A 2D bitriazole-bridging copper(II) polymer: Hydro thermal synthesis, crystal structure, and fluorescence

A new 2D metal-organic coordination polymer [Cu(trtr)₂]_n (1) (Htrtr = 3-(1,2,4-triazolyl-4-yl)-1H-1,2,4-triazole) is synthesized through the hydrothermal reaction of Cu(ClO₄)₂ with Htrtr. The crystal structure of 1 is determined by a direct method from X-ray diffraction data (Rigaku Mercury CCD, MoK _α radiation). 1 crystallizes in the monoclinic C2/c space group with unit cell parameters: a = 14.158(2) ?, b = 9.8050(14) ?, c = 11.413(3) ?, β = 127.9870(10)°, V = 1248.7(4) ?³, Z = 4, D _calc = 1.775 g/cm³. 1 features a 2D grid based on the propagation of 28-membered rings, which is further fabricated into a 3D supramolecular framework via the hydrogen bond linkage. The fluorescence of 1 shows a blue emission at 441 nm with a 14 nm red-shift compared to that of free Htrtr, which can be assigned to LMCT.     

Synthesis of Rigid and Optically Active Bis(binaphthyl) Cyclic Compounds

Optically active cyclic bis(binaphthyl)s (4a–d), which are composed of aromatics, ethers, and ketonic carbonyls, were synthesized through a two‐step nucleophilic aromatic substitution reaction. Bis(binaphthyl) cyclic compounds (4a and 4b) were obtained in moderate yields when difluoride 3a and 3b were employed. On the other hand, bis(binaphthyl)s 4c and 4d were scarcely obtained when 3c and 3d were employed.     

Chronocoulometric and rotating disc electrode determination of the charge propagation current through poly-4-vinylpyridine films containing hexachloroiridate anions

Charge propagation currents through polymer films coated on electrodes which contain redox active sites are usually determined by potential step methods. The aim of this study was to compare the charge propagation current obtained from chronocoulometric measurements with charge transport through a poly-4-vinylpyridine/IrCl₆²⁻ film during the mediated oxidation of Fe²⁺ at a rotating disc electrode. The two methods gave identical results for the model system chosen.     

Living Carbocationic Polymerization. LVII. Kinetic Treatment of Living Carbocationic Polymerization Mediated by the Common Ion Effect

Abstract

The effect of anion concentration on the apparent rate constant of polymerization k^A _p of isobutylene (IB) induced by the 2-chloro-2,4,4-trimethylpentane (TMPCl)/TiCl₄ initiating system using the CH₂Cl₂/nC₆H₁₄ (60/40 v/v) solvent system at ?40 and ?80°C was studied by the use of nBu₄NCl. Computer simulation has shown that k^A _p decreases several orders of magnitude upon the addition of even a very small amount of common anion TiCl^?- ₅ to the charge. The rate of change is reduced in the concentration range of experimental interest. It was concluded that the decrease of k^A _p with increasing TiCl ^?- ₅ concentration is mainly due to the decreasing contribution of propagation by free ions. The contribution (%) of propagation by free ions to the apparent rate of propagation was calculated.     

Isonitriles as source and fate of imidoyl radicals: a novel homolytic α-fragmentation

Imidoyl radicals 4a-c react with phenylacetylene to give annulation products and nitrile 12, arising from β-scission of the intermediate iminyl radical that is involved in the rearrangement of azaspirocyclohexadienyl 8. In contrast, imidoyls 4d and 15 do not react with the alkyne and give good yields of the corresponding isonitriles through a novel example of homolytic α-fragmentation.     

Structural characterisation of trimethylsilyl-protected DNA bases

The structures of the silylated DNA bases, bis(trimethylsilyl)thymine (1), bis(trimethylsilyl)cytosine (2), bis(trimethylsilyl)adenine (3) and tris(trimethylsilyl)guanine (4), have been determined. 1 is O-silylated and displays no intermolecular interactions. 2 is silylated at both exocylic O, N positions and forms a chain structure through intermolecular NH…O and NH…N hydrogen bonds. 3 contains two SiMe₃ groups, on the exocylic NH and endocyclic N⁹ position, respectively; of two independent molecules in the asymmetric unit, one dimerises through complementary NH…N hydrogen bonds, while the other forms a strained intramolecular hydrogen bond through the same pair of donor and acceptor centres. 4 incorporates N, N, O–SiMe₃ moieties and forms chains via bifurcated CH…O/N hydrogen bonds, while the NH function remains unexploited. The effects of silylation on these pyrimidine and purine ring structures are also discussed in comparison with the native bases.

The structures of the silylated DNA bases, bis-(trimethylsilyl)thymine (1), bis-(trimethylsilyl)cytosine (2), bis-(trimethylsilyl)adenine (3) and tris-(trimethylsilyl)guanine (4), have been determined. While 1 displays no intermolecular interactions. 2 forms a chain structure through intermolecular NH…O and NH…N hydrogen bonds, 3 incorporates two independent molecules in the asymmetric unit, one dimerises through complementary NH…N hydrogen bonds while the other forms a strained intramolecular hydrogen bond through the same pair of donor and acceptor centres and 4 forms chains via bifurcated CH…O/N hydrogen bonds while the NH function remains unexploited.     

Formal Synthesis of Ambrox® and 9-Epiambrox

(-)-Drimenol (5) was used as starting material for the synthesis of diastereoisomeric diols 3 and 4, through the nitrile 7, Compounds 3 and 4 are the direct precursors of Ambrox® (1) and 9-epiambrox (2).     

Ionic complex of Vanadyl(IV) in the polymerization of 2-hydroxyethyl methacrylate as probed by EPR

The vanadyl ionic complex VO(DMSO)₅(ClO₄)₂ (I) exhibits high catalytic activity in the polymerization of 2-hydroxyethyl methacrylate (HEMA). The changes in the vanadium oxidation state during polymerization under argon and in the presence of oxygen were studied by EPR. Under aerobic conditions, the HEMA chain propagation radical was detected; this indicates the presence of a radical chain polymerization pathway caused by the ability of I to perform one-electron reduction of molecular O₂. The radical generation rate is controlled by the initial concentration of I: its increase results in the formation of inactive species, presumably, μ-peroxo complexes V^v-O-O-V^v. It was shown by kinetic methods that the radical-chain pathway initiated by the reaction of I with O₂ is not crucial in the HEMA polymerization.     

An Improved Large Scale Synthesis of 2-Amino-4-chloropyridine and Its Use for the Convenient Preparation of Various Polychlorinated 2-Aminopyridines

An efficient large scale synthesis of 2-amino-4-chloropyridine (3) has been achieved through a modification of existing literature procedures. Compound 3 was used to prepare the previously unreported 2-amino-4,5-dichloropyridine (4). The known 2-amino-3,4-dichloropyridine (5) and 2-amino-3,4,5-trichloropyridine (6) were prepared from 3 by new routes and in higher yields than previously reported.     

系列单取代烷氧基-2-羟丙基-β-环糊精的合成与表征

以环氧氯丙烷和脂肪醇为原料, 通过相转移催化法合成了乙基、正丙基、正丁基和正戊基缩水甘油醚(1～4), 并利用所合成的缩水甘油醚和β-环糊精为原料, 分别在弱碱水溶液(1.5%)和强碱水溶液(30%)中制备并用硅胶柱分离出单2位取代的乙氧基、丙氧基、丁氧基和戊氧基-2-羟丙基-β-环糊精(1a～4a)和单6位取代的丙氧基、丁氧基和戊氧基-2-羟丙基-β-环糊精(2b～4b), 利用薄层色谱、红外光谱、差热扫描量热分析、质谱和核磁共振等手段对所合成的产品进行了表征.     

Bisabocurcumin, a new skeleton curcuminoid from the rhizomes of Curcuma longa L.

A new skeleton bisabolane-type sesquiterpene curcuminoid,bisabocurcumin(1),along with 5 known compounds,curcumin(2), demethoxycurcumin(3),bidemethoxycurcumin(4),(1E,4E)-1,5-bis(4-hydroxy-3-methoxyphenyl)-penta-1,4-dien-3-one(5),and (1E,4E)-1-(4-hydroxy-3-methoxyphenyl)-5-(4-hydroxy phenyl-)-penta-1,4-dien-3-one(6)were isolated from the rhizomes of Curcuma longa L.Their structures were determined on the basis of spectroscopic analysis.Bisabocurcumin(1) is firstly obtained from nature with a new skeleton combined by a bisabolane-type sesquiterpene and a 1,7-diphenylheptanoid through a C-C bond.     

A Statistical Evaluation of Methods of Chromatogram Interpretation-GPC

Abstract

Herein is reported a statistical evaluation of two common methods of determining the molecular weight calibration curve using broad molecular weight distribution standards. A Monte-Carlo simulation technique was employed to investigate and compare error propagation in these methods. It has been common practice to evaluate methods of chromatogram interpretation on an entirely theoretical basis without consideration of error propagation in the calculation procedures employed in the various methods. It is possible for a method which has a sounder theoretical basis to give less reliable results because of excessive error propagation. A statistical evaluation of error propagation also identifies the steps in calculation procedures where serious error propagation occurs leading perhaps to alternate and improved calculation paths.

The analysis of several sources of error is presented in detail including propagation errors due to errors in the molecular weight averages of the broad molecular weight distribution standards and chromatogram replication error.     

Monosubstituted ferrocene liquid crystals containing click triazole with a wide nematic phase temperature range

New monosubstituted ferrocenomesogens of the 1,4-substituted-1,2,3-triazole series 3a-3d and the 5-halogen-1,4-substituted-1,2,3-triazole series 4a-4d were successfully synthesised through a facile and versatile synthetic route using click reactions with moderate yields, in different atmospheres, and catalysed by different amounts of CuX (X = Br, I). Two series of compounds exhibited a typical nematic liquid crystal texture, and the 5-halogen-1,4-substituted-1,2,3-triazole series 4 had a wider mesomorphic temperature range than the corresponding series 3 due to the effect of the halogen atom substituent on the triazole. These compounds showed similar absorption spectra, but the fluorescence emission spectra of 4 were obviously redshift relative to 3. Cyclic voltammetry investigations revealed that the redox-active ferrocenyl groups of 3 and 4 follow one-electron transfer processes.     

A Facile Synthesis of the Pyranonaphthazarin System

The synthesis of pyranoquinone 9 starting from hydroxyquinone 4 through Michael adduct 5 is described.     

PHOSPHORORGANISCHE VERBINDUNGEN 88.1 OPTISCH AKTIVE PHOSPHINIGSÄUREAMIDE DARSTELLUNG,EIGENSCHAFTEN UND ABSOLUTE KONFIGURATION

Abstract

Optisch aktive Amidophosphoniumsalze, z.B. (7a) und (7b), werden elektroreduktiv unter Retention in die bisher unbekannten Phosphinigsäureamide (4a) und (4b) überführt. Die absolute Konfiguration von (4a) und (4b) wird durch chemische Korrelation mit Verbindungen bekannter absoluter Konfiguration ermittelt. Durch Umsetzung von optisch aktivem (4b) mit Trifluoressigsäure-p-kresylester erhält man unter Retention Ethyl-phenyl-phosphinigsäure p-kresylester (13).

Optically active amidophosphonium salts (e.g. 7a, 7b) may be electrochemically reduced with retention of configuration at phosphorus to the corresponding phosphinous acid amides (4a, 4b), previously unreported compounds. The absolute configuration were deduced through further chemical reaction under known stereochemical control to products of defined absolute configuration. Reaction of optically active (4b) with para-cresyl trifluoroacetate gives the ethyl–phenyl phosphinous acid para-cresyl ester (13) under retention of configuration.     

Crystal Structures of Aripiprazole, a New Anti-psychotic Drug, and of its Inclusion Compounds with Methanol, Ethanol and Water

Aripiprazole, 7-[4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy]-3,4-dihydrocarbostyril, is an important new neuroleptic drug used in the treatment of schizophrenia and related psychoses. This study elucidates its detailed molecular structure and two preferred conformational forms, and relates to the solvates of this compound when crystallized from different environments. The latter is associated with the hydrogen-bonding capacity of aripiprazole through the piperazinyl and dihydrocarbostyril functions. Four unique crystal forms of this compound have been characterized using X-ray single crystal determinations, including an anhydrous structure (1), methanol (2) and hemi-ethanol (3) solvates and a hydrate (4). They were found to consist of hydrogen bonded dimers of the aripiprazole moieties that involve the cyclic (–NH–CO–)₂ di-amide interaction synthon in 1–3 (with the solvent molecules attached to them in 2 and 3), or of hydrogen bonded polymeric aggregates sustained by extended multiple bonding through water bridges in 4. These modes of supramolecular association involve two different conformers with similar energy of the drug moiety.     

Crystal Structure of Monoprotonated Ni(II) Nitrilotriacetate Tetrahydrate

A Ni(II) complex of the composition Ni(HNta) · 4H₂O (I) was synthesized. Its structure was found to consist of neutral mononuclear [Ni(HNta)(H₂O)₃] complexes and crystallization water molecules. The Ni atom has octahedral surrounding and is coordinated to tridentate-chelate HNta^2– ligand through the N atom and O atoms of two deprotonated acetate groups and through the O atoms of three water molecules. The structure of I was compared with those of the Zn(HNta) · 4H₂O and Co(HNta) · 4H₂O complexes isostructural to I. Thermogravimetric method showed that the decomposition of compound I occurs through several successive stages of dehydration, deaquation, decarboxylation, and the formation of inorganic residue.     

Synthesis of the Repeating Unit of the Capsular Polysaccharide of Streptococcus Pneumoniae Type 3 as a Building Block Suitable for Formation of Oligomers

Abstract

The synthesis of a cellobiouronic thioglycoside donor 12, protected with a selectively removable 3′-O-benzyl group is described. The donor 12 is suitable as a monomer building block in the construction of oligomer structures corresponding to the capsular polysaccharide of Streptococcus pneumoniae type 3. The carboxyl function was introduced through regioselective TEMPO-oxidation of a 4′,6′-diol cellobiose derivative. If the oxidation was performed on a 2,3,2′,3′,4′,6′-hexaol derivative, oxidation also of the secondary 2- and 3-hydroxyl groups was observed to give a tricarboxyl derivative as one of the major products. The thioglycoside was formed by acidic mercaptolysis of a 1,6-anhydro bridge. The donor 12 was transformed into a suitable starting monomer acceptor through glycosylation with a spacer alcohol and subsequent debenzylation.     

Synthesis and Antibacterial Activity of Some New S-Triazole Derivatives

Abstract

Alkylation of 4-anilino-5-phenyl-4H-1,2,4-triazole-3-thiol (1) with some halo compounds yielded the corresponding sulfides 2a–f. Some sulfides 2e,f were cyclized to give triazolothiadiazines 3 and 4. Triazolothiadiazoles 5 and 6 were prepared through the reaction of compound 1 with carbon disulfide or ethyl orthoformate, respectively. Treatment of compound 1 with ethyl chloroformate or phenyl isothiocyanate yielded triazolo-thiadiazole and triazole 9 and 10, respectively. Reaction of compound 1 with Lawesson's reagent gave triazolothiadiazaphosphole derivative 11. Also, compound 1 underwent cyclocondensation reactions with some bidentate reagents to give triazolothiazines 4, 12, and 13. Triazolo-thiazepines and triaziepine 14–16 were synthesized via the reaction of compound 1 with β-ketoesters or ethyl cyanoacetate. Tricyclic systems 19 and 20 were prepared through the reaction of compound 4 with the appropriate reagent. Some synthesized compounds were tested for antibacterial activity.

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.     

Fluorinated styrene-based monomers for cyclopolymerizations

The synthesis of versatile fluorine compounds and monomers for conducting polymer research and cyclopolymerizations is presented. Semiprotected 2,3,5,6-tetrafluoroterephthaldehyde 1 could be elaborated through Wittig olefination chemistry, deprotection and reduction to the previously unknown 4-vinyl-2,3,5,6-tetrafluorobenzylalcohol 8 in good yields. Compound 8 can be reacted to form the malonate ester, and then alkylation on the malonate moiety in mild conditions affords difunctional monomer 3. Through sequential esterifications on the malonate moiety, and subsequent alkylation, compound 4, a difunctional monomer for cyclopolymerization bearing one styrene and one perfluoroaryl styrene moiety, has been obtained. Preliminary experiments show that it is possible to cyclopolymerize 4 under free radical conditions.