Synthesis of Optically Active endo,endo Bicyclo[2.2.2]octane-2,5-diol, Bicyclo[2.2.2]octane-2,5-dione, and Related Compounds

Optically active C(2)-symmetric (1S,2S,4S,5S)-bicyclo[2.2.2]octane-2,5-diol ((+)-12; 98% ee) and several selectively protected optically active intermediates useful for synthetic transformations were synthesized via a 1,2-carbonyl transposition route starting from the easily available optically active (1R,4S,6S)-6-hydroxybicyclo[2.2.2]octan-2-one ((-)-2). The synthetic route also allowed the preparation of optically active (1S,4S)-bicyclo[2.2.2]octane-2,5-dione ((+)-14; 98% ee).     

Synthesis and biological evaluation of water-soluble trans-[bicyclo[2.2.2]octane-7R,8R-diamine]platinum(II) complexes with linear or branched alkoxyacetates as leaving groups

Four platinum(II) complexes, trans-[bicyclo[2.2.2]octane-7R,8R-diamine]bis(alkoxyacetato-O,O’) platinum(II) (alkoxyacetate = methoxyacetate (2), ethoxyacetate (3), isopropoxyacetate (4), and tert-butoxyacetate (5)) were synthesized and spectrally characterized. The cytotoxicity of these water-soluble complexes was evaluated by CCK-8 assay in vitro against HCT-116, HepG-2, and A549 cancer cell lines. Most of the complexes had cytotoxic activity against the tested cancer cell lines. Among them, 3 showed more potent antitumor effect than cisplatin or oxaliplatin. Complex 3 could cause HCT-116 cell line death based on an apoptotic pathway since it has a dicyclic moiety similar to 1R,2R-diaminocyclohexane in oxaliplatin. Agarose gel electrophoresis on the interaction between 3 and DNA indicated that it has different behavior from that of cisplatin or oxaliplatin, which has a high correlation with the ligand used.     

Two chiral mononuclear and one-dimensional cadmium(II) complexes constructed by (1R,2R)-N1,N2-bis(pyridinylmethyl)cyclohexane-1,2-diamine derivatives: Effect of positional isomerism

Reactions of (1R,2R)-N¹,N²-bis(pyridinylmethyl)cyclohexane-1,2-diamine derivatives, (1R,2R)-2-bpcd and (1R,2R)-3-bpcd [(1R,2R)-2-bpcd = (1R,2R)-N¹,N²-bis(pyridin-2-ylmethyl)cyclohexane-1,2-diamine, (1R,2R)-3-bpcd = (1R,2R)-N¹,N²-bis(pyridin-3-ylmethyl)cyclohexane-1,2-diamine], with CdI₂ in an analogous way led to the formation of a chiral discrete mononuclear complex and a chiral one-dimensional polymeric chain, respectively, which may be attributed to the positional isomerism of the ligands. The chiral organic ligands and complexes display luminescent properties indicating that they may have a potential application as optical materials. Powder second-harmonic generation (SHG) efficiency measurement shows that the SHG efficiency of the complexes is approximately 0.3 and 0.45 times that of KDP, respectively.     

Synthesis of bicyclo[2.2.2]octane-2,3,5,6,7,8 hexols (Bishomoinositols) as glycosidase inhibitors

For the construction of the bicyclo[2.2.2]octane skeleton, 2,2-dimethyl-3a,7a-dihydro-1,3-benzodioxole was reacted with vinylene carbonate to give two isomeric cycloadditon products having the bicyclo[2.2.2]octane skeleton. Hydrolysis of the ketal ring and the opening of the carbonate functionality, followed by hydroxylation of the remaining double bond resulted in the formation of a symmetrical hexol. Epoxidation of the double bond in the cycloaddition products and the subsequent ring-opening reactions produce two additional hexol derivatives. One of the synthesized molecules exhibited enzyme-specific inhibition against alpha-glycosidase.     

Synthesis, structural characterization, thermal and electrochemical studies of the N,N'-bis[(3,4-dichlorophenyl)methylidene]cyclohexane-1,4-diamine and its Cu(II), Co(II) and Ni(II) metal complexes

In this study, N,N'-bis[(3,4-dichlorophenyl)methylidene]cyclohexane-1,4-diamine (L) and its Cu(II), Co(II) and Ni(II) complexes were prepared and characterized by the analytical and spectroscopic methods. The analytical data show the composition of the metal complex to be [M(2)L(Cl)(4)(H(2)O)(2)], where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. The compound (L) behaves as a monodentate ligand. But, obtained complexes have binuclear nature. The electrochemical properties of the metal complexes are dependent on reversible, irreversible and quasi-reversible redox waves in the anodic and cathodic regions due to oxidation and reduction of the metal ions. The single crystal of the ligand (L) was obtained from CH(3)CN solution. Space group and crystal system of the ligand are P2(1)/C and monoclinic, respectively.     

Synthesis and transformations of 2,3-dioxo-2,3-dihydroimidazo [1,2-a]-benzimidazole derivatives

9-(H)Alkyl-2,3-dioxo-2,3-dihydroimidazo[1,2-a]benzimidazoles were synthesized by the action of oxalyl chloride on 2-amino-1(H)alkylbenzimidazoles and subsequent cyclization of the resulting 2-amino-1-(H)alkyl-3-chlorooxalylbenzimidazolium chlorides in the presence of triethylamine. The behavior of the synthesized benzimidazoles with respect to the action of alkalis, lithium aluminum hydride, and ethylmagnesium bromide was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1391–1395, October, 1976.     

New Cu(II), Co(II), and Ni(II) complexes with thieno[2,3-b]pyridine and 2-methylthieno[2,3-b]pyridine as ligands: Synthesis and crystal structures

Although thienopyridines attract attention because of their biological activities, they have not been used as ligands in coordination compounds. Thieno[2,3-b]pyridine was prepared by known procedures; by reduction of 2-nitrothiophene, and reaction of the resulting 2-thienyl ammonium salt with malondialdehyde tetramethylacetal in the presence of zinc chloride. The same procedure was used for the preparation of a new derivative, 2-methylthieno[2,3-b]pyridine, starting from 2-methyl-5-nitrothiophene. The thienopyridines were used in the synthesis of coordination compounds. Chlorides, isothiocyanates, acetates, and chloroacetates of copper(II), nickel(II), or cobalt(II) were used as starting salts. The prepared complexes were characterized by elemental analysis and FT IR. Structures of the four complexes were determined by single-crystal X-ray diffraction analysis. Presented at the 1st International Conference “Applied Natural Sciences” on the occasion of the 10th anniversary of the University of Ss. Cyril and Methodius, Trnava, 7–9 November 2007.     

Mercury(II) halide adducts of a dicarboxylate-like ligand: Crystal structures of polymeric mercury(II) complexes with 1,4-diazoniobicyclo[2.2.2]octane-1,4-diacetate

Three mercury(II) complexes containing double-betaine and halide ligands, [(HgCl₂)₂(L¹)] _n (1), [(HgBr₂)₂(L¹)(H₂O)₂] _n (2), and [2HgCl₂(HL¹)·Hg₂Cl₆] _n (3) [L¹=^–O₂CCH₂N⁺(CH₂CH₂)₃-N⁺H₂CO₂ ^–], have been prepared and shown to have polymeric structures by single-crystal X-ray analysis. Complex (1) exhibits an infinite zigzag chain in which each mercury(II) atom is coordinated by pairs of carboxylate oxygen atoms and chloride ligands in a distorted tetrahedral geometry. In complex (2), the mercury(II) atom is in an unusual square-planar coordination geometry, and weak mercury-ligand and hydrogen bonding extend the structural skeletons into a three-dimensional network. Complex (3) consists primarily of an assembly of HgCl₂(HL¹) moieties and [Hg₂Cl₆]^– anions, and the mercury(II) atoms are in planar T-shaped and distorted tetrahedral coordination environments, respectively. The resulting three-dimensional network is based on the cross-linkage of nearly planar, wide ribbons running in thea direction.     

Synthesis and reactivity of thieno[2,3-b]quinoline derivatives (Part II)

As a continuation of our previous review entitled “Vilsmeier-Haack cyclisation as a facile synthetic route to thieno[2,3-b]quinolines (Part I).” This review describes the methods of preparation and the chemical reactivity of thieno[2,3-b]quinolines, which might show interesting biological activities.     

Ni(II) complexes with 8-aminoquinoline derivatives

Some Ni(II) complexes with 5,7-dicloro-8-aminoquinoline (dcaq), 5,7-dibromo-8-aminoquinoline(dbaq) and 5,7-diiodo-8-aminoquinoline(diaq) are described. The compounds are of stoichiometry NiL₂X₂(L= dcaq, dbaq, diaq; X= NO^?₃ and L= dbaq; X= Cl^?, Br^?, I^?, NCS^?) and NiLX₂·H₂O(L= dcaq, diaq; X= Cl^?). The electronic spectra and magnetic susceptibility data at room temperature, are consistent with octahedral geometry for the Ni(II) in each compound. I.r. spectra show the presence of ionic and bridging nitrate groups in the compounds NiL₂(NO₃)₂(L= dcaq, dbaq, diaq) and we assign them polymeric structures. Polymeric structures with bridging chloride are proposed for the compounds NiLCl₂·H₂O(L= dcaq, diaq) and monomeric octahedral structures for NiL₂X₂(L= dbaq; X= Cl, Br, I, NCS).     

Synthesis and in vitro cytotoxicity of platinum(II) complexes with chiral N-monosubstituted 1,2-cyclohexyldiamine derivatives as the carrier groups

Eight platinum(II) complexes with the new chiral ligands, (1R,2R)-N ¹-(pyridine-2-ylmethyl) cyclohexane-1,2-diamine (R) or (1S,2S)-N ¹-(pyridine-2-ylmethyl) cyclohexane-1,2-diamine (S) as the carrier groups were designed, synthesized, and spectrally characterized. All platinum(II) complexes showed much better aqueous solubility than cisplatin and oxaliplatin. In vitro cytotoxicity of the compounds against human HepG-2, MCF-7, A549, and HCT-116 cell lines was evaluated. Results indicate that all compounds with R as the carrier group showed cytotoxicity against HCT-116, A549, and MCF-7 cell lines; however, all compounds with S as carrier group exhibited disappointing cytotoxicity against tested cell lines. Compound R2, bearing ClCH₂COO^- as leaving group, exhibited better cytotoxicity than that of carboplatin against A549 and MCF-7 cell lines and also showed close activity to oxaliplatin against HCT-116 cell line.     

Thermogravimetric investigation of thermal decomposition of copper(II) complexes with methylpyrido[2,3-d]imidazole derivatives

Solid-state complexes with the formulae CuL _x X₂·nH₂O, wereL=2-methyl-, 5-methyl-, or 7-methylpyrido[2,3-d]imidazole,X=NO ₃ ^– or Cl^–,x=2 or 3, andn=1 or 2, were subjected to thermogravimetric analyses. The kinetic parameters were calculated according to the Coats-Redfern method. Reactions paths are proposed and their agreement with the data obtained from TG curves is checked.The authors thank Dr. W. Surga for XRD analyses, and Dr. B. Kowalczyk and Dr. M. Czerwinski from the Pedagogical University in Czestochowa for providing access to the computer application allowing calculation of the kinetic parameters.     

Synthesis of 5,6-benzo-1,2-diazabicyclo [2.2.2]octane

5,6-Benzo-1,2-diazabicyclo[2.2.2]octane was synthesized by nitrosation of 1,2,3,4-tetrahydrocinchoninic acid, reduction of the 1-nitroso derivative to 1-amino-1,2,3,4-tetrahydrocinchoninic acid, cyclodehydration of it to 3-oxo-5,6-benzo-1,2-diazabycyclo[2.2.2]octane, and reduction of the oxo group to a methylene group with lithium aluminum hydride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1369–1371, October, 1970.     

Synthesis and insecticidal bioactivities of 2,3-dihydroimidazo[1,2-a]pyridin-5(1H)-one derivatives

A novel synthesis of 2,3-dihydroimidazo[1,2-a]pyridin-5(1H)-one, and insecticidal derivatives were described.     

1，2-环己二胺缩邻香兰素单核与四核镱稀土配合物的近红外性质

通过配体1,2-环己二胺缩邻香兰素（H2L）和不同的镱盐反应,合成了4个镱稀土配合物[Yb（H₂L）₂]（ClO₄）₃·2CH₃OH·H₂O（1）,[Yb₄（L）₄（NO₃）₂（H₂O）₂]（PF₆）₂·4CH₃CN（2）,[Yb₄（L）₄（H₂O）₂Cl2]（PF₆）₂·2CH₂Cl₂·2H₂O（3）和[Yb₄（L）₄（NO₃）₂（H₂O）₂][Yb（NO₃）₃（H₂O）₂（CH₃OH）]（NO₃）₂·4CH₂Cl₂·6CH₃OH（4）。X射线单晶衍射分析表明配合物1为零维的单核结构,配合物2~4均为四核结构。研究了4个配合物的近红外发光性能。     

Synthesis and properties of 2,7-diazabicyclo[2.2.2]octane-3,8-diones and -3,8-dithiones

In an alkaline medium, 3,4-dihydropyridin-2(1H)-ones form 2,7-diazebicyclo[2.2.2]-octane-3,8-diones, which are thiolated to the corresponding dithiones. The alkylation of the last proceeds at the sulfur atoms with the formation of 2,7-diazabicyclo[2.2.2]octa-2,7-dienes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 620–625, May, 1989.     

Synthesis, characterization and biological evaluation of platinum(II) complexes with a chiral N-monosubstituted 1,2-cyclohexyldiamine derivative

Eight platinum(II) compounds with a new chiral ligand, 2-(((1R,2R)-2-aminocyclohexylamino)methyl)phenol (HL), were designed, prepared and spectrally characterized. All compounds showed better aqueous solubility than cisplatin and oxaliplatin. In vitro cytotoxicity of these compounds against human HepG-2, MCF-7, A549 and HCT-116 cell lines was evaluated. Results indicated that all compounds showed cytotoxicity against A549 and HepG-2 cell lines. Particularly, compounds B1 and B8, which have CF?SO?? and (CH?)?COCH?COO(-) as leaving groups, respectively, exhibited better cytotoxicitiy than that of carboplatin in these two cell lines.