Synthesis of a new complex Chromium (Ⅲ) 2-mercaptonicotinate

Chromium is an essential trace element for mammals[1-3].Diabetes is a chronic disease with major health consequence.Studies show that the occurrence of diabetes have great thing to do with the chromium deficient。Almost 40 years after the first report of glucose tolerance factor(GTF) [4] no conclusive evidence for an isolable ,biologically active form of chromium exited。Three materials have been proposed to be the biologically active form of chromium:“glucose tolerance factor”,chromium Pi…     

Spectrophotometric Determination of Trace Chromium(VI) in Mass Chromium(III)

There is little conclusive evidence of the toxic effects of Cr(III) so far, but Cr(VI) has carcinogenic activity, so the analysis of the chromine ions is very important in environmental research and the quality control of industry products. Usually Cr(III) and Cr(VI) interfere with each other in the species analysis, the measurement of Cr(VI) of numerous previous papers is related to the Cr(VI) samples, which contain a little Cr(III). When the amount of trivalent chromine exceeds ten …     

Preparation and Characterization of Chromium(Ⅲ)-Containing α-and β-Tungstosilicates

Eight new compounds of α- and β- M2H4[SiW16Cr2(OH2)2O ] .xH2O types, where M = K, Me4N, Et4N or n-Bu4N, and 0+6=6,were synthesized from trivacant heteropoly tungstate α-and β-[SiW9O34]10 precursors, and characterized by elemental analysis, thermal gravimetric analysis, IR, UV-visible spectra, X-ray photoelectron spectroscopy(XPS), polarography, magnetic measurements and X-ray powder diffraction. The IR and UV spectra conJEirm that α-and β-[SlW10Cr2(OH2)2O24]6- isomers possess α-and β-Keg-gin structures. The differences between α-and β-isomers in IR, UV spectra and polarography are discussed.     

Preparation and Characterization of Chromium ( Ⅲ )-Containing α-and β-Tungstosilicates( Ⅱ )

Two new compounds of A- type α-and β-K4.5H2.5[SiW9Cr3(OH2)3O37]·xH2O were synthesized. The two kinds of isomers of α-and β-SiW12-xCrx(x=2, 3) were identified by Second-derivative IR spectroscopy and cyclic voltammetry. The numbers of electrons involved in reductions were obtained by controlled potential electrolyses of the isomers.     

Synthesis and Structure of Dibenzoyl-bissemicarbazone Neodymium(Ⅲ) Perchlorate

A new Schiff base Dibenzoyl-bissemicarbazone C15H16N6O2(L) and its complex with neodymium(Ⅲ ) perchlorate [NdL2(H2O)2](ClO4)3 were synthesized. The crystal and molecular structure of the title complex were determined by single crystal X-ray diffraction. The crystal is monoclinic and conforms to space group P. with cell constants a=10. 893(2) A, b= 12. 118(3) A , c=22. 494(5) A , β=89. 86(3)% V = 2969.19A3. The final standard deviation R=0. 0919. In the complex Nd is coordinated by four nitrogen and six oxygen atoms, of which four nitrogen and four oxygen atoms are provided by two neutral ligands L, and the other two oxygen atoms are provided by two water molecules, forming a ten-coordinated complex cation, which the perchlorate groups exist in the outer sphere. The coordination polyhedron takes a bicapped anti-square prism arrangement. That the average bond length of Nd-N is 2. 735 A indicates that the coordination of N in groups to Nd( Ⅲ ) is very weak.     

Synthesis and Crystal Structure of Cobalt(Ⅲ) Tris(diethyldithiocarbamato) Complex

1INTR0DUCTI0NRecently,thedesignandsynthesisofdinuclearcomplexeshavebeenafascinat-ingareaofresearchowingt0theirimportanceinbasicandappliedchemistry"'.Par-ticularintersthasdevelopedindinuclearcomplexesasmodelsformeta1loproteins"'.Inanattempttosynthesizethetypeof[Ln(S,CN(C2H,)2)3j[Co(S2CN(C2H5)2)2jdinuc1earcomplex,thepurefinecrystalsofCo[S2CN(C2H5)2)2)3were0btained.2EXPERIMENTAL2'1Preparation0fC0[S,CN(C,H,),j,TotheclearsolutionoftheanhydrousSmCl3(0.5mmol)in5mLanhydrousethanolw…     

Synthesis of Diverse Aryliodine(Ⅲ) Reagents by Anodic Oxidation

An anodic oxidation enabled synthesis of hypervalent iodine(Ⅲ) reagents from aryl iodides is demonstrated.Under mild electrochemical conditions,a range of aryli...     

Synthesis and reactivity of carbazole-containing hypervalent iodine(Ⅲ) reagents

A range of bench-stable carbazole-containing hypervalent iodine(Ⅲ) reagents were synthesized by I-N bond formation in good yields.This kind of benziodoxolone reagents was used for a C-N coupling reaction to introduce a carbazole group to aromatic heterocycle compounds.     

First Total Synthesis of (±)-Ponganone Ⅲ

In recent years, the synthesis and pharmacology of pyranoflavanoids have been extensively investigated due to their wide range of pharmacological properties^[1-3]. Ponganone Ⅲ^[4],a new natural pyranoflavanone isolated from the Pongamia pinnala, was identified as (2S)-3',4'-dimethoxy-6',6"-dimethylpyrano-[2",3":7,8]-flavanone (2) on the basis of spectra data. Its precursor,3,4-dimethoxy-2'-hydroxy-6",6"-dimethylchromeno-[2",3":4',3']-chalcone (1) is also a new natural product^[5] isolated from the roots of Lonchocarpus subglaucescent. Their total synthesis have not been reported. Herein, we wish to report the first total synthesis of compounds 1 and 2 in order to confirm the proposed structure and further more to evaluate its biological activities.     

Synthesis and magnetism of μ-isophthalato dinuclear lanthanide(Ⅲ) complexes

Seven new μ-isophthalato dinuclear lanthanide(Ⅲ) complexes, namely [Ln2(IPHTA)(Me2-phen)4-(ClO4)2](ClO4)2 (Ln = La, Nd, Sm, Eu, Gd, Ho, Er), where Me2-phen denotes 2,9-dimethyl-1, 10-phenanthroline (Me2-phen) , IPHTA represents isophthalate dianion, have been synthesized and characterized by elemental analyses, molar conductance measurements, IR, ESR and electronic spectra. The variable-temperature magnetic susceptibilities of [Gd2( IPHTA) (Mez-phen)4 (ClO4)2] (ClO4)2 complex were measured in the temperature range of 4-300 K and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H = - 2JS1 · S2, giving the exchange parameter J =- 0.19 cm-1 . This result is commensurate with a weak antiferromagnetic spin-exchange interaction between Gd(Ⅲ)-Gd(Ⅲ) ions within the complex.     

Synthesis and relaxivity of Gd(Ⅲ), Fe(Ⅲ) and Mn(Ⅱ) complexes with dihydropyridine derivative of diethvlenetriaminepentaacetic acid

A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T1) were investigated. The results show that the NMR T1 relaxivitives (R1) for complexes of Fe(Ⅲ), Mn(Ⅱ) are less than that of Gd(Ⅲ) complex, which has a high relaxivity (R1) on the surrounding water protons, indicating that the Gd(Ⅲ) complex possesses the precondition to be contrast agents for magnetic resonance imaging.     

Synthesis and relaxivity of Gd(Ⅲ), Fe(Ⅲ) and Mn(Ⅱ)complexes with dihydropyridine derivative of diethylenetriaminepentaacetic acid

A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T1) were investigated. The results show that the NMR T1 relaxivitives (R1) for complexes of Fe(Ⅲ), Mn(Ⅱ) are less than that of Gd(Ⅲ) complex,which has a high relaxivity (R1) on the surrounding water protons, indicating that the Gd(Ⅲ) complex possesses the precondition to be contrast agents for magnetic resonance imaging.     

Total Synthesis of (±)- Cis -5-Hydroxycalamenene

A total synthesis of (±)-cis-5-hydroxycalamenene 1 has been achieved from tetralone 5, which in turn was prepared from 5-methoxy-α-tetralone 3. Grignard reaction of compound 5 with isopropylmagnesium chloride, followed by dehydration and aromatization, provided the substituted naphthalene 7 whose conversion to (±)-cis-5-hydroxycalamenene 1 was accomplished by demethylation, formylation, and hydrogenation.     

Synthesis of (±)-zearalenone

The aliphatic portion of (±)-zearalenone has been synthesised by a new simple route starting from 2,3-dihydropyran and 2-acetyl-γ-butyrolactone by employing dithiane for C-C bond formation. The final condensation of this segment with the aromatic part and subseqnet transformations led to (±)-zearalenone.     

Synthesis of (±) Combretastatin

Combretastatin (1) is a new plant product isolated recently by Pettit et al ¹. from the South African tree, Combretum caffrum that possesses central nervous system antineoplastic activity and is being evaluated against several of National Cancer Institute's key evaluation systems. The structure of 1 was established on the basis of its spectral properties and confirmed by X-ray analysis. However, the absolute configuration and the synthesis of 1 have not been reported so far. As combretastatin is present in the plant in only 0.0008% and the isolation technique is much tedious, there is an urgent need for the synthesis of 1 for further evaluation of its activity. This prompted us t o report the first synthesis of (±)1.     

Synthesis of (±)-Altaicadispirolactone

The first synthesis of (±) Altaicadisporolactane 1 is described starting from succinic anhydride.     

Synthesis of (±)-Bimatoprost

A general synthetic approach has been developed for the synthesis of a key intermediate (6) that can be elaborated into several ophthalmic prostaglandins and their derivatives. Using these strategy, we have obtained (±)-bimatoprost (1) and its analog, (±)-homobimatoprost (5).