bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Electrochemical Behaviour of Some 2,3‐Dihydrothiazolo[3,2‐a]Benzimidazol‐3‐One and 1‐Ethylmercapto‐3(4H)‐Isoquinolones Derivatives
Authors: Fahmy H. M. , Aboutabl M. , Abdel Azzem M.
Published: June 2015

The electrochemical behaviour of several derivatives containing the sequence S‐C‐CO‐N in their structure presented as such or in masked form in both aqueous and non‐aqueous media are reported. The results of electrooxidation indicated that when the S atom is present as hetero atom in the structure of the molecule the main product will be the sulphone derivative, on the other hand when present in the form C=S the preferential product is the dimer. The overall redox study indicated that the azo group at C‐2 is very active in both aqueous and non aqueous media. On the other hand derivatives substituted at C‐2 the preferential electrochemical step is the attack of the hetero ring itself.
Mixed Ligand Complexes of Palladium (II) with Diethylenetriamine as Primary Ligand and Peptides as Secondary Ligand
Authors: Soukry Mohamed M. , Darwish N. A. , Hosny W. M.
Published: June 2015

Solution equilibria of the system palladium (II)‐diethylenetriamine (dien) and peptides have been studied. The pH‐metric titration of the reaction mixture containing equimolar solutions of palladium (II), dien and peptide have shown the formation of 1:1:1 mixed ligand complex. The pKe of the peptides studied and formation constants of the resulting complexes have been determined at 25°C. The mode of chelation has been deduced from the conductivity measurements.
Studies of Surface Sulfidation and Distribution of Sulfur on Cu‐ZnO Catalysts
Authors: Chen Y. W. , Lai L. B.
Published: June 2015

The changes in the surface areas of copper and zinc oxide have been measured to evaluate the individual rates of sulfur coverage of each of these phases during catalyst exposure to sulfur‐containing gas. Zinc oxide surface areas have been measured by CO2 adsorption and copper surface areas by measurement of the nitrogen formed by exposure to nitrous oxide. The surface areas of both components decreased exponentially with increasing exposure time to the sulfur‐containing gas. The zinc oxide component is more sulfur‐resistant than copper. This is attributed to either kinetic limitation or the more stable surface sulfides of zinc.
The Special Nodal Structure of the Rydberg Orbitals
Authors: Hwang K. H. , Chang T. C.
Published: June 2015

A new scheme to account for the special nodal structure of the orbitals for Rydberg states is proposed. The scheme shows that in order to compute higher Rydberg states a new formula for choosing Gaussian exponentials is needed.
The Thermal Reaction of the Tris(μ‐Hydrido)‐Dodecacarbonyltrirhenium (o) Cluster with Triphenylphosphine and Triphenylphosphite
Authors: Liu Ling‐Kang , Lin S. C. , Cheng C. P.
Published: June 2015

The thermal reaction between the tris(μ‐hydrido)dodecacarbonyltrirhenium (o) cluster and triphenylphosphine or triphenylphosphite results in a trisubstituted rhenium cluster as the major product. The results of an X‐ray structural analysis of H3Re2(CO)9(PPh3) are: Mr=1597.57, Monoclinic, P21/n, a=15.598(1), b=9.530(2), c=41.685(3) Å, β=80.60(1)°, V=6113.(1) Å3, Z=4, Dc=1.736 g/cm3, CuKe, λ‐1.54056 Å, μ‐121.23 cm−1, F(000)=3059.17, room temperature, R=0.049 for 7361 reflections with I≥2.5σ(I). The molecule has a triangular Re2 core coordinated propellerwise by three PPh3 ligands in the molecular plane with virtual C3k symmetry.
Metal Chelates of Hydrazo‐Dimedon Dyes. Chelating Tendencies of 5,5‐Dimethylcyclohexane‐2‐(2‐Carboxyphenyl, and 3‐Carboxyphenyl)‐Hydrazono 1,3‐Dione (DC‐2‐CPHD and DC‐3‐CPHD)
Authors: Ramadan Atef A. T. , Abdel‐Moez Mohammed S. , Eid Mohammed F.
Published: June 2015

The consecutive stepwise formation constants of 1:1 and 1:2 chelate species formed by the interaction of DC‐2‐CPHD and DC‐3‐CPHD anions with tripositive lanthanon and divalent copper, nickel, cobalt, zinc, manganese, and cadmium cations were determined potentiometrically at ionic strengh of 0.1 (KNO3) and 30°C. The results indicate that two different coordination modes, one tridentate (DC‐2‐CPHD), and one bidentate (DC‐3‐CPHD), are in evidence.
Studies on the Constituents of Callicarpa Formosana Rolfe
Authors: Chen Rong‐Shiow , Lai Jeng‐Shiow , Wu Tian‐Shung
Published: June 2015

Two new naturally occurring flavonoids, 3,4′,5,7‐tetramethoxyflavone and 3,3′,4′,5,7‐pentamethoxyflavone, along with known compounds, 5‐hydroxy‐3,4′,7‐trimethoxyflavone, 5‐hydroxy‐3,3′,4,7‐tetramethoxyflavone, ursolic acid, 2α,3α‐dihydroxyurs‐12‐en‐28‐oic acid, phytosterols, and phytosteryl glucosides, have been isolated and characterized from the fresh leaves of Callicarpa formosana Rolfe.
The Oxidation of Isoquinoline Alkaloids with m‐Chloroperbenzoic Acid
Authors: Lu Sheng‐Teh , Wu Yang‐Chang , Leou Shiow‐Plaw
Published: June 2015

The physical properties of the N‐oxides prepared by the oxidation of tertiary isoquinoline alkaloids with m‐chloroperbenzoic acid are presented and are compared with those of their parent alkaloids.
A Convenient Method for the Preparation of Ellipticine
Authors: Zee Sheng‐Hsu , Su Hsiao‐Ping
Published: June 2015

A convenient method for the synthesis of ellipticine is reported. This synthesis is achieved by modifying the processes of Woodward and Sainsburg. The overall yield of this five step synthesis is 12 percent.
A Tin(II) Chloride Based Reduction Method for Multiple‐Metal Trace Analysis of Natural Waters
Authors: Jaffar M. , Ashraf M. , Tariq M.
Published: June 2015

Based on tin(II) chloride reduction in basic medium, a method of general use is proposed for the estimation of the whole gamut of multiple trace metals in natural waters by the atomic absorption method. The quantitative aspects of the method related to variables such as pH of the medium, amount of reductant and operational conditions are studied as a function of absorption sensitivity. The proposed method utilizes only a 50.0 ml portion of the water sample and yields above 90 per cent recoveries for various metals from a single aliquot of the sample. The reported data pertain to the estimation of silver, chromium, copper, iron, lead, mercury, manganese, magnesium, nickel and strontium, reported as averaged over replicate measurements at +‐2S confidence level. The precision in individual cases is found to be better than +1.8%.
Product Determination of Gaseous Radical Reactions Using Matrix Isolation‐Ftir Detection
Authors: Kuo Yu‐Ping , Ju Shan‐Sfian , Lee Yuan‐Pern
Published: June 2015

The matrix isolation technique with Fourier transform infrared detection has been applied to determine the products of gaseous radical reactions. The gas phase reactions were carried out in a discharge flow system and about 1% of the gas mixture was deposited onto a low temperature target through a pinhole. A differential pumping scheme was employed to maintain the pressure of the cryosystem below 10−5 torr while that of the flow system was kept at about 2 torr.

Species including HO2 (from the H+O2 reaction), ClO2 (from the Cl+O2 reaction) and ClO (from the Cl+O3 reaction) have been produced in the gas phase and were successfully trapped in matrices and detected with an FTIR spectrometer. In addition, both HCl and HOCl have been detected as the reaction products from the gaseous ClO+HO3 reaction. The production of HCl from the ClO+HO2 reaction may have a significant impact on catalytic ozone destruction in the atmosphere.
A Novel Spectrometer for Simultaneous Chemical Analyses
Authors: Huang Tzer‐Hsiang
Published: June 2015

A novel spectrometer incorporating a multichannel detector for simultaneous multi‐element atomic emission spectrometry (AES) is described. The spectrometer consists of a multi‐bandpass optical filter comprised of a concave and a fiat grating in substractive mode, and a high resolution stage which utilizes an echelle grating and an one inch 1024‐channel photodiode array as the detector. Characterization with respect to the spectral resolution, the spectral response, and the capability of multi‐element detection demonstrated the systems's potential for simultaneous chemical analyses without moving any mechanical parts. To adjust the system for the analyses of different sets of elements, the corresponding mask is simply placed in position.
Kinetic Study of the Bromine‐Catalyzed Isomerization of Methyl‐ and Chloro‐Maleic Acids in Aqueous Ce(IV)‐Br ‐H2SO4 Medium
Authors: Jwo Jing‐Jer , Huang Che‐Yuan , Chang Eng‐Fen , Wu Ru Rong
Published: June 2015

Methylmaleic (citraconic, CTA) acid and methylfumaric (measaconic, MSA) acid in aqueous sulfuric acid solution undergo bromine‐catalyzed reversible cis‐trans isomerization in the presence of ceric and bromide ions. The positional isomerization of CTA or MSA to itaconic acid (ITA) is not observed. The method of high performance liquid chromatography (HPLC) was applied to study the kinetics of this catalyzed isomerization. The major catalytic species is best expressed as the Br−2 · radical anion. Under suitable catalytic conditions, there is a tendency for the [MSA]/[CTA] ratio to reach an equilibrium value of 4.10 at 25° for the CTA+Br−2 · ⇄ MSA+Br−2 · reaction. Chloromaleic (CMA) and chlorofumaric (CFA) acids undergo similar isomerization with an equilibrium [CFA]/[CMA] ratio of 10.3 at 25°. The isomerization of maleic acid (MA) to fumaric acid (FA) is essentially irreversible with 50 as the lower limit of the equilibrium [FA]/[MA] ratio. The substituent has an important effect on the reversibility of this catalyzed isomerization of butenedicarboxylic acids. The thermodynamic parameters ΔH° and ΔS° at 25° for the CTA+Br−2 · ⇄ MSA+Br−2 · reaction were found to be −5.1±0.7 kj/mol and −6.0±3.3 J/mol K, respectively. The present method gives a plausible way to measure the differences in enthalpy and entropy between the trans‐ and cis‐isomers of butenedicarboxylic acids (CRCO2H=CR'CO2H) in aqueous solution.
Organotransition‐Metal Complexes of Multidentates 2. Synthesis and Allyl Bromination of N, N‐Bis(3,5‐Dimethylpyrazol‐1‐YL)Methane Derivatives of the Group VI Metal Carbonyls
Authors: Shiu Kom‐Bei , Chang Cho‐Jin
Published: June 2015

N,N‐Bis(3,5‐dimethylpyrazol‐1‐yl)methane (H2CPz'2) reacts with the hexacarbonyls of chromium, molybdenum, and tungsten to give cis‐(H2CPz'2)M(CO)4 derivatives with M=Cr, Mo, W. The direct allyl bromination of these complexes is also investigated and only the molybdenum complex is converted into (H2CPz'2)Mo(CO)2(π‐C3H3)(Br).
Syntheses and Electrical Conductivities of 9‐Fluorenone‐Iodine‐Alkali Iodide Complexes
Authors: Yang Hsin‐Sheng , Wang Chi‐Ming
Published: June 2015

A new series of 9‐fluorenone‐iodine‐alkali iodide complexes (FIMI, M=Na, K, Rb or Cs) has been prepared from chloroform. These complexes yield needle‐like crystals with metallic luster along the needle axis. The longitudinal dc conductivities at room temperature are in the order of 10−3 to 10−5 S cm−1. They all have semiconductive properties with activation energies of about 0.4 to 0.7 eV. A significant result is that the conductivity varies systematically with the cation size. A decrease in the cation size results in an increase in the conductivity. Resonance Raman spectra show that iodine is present as a linear chain of symmetric I−3 units in these complexes. Infrared spectra of these complexes are discussed with an attempt to estimate the interaction between the alkali cation and the carbonyl group of 9‐fluorenone.
Cycloaddition of Trichloronitrosomethane to Conjugated Dienes
Authors: Lin Cheng‐Tung , Chen Jyun‐Hung
Published: June 2015

Addition of trichloronitrosomethane to 1,3‐cycloalkadienes gives [2+4] cpclo‐adducts. However, reactions with acyclic 1,3‐butadienes afford unstable cycloadducts which hydrolyze in water‐ether solution to produce N‐chloroformyl‐3,6‐dihydro‐l, 2‐oxazines. The later compounds are reduced to N‐methyl or converted to N‐methoxylcarbonyl derivatives in high yields.
Determination of Polycyclic Aromatic Hydrocarbons in Airborne Particulate by High Performance Liquid Chromatography
Authors: Wang P. , Yen V. O. , Tsai H. T. , Cheng James C.
Published: June 2015

This paper presents a trisolvent ultrasonic extraction and HPLC analysis method for the determination of 11 polycyclic aromatic hydrocarbons in air particulate collected on an air filter by a commercial high volume air sampler. A reverse phase column, Vydac 201 TP, and a gradient mobile phase, acetonitrile/water, were used. The 11 PAHs, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a, h]anthracene, benzo[ghi]perylene, indeno[1,2,3‐cd]pyrene, and coronene were completely resolved under experimental conditions. All the PAHs except coronene were monitored by fluorescence with λex=270 nm, λem>389 nm. Coronene was monitored by UV with λ=300 nm. The methodology was evaluated by spiking SRM 1649 with a PAH standard and then going through different extraction procedures and analyzing the PAH concentrations without clean‐up. An external standard method was used for quantitation. The recovery yields for fluoranthene, benz[a]anthracene, benzo[a]pyrene, benzo[ghi]perylene and indeno[l,2,3‐cd]pyrene were above 90%. The detection limits of PAH with fluorescence at λex=270 nm, λem>389 nm ranged from 5.7 pg to 69.5 pg.
Synthesis and Biological Activity of Pyrazolo(3,4‐D)‐8‐Amino‐1‐Azaquinoxaline Dimethine Cyanine Dyes
Authors: El‐Maghraby M. A. , Khalafallah A. K. , Hassan M. E. , Soleiman H. A.
Published: June 2015

New asymmetrical dimethine cyanines (Va–f) and their bases (VIa,b), incorporating pyrazolo(3,4‐d)‐8‐amino‐1‐azaquinoxaline moiety or its ethiodide, have been prepared and tested for their antibacterial and fungicidal activities.
Synthesis of Novel 1,3,5‐Trisubstituted Pyrazoles as Potential Hypoglycemic Agents
Authors: Mokhtar Hassan M. , El‐Khawass S. M.
Published: June 2015

A novel series of 1,3,5‐trisubstituted pyrazoles was synthesized. Thus, ethyl 2,4‐dioxo‐6‐phenylhex‐5‐enoate (I) was condensed with phenylhydrazine to afford 3‐ethoxycarbonyl‐1‐phenyl‐5‐styrylpyrazole (II) which on fusion with hydrazine hydrate gave the corresponding acid hydrazide (III). Reaction of III with the appropriate isothiocyanate yielded the disubstituted thiosemicarbazides (IVa‐e) which were cyclized into thiotriazoles (Va‐e), thiadiazoles (Vla‐e) and oxadiazoles (VIIa‐). The structure of the newly synthesized compounds was elucidated by elemental analyses, IR and 1H NMR spectra.
Computer Control of a Multichannel Scaler and Quadrupole Mass Filter with an IBM pc
Authors: Yeh T. S. , Su T.‐M. , Lin H. C.
Published: June 2015

An interface for a Canberra Model 7880 fast multiscaler and an Extranuclear quadrupole controller with an IBM PC is described. With the interface and using only a few keystrokes one can choose to take either a mass spectrum or a time‐of‐flight spectrum of a given mass. The limitations and the minor modifications of the original hardware are also discussed.
Determination of Trace Metal Species in the Suspended Matter of Riverine and Estuarine Waters
Authors: Hung Jia‐Jang
Published: June 2015

A sequential extraction technique was used to determine the chemical species of six metals (Fe, Mn, Cu, Zn, Pb, Cd) in suspended matter of the Kaoping and Tsengwen river basins. The samples were taken to cover the fresh and marine characteristics. The precision of the species determination was estimated by the relative difference between the concentration of total metal and the sum concentation of the five species. The accuracy for the measurement of total metal was examined from the recovery of metal spiking. The accuracy of the total determination is better than 94% and the precision of speciation is greater than 90%.

Most of the studied metals were found in the Fe‐Mn oxides and residual fractions except that Cd, Zn and Cu have significant amounts in the exchangeable, carbonate, and organic matter phases, respectively. Species other than residual fraction are generally considered as potentially available for biota in aquatic systems, and in most cases, metal pollution could be reflected from the variation of fraction distributions.
Persulfate Oxidation and Diphenylcarbazide Photometric Determination of Chromium in Super Alloys
Authors: Tsai Suh‐Jen J. , Chen Shew‐Jiuan , Hwang Huey
Published: June 2015

The quantitative analysis of Cr in super alloys with the presence of a wide variety of elements, Al, B, C, Co, Cu, Hf, Fe, Mn, Mo, Ni, Nb, P, Si, S, Ti, Ta, W, Zr; and trace amounts (a few ppm) of Pb, Se, Bi, Tl and Te has been studied. Persulfate oxidation and diphenylcarbazide photometric method were studied with the purpose of developing a relatively fast and reliable measurement for Cr by wet chemical analysis. The results indicate that the latter is supperior to the former in practical view.

In the photometric method, solid sample (0.1g alloys) when treated with HClO4 and H2SO4 took ca. 72 hrs. for complete dissolution. When treated with HCl followed by HNO3, 0.1 g alloys were completely dissolved within 1&1/2; hours. The best experimental conditions for diphenylcarbazide photometric determination of Cr was thus established. Photometric determination of Cr complexes was made at 540 nm.
A Study of the Synthesis of Siloxyquinolines
Authors: Yang M.H. , Liu C.Y. , Wu T.Y. , Guo C.Y. , Chen H.M. , Liu S.L.
Published: June 2015

Sixteen new 8‐siloxyquinolines and 5‐chloro‐8‐siloxyquinolines were synthesized, Structures of all new compounds were determined by IR, NMR, MASS, and elemental analysis. The factors affecting the silylation reactions are disccussed. From the UV absorption pattern, it is shown that the (p→d)π interaction of the Si‐O bond does exist.
Flavonoids from Hypericum Nagasawai Hayata
Authors: Chen Ming‐Tyan , Wan Chao‐Hsiung , Chen Chiu‐Ming , Kuoh Chang‐Sheng
Published: June 2015

Five flavonoids, quercetin, quercitrin, hyperin, orientin, and kaempferol, were isolated from Hypericum nagasawai Hayata. The dominant component is quercitrin.
Acidity and Catalytic Activity of Phosphoric Acid Modified Titanium Oxide Surface
Authors: Cheng Soofin , Lee Jin‐Chur
Published: June 2015

By refluxing the anatase form of TiO2 powder in phosphoric acid, the surface acidity was observed to increase. The amount of acid was determined by n‐butylamine titration in n‐heptane media, and was found to be proportional to the reflux period in phosphoric acid. XRD patterns and IR spectra revealed that the products contained a mixture of the anatase form of TiO2 and titanium phosphate phases. Based on the calculated acid density on the surface, part of the titrant, n‐butylamine penetrated into the titanium phosphate layers. Further investigations using TGA, FT‐IR and TEM techniques along with surface area measurements indicated that the titanium phosphate phase was coated over the TiO2 phase. The surface acidity of the phosphoric acid treated anatase increased due to the substitution of Ti‐OH groups by phosphate groups. Nevertheless, the chemical properties of the resultant surfaces were found to be influenced by the internal anatase phase. The kinetic data on the 2‐propanol dehydration reaction, where the activation energies were found to decrease gradually with an increase in phosphate content, also support these conclusion.
Papain Catalyzed Synthesis of Aspartyl Dipeptides
Authors: Chen Shui‐Tein , Li Kuo‐Fang , Wang Kung‐Tsung
Published: June 2015

Procedures have been developed for the preparation of aspartyl containing dipeptides P‐L‐Asp‐AA2 (P=Boc, Cbz and Moz; AA2=Phe‐R or Ala‐R; R=OH, OBzl and OTMB) using papain as a catalyst. The pH dependent of esterase activity by papain catalyzed hydrolysis have been studied. The papain catalyzing reaction can be reacted in aqueous solution, buffer solution or cosolvent system in a thermodynamically controlled approach. A procedure for the conversion of the artificial sweetner precursor P‐Asp‐Phe‐OH to the aspartame is studied also.
Solution Behavior of Aromatic Dipeptides. II. The Mechanistic Aspect of the Coupling Reaction and Conformation Study of Diastereomers
Authors: Chu Yen‐Ho , Chen Shui‐Tein , Wang Kung‐Tsung
Published: June 2015

A systematic racemization study of the coupling of Z‐Phe with Phe‐OBzl has been carried in order to determine the optimal conditions. It is found that the L,D diastereomer is the favored product in the coupling of Z‐L‐Phe with D,L‐Phe‐OBzl. A possible mechanism is proposed and elucidated by NMR studies.
Syntheses of Bissydnone Derivatives and Studies of Their Biological Activities
Authors: Tien Hsien‐Ju , Lai Long‐Li , Lee Yao‐Kueng , Chuang Che‐Ping , Yeh Mou‐Yung , Wu Tian‐Shung
Published: June 2015

A new method to prepare 3,3′‐ethylenebissydnone (40%), 3,3′‐tetramethylenebissydnone (37%) and 3,3′‐hexamethylenebissydnone (43%) from the corresponding alkylene diamine with paraformaldehyde and potassium cyanide were investigated.

Some new bissydone: −3,3′‐trimethylenebissydnone (6%), 3,3′‐(4,4′‐diphenyl)bissydnonylmethane (9%) and 3,3′‐(4,4′‐diphenyi)bissydnonyl ether (28%) were synthesized from the corresponding diamine, paraformaldehyde, sodium bisulfite and potassium cyanide.

Biological test of 3,3′‐(4,4′‐diphenyl)bissydnonylmethane shows significant response for coronary dilgtion test, inhibition of collagen induced platelet aggregation and moderate carditropic response. 3,3′‐(4,4′‐Diphenyl)bissydnonyl ether also shows inhibition of collagen induced platelet aggregation and moderate carditropic response.
Selectivity and Stereospecificity in Synthetic Applications of Radical Reactions
Authors: Barton Derek H. R. , Ozbalik Nubar
Published: June 2015

The advantages of radical reactions for Organic Synthesis are summarised. Based on the idea of the disciplined radical, it is now possible to design radical reactions which afford a good yield of a single desired product. The system needs to contain a disciplinary group. In the case of radical reactions involving tin hydrides, it is the weak tin‐hydrogen bond that is the disciplinary group. For the esters of thiohydroxamic acids, the disciplinary group is the thione function. Examples are given. Recent work has involved the design of stereospecific radical reactions. The hindrance around one chiral center is used to control the formation of the second. The ketal of (+)‐ (2R, 3R) tartaric acid gives excellent stereospecificity (≌24:1) with retention of configuration.
The Synthesis of (±)‐α‐Vetispirene Via the Dieckmann Condensation of Ethyl 4‐(2,6‐Dimethyl‐1‐Carbethoxycyclohex‐2‐Enyl)‐Butyrate
Authors: Zee Sheng‐Hsu , Chou Shan‐Yen
Published: June 2015

A new process for the synthesis of (±)‐α‐vetispirene (1) starting from 2,4‐dimethyl‐3‐carbethaxycyclohexene (2) is described. The key steps include the stereoselective alkylation of 2 with ethyl 4‐bromo‐butyrate to yield ethyl 4‐(2,6‐dimethyl‐1‐carbethoxycyctohex‐2‐enyl)‐bytyrate (3) and spiroannulation of 3 by Dieckmann condensation to give 2‐carbethoxy‐6,10‐dimethyl spiro[4,5] deca‐6‐en‐1‐one (4).
Some Taxane Derivatives from the Heartwood of Taxus Mairei
Authors: Yeh Ming‐Kuo , Wang Jiunn‐Shyan , Liu Lu‐Peng , Chen Fa‐Ching
Published: June 2015

Five Taxane derivatives were isolated from Taxus mairei. Their structures were determined by spectroscopic methods and their physical constants were identical with the literature values. These are Taxa‐4(20), 11‐diene‐2α, 5α, 7β‐tetrol‐5α, 7β, 10β‐triacetate‐2α‐α‐methylbutyrate(I); Taxa‐4(20), 11‐diene‐2α, 5α, 9α, 10β, 13β‐pentol‐2α, 9α, 10β, 13α‐tetraacetate‐5α‐cinnamate(II);Taxa‐4(20), 11‐diene‐5α, 7β, 9α, 10β, 13α‐pentol‐pentaacetate(III); 7β‐acetate‐O‐taxinine A(IV), 1β‐hydroxy‐baccatin‐I(V).
The Crystal Structure of Binuclear Metal Complexes of 7‐Azaindole: Cu2 (CH3CO2)2 (C7H5N2)2(C7H6N2)2 AND Ni2(C7H5N2)4.2DMF
Authors: Peng Shie‐Ming , Lai Chien‐Hsien
Published: June 2015

The crystal and molecular structures have been determined by single‐crystal X‐ray methods for the binuclear metal ions (II) complexes of 7‐azaindole (1H‐pyrrolo [2,3‐b] pyridine, C7H6N2 denoted by HL), Cu2(CH3CO2)2.·L2(HL)2 and Ni2L4.2DMF. The dark green crystal of Cu2(CH3CO2)2L2(HL)2 was found to crystallize in the monoclinic space group P 21/n with a = 9.566(2), b = 12.752(2), c = 12.852(4) Å, β = 99.23(3)0, V = 1547 Å, Z = 2, the final R = 0.062 and Rw = 0.053 for 1488 observations from 2722 unique reflections. The Cu‐Cu distance is 2.747(2), Cu‐N (L−, bridge) is 1.966(7), Cu‐N (HL, axial) is 2.229(8), and Cu‐O is 2.031(6)Å. The red crystal of Ni2L4.2DMF was was found to crystallize in the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm P \bar 1} $$\end{document} with a = 8.907(5), b = 9.462(2), c = 10.217(2) Å, α = 90.48(2), β = 91.09(3), γ = 110.69(3)0, V =805 Å3, Z = 1, the final R = 0.063 and Rw = 0.069 for 1489 observations from 2834 unique reflections. The Ni‐Ni distance is 2.594(2), Ni‐N is 1.905(7) Å. These two molecules lie on crystllographic inversion centers and exhibit ligand disorder.
In‐Situ Electron Spin Resonance Studies of Polyaniline
Authors: Yang Sze‐Ming , Un Tsair‐Sheng
Published: June 2015

In‐situ electron spin resonance studies of polyaniline at various applied potentials in media of pH 0.49, 2.09, 3.96, anf 9 are reported. The g factor of the esr signal is 2.0036 and does not vary with the applied potential. The peak to peak linewidth decreases to a minimum in a potential range which depends on the pH of the medium. On the other hand, the spin density increases to a maximum in the same potential range. The pH‐potential range where the highly conductive form exists, matches very well the range of narrow linewidth and high spin density of the esr signal. The conductive form of polyaniline consists of highly mobile radical cations or polarons.
Mass Spectra of 2‐ and 6‐Substituted‐3‐Pyrones: Competition Between “RETRO‐DIELS‐ALDER” Fragmentation and Substituent Loss
Authors: Lin Shaw‐Tao , Kuo Yueh‐Hsing , Lee Ming‐Shi
Published: June 2015

The mass spectra of a series of 6‐hydroxy‐3‐pyrones and their derivatives showed a marked dependence upon the nature of the substituent. The “retro‐Diels‐Alder” reaction is the primary decomposition observed for the parent compounds, while the α‐cleavage (substituent loss) competes with the “retro‐Diels‐Alder” reaction for their derivatives. An interpretation of this difference based on the charge location and the thermochemical data is proposed.
Determination of Lead in Heavy Oil by Flow Injection‐Flame Atomic Absorption Spectrometry
Authors: Hwang Jon‐Mau
Published: June 2015

A simple on‐line flow injection analysis pre‐concentration technique has been developed. The flow injection system consisted of a 4‐channel peristaltic pump, two 6‐way rotary injection valves containing a microcolumn of Chelex‐100 resin, and a flame atomic absorption spectrometer, allowing the determination of lead at a concentration as low as ppb. The degree of pre‐concentration depended on the injected sample volume. Lead contained in NBS 1634b and other heavy oil samples was determined using the system. Samples were ashed directly in a furnace at 550°C for two hours, dissolved with perchloric acid and then injected into the system. The sampling frequency also depended on the injected sample volume.
The 1,3‐Dipolar Cycloadditions of 3‐Arylsydnone‐4‐Carbonitrile Oxides with Alkenes
Authors: Yeh Mou‐Yung , Chu Wai‐Cheung
Published: June 2015

3‐Arylsydnone‐4‐carbonitrile oxides may undergo 1,3‐dipolar cycloadditions with alkenes to produce the corresponding 3‐aryl‐4‐(5‐substituted‐isoxazolin‐3‐yl)sydnones. The direct reaction of 3‐arylsydone‐4‐carbohydroximic acid chlorides with alkenes may also give the same products, and with higher yield.
The Inhibition of the Dissolution of Aluminium in Sodium Hydroxide by Some Organic Phosphorus Compounds
Authors: Mourad M.Y. , Ibrahim E.H. , Al‐Thani M.J. , Nieroukh S.A.
Published: June 2015

The inhibition of the corrosion of aluminium in 1M sodium hydroxide solution by some cyclodiphosphazane derivatives has been studied using hydrogen evolution technique. The results indicate that the additives reduce the corrosion rate. The inhibitory character of these compounds depends upon the concentration of the inhibitor, as well as on its chemical composition.
Spectrophotometric Determination of Titanium in Super Alloys with Diantipyrylmethane and Tiron
Authors: Tsai Suh‐Jen J. , Hwang Huey
Published: June 2015

Diantipyrylmethane and tiron spectrophotometric determinations of Ti in the super alloys, Inconel 718 and Inconel 600, have been studied thoroughly. Both reagents formed stable yellow complexes with Ti(IV) in acidic medium. The possible interference from Ni, Fe and Cr was examined. Interference from Fe(III) was eliminated by the reduction of Fe(III) to Fe(II). Cr was removed as chromyl chloride which led to a dramatic improvement in the analytical results for Ti by the tiron photometric method. However, the removal of Cr was not necessary when the diantipyrylmethane method was employed. Consequently, lengthy manipulation of super alloys was required for the tiron determination. These two spectrophotometric methods are compared in terms of simplicity, reproducibility and accuracy.
Dissociation Kinetics of Aqua[(1SR, 4RS, 7RS, 8SR, 11RS, 14RS)‐5,5,7,12,12,14‐Hexamethyl‐1,4,8,11‐Tetraazacyclotetradecane]Copper(II) (Red) Cation in Strongly Acidic, Aqueous Media
Authors: Chen Lien‐Huei , Chung Chung‐Sun
Published: June 2015

In order to investigate the effect of structure variation upon complex dissociation rate constants, the kinetics of the dissociation of (C·rac·5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane)copper(II) (red) cation has been examined spectrophotometrically at 25.0°C in 0.1–5.0 M HNO3. The cleavage of the second copper‐nitrogen bond is proposed as the rate‐determining step for this reaction. The possible pathways for the cleavages of the copper‐nitrogen bonds, the factors influencing the dissociation rates, and the factors affecting the relative importance of each of these possible pathways are considered.
Correlation of Nucleophilic Reactivity, Dissociation Constant and Proton Magnetic Resonance of Some 2‐Substituted Naphthols
Authors: Kharaba Mohamed A.H. , Nassar Ahmed M.G. , Youssef Abdel‐Hamid A. , El‐Banna Mohamed M.
Published: June 2015

The rates of reaction of a series of substituted naphthoxides with 1‐chloro‐2,4‐dinitrobenzene in methanol, and the pKa values of the naphthols in 50% methanol have been measured. A linear free energy relationship applies well to these reactions. The rate constants are correlated with the pKa values of the corresponding naphthols via the Brönsted equation giving a β values of 0.94. A linear correlation between ΔH‡ and ΔS‡ is indicative of single mechanism. The nmr spectra of the substituted naphthols have been measured in DMSO·d6.
Oxidation of Benzylic Methyl Groups by Supported MnO2/Al2O3 Oxidant
Authors: Liu Lilian Kao , Lee Yu‐Hsuan , Leu Lee‐Shan
Published: June 2015

An investigation of benzylic oxidations with manganese dioxide supported on neutral alumina has been carried out. Isolation of intermediated products, which is possible in some cases, gives strong support for the reaction mechanism proposed. With 2,6‐di‐tert‐butyl‐4‐methylphenol, 4,4′‐dihydroxy‐3,5,3′,5′‐tetra‐tert‐butyldiphenylmethane,2,6‐di‐tert‐butylphenol and 4‐methyl‐phenol, selective formation of essentially a single product in excellent yield was obtained.
Identification of Polycyclic Aromatic Hydrocarbons Produced During Combustion of Fuel With Carbon Disulfide as Additive
Authors: Sye Wen‐Fa , Hwang Shi‐Shyan
Published: June 2015

That polystyrene and benzene as additives to gasoline increase the amount of polycyclic aromatic hydrocarbons (PAHs) has been studied previously in our laboratory. This paper describes the use of carbon disulfide as the solvent instead of benzene brings a marked reduction of the formation of polycyclic aromatic hydrocarbons.
Organosilanes in Free Radical Cyclization Reactions (II)
Authors: Chuang Che‐Ping , Ngoi Tak Ho Johnny
Published: June 2015

Free radical cyclization reactions could he achieved by bis(tributyltin)oxide‐organosilane system.
Polarographic Determination of the Formation Constants of the Mixed Ligand Complexes of Cd(II) and Pb(II) with Thiosulphate and Halide Ions
Authors: Ghandour M.A. , Hassan R.M. , Ibrahim S.A. , Abo El‐Maaly N.
Published: June 2015

The mixed ligand complexes of Cd(II) and Pb(II) with thiosulphate as a primary ligand and chloride, bromide of iodide (individually) as a secondary ligand have been polarographically, investigated at 30°C and at a constant ionic strength of μ = 1.0 M (NaClO4). Two mixed ligand complexes were formed with the Cd(II) ion: log β12 = 4.77, 5.30 and 6.78 for the chloride, bromide and iodide ions, respectively; and log β21 = 5.36, 5.04 and 6.22 for the same ions. For the Pb(II)‐Ts‐Cl system, only one mixed ligand complex was formed with a log stability constant log β21 =4.35. For the Pb(II)‐Ts‐Br system, three mixed ligand complexes are obtained with log β11 = 3.63, log β12 = 4.51 and log β21 = 4.85.
Triazoles and Fused Triazoles II: Synthesis of Certain Substituted s‐Triazoles, s‐Triazolo[3,4‐b]‐1,3,4‐Thiadiazoles and s‐Triazolo [3,4‐b]‐1, 3,4‐Thiadiazines
Authors: El‐Emam A. A. , Moustafa M. A. , Bayomi S. M. , El‐Ashmawy M. B.
Published: June 2015

The synthesis of a certain series of s‐triazoles and fused s‐triazoles namely: 3‐(3,4‐dimethoxyphenyl)‐4‐arylideneamino‐5‐mercapto‐s‐triazoles 3.8, 3‐(3,4‐dimethoxyphenyl)‐6‐substituted‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles 11‐17, 3‐(3,4‐dimethoxyphenyl)‐6‐substituted thio‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles 19, 20 and 3‐(3,4‐dimethoxyphenyl)‐6‐substituted‐7H‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazines 21, 22, is described.
Chelating Resins in Analytical Chemistry
Authors: Liu Chuen‐Ying
Published: June 2015

Chelating resins, the polymeric complexing compounds, are specific and selective ion exchange resins. A chelating ion exchange resin consists essentially of two components, i.e. a chelating group and a polymeric matrix. The properties of both components affect the selectivity of the synthesized resin. Methods used to synthesize chelating resins are reviewed. The analytical and physical techniques used to characterize the dissociation constant, metal capacity and distribution coefficient of the newly synthesized resin as well as the coordination site, the composition and the formation constant of the metal‐resin complexes are discussed. Chelating resins could be used in various forms. Some important features of the analytical application of chelating resins, including selective concentration and separation both in inorganic analysis and organic analysis are also discussed. The techniques by which sorption or separation with the help of chelating resins achieved can be static, dynamic, or chromatographic. After sorptive concentration or separation, the elements can be determined either directly in the sorbent phase, its decomposition residue, the eluent solution after desorption, or the effluent after the solution has been passed through the sorbent. Various objects such as natural waters, geological objects, industrial materials, foodstuffs, coal, fuel oil. shale oil, transuranium elements and biological materials could be analyzed with the help of chelating resins.
Rapid Protein Hydrolysis by Microwave Irradiation Using Heat‐Resistant Teflon‐Pyrex Tubes
Authors: Chiou Shyh‐Horng
Published: June 2015

A rapid peptide‐bond hydrolysis by means of microwave irradiation is introduced for the facile preparation of protein hydrolysates used for amino acid analysis. The optimal hydrolysis condition has been determined using several enzymes with known amino acid compositions. The effects of hydrolysis time on the recovery of various labile and hydrophobic amino acids are also exemplified in the microwave heating of standard amino acids. The method has been applied to the complete amino acid analysis with a single nonvolatile solvent of methanesulfonic acid with good recovery of tryptophan and half‐cystine. It provides a radical expedition of protein and peptide hydrolysis via commercial microwave ovens and specially‐designed Teflon‐Pyrex tubes, circumventing the tedious procedures using vacuum‐sealed pyrex lubes heating at 110°C for more than 24 h. This novel type of microwave chemistry associated with rapid peptide‐bond cleavage is of great potential in the automation of the complete process of amino acid analysis starting from the preparation of protein hydrolysates.
Two Hypusine‐Containing Proteins Identified by Metabolic Labeling in Chick Embryo Fibroblasts
Authors: Dou Qing‐Ping , Chen Kuang‐Yu
Published: June 2015

Incubation of various cultured mammalian cells under growth‐stimulatory condition with [3H]putrescine or [3H]spermidine results in a labeling of an 18, 000‐dalton protein (Cell, 1982, 29, 791; BBA, 1983, 756, 395). The labeling is due to post‐translational conversion of a lysine residue to hypusine residue, using the butylamino moiety derived from spermidine. In order to search for an abundant source for the purification of this protein, we have examined possible existence of this hypusine‐containing 18, 000‐dalton protein (hyp‐18k) in chick embryos by the metabolic labeling method. Metabolic labeling of chick embryo fibroblasts, prepared from the Day 11 embryos, by [3H]putrescine resulted in two prominently labeled protein bands. Mr=18, 000 and 20, 000, as shown by sodiun dodecyl sulfate‐polyacrylamide gel electrophoresis and fluorography. Two‐dimensional gel analysis indicated that the labeled 20, 000‐dalton protein had a pI value of 5.5 and the labeled 18, 000‐dalton protein exhibited isoform structures with pI values ranging from 4.6 to 5.1. Peptide map analysis showed that these two proteins are similar but not identical. Both labeled proteins contained radioactive hypusine residue and exhibited strong binding to Cibacron Blue dye. The time course of the metabolic labeling of these two proteins, however, differed dramatically. The labeling of the 18, 000‐dalton protein appeared early and continued to increase 24 h after serum stimulation. In contrast, the labeling of the 20, 000‐dalton protein became prominent only after much longer period of incubation.
Studies on Angiotensin‐Converting Enzyme Inhibitors: Protease Catalyzed Resolution of Aryl 3‐Mercapto‐2‐Methylpropionic Ester
Authors: Chen Shui‐Tein , Wong Chi‐Huey
Published: June 2015

Optically active 3‐benzylthio‐2‐methylpropionic acid and 3‐benzoylthio‐2‐methylpropionic acid have been prepared via protease‐catalyzed hydrolysis of their corresponding ester and thioester. Subtilisin catalyzed the hydrolysis of the thioester of methyl 3‐benzoylthio‐2‐methylpropionate twice as fast as that of the methyl ester derivative. The stability of the enzyme in organic cosolvents was studied. Immobilization of subtilisin on the solid support XAD‐8 improved the stability of the enzyme. A practical preparative resolution of the title compound is reported.
Enantioselective Syntheses of Plate Let‐Activating Factor and a Phospholipase A2 Inhibitor from Chiral Synthons Prepared Enzymatically
Authors: Wanc Yi‐Fong , Wong Chi‐Huey
Published: June 2015

Efficient procedures have been developed for the stereospecific syntheses of platelet‐activating factor and its 2‐acetamido analog, an inhibitor of phospholipase A2. (S)‐3‐O‐Actyl‐2‐O‐benzylglycerol and (S)‐2‐N‐benzyloxycarbonyl‐3‐O‐valerylserinol are used as starting materials for the syntheses. Both chiral synthons are prepared from lipase‐catalyzed acetylation and hydrolysis of the corresponding meso precursors.
Synthesis of [1, 2‐13C2]‐S‐Lysine Hydrochloride
Authors: Yuan Sun‐Shine , Ajami Alfred M.
Published: June 2015

Cobalt catalyzed hydroformylation‐amidocarbonylation of 3‐cyanopropene by carbon‐13 monoxide and acetamide produced a [1,2‐13C2]‐labelled mixture of 5‐cyano‐2‐acetamidopentanoic acid and 4‐cyano‐3‐methyl‐2‐acetamidobutanoic acid (n to b ratio of 7 to 3. 55% yield). Acylase I resolution of this mixture gave the free S‐amino acids which could be separated by crystallization. Catalytic reduction of the cyano group of the straight chain acid furnished [1,2‐13C2] ‐S‐lysine. HCl.
A Study of the Constituents of the Wood of Armand Pine
Authors: Fang Jim‐Min , Su Wen‐Chiung , Liang Wen‐Chuan , Cheng Yu‐Shia
Published: June 2015

Long‐chain esters, 4‐hydroxy‐3‐methoxycinnamate esters, cinnamaldehyde, two diterpenoid acids, seven flavonoids, seven stilbenes and a novel lignan were isolated from the heartwood of Pinus armandii Franchet var. mastersiana Hayata.
Synthesis and Mossbauer Spectra Studies of Mono‐Binuclear Iron(III) Complexes with a Quinquedentate Ligand Derived from Saucylaldehyeds and Diethylenetriamine
Authors: Sheu Jinn‐Fwu , Wei Ho‐Hsiang
Published: June 2015

Mono‐ and bi‐nuclear iron(III) complexes of general formula [FeXL] and [LFe‐Y‐FeL](Bph4)2 have been prepared, and their spin state of iron atom in the complexes has been studied by means of the temperature dependence of the Mössbauer spectra, electronic spectra and magnetic measurement, where X is a mono‐ dentate ligand such as Cl‐, NCS‐, NCO‐, N3‐, pyridine and L denotes a quinquedentate Schiff base derived from salicylaldehyde and diethylenetriamine, and Y denotes bridged ligand such as pyrazine(pyr), 4,4′‐bipyridine(bpy) and 4,4′‐vinylenebipyridine(vibpy). On the basis of the Mössbauer and magnetic data, it was concluded that these complexes were all the high‐spin (S = 5/2) slate. The effect of gamma ray irradiation for these complexes has been discussed.
Characterization and Activity of Iron‐Manganese Catalysts for Carbon Monoxide Hydrogenation
Authors: Kuei Chi‐Kung , Chian Wan‐Lan , Chen Wen‐Shing , Lee Min‐Dar
Published: June 2015

Studies on the structural changes and catalytic behavior of iron‐manganese catalysts for CO hydrogenation were conducted using Mossbauer spectroscopy, X‐ray diffraction, temperature programmed reduction and kinetic measurements. It was observed that the reduction of the mixed oxide catalyst precursors proceeds via the formation of Fe3‐xMnxO4,Mn3‐xFexO4 mixed spinel and Fe1‐zMn2O mixed oxide to α‐iron and MnO. After use for CO hydrogenation, catalysts are oxidized as well as carburized. The Mn3‐yFeyO4 mixed spinel and Fe1‐2MnzO mixed oxide are the most powerful phases for olefin production. The highest attainable 2–4 low carbon olefin selectivity is 41% with an 86% conversion level. Higher manganese content or lower reduction temperatures may change the carbide formed from χ‐Fe5C2 to the more unstable ϵ′‐Fe22C. Carbide formation is greatly dependent on manganese content and activation procedure used.
The McConnell Relation of Newly Modified Indo‐Mo Method
Authors: Chen Cheng
Published: June 2015

The s‐p separation model INDO‐MO method has been introduced and developed for open and closed shell problems1–3 In order to demonstrate the importance of σ–π interaction between 2pπ of carbon and 1s of hydrogen in this newly modified MO1 we apply “McConnell Relation”4–7 to a linear correlation calculation 122 data points of 1H hyperfine coupling constant in the cases of free radicals and ions with π type SOMO (singly occupied molecular orbital). The calculated McConnell constant, Q, is equal to −24.6 gauss. The standard deviation and correlation coefficient of this statistical treatment are 1.011 gauss and 0.980, respectively. Most of the results in this calculation are reasonable.
Spirodialkylation of 3‐(Phenylthio)‐3‐Sulfolene and Subsequent Synthetic Transformations
Authors: Chou Shang‐Shing P. , Sung Chin‐Chuan
Published: June 2015

3‐(Phenylthio)‐3‐sulfolene (1) underwent spirodialkylation to give products 2 which were desulfonylated to afford the dienes 3. The Diels‐Alder reaction of 3 was achieved for some reactive dienophiles to yield spiro compounds. Compounds 2 were also converted to sulfonyldienes 9 which reacted as Michael acceptors.
Laser‐Induced Addition Reactions of Iodine with Acetylene
Authors: Chen Kuo‐Mei , Wang Gaw‐Pying , Kuo Chen‐Nan , Chen Jui‐Chi
Published: June 2015

Laser‐induced addition reactions of iodine with acetylene at 5145 and 4880 Å excitation wavelengths are studied, while trans‐1,2‐diiodoethylene is identified as the exclusive reaction product. A sequential addition reaction mechanism initiated by iodine atoms from the direct photodissociation process or collisional induced dissociation can be inferred.
Inhibitive Effect of Butyltin Trichloride on Dissolution and Localized Corrosion of Aluminium in Sodium Hydroxide and Hydrochloric Acid
Authors: Mourad M.Y. , Ibrahim E.H. , Seliman S.A.
Published: June 2015

The dissolution of aluminium in sodium hydroxide and hydrochloric acid in the presence of butyltin trichloride as corrosion inhibitor has been studied by hydrogen evolution and thermometric methods.

Experimental findings indicate that the inhibition effect of butyltin trichloride takes place through an adsorption mechanism following the Frumkin's isotherm.

Butyltin trichloride acts as a weakly adsorbed inhibitor in NaOH and as a strongly adsorbed inhibitor in hydrochloric acid medium.
Studies on the Preparation and Biological Activities of 3‐(O‐Methoxybenzyl)Sydnone Derivatives and 3‐(Fluorophenyl)Sydnones
Authors: Tien Hsien‐Ju , Tsai Yan‐Hong , Yeh Wen‐Yuan , Yeh Jong‐Chuan , Lee Yaw‐Kuen , Ho Young‐Shang
Published: June 2015

Two new sydnones; 3‐(o‐methoxybenzyl)sydnone(1) and 3‐(o‐melhoxybenzyl)‐4‐morpholinomethylsydnone(2) were synthesized from o‐methoxybenzylamine and ethyl bromoacetat in moderate yields.

3‐(o‐,m‐,p‐Fluorophenyl)sydnones were prepared from the corresponding fluoroaniline and chloroacetic acid in higher yields with a conventional method.

From the biological activity test, 1 shows significant response of coronary dilation test, collagen induced platelet aggregation inhibition, local anesthetic and moderate cardiotropic activity. In addition, 1 also leads to anticonvuls, muscle relaxation and behavior depression. But 2 only shows inhibition of collagen induced platelet aggregation and antiwrithing.

3‐(p‐Fluorophenyl)sydnone (5) shows significant response of coronary dilation, collagen induced platelet aggregation inhibition, moderate cardiotropic activity, antiwrithing and local anesthetic But 3‐(o‐Fluorophenyl)sydnone(3) and 3‐(m‐fluorophenyl)sydnone(4) only show coronary dilation and moderate cardiotropic activity.
The Studies of Free Radical Cyclization Reactions Mediated by Sulfonyl Chloride (I)
Authors: Chuang Che‐Ping , Hou Sheng‐Shu , Ngoi Tak Ho, Johnny
Published: June 2015

A study of the free racinoal reaction of vinylcycloprelpane mediated by p‐toluenesulfonyl chloride is described.
The Studies of Free Radical Cyclization Reactions Mediated by Sulfonyl Chloride (II)
Authors: Chuang Che‐Ping , Wang Ren‐Tzong
Published: June 2015

A study on the free radical cyclization reaction of substituted 1,6‐dienes mediated by p‐toluenesulfonyl chloride is described.
Ammonia Chemical Ionization Mass Spectra of Sydnones
Authors: Lin Shaw‐Tao , Tien Ling‐Ling
Published: June 2015

The mass spectra of twenty‐nine sydnones were measured by using NII3 as a reagent gas. The [M + H + NH3]+ ions are the base peaks for the entire series. Very few fragment ions were observed except for the derivatives of 4‐hydroxymethylenesydnones (XXI‐XXIX). Only the relatively stable sydnonyl‐methylene cations are formed. With consistent formation of [M + 18]+ ion as the base peaks with simple spectra, the NH3 CI‐MS can be an excellent method for the molecular weight determination.
Temperature Programmed Reduction and Spectroscopic Studies of Reduction Behavior of fe/tiO2 Catalyst
Authors: Chien Shu‐Hua , Chiang Wan‐Lan
Published: June 2015

Fe/TiO2 catalyst was prepared by incipient wetness impregnation of TiO2 with aqueous solution of ferric nitrate. The reduction behavior of the catalyst was studied by temperature programmed reduction profiles, Mössbauer spectroscopy, x‐ray diffraction and x‐ray photoelectron spectroscopy. The results show that the reduction of Fe/TiO2 was accompanied by a phase transition of anatase to rutile titania. α‐Fe2O3 was reduced to Fe3O4 in the initial reduction stage. Due to the strong support effect of TIO2, FeTiO3 was gradually formed as the reduction temperature reached 450°C. Complete reduction to the metallic Fe° particles occurred at temperatures higher than 670°C. The anatase‐rutile transition was initiated by the reduced Ti3+ ions and led to the formation of TiOx. At higher reduction temperature, TiOx migrated to the surface of metallic Fe° particles forming FeTiOx in the so‐called strong metal‐support interaction (SMSI) state.