Fluorophenyl Bilirubins: Synthesis and Stereochemistry

Summary.  Analogs of bilirubin with vinyl groups replaced by symmetrically-disposed o-fluorophenyls (1, bis-exo, and 2, bis-endo) were synthesized and characterized spectroscopically. Their ¹H NMR spectra and NOE data are consistent with an intramolecularly hydrogen-bonded ridge-tile conformation where each propionic acid group embraces an opposing dipyrrinone. Like bilirubin, 1 and 2 exhibit negative chirality induced circular dichroism (ICD) Cotton effects in chloroform containing quinine. Unlike bilirubin, however, in aqueous buffer containing human serum albumin, 2 exhibits a negative exciton chirality ICD, whereas that of 1 is positive. Received May 22, 2001. Accepted May 29, 2001     

Synthesis,crystal structure and catalytic performance of bis (imino)pyridyl nickel complexes

Two new Ni(II) complexes of 2,6-bis[1-(2,6-diethylphenylimino)ethyl]pyridine (L¹), 2,6-bis[1-(4-methylphenylimino)ethyl]pyridine (L² ) have been synthesized and structurally characterized. Complex Ni(L¹)Cl₂?·?CH₃CN (1), exhibits a distorted trigonal bipyramidal geometry, whereas complex Ni(L¹)(CH₃CN)Cl₂ (2), is six-coordinate with a geometry that can best be described as distorted octahedral. The catalytic activities of complexes 1, 2, Ni{2,6-bis[1-(2,6-diisopropyl-phenylimino)ethyl]pyridine} Cl₂?·?CH₃CN (3), and Ni{2,6-bis[1-(2,6-dimethylphenylimino) ethyl]pyridine}Cl₂?·?CH₃CN (4), for ethylene polymerization were studied under activation with MAO.     

A Water-Soluble Synthetic Bilirubin with Carboxyl Groups Replaced by Sulfonyl Moieties

 The first symmetrical bilirubin analog with CO₂H groups replaced by SO₃H, 8,12-bis-(2-sulfo-ethyl)-3,17-diethyl-2,7,13,18-tetramethyl-(10H,21H,23H,24H)-bilin-1,19-dione, was synthesized from methyl (2,4-dimethyl-5-ethoxycarbonyl-1H-pyrrol-3-yl) acetate in nine steps via the sulfonic acid analog of xanthobilirubic acid (XBR) and isolated as its disodium salt. The sulfonic acid group was introduced at an early stage of the synthesis by reaction of an intermediate, ethyl 4-(2-bromoethyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate, with sodium sulfite. The disodium bilirubin disulfonate exhibits NMR spectroscopic properties rather similar to those of the parent carboxylic acid, mesobilirubin-XIIIα; however, its UV/Vis spectra are blue-shifted and broadened relative to those of the parent compound. Like mesobilirubin, the disulfonate displays a positive exciton chirality circular dichroism spectrum, albeit with weaker Cotton effects, in a buffered aqueous solution (pH = 7.4) containing a 2:1 molar ratio of human serum albumin.     

A Water-Soluble Synthetic Bilirubin with Carboxyl Groups Replaced by Sulfonyl Moieties

Summary.  The first symmetrical bilirubin analog with CO₂H groups replaced by SO₃H, 8,12-bis-(2-sulfo-ethyl)-3,17-diethyl-2,7,13,18-tetramethyl-(10H,21H,23H,24H)-bilin-1,19-dione, was synthesized from methyl (2,4-dimethyl-5-ethoxycarbonyl-1H-pyrrol-3-yl) acetate in nine steps via the sulfonic acid analog of xanthobilirubic acid (XBR) and isolated as its disodium salt. The sulfonic acid group was introduced at an early stage of the synthesis by reaction of an intermediate, ethyl 4-(2-bromoethyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate, with sodium sulfite. The disodium bilirubin disulfonate exhibits NMR spectroscopic properties rather similar to those of the parent carboxylic acid, mesobilirubin-XIIIα; however, its UV/Vis spectra are blue-shifted and broadened relative to those of the parent compound. Like mesobilirubin, the disulfonate displays a positive exciton chirality circular dichroism spectrum, albeit with weaker Cotton effects, in a buffered aqueous solution (pH = 7.4) containing a 2:1 molar ratio of human serum albumin. Received April 24, 2001. Accepted May 7, 2001     

杯[4]芳烃二肟酸-Cu(Ⅰ)配合物的设计与自组装合成

Cu是许多酶中的必须元素[1],Cu与有机配体形成的配合物不仅具有氧化、还原、催化、超分子化合物结构控制等重要作用,而且具有抗菌、抗癌、抗病毒等生物活性.     

Crystal and molecular structures of binuclear caesium complexes with 1,3-calix[4]-bis-crown-6 and 1,3-calix[4]-bis-benzo-crown-6

The crystal structures of two binuclear complexes between caesium and 1,3-calix[4]-bis-crowns have been determined. Cs₂ Bis-benzoC6(NO₃)₂. 3CHCl₃ (1) in whichBis-benzoC6 is 1,3-calix[4]-bis-benzo-crown-6, crystallizes in the orthorhombic system: space groupPca2 ₁ a=19.513(10),b=15.382(5),c=23.708(9) Å,V=7116(5) ų,Z=4. Refinement led to a final conventionalR value of 0.065 for 2321 reflections. The structure of (1) is analogous to those already reported withBis-C6, (in whichBis-C6 is, 1,3-calix[4]-bis-crown-6) and NO ₃ ^– as a counter-ion. Cs₂ Bis-C6(NCS)₂ (2) crystallizes in the monoclinic system: space, groupC2 a=36.57(2),b=11.47(1),c=13.65(1) Å, =109.03(5)°.,V=5415(6) ų,Z=4. Refinement led to a final conventionalR value of 0.063 for 2227 reflections. Compound (2) is made of dimers bridged by a disordered NCS^– ion. The crown ether chain conformations are discussed. Supplementary data relating to this article (atomic coordinates, anisotropic displacement parameters, bond distances and angles and observed and calculated structure factors) are deposited with the British Library as Supplementary Publication No. SUP 82199 (52 pages).     

Trans-bis(dicyanamido)nickel(II) complexes with polyaza macrocyclic ligands

Two new trans-bis(dicyanamido)nickel(II) macrocyclic complexes, [Ni(II)(L1){N(CN)₂}₂] · H₂O (1) and [Ni(II)-(L3){N(CN)₂}₂] (2), where L1 is 3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane and L3 is 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane, have been synthesized and structurally characterized by spectroscopic and X-ray crystallographic methods. In (1) and (2), each central nickel(II) ion possesses a distorted octahedral geometry with four equatorial nitrogen atoms from the macrocycle and two axial nitrogen atoms from dicyanamide anions, which are terminally bonded to the central nickel atom. The solid state electronic spectra of (1) and (2) using the diffuse reflectance method show a characteristic high-spin d⁸ nickel(II) ion in a distorted octahedral environment.     

Synthesis,characterization, and structures of copper(I) complexes with N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine and N,N′-bis[1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine

Two ligands, N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine (L¹ ) and N,N′-bis- [1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine (L² ) and their corresponding copper(I) complexes, [Cu(L ¹)₂]ClO₄ (1) and [Cu(L ²)₂]ClO₄ (2), have been synthesized and characterized by CHN analyses, ¹H-NMR, IR, and UV–Vis spectroscopy. The crystal structures of L¹ and [Cu(L ¹)₂]ClO₄ (1) were determined from single crystal X-ray diffraction. L¹ lies across a crystallographic inversion center and the C=N is approximately coplanar with the benzene ring and adopts E configuration. The coordination polyhedron about copper(I) in 1 is best described as a distorted tetrahedron. Quasireversible redox behavior is observed for the complexes.     

Fading of a novel colorimetric receptor after recognizing H2PO4−

A novel selective and sensitive colorimetric receptor 1 (1, 10-phenanthroline-2, 9-dialdehyde bis-(-p-nitrophenylureasemicarbo-hydrazone)) based on urea showing distinctive color fading phenomenon towards H₂PO₄^? ion was reported. Fancifully, the recognition process of receptor 1 to H₂PO₄^? was not interfered by the existence of others anions. We have probed the binding mechanism of 1-H₂PO₄^? that H₂PO₄^? ion induced competitive hydrogen binding process via intramolecular hydrogen-bond by UV–vis, fluorescence, ¹H NMR titrations and ESI-MS experiments.     

Synthesis,characterization, and fluorescence properties of dinuclear cadmium(II) complexes

Four dinuclear cadmium(II) complexes, [Cd₂(L¹)(μ₂-Cl)Cl₂] (1), [Cd₂(L²)(μ₂-Cl)Cl₂] (2), [Cd₂(L³)(μ₂-Cl)Cl₂] (3), and [Cd₂(L⁴)₃ClO₄] (4), where HL¹ = 4-methyl-2,6-bis(1-(2-piperidinoethyl)iminomethyl)-phenol, HL² = 4-methyl-2,6-bis(1-(2-pyrrolidinoethyl)iminomethyl)-phenol, HL³ = 4-methyl-2,6-bis(1-(2-morpholinoethyl)iminomethyl)-phenol and HL⁴ = 4-methyl-2,6-bis(cyclohexylmethyl)iminomethyl)-phenol, were synthesized. They were characterized by elemental analysis, FT-IR, UV–Vis, fluorescence and electronspray ionization mass spectroscopy. Complexes 1 and 4 were also characterized by single crystal X-ray analysis. The cadmiums atoms in 1 are linked by μ₂-chloride in a distorted square pyramidal geometry, whereas cadmium atom in 4 is in a distorted octahedral environment. The complexes show emission bands around 500 nm with excitation at 395 nm.     

Chirality driven mesomorphic behaviour difference: dichiral compounds containing two lactate groups

ABSTRACT

Four compounds containing two lactate groups and one perfluorocarbon chain are designed and synthesised, whose chirality is tuned by changing the chirality of the lactic acid residues. (R,S)- and (S,R)-2 stereoiosomers exhibit an enantiotropic SmA phase, while (R,R)- and (S,S)-2 stereoisomers exhibit an enantiotropic SmA phase and an enantiotropic SmC_d* one. Therefore, the chirality of the compounds plays an important role in the mesomorphic behaviours of the compounds. The optical activity of these liquid crystals is dominated by the chirality of the lactate group near the core. (R)- and (S)-1 with one lactic acid residue and one perfluorocarbon chain exhibit only an enantiotropic SmA phase.     

4,6-Diacetylresorcinol in Heterocyclic Synthesis,Part I: Synthesis and Biological Evaluation of Some New Linearly and Angularly Substituted Pyrano[3,2-g] Chromenes via Vilsmeier–Haack Formylation of 4,6-Diacetylresorcinol,Its Schiff Bases,and Hydrazones

Application of Vilsmeier–Haack reaction on 4,6-diacetylresorcinol (1) led to the formation of 4,6-dioxo-4H,6H-pyrano[3,2-g]chromene-3,7-dicarboxaldehyde (2) in good yield. The dicarboxaldehyde 2 was condensed with some carbon and nitrogen nucleophiles. Some aliphatic and aromatic Schiff bases of 4,6-diacetylresorcinol (1) were subjected to Vilsmeier–Haack formylation reaction to afford 4,6-bis(alkyl/arylimino)-4H,6H-pyrano[3,2-g]chromene-3,7-dicarbaldehydes 10, 14, and 15. Also, treatment of some bis-hydrazones of 4,6-diacetylresorcinol 16–19 with Vilsmeier–Haack reagent afforded the corresponding 4,6-bis(4-formylpyrazol-3-yl)resorcinols 20 and 21, which underwent oxidation with iodine to yield the pyrano[3,2-g]chromeno[4,3-c:7,6-c]dipyrazole-4,8-diones 22 and 23, respectively. Most of the synthesized compounds revealed weak antimicrobial activities. It was noticed that the dicarboxaldehydes 2, 10, 14, and 15 exhibited moderate antibacterial activity against Gram-positive bacteria, yeast, and fungus.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

DI-μ-CHLORO-BIS[l,2-BIS(DIPHENYLPHOSPHINO)-ETHANEPALLADIUM(II)]: SYNTHESIS AND CRYSTAL STRUCTURE

Abstract

On reacting 1,2-bis(diphenylphosphino)ethanedichloropalladium(II) with equimolar amount of silver perchlorate, a binuclear complex, di-μ-chloro-bis[1,2-bis(diphenylphosphino)ethane-palladium(II)] (1) is formed. The crystal structure of 1 has been solved. It crystallizes with two chloroform molecules. Chloro bridges are symmetrical and normal (Pd-Cl～2.414(3) Å). The immediate environment around palladium is slightly distorted square planar and the P-Pd-P angle is ～85°. IR bands at 290 and 270cm^?1 are observed for the chloro-bridged core of the complex.     

Triorganotin(IV) esters of 2-{[ N -(2-oxo-2H-naphthalene-1-yliden)hydrazo]}benzoic acid,instability of the cyclohexyl derivative

Three triorganotin(IV) esters of 2-{[N-(2-oxo-2H-naphthalene-1-yliden)hydrazo]}benzoic acid were prepared and studied by IR and NMR spectroscopy and X-ray crystallography for the tributyl- and triethyltin(IV)-2-{[N-(2-oxo-2H-naphthalene-1-yliden)hydrazo]}benzoates (2, 3). These compounds are monomeric in solution with four-coordinate tin. The hydrazo tautomeric forms are present in chloroform solution as well as in the solid state. The coordination geometries of tin in 2 and 3 are trigonal bipyramidal with all three carbons in equatorial positions, one carboxylic oxygen and the quinone-type oxygen from adjacent molecules are in axial positions forming centrosymmetric dimers with the ring containing 20 members. The yield of the tricyclohexyltin(IV) derivative (4) is much lower than 2 or 3, with instability towards moisture in solution. The product of the reaction with water is the bis(µ²-hydroxo)-bis{2-{[N-(2-oxo-2H-naphthalene-1-yliden)hydrazo]}benzoato}tetracyclohexylditin (4a) dimer. The tin is five-coordinate in the solid state by two cyclohexyl and two hydroxy groups, the last coordination site is occupied by a monodentate carboxy group. The dimeric form of this compound remains in chloroform solution.     

Synthesis,crystal structure,magnetic property,and nuclease activity of a binuclear iron(III) complex

A μ-oxo-di-μ-carboxylato-bridged iron(III) complex containing two tridentate nitrogen ligands, {[Fe₂(bpma)(bpea)(μ-CH₃COO)₂ μ-O)] · (ClO₄)₂ · 0.5CH₃OH} (1) (bpma = N, N-bis(2-pyridylmethyl)methyl-amine, bpea = N,N-bis(2-pyridylmethyl)ethylamine), has been synthesized and determined by X-ray diffraction. Complex 1 crystallizes in the monoclinic space group P2₁/c with a = 10.9434(12) Å, b = 23.118(3) Å, c = 15.8721(18) Å, β = 92.736(2)° and Z = 4. In 1, each Fe(III) has a distorted octahedral geometry with a N₃O₃ donor set. The Fe(III) atoms are bridged by two carboxyl groups and one μ-oxo oxygen with Fe1–Fe2 separation of 3.064 Å. Susceptibility data of 1 indicate strong intramolecular antiferromagnetic coupling of the high-spin Fe(III) atoms with J = ?121.0 cm^?1 and g = 2.04. The interaction with calf thymus DNA was investigated by UV absorption and fluorescent spectroscopy. Results show that the complex binds to ct-DNA with a moderate intercalative mode. The interaction between 1 and pBR322 DNA has also been investigated by submarine gel electrophoresis; the complex exhibits effective DNA cleavage activity in the absence of activating agents under similar physiological conditions.     

Synthesis and characterization of the [Cu(Cin2bda)2]ClO4 and [Cu(Ncin2bda)2]ClO4 complexes: Crystal structure of [Cu(Ncin2bda)2]ClO4

Two copper(I) complexes [Cu(Cin₂bda)₂]ClO₄ (I) and [Cu(Ncin₂bda)₂]ClO₄ (II) have been prepared by the reaction of the ligands N²,N²′-bis(3-phenylallylidene)biphenyl-2,2′-diamine (L¹) and N²,N²′-bis[3-(2-nitrophenyl)allylidene]biphenyl-2,2′-diamine (L²) and copper(I) salt. These compounds were characterized by CHN analyses, ¹H NMR, IR, and UV-Vis spectroscopy. The C=N stretching frequency in the copper(I) complexes shows a shift to a lower frequency relative to the free ligand due to the coordination of the nitrogen atoms. The crystal and molecular structure of II was determined by X-ray single-crystal crystallography. The coordination polyhedron about the copper(I) center in the complex is best described as a distorted tetrahedron. A quasireversible redox behavior was observed for complexes I and II. The article is published in the original.     

A 2D coordination polymer with 4*82 topology constructed from a new T -shaped ligand: synthesis,crystal structure and photoluminescence

A cadmium(II) coordination polymer [CdL(H₂O)] (1) (H₂L?=?3,3-bis(carboxymethyl)imidazo[1,2-a]pyridin-2-one) was synthesized under hydrothermal conditions and characterized by X-ray structure analysis. Compound 1 crystallizes in the monoclinic space group P2₁/n with a?=?11.945(2)?Å, b?=?8.0865(16)?Å, c?=?13.114(3)?Å, β?=?91.36(3)°, Z?=?4, and represents a 2D network with the 4*8² topology constructed from combination of metal centers with a T-shaped geometry and ligands with T-shaped structure simultaneously. Compound 1 also exhibits strong photoluminescence at room temperature.     

Facile synthesis and characterization of novel benzo-fused macrocyclic dicarbonitriles and pyrazolo-fused macrocycles containing thiazole subunits

Abstract

Novel bis[2-(thiazol-2-yl)acetonitriles], linked to aliphatic cores via ethers, were prepared by the reaction of the appropriate bis(2-bromoethan-1-one) with 2-cyanothioacetamide in dioxane at reflux. Bis[2-(thiazol-2-yl)acetonitriles] were taken as key intermediates for the preparation of a new class of macrocyclic dicarbonitriles bearing two thiazole units and containing two O₂-donor sets and fused with two benzene units. The target macrocyclic dicarbonitriles were prepared by the cyclocondensation of bis[2-(thiazol-2-yl)acetonitriles] with the appropriate bis(aldehydes) in N,N-dimethylformamide in the presence of piperidine at reflux. Moreover, a new class of pyrazolo-fused macrocycles containing thiazole subunits were prepared by the reaction of macrocyclic dicarbonitriles with hydrazine hydrate in ethanol at reflux. The structures of the novel macrocycles bearing thiazole subunits were elucidated by considering their elemental analyses as well as their IR, mass, ¹H NMR and ¹³C NMR spectral data.