of seven novel f-element bearing hybrid materials have been prepared from either methyl substituted 3,4 and 4,5-pyrazoledicarboxylic acids, or heterocyclic 1,3- diketonate ligands using hydrothermal conditions. Compounds 1, [UO₂(C₆H₄N₂O₄)₂(H₂O)], and 3, [Th(C₆H₄N₂O₄)₄(H₂O)₅]·H₂O feature 1-Methyl-1H-pyrazole-3,4-dicarboxylate ligands (SVI-COOH 3,4), whereas 2, [UO₂(C₆H₄N₂O₄)₂(H₂O)], and 4, [Th(C₆H₅N₂O₄)(OH)(H₂O)₆]₂·2(C₆H₅N₂O₄)·3H₂O feature 1-Methyl-1H-pyrazole-4,5-dicarboxylate moieties (SVI-COOH 4,5). Compounds 5, [UO₂(C₁₃H₁₅N₄O₂)₂(H₂O)]·2H₂O and 6, [UO₂(C₁₁H₁₁N₄O₂)₂(H₂O)]·4.5H₂O feature 1,3-bis(4-N¹-methyl-pyrazolyl)propane-1,3-dione and 1,3-bis(4-N¹,3-dimethyl-pyrazolyl)propane-1,3-dione respectively, whereas the heterometallic 7, [UO₂(C₁₁H₁₁N₄O₂)₂(CuCl₂)(H₂O)]·2H₂O is formed by using 6 as a metalloligand starting material. Single crystal X-ray diffraction indicates that all coordination to either [UO₂]²⁺ or Th(IV) metal centers is through O-donation as anticipated. Room temperature, solid-state luminescence studies indicate characteristic uranyl emissive behavior for 1 and 2, whereas those for 5 and 6 are weak and poorly resolved.     

Substituent effects in the ring-chain tautomerism of 1,3-diaryl-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazines

Condensation of Betti base analogue amino naphthols with substituted benzaldehydes led to 1,3-diaryl-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazines (3-9) which proved to be three-component (r¹-o-r²) tautomeric mixtures in CDCl₃ at 300 K. The electronic effects of the 3-aryl groups on the ratios of the ring-chain tautomeric forms at equilibrium could be described by the equation log K_X=ρσ⁺+log K_X=H. The value of the intercept was found to be strongly influenced by the steric arrangement of the 1,3-diaryl substituents.     

Quantum chemical modeling of the structure formation and proton transfer in 2-hydroxybenzenesulfonic, 4-hydroxy-1,3-benzenedisulfonic, and 1,3-benzenedisulfonic acids

Hydrate clusters of 2-hydroxybenzenesulfonic and 1,3-benzenedisulfonic acids were calculated in terms of the density functional theory (DFT) by the B3LYP/6-31G** method. The process of water adsorption on the crystal surface of 4-hydroxy-1,3-benzenedisulfonic acid dihydrate was simulated using the generalized gradient approximation (DFT/PBE) and periodic boundary conditions. For the model system (OHC₆H₄SO₃ ^?)·H₅O₂ ⁺, the activation barriers for the proton transfer were calculated depending on the distance between the O atoms and the deviation of the proton from the O...O bond line. The presence of one H₂O molecule per SO₃H group is energetically most favorable for the formation of clusters of 1,3-benzenedisulfonic acid containing a stoichiometric amount of water. The simulation of the hydration of 4-hydroxy-1,3-benzenedisulfonic acid dihydrate (OHC₆H₃(SO₃H)₂·2 H₂O + n H₂O, n = 1–3) showed that the superstoichiometric H₂O molecule is adsorbed on the crystal surface of this dihydrate with energy release of 0.75–0.95 eV. The position of this water molecule is less favorable in the bulk than on the surface.     

Mono- and bi-iron chalcogenocarboxylate complexes

A series of thiocarboxylato and selenocarboxylato monomeric CpFe(CO)₂ECORCOCl and dimeric [CpFe(CO)₂ECO]₂R iron complexes have been synthesized and characterized. The interaction of (μ-E_x)[CpFe(CO)₂]₂ (E = S; x = 2–4. E = Se; x = 1) with di-acid chlorides (ClCORCOCl) in a 1:1 molar ratio gave the monomeric complexes CpFe(CO)₂ECORCOCl for R = 1,3-C₆H₄, 2,6-C₅H₃N, 1,2-C₆H₄. However, the dimeric complexes [CpFe(CO)₂ECO]₂R were obtained from the same reactants in a 2:1 metal-to-ligand molar ratio in which R is 1,3-C₆H₄, 2,6-C₅H₃N or C₂H₄. The monomer versus dimer production mainly depends on the electronic and steric factors of the R-moiety. The new monomeric and dimeric thio- and selenocarboxylato iron complexes have been characterized by spectroscopic techniques (¹H- and ¹³C-NMR, IR) and by elemental analysis. The structures of [CpFe(CO)₂SCO]₂(1,3-C₆H₄) and its seleno analogue [CpFe(CO)₂SeCO]₂(1,3-C₆H₄) were determined by X-ray structure determination.     

Chiral S,S-donor ligands in palladium-catalysed allylic alkylation

Chiral dithioether ligands have been tested in the model Pd-catalysed allylic alkylation reaction of (±)-3-acetoxy-1,3-diphenyl-1-propene with dimethyl malonate, giving high enantioselectivity (up to 81% e.e.) for the first time in this type of system. Pd(II)-allylic intermediates, [Pd(η³-1,3-Ph₂-C₃H₃)(dithioether)]PF₆ were prepared and characterised both in solution by NMR spectroscopy and solid state. The X-ray structure for [Pd(η³-1,3-Ph₂-C₃H₃)(L)]PF₆ (L=(R,R)-7,8-O-isopropylidene-1,5-dithia-cyclononane) was determined.     

Tetrahedral intermediates 4. The effect of chloro-substituents on the kinetics of the breakdown of hemiorthoesters

1-Hydroxy-2-chloromethyl-1,3-dioxolane (4) and 1-hydroxy-2-dichloromethyl-1, 3-dioxolane (5) have been detected as intermediates by¹H NMR spectroscopy in the hydration of respectively 2-chloromethylene-1, 3-dioxolane and 2-dichloromethylene-1, 3-dioxolane in aqueous acetonitrile. The kinetics of the breakdown of (4) and (5) into ethylene glycol monochloroacetate and monodichloroacetate have been studied by uv spectroscopy and values ofk_H+,k_HO-, andk_H2O evaluated. It was found that the introduction of chlorosubstituents into 2-hydroxy-2-methyl-1, 3-dioxolane caused a decrease ink_H+ and increase ink_H2O- and little change ink_H2Ofor its breakdown. The mechanisms of these reactions are discussed. Present     

Dealkylation of alkylcobalt complexes by the mercury(II) electrophile

The dealkylation of a variety of RCo(BDMBg)⁺ complexes by Hg²⁺ is discussed. (The ligand BDMBg^- is formed by the condensation of two moles of 2,3-butanedionemonoxime with one mole of 1,3-propanediamine or 1,2-ethanediamine.) The products of the dealkylation reaction are Co^III(BDMBg)(H₂O)²⁺₂ and RHg⁺. All reactions are first order in the [Hg²⁺]. The second order rate constants (k₂) vary from 5.9 M^-1 sec^-1 (R = CH₃) to 5.7 x 10^-3M^-1 sec^-1 (R = n-C₃H₇). The relative rates for R are: CH₃ ? C₂H₅ τ C₆H₅CH₂ τ n-C₄H₉ ? n-C₃H₇. This order and other evidence are indicative of an S_E2 mechanism with an attack by Hg²⁺ on the carbon bonded to the cobalt.