Acetals and Ethers. XVIII. Reaction products of prop-2-enal and but-2-enal with mixture: n-Aliphatic alcohol and ethylene glycol

The direct condensation reaction of prop-2-enal or but-2-enal with mixture of n-aliphatic alcohol and ethylene glycol, in the presence of p-toluenesulphonic acid as catalyst, leads to a complex mixture of saturated, unsaturated, cyclic and linear acetals, moreover, 2-(2-alkoxy-alkyl)-1,3-dioxolanes are the main reaction products. The detailed investigations for n-butanol showed that unsaturated cyclic acetals: 2-vinyl-1,2-dioxolane 1a or 2-(1-propenyl)-1,3-dioxolane 1b , as well as unsaturated linear acetals: 1,1-dibutoxy-prop-2-en 2a or 1,1-dibutoxy-but-2-en 2b are intermediate reaction products. Additionally, it was found in final products presence of eight by-products: 5-butoxy- 4a or 5-butoxy-7-methyl-1,4-dioxepane 4b , 1,1,3-tributoxypropane 5a or 1,1,3-tributoxybutane 5b , 2-[2-(2-hydroxyethoxy)ethyl]- 6a or 2-[2-(2-hydroxyethoxy)propyl]-1,3-dioxolane 6b , 5-(2-hydroxyethoxy)-7-methyl-1,4-dioxepane 7b , 1,3-dibutoxy-1-(2-hydroxyethoxy)-propane 8a or 1,3-dibutoxy-1-(2-hydroxyethoxy)-butane 8b , 1,1-dibutoxy-3-(2-hydroxyethoxy)-propane 9a or 1,1-dibutoxy-3-(2-hydroxyethoxy)-butane 9b , 3-butoxy-1,1-bis-(2-hydroxyethoxy)-propane 10a or 3-butoxy-1,1-bis-(2-hydroxyethoxy)-butane 10b , and 1-butoxy-1,3-bis-(2-hydroxyethoxy)-propane 11a or 1-butoxy-1,3-bis-(2-hydroxyethoxy)-butane 11b , respectively.     

Extent of the Acidification by N7-Coordinated cis-Diammine-Platinum(II) on the Acidic Sites of Guanine Derivatives

Coordination of two monoprotonated 2'-deoxyguanosine 5'-monophosphate species, H(dGMP)(-), via N7 to cis-(NH(2))(2)Pt(2+) gives the complex cis-(NH(2))(2)Pt(H.dGMP)(2) which is a four-protonic acid. The corresponding acidity constants were measured by potentiometric pH titrations (25; I = 0.1 M, NaNO(3)). The first two protons are released from the two -P(O)(2)(OH)(-) groups (PK(a/1)= 5.57; PK(a/2) = 6.29) and the next two protons are from the H(N1) sites of the guanine residues (PK(a/3) = 8.73; PK(a/4) = 9.48). The micro acidity constants of the various sites are also evaluated. Comparison of these data with those determined for the three-protonic H(2)(dGMP)(+/-) (PK(a/1) = 2.69 for the H(+)(N7) site; PK(a/2) = 6.29 for -P(O)(2)(OH)(-) ;PK(a/3) = 9.56 for H(N1)) shows that on average the N-7-coordinated Pt(2+) acidifies the phosphate protons by Delta pK(a) = 0.36 and the H(N1) sites by Delta pK(a) = 0.46. These results are further compared with those obtained previously for cis-(NH(2))(2)Pt(L)(2), where L = 9-ethylguanine or monoprotonated 2'-deoxycytidine 5'-monophosphate. Conclusions regarding platinated DNA are also presented.     

Synthesis and Anti-Candida Activity of Cobalt(II) Complexes of Benzene-1,2-Dioxyacetic Acid (bdoaH(2)). X-Ray Crystal Structures of [Co(bdoa)(H(2)O)(3)] 3.5H(2)O and {[CO(phen)(3)](bdoa)}(2)24H(2)O (phen = 1,10-Phenanthroline)

Co(CH(3)CO(2))(2)4H(2)O reacts with benzene-1,2-dioxyacetic acid (bdoaH(2)) to give the Co(2+) complexes [Co(bdoa)(H(2)O)(3)]H(2)O (1a) and [Co(bdoa)(H(2)O)(3)] 3.5H(2)O (1b). Subsequent reaction of 1a with 1,10- phenanthroline produces [CO(phen)(3)] bdoa10H(2)O (2a) and {[CO(phen)(3)](bdoa)}(2)24H(2)O (2b). Molecular structures of 1b and 2b were determined crystallographically. In 1b the bdoa(2-)- ligates the metal by two carboxylate oxygens and two ethereal oxygens, whereas in 2b the bdoa(2-) is uncoordinated. The Mn(2+) and Cu(2+) complexes [Mn(bdoa)(phen)(2)]H(2)O (3) and [Cu(pdoa)(imid)(2)] (4) were also synthesised, 1a-4 and other metal complexes of bdoa H(2) (metal = Mn(2+), Co(2+) ,Cu(2+), Cu(+) ) were screened for their ability to inhibit the growth ofhe yeast Candida albicans. Complexes incorporating the 1,10-phenanthroline ligand were the most active.     

Syntheses and characterization of new nickel coordination polymers with 4,4'-dipyridylsulfide. Dynamic rearrangements of one-dimensional chains responding to external stimuli: temperature variation and guest releases/re-inclusions

Crystal structures and dynamic rearrangements of one-dimensional coordination polymers with 4,4'-dipyridylsulfide (dps) have been studied. Reaction of Ni(NO(3))(2)·6H(2)O with dps in EtOH yielded [Ni(dps)(2)(NO(3))(2)] ·EtOH (1), which had channels filled with guest EtOH molecules among the four Ni(dps)(2) chains. This coordination polymer reversibly transformed the channel structure responding to temperature variations. Immersion of 1 in m-xylene released guest EtOH molecules to yield a guest-free coordination polymer [Ni(dps)(2)(NO(3))(2)] (2a), which was also obtained by treatment of Ni(NO(3))(2)·6H(2)O with dps in MeOH. On the other hand, removal of the guest molecules from 1 upon heating at 130 °C under reduced pressure produced a guest-free coordination polymer [Ni(dps)(2)(NO(3))(2)] (2b). Although the 2a and 2b guest-free coordination polymers have the same formula, they showed differences in the assembled structures of the one-dimensional chains. Exposure of 2b to EtOH vapor reproduced 1, while 2a did not convert to 1 in a similar reaction. Reaction of Ni(NO(3))(2)·6H(2)O with dps in acetone provided [Ni(dps)(NO(3))(2)(H(2)O)] ·Me(2)CO (4) with no channel structure. When MeOH or acetone was used as a reaction solvent, the [Ni(dps)(2)(NO(3))(2)] · (guest molecule) type coordination polymer, which was observed in 1, was not formed. Nevertheless, the reaction of Ni(NO(3))(2)·6H(2)O with dps in MeOH/acetone mixed solution produced [Ni(dps)(2)(NO(3))(2)]·0.5(MeOH·acetone) (5), which has an isostructural Ni-dps framework to 1.     

Synthesis and Biological Activity of Manganese (II) Complexes of Phthalic and Isophthalic Acid: X-Ray Crystal Structures of [Mn(ph)(Phen)(2)(H(2)O)]. 4H(2)O, [Mn(Phen)(2)(H(2)O)(2)](2)(Isoph)(2)(Phen). 12H(2)O and {[Mn(Isoph)(bipy)](4). 2.75biby}(n)(phH(2) = Phthalic Acid; isoph = Isophthalic Acid; phen = 1,10-Phenanthroline; bipy = 2,2-Bipyridine)

Manganese(II) acetate reacts with phthalic acid (phH(2)) to give [Mn(ph)].0.5H(2)O (1). Reaction of 1 with 1,10-phenanthroline produces [Mn(ph)(phen)].2H(2)O (2) and [Mn(ph)(phen)(2)(H(2)O)].4H(2)O (3). Reaction of isophthalic acid (isophH(2)) with manganese(II) acetate results in the formation of [Mn(isoph)].2H(2)O (4). The addition of the N,N-donor ligands 1,10-phenanthroline or 2,2'-bipyridine to 4 leads to the formation of [Mn(2) (isoph)(2)(phen)(3))].4H(2)O (5), [(Mn(phen)(2)(H(2)O)(2)](2)(isoph)(2)(phen).12H(2)O (6) and {[Mn(isoph)(bipy)](4).2.75 biby}(n) (7), respectively. Molecular structures of 3, 6 and 7 were determined crystallographically. In 3 the phthalate ligand is bound to the manganese via just one of its carboxylate groups in a monodentate mode with the remaining coordination sites filled by four phenanthroline nitrogen and one water oxygen atoms. In 6 the isophthalates are uncoordinated with the octahedral manganese center ligated by two phenanthrolines and two waters. In 7 the Isophthalate ligands act as bridges resulting in a polymeric structure. One of the carboxylate groups is chelating a single manganese with the other binding two metal centres in a bridging bidentate mode. The phthalate and isophthalate complexes, the metal free ligands and a number of simple manganes salts were each tested for their ability, to inhibit the growth of Candida albicans. Only the "metal free" 1,10-phenanthroline and its manganese complexes were found to be active.     

Fabrication of a transparent ultraviolet detector by using n-type Ga(2)O(3) and p-type Ga-doped SnO(2) core-shell nanowires

This study investigates the feasibility of synthesizing high-density transparent Ga(2)O(3)/SnO(2):Ga core-shell nanowires on a sapphire substrate at 1000 °C by VLS. The doping Ga concentrations are 0.46, 1.07, 2.30 and 17.53 atomic%. The XRD spectrum and HR-TEM reveal Ga(2)O(3) and SnO(2) as having monoclinic and tetragonal rutile structures, respectively. Experimental results indicate that the XRD peak shift of SnO(2) to a larger angle increases with the increasing amount of Ga doping. According to the CL spectrum, SnO(2) and Ga(2)O(3) peak at approximately 528-568 nm and 422-424 nm, respectively. The maximum quantum efficiency of Ga(2)O(3)/SnO(2):Ga core-shell nanowires is around 0.362%. The UV light on-off current contrast ratio of Ga(2)O(3)/SnO(2):Ga core-shell nanowires is around 1066.7 at a bias of 5 V. Moreover, the dynamic response of Ga(2)O(3)/SnO(2):Ga core-shell nanowires has an on-off current contrast ratio of around 16. Furthermore, the Ga(2)O(3) region functions similar to a capacitor and continues to accumulate SnO(2):Ga excited electrons under UV light exposure.     

60]fullerene--metal cluster complexes: novel bonding modes and electronic communication

[60]Fullerene can bind a variety of metal clusters via eta(2)-C(60), mu-eta(2):eta(2)-C(60), and mu(3)-eta(2):eta(2):eta(2)-C(60) pi-type bonding modes. Multiple C(60) additions to a single cluster core have also been demonstrated. Modification of the coordination sphere of cluster moieties has resulted in novel transformation of the coordination mode of the C(60) ligand between pi and sigma (mu(3)-eta(1):eta(1):eta(2)-C(60) and mu(3)-eta(1):eta(2):eta(1)-C(60)) types as well as reversible interconversion between mu(3)-eta(2):eta(2):eta(2)-C(60) and mu-eta(2):eta(2)-C(60). The mu(3)-eta(2):eta(2):eta(2)-C(60) metal cluster complexes show remarkable electrochemical stability and an unusually strong electronic communication between C(60) and metal cluster centers.     

X-Ray Structure and In Vitro Anti-Tumoural Activity of the Dimeric Bis[(2-Phenyl-1,2-Dicarba-Closo-Dodecaborane-1-Carboxylato)-Di-n-Butyltin] Oxide

X-ray diffraction studies reveal the structure of {[(2-C(6)H(5)-1,2-C(2)B(10)H(10)-1-COO)Bu(2)Sn](2)O}(2), 1, to conform to the common motif found for {[(R'COO)R(2)Sn](2)O}(2) compounds. The dimer features a central Bu(2)Sn(2)O(2) unit (two-fold symmetry) with the two Bu(2)Sn groups being linked via bridging oxygen atoms, each of which also carries an exocyclic Bu(2)Sn moiety. The two pairs of exo- and endo-cyclic tin atoms are each linked via an almost symmetrically bridging carboxylate ligand and the two remaining ligands coordinate an exocyclic tin atom only, in the monodentate mode. The in vitro anti-tumour activity of 1, determined against a variety of cell lines, is compared with those of the corresponding 2-methylcarboranylacetate, derivative 2, and with clinically used compounds.     

Ring transformation and cyclization reactions of 1,1-dioxo-1,2-thiazines – syntheses of pyridines and benzo[c]thiazines with new substitution pattern

In presence of ammonia/ammonium acetate the 3,5-dimethyl-2-phenyl-1,1-dioxo-1,2-thiazine-4-carbaldehyde ( 1 ) reacts with ethyl cyanoacetate to the ethyl 2-cyano-4-[1-methyl-2-methylthio-2-(N-phenylsulfamoyl)vinyl)-hexa-2,4-dienoate] ( 3 ) and the Knoevenagel condensation product 4-(2-ethoxycarbonyl-2-cyanovinyl)-3,5-dimethyl-6-methylthio-1,1-dioxo-2-phenyl-2H-1,2-thiazine ( 2 a). The 4-(2,2-dicyanovinyl)-3,5-dimethyl-6-methylthio-1,1-dioxo-2-phenyl-2H-1,2-thiazine ( 2b ) is obtained from 1 and malononitril. The masked 1,5-dicarbonyl compound 2a undergoes ring transformation to the 3-cyano-1,6-dimethyl-5-[1-methylthio-2-(N-phenylsulfamoyl)vinyl]pyridin-2-one ( 5 ) with methylamine. With ethanolic ethoxide the condensation products 2a,b afford the 7-amino-6-ethoxycarbonyl-4-methylthio-2,2-dioxo-1-phenyl-benzo[c]1,2-thiazine ( 6a ), respectively the corresponding 6-cyano derivative 6b , while 3 cyclizises to furnish ethyl 2-amino-6-methyl-5-[1-methyl-2-methylthio-2-(N-phenyl-sulfamoyl)vinyl]nicotinate ( 4 ).     

Oxygen Radical Scavenger Activity, EPR, NMR, Molecular Mechanics and Extended-Hückel Molecular Orbital Investigation of the Bis(Piroxicam)Copper(II) Complex

The oxygen radical scavenger activity (ORSA) of [Cu(II)(Pir)(2)] (HPir = Piroxicam = 4-hydroxy -2- methyl -N-2- pyridyl -2H- 1,2-benzothiazine -3- carboxamide 1,1-dioxide) was determined by chemiluminescence of samples obtained by mixing human neutrophils (from healthy subjects) and [Cu(II)(Pir)(2)(DMF)(2)] (DMF = N,N -dimethylformammide) in DMSO/GLY/PBS (2:1:2, v/v) solution (DMSO = dimethylsulfoxide, GLY = 1,2,3-propantriol, PBS = Dulbecco's buffer salt solution). The ratio of the residual radicals, for the HPir (1.02.10(-4)M) and [Cu(II)(Pir)(2)(DMF)(2)] (1.08.10(-5)M)/HPir (8.01.10-(-5)M) systems was higher than 12 (not stimulated) [excess of piroxicam was added (Cu/Pir molar ratio approximately 1:10) in order to have most of the metal complexed as bischelate]. In contrast, the ratio of residual radicals for the CuCl(2) (1.00.10(-5)M) and [Cu(II)(Pir)(2)(DMF)(2)] (1.08.10(-5)M)/Hpir (8.01.10(-5)M)system was 5. The [Cu(II)(Pir)(2)] compound is therefore a stronger radical scavenger than either HPir or CuCl(2). A molecular mechanics (MM) analysis of the gas phase structures of neutral HPir, its zwitterionic (HPir(+-)) and anionic (Pir(-)) forms, and some Cu(II)-piroxicam complexes based on X-ray structures allowed calculation of force constants. The most stable structure for HPir has a ZZZ conformation similar to that found in the Cu(II) (and Cd(II) complexes) in the solid state as well as in the gas phase. The structure is stabilized by a strong H bond which involves the N(amide)-H and O(enolic) groups. The MM simulation for the [Cu(II)(Pir)(2)(DMF)(2)] complex showed that two high repulsive intramolecular contacts exist between a pyridyl hydrogen atom of one Pir(-) molecule with the O donor of the other ligand. These interactions activate a transition toward a pseudo-tetrahedral geometry, in the case the apical ligands are removed. On refluxing a suspension of [Cu(II)(Pir)(2)(DMF)(2)] in acetone a brown microcystalline solid with the Cu(Pir)(2).0.5DMF stoichiometry was in fact prepared. (13)C spin-lattice relaxation rates of neutral, zwitterionic and anionic piroxicam, in DMSO solution are explained by the thermal equilibrium between the three most stable structures of the three forms, thus confirming the high quality of the force field. The EPR spectrum of [Cu(II)(Pir)(2)(DMF)(2)] (DMSO/GLY, 2:1, v/v, 298 and 110 K) agrees with a N2O2+O2 pseudo-octahedral coordination geometry. The EPR spectrum of [Cu(II)(Pir)(2).0.5DMF agrees with a pseudo-tetrahedral coordination geometry. The parameters extracted from the room temperature spectra of the solution phases are in agreement with the data reported for powder and frozen solutions. The extended-Hückel calculations on minimum energy structures of [Cu(II)(Pir)(2)(DMF)(2)] and [Cu(II)(Pir)(2)] (square planar) revealed that the HOMOs have a relevant character of d(x) (2)-y(2). On the other hand the HOMO of a computer generated structure for [Cu(II)(Pir)(2)] (pseudo-tetrahedral) has a relevant character of d(xy) atomic orbital. A d(xy) orbital is better suited to allow a dpi-ppi interaction to the O(2) (-) anion. Therefore this work shows that the anti-inflammatory activity of piroxicam could be due in part to the formation of [Cu(II)(Pir)(2)] chelates, which can exert a SOD-like activity.     

N1-(2-苯基-1,2,3-三唑-4-甲酰基)-吡唑类衍生物的合成

利用２－苯基－１,２,３－三唑－４－甲酰肼（１）分别与３－芳基偶氮乙酰丙酮（２）和３－芳基偶氮乙酰乙酸乙酯（３）在酸性条件下环化,制得１２个新的Ｎ１－（２－苯基－１,２,３－三唑－４－甲酰基（－３,５－二甲基－４－芳基偶氮吡唑（４）和Ｎ１－（２－苯革－１,２,３－三唑－４－甲酰基）－３－甲基－４－芳基偶氮－２－吡唑啉－５－酮（５）,用元素分析、ＩＲ、＾１ＨＮＭＲ和ＭＳ确定了它们的结构。     

Bildung von Azoolefinen durch Umsetzung von Hydrazinen mit Amino-hydroxy-hydrobenzoxazol

About the Reaction between Hydrazines and Aminohydroxy-hydrobenzoxazol. Synthesis of Azoolefines By the reaction of 1-hydroxy-2-oxocyclohexane-carboxamide ( 1 ) with cyanamide 2-amino-7a-carbamoyl-3a-hydroxy-3a,4a,5,6,7,7a-hexahydrobenzoxazole ( 2 ) is formed. Compound 2 and arylhydrazine-hydrochloride yield 1-carbamoyl-2-arylazocyclohex-1-ene ( 4a , b ). In morpholine azocompounds 4a , b rearrange to hydrazones 5a , b . Compound 2 and hydrazine yield 4-(2-carbamoyl-cyclohexyl)-semicarbazide ( 10 ), 10 forms perhydroquinazoline-2,4-dione ( 11 ) by oxidation with iodine. 2 and cyanic acid yield the urea derivative 12 . 2 and arylamine-hydrochloride afford the 2-arylamino-3a-hydroxy-7a-carbamoyl-hexahydrobenzoxazoles 13a , b . By fragmentation and “Dimroth-rearrangement” of 2 tetrahydrobenzoimidazolone, ( 14 ) is formed, 12 gives 1-carbamoyl-tetrahydrobenzoimidazolone ( 15 ). 2 and m-nitrobenzaldehyde yield “Schiff-base” 16 . 2 and hydroxylamine sulphate form 2′-amino-2-hydroximino-cyclohexane-spiro-5′-oxazolin-4′-one ( 18 ) 18 and phenylhydrazine hydrochloride yield 1-phenylazo-2-ureido-carboxy-cyclohex-1-ene ( 19 ).     

铬(Ⅲ)与α-甲基丙烯酸根配合物的合成及结构表征

合成了Cr(Ⅲ)与α-甲基丙烯酸根配合物,进行了元素分析,红外光谱研究,确定配合物的组成为Cr2(H2O)8(CH2=C(CH3)-COO-)2Cl4,测定了它的晶体结构,晶体属单斜晶系P21/c,晶胞参数:a=0.5327(12)nm,b=0.9984(10)nm,c=1.6139(7)nm,最终因子β=114.98(3)°,z=4,R=0.0699,Cr(Ⅲ)具有畸变的八面体配位环境,两个Cr(Ⅲ)由两个α-甲基丙烯酸根桥联。     

Novel hollow mesoporous 1D TiO2 nanofibers as photovoltaic and photocatalytic materials

Hollow mesoporous one dimensional (1D) TiO(2) nanofibers are successfully prepared by co-axial electrospinning of a titanium tetraisopropoxide (TTIP) solution with two immiscible polymers; polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) using a core-shell spinneret, followed by annealing at 450 °C. The annealed mesoporous TiO(2) nanofibers are found to having a hollow structure with an average diameter of 130 nm. Measurements using the Brunauer-Emmett-Teller (BET) method reveal that hollow mesoporous TiO(2) nanofibers possess a high surface area of 118 m(2) g(-1) with two types of mesopores; 3.2 nm and 5.4 nm that resulted from gaseous removal of PEO and PVP respectively during annealing. With hollow mesoporous TiO(2) nanofibers as the photoelectrode in dye sensitized solar cells (DSSC), the solar-to-current conversion efficiency (η) and short circuit current (J(sc)) are measured as 5.6% and 10.38 mA cm(-2) respectively, which are higher than those of DSSC made using regular TiO(2) nanofibers under identical conditions (η = 4.2%, J(sc) = 8.99 mA cm(-2)). The improvement in the conversion efficiency is mainly attributed to the higher surface area and mesoporous TiO(2) nanostructure. It facilitates the adsorption of more dye molecules and also promotes the incident photon to electron conversion. Hollow mesoporous TiO(2) nanofibers with close packing of grains and crystals intergrown with each other demonstrate faster electron diffusion, and longer electron recombination time than regular TiO(2) nanofibers as well as P25 nanoparticles. The surface effect of hollow mesoporous TiO(2) nanofibers as a photocatalyst for the degradation of rhodamine dye was also investigated. The kinetic study shows that the hollow mesoporous surface of the TiO(2) nanofibers influenced its interactions with the dye, and resulted in an increased catalytic activity over P25 TiO(2) nanocatalysts.     

Potential of a Novel Chemical Compound Targeting Matrix Metalloprotease-13 for Early Osteoarthritis: An In Vitro Study

Osteoarthritis is a progressive disease characterized by cartilage destruction in the joints. Matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) play key roles in osteoarthritis progression. In this study, we screened a chemical compound library to identify new drug candidates that target MMP and ADAMTS using a cytokine-stimulated OUMS-27 chondrosarcoma cells. By screening PCR-based mRNA expression, we selected 2-(8-methoxy-2-methyl-4-oxoquinolin-1(4H)-yl)-N-(3-methoxyphenyl) acetamide as a potential candidate. We found that 2-(8-methoxy-2-methyl-4-oxoquinolin-1(4H)-yl)-N-(3-methoxyphenyl) acetamide attenuated IL-1β-induced MMP13 mRNA expression in a dose-dependent manner, without causing serious cytotoxicity. Signaling pathway analysis revealed that 2-(8-methoxy-2-methyl-4-oxoquinolin-1(4H)-yl)-N-(3-methoxyphenyl) acetamide attenuated ERK- and p-38-phosphorylation as well as JNK phosphorylation. We then examined the additive effect of 2-(8-methoxy-2-methyl-4-oxoquinolin-1(4H)-yl)-N-(3-methoxyphenyl) acetamide in combination with low-dose betamethasone on IL-1β-stimulated cells. Combined treatment with 2-(8-methoxy-2-methyl-4-oxoquinolin-1(4H)-yl)-N-(3-methoxyphenyl) acetamide and betamethasone significantly attenuated MMP13 and ADAMTS9 mRNA expression. In conclusion, we identified a potential compound of interest that may help attenuate matrix-degrading enzymes in the early osteoarthritis-affected joints.     

制备不同稀土掺杂的纳米氧化钛光催化剂及其光催化活性

以钛酸丁酯为原料,通过溶胶-凝胶法合成了Dy2O3-TiO2,CeO2-TiO2和Gd2O3-TiO2光催化剂。以甲基橙和亚甲基蓝为目标降解物,研究了3种复合光催化剂的光催化活性。通过紫外可见光光谱分析发现：3种光催化剂对不同降解物均表现出一定的光催化活性。掺杂质量分数(下同)为1．25％Gd2O3的光催化剂对甲基橙的降解效率较高,掺杂1．25％CeO2的光催化剂对亚甲基蓝具有较好的降解活性。因此,掺杂不同稀土氧化物的纳米TiO2光催化剂对不同有机物具有选择性降解活性。     

Aspirin analogues as dual cyclooxygenase-2/5-lipoxygenase inhibitors: synthesis, nitric oxide release, molecular modeling, and biological evaluation as anti-inflammatory agents

Analogues of aspirin were synthesized through an efficient one-step reaction in which the carboxyl group was replaced by an ethyl ester, and/or the acetoxy group was replaced by an N-substituted sulfonamide (SO(2)NHOR(2):R(2) =H, Me, CH(2)Ph) pharmacophore. These analogues were designed for evaluation as dual cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitors. In vitro COX-1/COX-2 isozyme inhibition studies identified compounds 11 (CO(2) H, SO(2)NHOH), 12 (CO(2)H, SO(2)NHOCH(2)Ph), and 16 (CO(2)Et, SO(2)NHOH) as highly potent and selective COX-2 inhibitors (IC(50) range: 0.07-0.7 μM), which exhibited appreciable in vivo anti-inflammatory activity (ED(50) range: 23.1-31.4 mg kg(-1)). Moreover, compounds 11 (IC(50) =0.2 μM) and 16 (IC(50) =0.3 μM), with a sulfohydroxamic acid (SO(2)NHOH) moiety showed potent 5-LOX inhibitory activity. Furthermore, the SO(2)NHOH moiety present in compounds 11 and 16 was found to be a good nitric oxide (NO) donor upon incubation in phosphate buffer at pH 7.4. Molecular docking studies in the active binding site of COX-2 and 5-LOX provided complementary theoretical support for the experimental biological structure-activity data acquired.     

Surface-nitrogen removal in NO and N2O reduction on Pd(1 1 0): Angular distribution studies of desorbing products

This paper is a report of angle-resolved product desorption measurements in the course of catalyzed NO and N₂O reduction on Pd(1 1 0). Surface-nitrogen removal processes show different angular distributions, i.e. normally directed N₂ desorption takes place in process (i) 2N(a) → N₂(g). Highly inclined N₂ desorption towards the [0 0 1] direction is induced in process (ii) N₂O(a) → N₂(g) + O(a). N₂O or NH₃ desorption follows the cosine distribution characterizing the desorption after the thermalization in process (iii) N₂O(a) → N₂O(g) or (iv) N(a) + 3H(a) → NH₃(a) → NH₃(g). Thus, a combination of the angular and velocity distributions provides the analysis of most of surface-nitrogen removal processes in the course of catalyzed NO reduction.

At temperatures below 600 K, processes (ii) and (iii) dominate and process (iv) is enhanced at H₂ pressures higher than NO. Process (i) contributes significantly above 600 K. Only three processes except for NH₃ formation are operative when CO is used. Only process (ii) was observed in a steady-state N₂O + CO (or H₂) reaction.     

3-Amino-thieno[2,3-b]furane und 3-Amino-thieno[3,2-b]furane

3-Amino-thieno[2,3-b]furans and 3-Amino-thieno[3,2-b]furans The O-alkylation of 2-hydroxy-thiophene-3-carbonitriles ( 1 ) with α-bromocarbonyl compounds yields the 2-alkoxy-thiophene-3-carbonitriles ( 2a–f ) among them 2-benzoylmethoxy-thiophene-3-carbonitriles ( 2a–c ) which undergo Thorpe-Ziegler-cyclization to form the 3-amino-2-benzoyl-thieno[2,3–b]furans ( 3 ) in low yields. The 2-acyl-3-amino-thieno[3,2–b]furans and ethyl 3-amino-thieno[3,2–b]furan-2-carboxylates ( 6 ) are synthesized in similar manner from 3-hydroxy-thiophene-2-carbonitriles ( 4 ) and α-halogencarbonyl compounds via 3-acylmethoxy- and 3-ethoxycarbonylmethoxy-thiophene-2-carbonitriles ( 5 ) with high yields.     

Synthese und Polymerisation von 2-Aryl-5-methylen-1,3-dioxolan-4-onen und Arylbis(5-methylen-1,3-dioxolan-2-yl-4-on)en

Synthesis and Polymerization Behaviour of 2-Aryl-5-methylene-1,3-dioxolan-4-ones and Arylbis(5-methylene-1,3-dioxolan-2-yl-4-on)es Starting from 2,6-di(hydroxymethyl)-4-methylphen-ol-Na-salt-1-hydrate ( 1 ) a synthesis of 2-alkoxy-5-methyliso-phthaldialdehydes ( 3a,b ) is described via alkylation and oxidation. Condensation of aromatic aldehydes with 3-bromo-2-hydroxypropanoic acid (β-bromolactic acid) affords diastereoisomeric mixtures of new 2-aryl-5-bromomethyl-1,3-dioxolan-4-ones ( 6a–h ) as well as the corresponding bisdioxolanones ( 6i–l ). Dehydrobromination of 2-aryl-5-bromomethyl-1,3-dioxolan-4-ones ( 6a–d,i ) with DBU leads to 2-aryl-5-methylene-1,3-dioxolan-4-ones ( 8a–e ). Polymerization of compounds 8a , b , d and e proceed via opening of the dioxolanone ring.