Thermal and photochemical addition of alkyl and aryl halides to tetrakis(μ-pyrophosphito) diplatinum(II) tetraanion

Alkyl halides RI (R = Me, Et, n-Pr, i-Pr, n-pentyl, CF₃, CH₂I₂) undergo a thermal reaction with Pt₂(pop)₄⁴⁻ (pop = pyrophosphite) to give the axially substituted “lantern” complexes Pt₂(pop)₄RI⁴⁻. For R = Me, the pure complex can be isolated The solution structure has been characterized by a combination of ¹H, ¹³C, ³¹P and ¹⁹⁵Pt NMR spectroscopy. With the higher homologues, (R = Et, n-Pr, i- Pr, n-pentyl) the reaction gives a mixture of Pt₂(pop)₄RI⁴⁻ and Pt₂(pop)₄I₂⁴⁻. A radical pathway is proposed. Aryl halides ArX (X = Cl, Ar = Ph; X = Br, Ar = Ph, p-FC₆H₄, p-HOC₆H₄, p-CH₃OC₆H₄, p-HO₂CCH₄, p-CH₃C₆H₄; X = I, Ar = Ph) photochemically add to the triplet excited state Pt₂(pop)₄⁴⁻ to give Pt₂(pop)₄ArX⁴⁻. For the photochemical reaction with C₆F₅Br, CCl₄, CHCl₃, CH₂ClCO₂H, CH₂BrCO₂H and p-BrC₆H₄NH₃⁺ the product is the dihalo complex Pt₂(pop)₄X₂⁴⁻ (X = Cl, Br).     

Hexafluorophosphate salts of bis and tetrakis(2,2′-bipyridine)lead(II) complexes

Both bis- and tetrakis-substituted 2,2′-bipyridine complexes of lead(II), [Pb(bpy)₂](PF₆)₂ and [Pb(bpy)₄](PF₆)₂ · bpy, respectively, have been characterized by X-ray crystallography as hexafluorophosphate salts when three equivalents of bipyridine is combined with Pb(NO₃)₂ in aqueous solution prior to metathesis. The tetrakis-substituted product, [Pb(bpy)₄](PF₆)₂ · bpy, shows an unusual combination of intramolecular and intermolecular π-stacking of two of the bipyridine ligands throughout the crystal. Incomplete metathesis also produces a catenated, mixed-anion complex, [Pb(bpy)₂(µ-NO₃)](PF₆), where the nitrate bridges lead(II) metal centers to form a 1-D coordination polymer. If metathesis is carried out using perchlorate, a known [Pb(bpy)₂](ClO₄)₂ analog is produced along with [bpyH](ClO₄), which has not been previously characterized by X-ray crystallography.     

Base-promoted O-deprotonation/alkylation reaction of P(O)–OH compounds with alkyl halides

A novel base-promoted O-deprotonation/alkylation reaction of P(O)–OH compounds with alkyl halides has been developed. The protocol is practical, representing a simple way to produce a broad spectrum of functionalized phosphinates, phosphonates, and phosphates from basic starting materials with good to excellent yields. A plausible mechanism was proposed for this reaction.     

Selective nickel-electrocatalyzed benzylic C–H oxygenation of functionalized alkyl arenes

Herein, a site-selective paired electrochemical C–H oxidation of functionalized alkyl arenes promoted by nickel catalyst is disclosed. A Ni(Ⅱ)-dioxygen species formed in situ efficiently enable the oxidation process under mild conditions with a broad substrate scope with excellent functional group compatibilities,such as free carboxylic acid, aldehyde, halogen(including aryl iodide), amide and amino acid. The use of the nickel catalyst in combination with water provides a safe, green and economi...     

Extraction of copper(II) with N-(para-tert-butylbenzoyl)-N′,N′-dialkylhydrazines

Extraction of Cu(II), Co(II), Ni(II), and Zn(II) with N-(para-tert-butylbenzoyl)-N??,N??-dialkylhydrazines was studied. In contrast to other listed elements, copper(II) is extracted with these reagents in a wide pH range and NH₃ concentrations, which provides its selective separation. Effect of chain length of the N??,N??-alkyl groups and solvent nature on copper extraction and its stripping conditions were determined. Extraction constants were calculated. Ammonium salts decrease the extraction degree of copper(II). The studied reagents are superior to the known industrial reagent of ??-diketone class, LIX 54, in terms of copper(II) extraction efficiency from ammonia media.     

Formation of asymmetric N-hydroxyaryl-N′-aryl(hetaryl)diazenes in the reaction of N-aryl(hetaryl)-N′-phosphoryldiazene-N-oxides with bases

Aromatic and heterocyclic N-phenoxyphosphoryldiazene N-oxides react with bases to give asymmetric N-hydroxyaryl-N-aryl- and N-hydroxyaryl-N-hetaryldiazenes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 609–610, March, 1993.     

Chromium(II) chloride-promoted reductive β-elimination of 1,1-dihalo alditols. Synthesis of highly functionalized alk-1-enyl halides

A new general synthetic route to obtain highly functionalized (Z)- and (E)-alk-1-enyl halides is described, where the halogen can be indistinctly F, Cl, Br, and I. The procedure involves CrCl₂-promoted reductive elimination of β-O-substituted gem-dihalo alditols easily accessible from carbohydrates. The simplicity and mildness of the reaction conditions and their compatibility with different functional groups increase the synthetic potential of this methodology.     

Reactions of Zincke’s salts with 2,3-dimethylbenzothiazolium iodide

Reactions of 1-(2,4-dinitrophenyl)pyridinium chloride and 2-(2,4-dinitrophenyl)isoquinolinium chloride with 2,3-dimethylbenzothiazolium iodide in hot pyridine allows introduction of an aryl residue into the thiazole ring via intermolecular transformation of the pyridine ring of Zincke’s salts with participation of the methyl group in position 2 of the benzothiazolium salt.     

Stereoselective synthesis of 2-(α-hydroxyalkyl)benzimidazoles

Lithiated oxazolo[3,4-a]benzimidazole 4 reacted with various alkyl halides to give oxazolo[3,4-a]benzimidazoles 5a–d in good yields as single diastereoisomers. (R)-Benzimidazol-2-yl carbinols 6a–d were obtained upon hydrolysis under acidic conditions of 1H,3H-oxazolo[3,4-a]benzimidazole derivatives.     

Reactions of 2(3′-oxoalkyl)-1,3-cyclohexanediones with nitrogenous reagents

Condensed 1,4-dihydropyridines, which do not contain a substituent in position 4 and which are formed in the reaction of 2-(3-oxoalkyl)-1,3-cycohexanediones with ammonium acetate in acetic acid, undergo disproportionation. Pyridine bases are formed as the result of two competing reactions: disproportionation and oxidation of 1,4-dihydropyridines, intermediates in the heterocyclization of oxo-1,3-diketones with participation of the nitrogen atom, by air oxygen.N. G. Chernyshevskii Saratov State University Saratov 410026. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 647–651, May, 1994. Original article submitted April 22, 1994.     

Synthesis,Structure, and Biological Activity of N-p-(Dimethylamino)-N′-(p-dimethylaminobenzylidene)-N,N′′-diphenylbenzohydrazonohydrazide

Russian Journal of General Chemistry - A three-component reaction of 3,5-diacetyl-2,6-dimethylpyridine, p-N-dimethylaminobenzaldehyde and phenylhydrazine in the presence of KOH in ethanol gave the...     

Colloid and nanosized catalysts in organic synthesis: V. Reactions of alkyl halides and alcohols with β-diketones in the presence of metal nanoparticles

Reaction of copper, nickel, and iron nanoparticles with β-diketones directly yields corresponding metal β-diketonates. Reaction of alkyl halides, β-diketones, and nanodispersed metals leads to a mixture of monoketone and the alkylated β-diketone. When alcohol is used as the alkylating agent instead of alkyl halide, corresponding ester is formed.     

Synthesis of n-(phenoxathiin-2-carbonyl)-or N-(thianthrene-2-carbonyl)-N′-arylthioureas

The reactions of phenoxathiin-2-carbonyl-or thianthrene-2-carbonyl-isothiocyanates with certain primary amines lead to the formation of corresponding N-substituted-N-hetaroylthiocarbamides. The aforementioned isothiocyanates were obtained in situ by reactions of phenoxathiin-2-or thianthrene-2-carbonyl chlorides with KSCN. The new compounds were characterized by elemental analysis and spectral data (IR,¹H and¹³C NMR).Analytical Laboratory-Biofarm, 99 Logofat Tautu Street, Bucharest, Roumania. Faculty of Pharmacy, Organic Chemistry Departament, University of Medicine and Pharmacy Carol Davila, 6 Traian Vuia Street, Bucharest, Roumania, Faculty of Chemistry, Organic Chemistry Department, University of Bucharest, 90–92 Panduri Road, 76233, RoumaniaPublished in Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1681–1686, December, 1999.     

Alkylation of aralkyl bromides with tetra alkyl tin compounds in presence of (2,2′-bipyridine)fumaronitrile palladium(0)

(2,2′-bipyridine)fumaronitrile palladium(0) acts catalytically in the alkylation of benzylic halides with tetra alkyl tin even for an alkyl halide with hydrogen atoms on a sp³ carbon β to the leaving group.     

An assessment of alkyl chain length effect of symmetric İmidazolium salts as a carrier for selective separation of Cr(VI)

Selective solvent extraction (SSX) of Cr(VI) and recovery was evaluated by using a homologous series of symmetric imidazolium bromide salts (SIMs) having various alkyl chain length. Therefore, propyl, pentyl, hexyl, octyl, and decyl substituted SIMs were used as an ion carrier. The executive parameters affecting both extraction and stripping conditions were investigated for optimization. Finally, a direct correlation was observed a between increasing alkyl chain length and selective Cr(VI) extraction from acidic solutions containing Cr(VI), Fe(III), Co(II), Cd(II), Ni(II). This relationship was reversed in the stripping conditions. Optimal extraction and stripping were obtained for SIM5 and SIM2 as 97.49% and 70.00%, respectively.     

Effect of some added salts on the kinetics of dissociation of tris-2,2′-bipyridine-Fe(II) complex

Both monovalent cations and anions show a regular gradation, according to their sizes, in their effect on the rate and the activation parameters for the dissociation of tris(2,2′-bipyridine)-Fe(II) complex in acid. ΔS and ΔH of activation in M, 0.1 M and 0.01 M acid decrease in the order Cl⁻ > Br⁻ > I⁻ for anions and Li⁺ > Na⁺ > Cs⁺ for cations. The effect of the bulky tetra-alkyl ammonium ions is anomalous and does not depend on their sizes. The effect of the anions can be rationalized in terms of their involvement with the vacant coordination site of the partially bonded intermediate. The effect of cations is probably due to their altering the water structure at high concentration. The anomalous of the tetra-alkyl ammonium ions supports this view.     

Preparation and reaction of bis (perfluoroalkanesulfonyl) methyl halides

Halogenation of the potassium or silver salts of bis(trifluoromethanesulfonyl)methane (CF3SO2)2CH2 and its cyclo analogues 1 with N-fluoro-bis(trifluoromethanesulfonyl)imine [(CF3SO2)2-NF], chlorine or bromine gave good yields of the corresponding α-halo disulfone (CF3SO2)2CHX and cyclo analogues 9, 10. The chemical transformation of these fluorinated α-halo-disulfones are described.     

Reactions of 2′-NHR-Chalcone Dibromides with Ammonia

Synthesis of 2′-NHR-chalcone dibromides and their reaction with methanolic ammonia are discussed. Depending on the character of the R group, ethylenimine, -bromochalcone, 2,3-dimethoxypropan-1-one and 1,2,3,4-tetrahydro-4-quinolone derivatives were obtained.