One-pot synthesis of pyrrolo[1,2-a]pyrazines via three component reaction of ethylenediamine,acetylenic esters and nitrostyrene derivatives

An effective route to pyrrolo[1,2-a]pyrazines is described via reaction of ethylenediamine,acetylenic esters and nitrostyrene derivatives in the presence of 20 mol%of sulfamic acid.

Study on Antibacterial Activity of 2-Methyl-3-(methylthio)Pyrazine Against Three Strains of Spoilage Bacteria

Previous studies have shown that glycine and proline are pharmacophores that display antibacterial activity.In the present study,glycine and proline were derivated to diketopiperazine compounds by chemical synthesis method,and their antibacterial activities were evaluated by three strains of spoilage bacteria,Escherichia coli,Pseudomonas aeruginosa and Shewanella putrefaciens,and the relationship of their antibacterial activities and structures was also investigated.Uv-vis spectrophotometry was used to determine the growth curves of three kinds of active indicator bacteria.Minimum inhibitory concentration(MIC)was determined by micro broth dilution method.The results showed that 2-methyl-3-(methylthio)pyrazine had significant antibacterial activity against three strains of the bacteria,and its MIC was 1.25%.It indicates 2-methyl-3-(methylthio)pyrazine has the potential to be developed as a kind of preservative in future.

Microwave Assisted Synthesis of a New Triplet Iridium（Ⅲ） Pyrazine Complex

A new cyclometalated iridium（IlI） complex Ir（DPP）3 （DPP=2,3-diphenylpyrazine） was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confirmed by elemental analysis, ^1H NMR, and mass spectroscopy. The UV-Vis absorption and photoluminescent properties of the complex were investigated. The complex shows strong ^1MLCT （singlet metal to ligand charge-transfer） and aMLCT （triplet metal to ligand charge-transfer） absorption at 382 and 504 nm, respectively. The complex also shows strong photoluminescence at 573 nm at room temperature. These results suggest the complex to be a promising phosphorescent material.

Tetramethylpyrazine stimulates cystic fibrosis transmembrane conductance regulator-mediated anion secretion in distal colon of rodents

AIM： To investigate the effect of tetramethylpyrazine （TMP）, an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS： The short-circuit current （Isc） technique in conjunction with pharmacological agents and specific inhibitors were used in analyzing the electrolyte transport across the distal colon of rodents. The underlying cellular signaling mechanism was investigated by radioimmunoassay analysis （RIA） and a special mouse model of cystic fibrosis.RESULTS： IMP stimulated a conoentration-dependent rise in ISCl, which was dependent on both Cl^- and HCO3^-, and inhibited by apical application of diphenylamine-2,2＇-dicarboxylic acid （DPC） and glibenclamide, but resistant to 4,4＇-diisothiocyanatostilbene-2,2＇-disulfonic acid disodium salt hydrate （DIDS）. Removal of Na^＋ from basolateral solution almost completely abolished the Isc response to TMP, but it was insensitive to apical Na^＋ replacement or apical Na^＋ channel blocker, amiloride. Pretreatment of colonic mucosa with BAPTA-AM, a membrane-permeable selective Ca2＋ chelator, did not significantly alter the TMP-induced Iso No additive effect of forskolin and 3-isobutyl-l-methylxanthine （[BMX） was observed on the TMP-induced Isc, but it was significantly reduced by a protein kinase A inhibitor, H89.RIA results showed that TMP （1 mmol/L） elicited a significant increase in cellular cAMP production, which was similar to that elicited by the adenylate cyclase activator, forskolin （10μmol/L）. The TMP-elicited Isc as well as forskolin- or IBMX-induced Isc were abolished in mice with homozygous mutation of the cystic fibrosis transmembrane conductance regulator （CFTR） presenting defective CFTR functions and secretions.CONCLUSION： TMP may stimulate cAMP-dependent and CFTR-mediated Cl^- and HCO3^- secretion. This may have implications in the future development of alternative treatment for constipation.

Synthesis and structure determination of pyrazine-containing macrocyclic polyazomethines

Two pyrazine-containing macrocyclic polyazomethines 2 and 3 were synthesized by direct [2 ＋ 2] and [3 ＋ 3] condensation reactions between 2,21-[pyrazine-2,3-diylbis（oxy）]dibenzaldehyde （1） and hydrazine. Both 2 and 3 were characterized by NMR, HRMS, and their structures were determined via X-ray crystal diffraction studies.

6-硝亚氨基-4,8-二硝基-5,6,7,8-四氢化-4H-咪唑烷并[4,5-e]呋咱并[3,4-b]哌嗪的合成(英文)

1 Introduction In the last decades,the furazan fused ring compounds have been paid much more attention owing to their characteristics,such as high density,high specific volume and high nitrogen content.A novel energetic compound based on furazan fused ring,6-nitroimino-4,8-dinitro-5,6,7,8-tetrahydro-4H-imidazo furazano pyrazine(NIFDNP),was firstly designed and its properties of physico-chemical and detonation were calculated by Gaussian 09 program[4] and VLW method[5].Using glyoxal

Hydrothermal Synthesis and Structure of [(PbCl_2)(μ-Pyz)_(1/2)]_n (Pyz = Pyrazine)

A novel 2-D lead-containing hybrid compound, [（PbCl2）（μ-Pyz）1/2], （Pyz = pyrazine） 1, has been synthesized by the hydrothermal assembly of pyrazine with lead chloride. Elemental analysis and X-ray crystal structure analyses were carded out for the structural determination and characterization of the title compound. Compound 1 crystallizes in orthorhombic, space group lbam, with a = 19.5558（18）, b = 7.1939（6）, c = 7.5449（6） A, V = 1061.44（16） .A^3, C2H2Cl2NPb, Mr= 318.14, Z = 8, Dc= 3.982 g/cm^3, μ = 32.63 mm^-1, F（000） = 1096.0, R = 0.0368 and wR = 0.0901 for 623 observed reflections （I 〉 2σ（I））.

Synthesis,Crystal Structure and Luminescence of a Novel One-dimensional Silver(Ⅰ)Sulfonate Complex with Pyrazine Ligand

The title complex,[Ag 2 （L1） 2 （Pyr）·2.5H 2 O] 1 （L1=6-amino-1-naphthalenesulfonate anion,Pyr=pyrazine）,has been synthesized and characterized by single-crystal X-ray diffraction analysis.It crystallizes in triclinic,space group P1,with a=7.339（5）,b=13.105（5）,c=14.097（5）,α=84.377（5）,β=76.921（5）,γ=79.628（5）°,V=1296.7（11） 3,C 48 H 50 Ag 4 N 8 O 17 S 4,M r=1570.68,Z=1,D c=2.011 g/cm 3,μ=1.732 mm-1,F（000）=782,S=1.148,the final R=0.0436 and wR=0.1181 for 4130 observer reflections （I 2σ（Ⅰ））.Compound 1 shows a rare one-dimensional （1D） double chain,and the chains are further connected through secondary bonding,hydrogen bonds,and π-π interactions to generate a three-dimensional （3D） supramolecular structure.The luminescent property of 1 was also studied in the solid state at room temperture.

BTATz晶体及其共晶的热分解及释放氮气机理:从头算分子动力学模拟

为了分析BTATz与pyrazine分子形成共晶后高温热分解机理的变化,采用从头算分子动力学(AIMD)方法,对BTATz晶体及其共晶BTATz/pyrazine的热分解过程进行了模拟。结果表明,在BTATz晶体中,BTATz分子的初始分解路径包括四唑环上N—H键断裂、四唑环上N—N键断裂和H自由基与四嗪环相连生成N—H键;在BTATz/pyrazine共晶中,BTATz分子的分解路径与在BTATz晶体中的情况有所不同。在这两种晶体中,N_(2)的生成速率不同,但是最终生成的N_(2)数量是相同的。在这两种晶体中N_(2)的生成机理相似,都是由四嗪环或四唑环反应得到的,仅仅是N_(2)产生的时间不同。这表明pyrazine分子的存在影响BTATz分子的初始分解过程,但不会影响产物的生成机理和最终数量。

Synthesis and Crystal Structure of 2,6-Bis(2-pyridinylmethyl)-3,5-bis(2-hydroxyl-5-chlorophenyl)pyrazine

The title compound,2,6-bis（2-pyridinylmethyl）-3,5-bis（2-hydroxyl-5-chlorophe nyl）-pyrazine（C26H12Cl2N4O2C2H8O2,Mr=551.41）,has been synthesized and characterized by LC-ESIMS,NMR,UV and IR spectroscopy as well as by X-ray single-crystal diffraction.The compound behaves as a substituted pyrazine.The hydrogen atoms on C（2） and C（3） are substituted by 2-pyridinyl,whereas those on C（1） and C（4） are substituted by 2-hydroxyl-5-chlorophenyl.It crystallizes in the monoclinic system,space group P21/c with a=8.9433（12）,b=32.003（4）,c=10.5209（18）,β=111.199（2）°,V=2807.5（7）3,Z=4,Dc=1.305 mg/m3,F（000）=1144 and μ=0.094 mm-1.A total of 13235 reflections were collected in the range of 2.17～25.01o by using a phi and omega scan mode,of which 4923 were unique（Rint=0.0692） and 2872 observed reflections with Ⅰ 〉2σ（Ⅰ） were used in the structure solution and refinement.

Antifungal Evaluation of Copper(Ⅱ) Complex from a Schiff Base Derivative of Pyrazine on Schizosaccharomyces pombe

A new copper(Ⅱ) complex of CuLCl_2, where L = N^1-(1-pyrazin-2-yl-ethylidene)-ethane-1,2-diamine, a tridentate Schiff base derived from 2-acetylpyrazine has been prepared. The complex has been characterized by FT-IR, elemental analysis and single-crystal X-ray diffraction studies. Structural studies reveal that CuLCl_2 is a mononuclear copper(Ⅱ) complex with distorted square pyramidal geometry. Antifungal activity of CuLCl_2 was investigated by use of microcalorimetric measurement system and evaluated against S. pombe. It has high antifungal activity with IC_(50) = 213 μg/mL.

Syntheses and Crystal Structures of Two Two-dimensional Coordination Polymers with 2,3-Dimethylpyrazine-1,4-dioxide and Thiocyanate as Mixed Bridge Ligands

Two two-dimensional coordination polymers, [Cd（μ1,3-SCN-）2（μ1,6-L）]n 1 and [Co（μ1,3-SCN-）2（μ1,6-L）]n 2, have been synthesized with 2,3-dimethylpyrazine-1,4-dioxide （L） and thiocyanate as mixed bridging ligands, and their crystal structures were determined by X-ray crystallography. Both crystals belong to monoclinic system, space group C2/c. The other crystal parameters are as follows： for complex 1： α = 9.732（3）, b =14.658（5）, c = 8.811（3） A, β = 102.935（4）°, Z = 4, V= 1225.1（7） A^3, C8H8CdN4O2S2, Mr = 368.71, Dc = 1.999 g/cm^3, F（000） = 720 and μ= 2.117 mm^-1; for complex 2： α = 9.528（7）, b = 14.563（11）, c = 8.415（6） A, β= 102.195（9）°, V= 1141.3（14） A^3, Z = 4, C8H8CoN4O2S2, Mr = 315.23, Dc = 1.835 g/cm^3, F（000） = 636 and μ = 1.863 mm^-1. The two complexes show similar two-dimensional sheet structures. Along the c axis one-dimensional chains are constructed by the coordination of Cd（Ⅱ） （or Co（Ⅱ）） ions with μ1,6-L bridging ligand, and the μ1,3-SCN- bridging ligands make the chains connect to each other, resulting in the formation of a two-dimensional sheet on the ac plane.

Design and Selection of High Energy Materials based on 4,8-Dihydrodifurazano[3,4-b,e]pyrazine

In order to search for high energy density materials,various 4,8-dihydrodifurazano[3,4-b,e]pyrazine based energetic materials were designed.Density functional theory was employed to investigate the relationships between the structures and properties.The calculated results indicated that the properties of these designed compounds were influenced by the energetic groups and heterocyclic substituents.The-N3 energetic group was found to be the most effective substituent to improve the heats of formation of the designed compounds while the tetrazole ring/-C(NO_(2))_(3) group contributed much to the values of detonation properties.The analysis of bond orders and bond dissociation energies showed that the addition of-NHNH2,-NHNO_(2),-CH(NO_(2))_(3) and-C(NO_(2))_(3) groups would decrease the bond dissociation energies remarkably.Compounds A8,B8,C8,D8,E8,and F8 were finally screened as the potential candidates for high energy density materials since these compounds possess excellent detonation properties and acceptable thermal stabilities.Additionally,the electronic structures of the screened compounds were calculated.

Hydrothermal Synthesis and Characterization of a Two-dimensional Layer Based on Keggin POM Cluster Units:[Cu_2(DMPz)_2PMo_(12)O_(40)]·HDMPz

The title compound, [Cu2（DMPz）2PMo12O40]·HDMPz （1, DMPz = 2,5-dimethyl pyrazine）, has been synthesized and characterized by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1 with a = 11.075（2）, b = 11.551（2）, c = 11.886（2） A.α = 106.352（2）, β = 109.862（3）, γ = 109.504（1）°, V = 1206.8（3） A3, C18H26CU2Mo12N6O40P, Mr = 2275.78, Z = 1, Dc = 3.131 g/cm3, μ = 4.011 mm^-1, F（000） = 1073, S = 1.066, the final R = 0.0389 and wR = 0.1056 for 3739 observed reflections with I 〉 2σ（I）. The structural analysis indicates that the title compound is composed of Keggin clusters [PMo12O40]3- connected by one-dimensional [CB（DMPz）]2n^2n＋ chains to form a two-dimensional grid layer with holes occupied by monoprotonated DMPz molecules. In the solid of the title compound, the 2D grid layers are stacked together in an ABAB packing mode.

Synthesis and Biological Evaluation of Some Schiff Bases Compounds Derivative of 2,5-di（p-aminophenyl） -3,6-diphenyl Pyrazine

In this present, a new series of Schiffbases from 2,5-di（p-aminophenyl）-3,6-diphenyl pyrazine in the presence of the benzil, 4-bromo benzaldehyde, 4-chlor benzaldehyde, 4-hydroxy benzaldehyde, 4-nitro benzaldehyde and 4-methyl benzaldehyde were studied. The structures of the synthesized compounds were determined on the basis of their Infra-red spectra, H-nuclear magnetic resonase and analysis elemental analysis spectral data. The purity of the synthesized compounds was checked by performing thin layer chromatography. The antibacterial activity was evaluated by paper disc diffusion method.

Synthesis and Crystal Structure of a Cadmium(Ⅱ) Coordination Polymer:[Cd_2Cl_4(bpme)]_n·n(2H_2O)

A novel coordination polymer, [Cd2Cl4（bpme）]n·n（H2O） （1, bpme=2,5-bis（be-nzoimidazol-2-yl）pyrazine）, has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal of the complex belongs to the triclinic system, space group P , with a=7.0737（9）, b=8.7886（11）, c=9.4561（12） , α=105.3580（10）, β=94.981（2）, γ=96.879（2）°, V=558.46（12） 3, Mr=714.97, Z=1, F（000）=346, Dc=2.126 g/cm3, μ=2.412 mm-1, T=296（2） K, S=1.057, R=0.0533 and wR=0.1480. According to the structural analysis, the Cd（Ⅱ） ion adopts a slightly distorted six-coordinated octahedral geometry. The Cd（Ⅱ） atoms are bridged by four Cl atoms along the a direction, forming infinite straight chains which are further constructed to generate 2D network layer structures through the μ4-N bpme ligand in the b direction, and such 2D network layer structures finally form a novel three-dimensional infinite supramolecular framework through weak π-π stacking between two network layers and hydrogen bonds.

Preparation, Characterization and Biological Activity Studies of New Azo Compounds

A new series of azo were derived from 2,5-di（p-amino phenyl）-3,6-diphenyl pyrazine in the presence of benzoic acid, salicylic acid, p-amino salicylic acid, p-methoxy phenol and pmethyl phenol. The structures of the synthesized compounds were determined on the basis of their FTIR, UV （ultraviolet）, elemental analysis and H-NMR （H-nuclear magnetic resonance） spectral date. The purity of synthesized compounds was checked by performing TLC （thin layer chromatography）. The antibacterial activity was evaluated in DMSO （dimethyl sulfoxide）.

Binary and Ternary Complexes of Cd（ll） Involving Pyrazine 2,3-Dicarboxylic Acid and Various Biologically Relevant Ligands

Binary and ternary complexes of Cd（II） involving pyrazine 2,3-dicarboxylic acid （pzdca） and various biologically relevant ligands containing different functional groups are investigated at 25 ℃, I = 0.10 M （NaNO3） and in 20% （v/v） ethanol-water media. The ligands （L） used are amino acids, dicarboxylic acids and peptides. The results showed the formation of Cd （pzdca） （L） complexes with amino acids and dicarboxylic acids. Peptides form both Cd （pzdca） （L） complexes and the corresponding deprotonated amide species Cd （pzdca） （LH-1）. The relative stabilities of ternary complexes are compared with those of the corresponding binary complexes in terms of AlogK values. The concentration distribution of the complexes in solution was evaluated.

Synthesis,Spectra,X-ray Diffraction and Thermal Studies of New Zn(Ⅱ) Compounds Based on Dibenzoylmethane

Two new zinc（Ⅱ） compounds with dibenzoylmethane and N-donor ancillary ligands,[Zn（μ-pyz）（dbm）_2]_n（1） and [Zn（dbm）_2（μ-bpe）Zn（dbm）_2]（2）（Hdbm = dibenzoylmethane,pyz = pyrazine and bpe = 1,2-bis（4-pyridyl）ethane）,have been prepared and characterized using elemental analysis,IR,~1H NMR and 13 C NMR spectroscopy,and studied by thermal gravimetric analysis as well as single-crystal X-ray diffraction. The crystal and molecular structures of 1 and 2 have been solved by X-ray diffraction and they turned out to be a one-dimensional coordination polymer with linear dispositions of metal atoms and binuclear compound,respectively. These one-dimensional polymers are further connected to form a 3D supramolecular network by C–H···O（only in 2） and π-π interactions.

14C-川芎嗪的标记合成

川芎嗪是北京制药工业研究所从川芎中分离得到的生物碱之一,经鉴定是四甲基吡嗪,Tetramethyl-pyrazine,以下简称 TMP。TMP 对于治疗急性闭塞性脑血栓具有良好的疗效。北京制药工业研究所曾做过它的药理研究。为了进一步研究 TMP