Preparation oftrans- andcis-2-allyl-6-alkyl(aryl)-1,2,3,6-tetrahydropyridines based on the reductivetrans-2,6-dialkylation of pyridine. Synthesis of (±)-epidihydropinidine and (±)-dihydropinidine

A general method for the preparation of unsymmetricaltrans-2-allyl-6-alkyl(aryl)-1,2,3,6-tetrahydropyridines6 based on a combination of 1,2-addition of RLi to pyridine andtrans-6-allylation with triallylborane in the presence of methanol was elaborated. It was shown thattrans-piperideines (6 (R=Alk, Ph) isomerize into the correspondingcis-2-allyl-6-alkyl(phenyl)-3-piperideines14 on heating with triallylborane followed by deboronation of aminoborane (16) with methanol and an alkali. The stereochemistry of compounds6 and14 was determined by two-dimensional NOE spectroscopy. A possible mechanism of the formation oftrans-amines6 and their transformation intocis-isomers14 is discussed. Alkaloids (±)-epidihydropinidine (trans-2-methyl-6-propylpiperidine2a, 70%) and (±)-dihydropinidine (cis-2-methyl-6-propylpiperidine1d, 71%) were synthesized by hydrogenation of compound6a (R=Me) and14a (R=Me), respectively, over Raney nickel. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 467–474, March, 1998.     

(18-Crown-6)potassium 0.84(diiodobromide) 0.16(dibromoiodide) and diaqua(18-Crown-6)chlororubidium: Syntheses and crystal structures

New host-guest compounds are synthesized and studied by X-ray diffraction analysis: (18-crown-6) potassium 0.84(diiodobromide) 0.16(dibromoiodide), [K(18-crown-6)]⁺ · (Br_1.16I_1.84)⁻, (I) and diaqua (18-crown-6)chlororubidium, [RbCl(18-crown-6)(H₂O)₂], (II). The crystals of compound I are monoclinic (space group P2₁/n, a = 9.157 ?, b = 8.589 ?, c = 14.072 ?, β = 102.27°, Z = 2). The structure of compound II is orthorhombic (space group Pnma, a = 9.813 ?, b = 15.231 ?, c = 12.629 ?, Z = 4). The structures are solved by a direct method and refined by the full-matrix anisotropic least squares to R = 0.062 (I) and 0.079 (II) for 3149 (I) and 2840 (II) independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). The crystal structures of compounds I and II are different: compound I is built of infinite chains of the alternating cations [K(18-crown-6)]⁺ and mixed halide anions linked by weak coordination bonds K-Br or K-I, whereas individual molecules [RbCl(18-crown-6)(H₂O)₂] form structure II. Original Russian Text ? A.N. Chekhlov, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 8, pp. 1385–1391.     

A zinc(II) coordination polymer, [Zn4( o -bda)4( p -pbim)4] n,with strong blue fluorescence

A zinc(II) coordination polymer, [Zn₄(o-bda)₄(p-pbim)₄] _n (1) (p-pbim = 4-pyridylbenzimidazole, o-bda^2? = o-phenylenediacetic acid dianion), has been synthesized by hydrothermal method and characterized by elemental analysis, IR, TG, photoluminescence and X-ray single crystal diffraction. Complex 1 crystallizes in a monoclinic system and space group P2₁ /n, with a = 14.231(3) Å, b = 16.257(4) Å, c = 16.794(4) Å, β = 100.262(1)°, and Z = 8; R ₁ for 6475 observed reflections [I > 2σ(I)] was 0.0420. Complex 1 shows a bi-chain structure fabricated by the tetranuclear zinc unit. Two zinc(II) ions are five coordinate with distorted trigonal-bipyramid geometry; the other two zinc(II) ions are four coordinate with distorted tetrahedral geometry. Complex 1 builds the 1-D bi-chain structure with two different subrings A and B, which are 32-member and 14-member rings, respectively. There exists a 2-D supramolecular network linked by hydrogen-bonding interactions (2.695 and 2.807 Å). A 3-D supramolecular network is further constructed by non-covalent interactions between the 1-D bi-chain structure. The TG/DTG shows that the chain skeleton is thermally stable to 356°C. Blue fluorescent emission of the complex was determined at 404 nm in the solid state with short decay lifetime of 1.67 ns.     

Spectrophotometric Study of 1,2,7-Trihydroxyanthraquinone-Mg(II) Complex. Determination of Mg(II)

Abstract

The spectrophotometric study of violet complex Anthrapurpurin-Mg(II) in a basic medium and a hydroalcoholic solution was made (δ_max - 530 nm., ? = 3.5 × 10³ 1 mol^?1 cm^?1, stoichiometry 1:1, apparent constant of stability log K = 9. 26). A new method for the spectrophotometric determination of Mg(II) is proposed for concentrations between one and six ppm. Relative errors between replicate samples were 0.90 %.     

Fluorimetric Determination of Thiamine with Cobalt(II)

Abstract

A rapid fluorimetric method is reported for the determination of thiamine based upon its interaction with Co(II) ion in the presence of base and a nonionic Triton X-100 micellar medium. The effect of different experimental variables upon the fluorescence intensity were assessed. The detection limit for thiamine is 5.0 × 10^?8M (λ_ex =375nm, λ_em =433nm). The method was successfully applied for determination of thiamine in variety of samples with good accuracy being achieved.     

SYNTHESIS AND STRUCTURES OF DICHLOROTETRAKIS-(PHENYLTHIOUREA) CADMIUM(II) AND CATENA-BIS(THIOCYANATE) BIS(PHENYLTHIOUREA)CADMIUM(II)

Abstract

Two new cadmium(II) complexes with phenylthiourea (PTU), namely Cd(PTU)₄Cl₂ (1) and [Cd₂(NCS)₂(μ₂-SCN)₂(PTU)₂(μ₂-PTU)₂] _n (2), have been prepared and characterized structurally by X-ray diffaction. Complex 1 crystallizes in the monoclinic space group C2/c, with a = 27.057(13), b = 8.108(3), c = 16.751(8) Å, β = 114.46°, V = 3345(3) ų, Z = 4. Complex 2 crystallizes in the triclinic space group P-1, with a = 9.336(3), b = 14.686(5), c = 16.911(5) Å, α = 71.36(2), β = 84.31(2), γ = 72.470(10)°, V = 2095.0(12) ų Z = 4. The structural analysis shows that each metal atom in both the mononuclear complex 1 and polynuclear complex 2 is octahedrally coordinated by four sulfur atoms and two chloro ligands or two nitrogen atoms from the thiocyanate groups, respectively. The PTU ligand can serve as either a monodentate ligand or a μ₂-bridging ligand upon coordination to a metal atom.     

Metal derivatives of thiosemicarbazones: crystal structure of [chloro bis(triphenylphosphino) (thiophene-2-carbaldehyde thiosemicarbazone) copper(I)] complex

Reactions of copper(I) halides (X = Cl, Br, I) with thiophene-2-carbaldehyde thiosemicarbazone and triphenylphosphine in 1 : 1 : 2 molar ratio yield tetrahedral mononuclear complexes, [CuX(η¹-S-Httsc)(Ph₃P)₂] (X = Cl, 1; Br, 2; I, 3), characterized by elemental analysis, IR, NMR (¹H, ¹³C, ³¹P), and single crystal X-ray crystallography (1). The unit cell of 1 has two independent distorted tetrahedral molecules (1a and 1b) with different bond parameters. One acetonitrile is entrapped between them. Crystal data: C₈₆H₇₇Cl₂Cu₂N₇P₄S₄ 1: triclinic, P-1, a = 12.8810(9), b = 18.5049(13), c = 18.7430(13) Å, α = 63.7130(10), β = 89.0960(10), γ = 85.5010(10)°, V = 3992.4(5) ų, Z = 2, R _(int) = 0.0314. Bond parameters: 1a, Cu(1A)–Cl(1A), 2.3803(5); Cu(1A)–S(1A), 2.3822(5); Cu(1A)–P(1A), 2.2498(5) Å; P(1A)–Cu(1A)–P(2A), 124.294(19)°; 1b, Cu(1B)–Cl(1B), 2.3975(5); Cu(1B)–S(1B), 2.3756(5); Cu(1B)–P(1B), 2.2777(5) Å; P(1B)–Cu(1B)–P(2B), 127.156(19)°.     

Determination of Chromium(III) with Eriochrome Cyanine R by Fourth-Derivative Spectrophotometry

Summary

A fourth-derivative spectrophotometric determination of chromium(III) with Eriochrome Cyanine R (ECR) was described. The method was based on measuring the fourth-derivative value (D₄) at 545 nm. The experimental and instrumental variables (wavelength range, scan speed, band width and order of derivative) were optimized. Under the optimum conditions, the calibration graph fit the equation d⁴ A/d⁴ = 3.75 × 10⁵ [Cr(III)] + 0.003 (r=0.9991) and have a relative standard deviation of 1.19%. The method was valid for concentrations between 20 ng/ml and 80 ng/ml of chromium(III). The molar ratio of the formed complex was 1:2 (M:L). The proposed method was successfully applied to the determination of chromium in steel.     

Capillary Electrophoretic Determination of Tetramethylthiuram Disulphide (Thiram)

SUMMARY

A simple and sensitive capillary electrophoretic method was developed for the separation and determination of Thiram in boric acid buffer by direct UV absorbance detection at λ = 254 nm. The separation behaviour of Thiram from Nabam was studied and it is dependent on pH and the nature of the buffer. The detection limit (S/N = 3) is 0.5 μg/ml for Thiram. The method was successfully applied to the analysis of wheat samples spiked with Thiram.     

Spectrophotometric Study of 1, 3-Cyclohexanedione Bisthiosemicarbazone Monohydrochloride -Bi (III) Complex. Determination of Bi (III)

Abstract

The spectrophotometric study was made of red-violet 1, 3-cyclohexanedione bis-thiosemicarbazone-Bi (III) in an acidic dimethylformamide-water solution (λ_max = 540 nm, ? = 3.3 × 10^?4 1. mol^?1. cm^?1, stoichiometry 3:1, apparent stability constant (6.0 × 10¹⁰). A new method for the spectrophotometric determination of Bi (III) is proposed for concentrations between 0.7 and 7.4 ppm. The relative error (95 % confidence level) is 0.5 % for 3.7 ppm of Bi (III).

The extraction with methyl isobutyl ketone of the red-violet complex was also studied spectrophotometrically (λ_max = 550 nm, ? = 3.34 × 10⁴ 1. mol^?1.cm^?1, stoichiometry 2:1). A new method for the extraction-spectrophotometric determination of Bi (III) is proposed for concentrations, in aqueous phase, between 0.2 and 1.2 ppm. The relative error (95 % confidence level) is 0.8 % for 0.9 ppm of Bi (III).     

N -oxide bridged manganese(II) coordination polymers

A simple method for synthesis of manganese(II) coordination polymers with different benzoate ligands and pyridine N-oxide having general composition [Mn(RC₆H₄CO₂)₂(PyO)] _n is presented (where PyO = pyridine N-oxide and R = H, 1a; R = 4-NO₂, 1b; R = 4-Cl, 1c; R = 4-OH, 1d; R = 2-NO₂, 1e). All these polymers are characterized by X-ray crystallography and other spectroscopic techniques. The coordination polymers have similar structures, but the positions of the manganese atoms differ. For example, 1c is highly symmetric and a mirror plane exists between each manganese site (2/m). In 1d, the manganese centers are related by an inversion center (?1) whereas in 1e the manganese centers are related by C₁ rotation (1). Reaction of manganese(II) acetate tetrahydrate with 4-chlorobenzoic acid and PyO upon crystallization from methanol/pyridine gave crystals of coordination polymer 1c along with aqua-bis-pyridine bis-4-chlorobenzoato manganese(II) (2). The structure of 2 also determined by single-crystal X-ray diffraction has a 1-D hydrogen bonded chain structure. Temperature-dependent zero-field cooled and field-cooled magnetization data of 1a–1c measured at 20 Oe and 1000 Oe show field-dependent magnetization spread over a wide temperature range from 5 to 300 K. These coordination polymers show anti-ferromagnetic behavior below 20 K.     

Crystal structures of ethylenediaminecadmium(II) tetracyanocadmate(II)-benzene(1/2) and ethylenediaminecadmium(II) tetracyanocadmate(II)

The crystal structure of ethylenediaminecadmium(II) tetracyanocadmate(II)-benzene(1/2),I, has been redetermined based on 1632 reflections collected anew for the crystal coated with epoxy resin, with a final conventionalR=0.038;I crystallizes in space groupP4₂22, witha=b=8.265(1) andc=15.512(3) Å, andZ=2. Ethylenediaminecadmium(II) tetracyanocadmate(II),II, is concluded to be identical with the residual metal complex host ofI, remaining after the liberation of the guest benzene molecules;II crystallizes from an aqueous solution containing bis- or tris-ethylenediaminecadmium(II) tetracyanocadmate(II) in space groupI4₁/acd, witha=b=14.366(1) andc=23.771(4) Å, andZ=16; refinement led to a conventionalR=0.043 for 1181 reflections. The bridging ethylenediamine ligand inI turns to a chelating one inII; dissociation and recombination should occur in the coordination sphere of the six-coordinate cadmium atom, whenII is derived fromI by the liberation of the guest molecules. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82018 (30 pages).Dedicated to Professor H. M. Powell.     

(18-Crown-6)potassium tetrachloroferrate(III), dibromodichloroferrate(III), and tetrabromoferrate(III): Synthesis and crystal structures

Three new crystalline complexes are synthesized: [K(18-crown-6)]⁺ · An, where An = [FeCl₄]^?(I), [FeBr₂Cl₂]^? (II), and [FeBr₄]^? (III). The crystals of compounds I–III are cubic and isomorphic, space group Fd $ \bar 3 Three new crystalline complexes are synthesized: [K(18-crown-6)]⁺ · An, where An = [FeCl₄]⁻(I), [FeBr₂Cl₂]⁻ (II), and [FeBr₄]⁻ (III). The crystals of compounds I–III are cubic and isomorphic, space group Fd (Z = 16): a = 20.770(2) ? for I, 20.844(3) ? for II, and 20.878(4) ? for III. Structures I–III are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.047 (I), 0.059 (II), and 0.098 (III) for all 680 (I), 684 (II), and 686 (III) independent reflections. In two tetrahedral anions [Fe(1)X₄]⁻ and [Fe(2)X₄]⁻ in structures I–III, all halogen atoms (X = Cl and Br) are randomly disordered over three close positions relative to the crystallographic axes 3. Structures I–III contain the [K(18-crown-6)]⁺ host-quest complex cation. The K⁺ cation (CN = 8) resides in the cavity of the 18-crown-6 ligand and coordinated by its six O atoms and two disordered halogen X atoms. The coordination polyhedron of the K⁺ cation in complexes I–III is a distorted hexagonal bipyramid. Original Russian Text ? A.N. Chekhlov, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 9, pp. 1566–1570.     

Synthesis,characterization, in vitro antimicrobial and cytotoxic evaluation of Co(II), Ni(II), Cu(II) and Zn(II) complexes derived from bidentate hydrazones

Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized from hydrazone ligands (HL¹–HL⁴) obtained by condensation reaction of 6-chlorothiochroman-4-one with benz hydrazide/nicotinic hydrazide/isonicotinic hydrazide/p-toluic hydrazide. The synthesized compounds (1–20) were characterized by physicochemical procedures, i.e. (FTIR, ¹H NMR, ¹³C NMR, mass, ESR, UV–Vis), TGA/DTA, powder XRD, elemental analysis (CHN), magnetic susceptibility and molar conductance measurements. The various data suggested bidentate nature (NO) of hydrazones, which coordinate with central metal ions via nitrogen of azomethine (–C=N–) group and deprotonated carbonyl oxygen in the enolized form, resulting in octahedral complexes. Low values of molar conductance suggested their non-electrolytic nature. Thermal decomposition pattern of complexes confirms the metal oxides as end product. In vitro antimicrobial activity of hydrazones and their metal complexes were evaluated against two gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus); two gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli); and two fungal strains (Candida albicans and Aspergillus niger) by serial dilution method, and it was found that the metal complexes were highly active as compared to hydrazones. Among all the compounds, complexes 11, 13, 14 and 19 were found most efficient antimicrobial agent. The anticancer activity of (1–20) compounds was performed on human cancer cell lines A549 (lung), DU145 (prostate) and SW620 (colorectal) by MTT assay using paclitaxel as reference drug. The cytotoxicity results suggested compounds [Cu(L²)₂(H₂O)₂] 11 as most potent against A549, DU145 and SW620 cancer cell lines with IC₅₀ values of 3.46, 18.21 and 7.61 µM. Furthermore, compounds (9, 10, 11, 12) were also investigated on A549 cell line for their ROS generation and mitochondrial membrane potential loss and suggested that complex [Cu(L²)₂(H₂O)₂] 11 has highest ROS production and induction of apoptosis by mitochondrial depolarization in cancer cells.

Graphic abstract

The synthesized compounds (1–20) were screened for in vitro cytotoxicity against A549 (lung), DU145 (prostate), SW620 (colorectal) human cancer cell lines. Copper complex (11) was found to be the most active antitumor agent which enhance ROS production and MMP loss on A549 cells.

     

Synthesis of a Novel Series of (E,E)-4,6-bis(styryl)-2-O-Glucopyranosyl-Pyrimidines and Their Potent Multidrug Resistance (MDR) Reversal Activity Against Cancer Cells

A novel series of methoxy or benzyloxy substituted (E,E)-4,6-bis(styryl)-2-O-glucopyranosyl-pyrimidines as curcuminoid analogs were synthesized in four steps with total yields of 21.5% to 33.9%. A549 and HL60 cells were employed for the anticancer activity testing. The results demonstrated that 5a, 5c, and 5e have some inhibitory activity against the HL-60 cell line. Unfortunately, no compound displayed inhibitory activity against A549 except for 5c. MDR reversal activity results demonstrated that compounds 4a (RF = 12.3) and 4b (RF = 18.5) showed strong reversal activity to the P-gp-mediated LCC6MDR cells compared to verapamil (RF = 3.2) and no cytotoxicity to cancer or normal cell lines even at a high concentrations (100 μM).     

STRUCTURES OF PYRIDINE CARBOXYLATE COMPLEXES OF COBALT(II) AND COPPER(II)

Abstract

The syntheses and crystal structures of [Co(nic)₂(H₂O)₄] (1). [Co(iso)₂(H₂O)₄] (2). [Cu(nic)₂(H₂O)₄] (3), and [Cu(iso)₂(H₂O)₄] (4) (nic = nicotinate; iso = isonicotinate) are reported. Complex 1 crystallizes in monoclinic, space group C2/m with cell parameters a =14.150(4). b = 6.883(2)., c = 8.497(2) Å, β= 118.28(2)° and Z = 2. The other crystals. 2. 3. and 4. are all triclinic, Pī; a = 9.777(3), b = 6.348(4), c = 6.888(3)Å, a= 113.10(6)., β= 110.55(3). γ = 97.61(5)°, and Z=l for 2; a = 7.0281(4), b = 7.7176(6), c = 8.6978(7)Å, a = 68.103(7), β = 68.526(5), γ = 62.550(6)°, and Z=1 for 3; a = 9.1807(4), b = 6.3334(3), c = 6.8871(3)Å, a= 108.213(4), β = 99.433(4), γ= 105.190(4)°, and Z= 1 for 4. The arrangements around the metal ions are trans-octahedra with two pyridyl nitrogens and two aqua oxygens in the equatorial positions and two aqua oxygens in the axial positions, although the Cu(II) complexes show a larger Jahn-Teller distortion.     

Synthesis and Characterization of New Schiff Bases 2-(2-(2-(Aryl)Methyleneamino)Phenylthio) Ethylthio)-N-((aryl)Methylene)Benzeneamine

A series of Schiff bases containing four to six coordination sites N₂S₂ X₂(X = O,N) 2-(2-(2-(aryl)methyleneamino)phenylthio)ethylthio)-N-((aryl)methylene)benzeneamine (2c–f) were prepared from the reaction of 1,2-di(2-aminophenylthio)ethane (1) with aromatic aldehydes. All compounds were characterized by means IR, mass, ¹H and ¹³C NMR spectroscopy, and elemental analysis, and in the case of 2b with a single crystal X-ray diffraction. The X-ray crystal structure of 2b showed that the resonance occurs between aromatic rings, through the C=N bonds of the molecule.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Bis[(1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane)-(isothiocyanato)potassium] [K2(NCS)2(C18H22O6)2]: Crystal and Molecular Structure

Complex of podand 1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane (L) with potassium thiocyanate, [K₂(NCS)₂L₂] (I) was synthesized and studied using X-ray diffraction analysis: space group P , a = 7.771 Å, b = 11.711 Å, c = 11.965 Å, = 72.22°, = 79.21°, = 89.07°, Z = 1. Structure I was solved by direct method and anisotropically refined by the full-matrix least-squares method to R = 0.040 for all 4370 independent reflections (CAD4 autodiffractometer, MoK ). Structure I contains [K(NCS)L] monomers of the host–guest type united into centrosymmetrical [K₂(NCS)₂L₂] dimers via two bridging OH groups (one group from two L podands). In the monomer, the L podand appears as though to envelope the octacoordinated K⁺ cation, whose the coordination polyhedron is a strongly distorted hexagonal bipyramid with all six oxygen atoms of the L podand in its base and the N atom of the SCN^– ligand and the O atom of one of OH group of the neighboring (in dimer) L podand at its axial vertices. Molecules of I in crystal are joined through the O–H···N hydrogen bonds to form broad infinite chains along the x-axis.     

Complexes of Co(II) and Zn(II) with N-(Thio)phosphorylthioureas AdNHC(S)NHP(O)(OiPr)2 and MeNHC(S)NHP(S)(OiPr)2

The reaction of the potassium salt of the N-(thio)phosphorylated thioureas AdNHC(S)NHP(O)(OiPr)₂ (HL^I , Ad = Adamantyl) and MeNHC(S)NHP(S)(OiPr)₂ (HL^II ) with Co(II) and Zn(II) in aqueous EtOH leads to [ML^I,II ₂] chelate complexes. They were investigated by UV-vis, ¹H and ³¹P NMR spectroscopy, and microanalysis. The molecular structures of [ML^I ₂] were elucidated by single crystal X-ray diffraction analysis. The metal centers in both complexes are found to be in a distorted-tetrahedral O₂S₂ environment formed by the C=S sulfur atoms and the P=O oxygen atoms of two deprotonated L^I ligands. The photoluminescence properties of [ZnL^II ₂] are also reported.     

Determination of Metoprolol Tartrate as Cu(II)-Dithiocarbamate Complex

Abstract

An HPLC method has been developed for the determination of the beta adrenergic blocking drug metoprolol tartrate. The method is based on the formation of a Cu (II) - dithiocarbamate complex by precolumn derivatization of secondary amino group of metoprolol with CS₂ and CuCl₂ in the presence of ammonia. The complex is extracted into chloroform and injected into the chromatograph. Chromatographic separation was performed by a RP (μ Bondapak C₁₈) column with methanol - pH 5.8 phosphate buffer (80 : 20) as the isocratic mobile phase. A variable wavelength absorbance detector (λ = 275 nm) was used. A linear relationship was obtained between peak areas and metoprolol tartrate concentrations over the range of 35 - 180 nmol ml^?1. The method was applied to the analysis of metoprolol tartrate tablets and the results were statistically compared with those obtained by official method using t - and F - tests.