bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of (βDiketonate)(7‐norbornadienyl acetate)Copper(l) Complexes, Single‐Crystal Structure of (hfac)Cu(7‐AcO‐NBD)
Authors: Chi Kai‐Ming , Houa Hung‐Chang , Chen Kuo‐Hsien , Shyu Shin‐Guang , Wen Yuh‐Sheng
Published: May 2015

Copper(I) complexes of general formula (β‐diketonate)Cu(7‐AcO‐NBD), where 7‐AcO‐NBD = 7‐norbornadienyl acetate and β‐diketonate = 1,1,1,5,5,5‐hexafluoro‐2,4‐pentanedionate (1), 1,1,1‐trifluoro‐2,4‐pentanedionate (2), 2,4‐pentanedionate (3), 4,4,4‐trifluoro‐1‐(2‐thienyl)‐1,3‐butanedionate (4), 4,4,4‐trifluoro‐1‐phenyl‐1,3‐butanedionate (5), were prepared from reactions of CuCl with Na(β‐diketonate) in the presence of 7‐AcO‐NBD. AH compounds were characterized by elemental analyses, 1H, 13C, 19F NMR and IR spectra. Single‐crystal strucutre of compound 1 was determined by X‐ray diffraction analysis that showed a mononuclear copper species with coordination of a chelating β‐diketonate ligand through two oxygen atoms and the 7‐AcO‐NBD through its CC double bond and an oxygen atom in the solid state. For compound 1, the crystal data are: triclinic, space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document}, a= 5.4519(14) Å, b= 11.852(3) Å, c= 13.304(3) Å, α = 74.721(20)° β = 80.220(20)°, γ= 76.848(19)°, Z = 2, RF = 0.060 and Rw = 0.064. Hot‐wall chemical vapor deposition experiments revealed that compound 1 is suitable as a precursor for deposition of copper films in the temperature range 170–260 °C.
A Convenient Synthesis of Antihyperlipoproteinemic Agent Gemfibrozil
Authors: Wang Hui‐Po , Lee On , Fan Chin‐Tsai , Lee Lain‐Tze
Published: May 2015

A new synthesis of antihyperlipoproteinemic agent 2,2‐dimethyl‐5‐(2,5‐dimethylphenoxy)pentanoic acid (gemfibrozil, 1) is developed via hydrogenolysis of a novel β‐lactone 6, prepared from [2+2] cycloaddition of 3‐(2,5‐dimethylphenoxy)propanal with dimethylketene. The mild conditions applied in this process are especially convenient for the preparation of gemfibrozil on an industrial scale of production.
Regiospecific Displacement of the C‐B Bond of Tris[4‐(substituted)furan‐3‐yl]boroxines with C‐Sn Bond and C‐O Bond: Syntheses of 3,4‐Disubstituted Furans and 4‐Substituted‐3(2H)‐furanones,
Authors: Song Zhi Zhong , Wong Henry N. C.
Published: May 2015

Tris[4‐(substituted)furan‐3‐yl]boroxines2, prepared from the corresponding 4‐(substituted)‐3‐(trimethylsilyl) furan 1, were converted successfully to 4‐(substituted)‐3‐(tributylstannyl)furans3through palladium‐catalyzed cross‐coupling reactions with tributylstannyl chloride. Palladium‐catalyzed cross‐coupling reactions of3with organohalides afforded 3,4‐disubstituted furans4. Regiospecific iodination of 4‐(trimethylsilyl)‐3‐((tributylstannyl) furan (3a) gave 4‐iodo‐3‐(trimethylsilyl)furan (5), which reacted with excess ethyl acrylate under a common Heck‐condition to produce 2,3‐bis(trans‐ethoxycarbonylvinyl)‐4‐(trimethylsilyl)furan (6). A thermal 6‐electrocyclic reaction followed by dehydration converted6into benzo[2,3‐6]furan8. Oxidation of2generated the corresponding 4‐substituted‐3(2H)‐furanones9.
Trace Analysis of Heavy Metals with Two New Disodium Bisdithiocarbamates
Authors: Liu Lilian Kao , Cheng Tsai‐Heung , Young Dun‐Shyurng , Hsieh Tsing‐Pai
Published: May 2015

Two chelating reagents, disodium N,N′‐dibenzylethylenebisdithiocarbamate 1 and disodium piperazinebisdithiocarbamate 2, were synthesized and used to preconcentrate trace metals in aqueous samples. For analysis of Cu(II) using a UV‐vis spectrometer, Beer's law was obeyed from 5.0 μg L−1 to 6.0 mg L−1 for reagent 1, and from 0.2 mg L−1 to 6.0mg L−1 for reagent. 2. The chelation ratio for reagent 1 to Cu(II) was determined to be 1:1, with a formation constant 1.0 × 109 M−l. The dependence of extraction and extraction efficiency of reagent 1 on pH was also studied with an atomic absorption spectrometer for nine heavy‐metal ions‐Cu(II), Fe(III), Pb(II), Co(II), Cr(VI), Ni(II), Zn(II), Mn(II) and Cd(II). Except Cr(VI) and Mn(II), the recovery yields of the other seven metal ions were almost quantitative at pH = 4 − 6. The recovery was 82% for Cr(VI) at pH = 4 − 5, and 52% for Mn(II) at pH = 6 − 7.
Magnetic Properties of M3[Fe(Cn)6]2Xh2O (M = Co (II), Ni(II), Cu(II), Zn(II))
Authors: Shyu H. L. , Lin S. N. , Wei H. H.
Published: May 2015

Compounds of the type M3[Fe(CN)6]2XH2O (M = Co(II), Ni(II), Cu(II), and Zn(II)) were prepared and magnetic properties of their powders were investigated by means of EPR spectra, Mössbauer effect and magnetic susceptibility measurements. The temperature dependence of the magnetization for the complexes Co3[Fe(CN)5]2‐ 10H2O, Ni3[Fe(CN)6]2‐10H2O and Cu3[Fe(CN)6]2‐4H2O revealed that below the critical temperatures 15, 22 and 20 K respectively, these complexes have zero‐field magnetization. The magnetic hysteresis at 10 K for Co(II), Ni(II) and Cu(II) complexes was observed. Mössbauer spectra at 4.2 K for the compounds are discussed.
Gelsemine Support Studies: Observation of an Unusual Free Radical Cyclization‐Fragmentation Sequence
Authors: Hart David J. , Kuzmich Daniel
Published: May 2015

Treatment of vinylogous urethanes 9a and 9b with tri‐n‐butyl in hydride generated a tree radical that underwent cyclization‐fragmentation to afford oxindole‐ketones 10 and 11 in high yield. Vinylogous urethane 13, gave only cyclization‐reduction products 15 and 16 upon treatment with tri‐n‐butyltin hydride at 80 °C, but also afforded a low yield of cyclization‐fragmentation product 14 upon treatment with tris(trimethyl‐silyl)silane at 140 °C.
Constituents of Leaves of Tetradium Glabrifolium
Authors: Wu Tian‐Shung , Chang Feng‐Chu , Wu Pei‐Lin , Kuoh Chang‐Sheng , Chen Ih‐Sheng
Published: May 2015

Twenty‐nine compounds including three alkaloids, live triterpenoids, five coumarins, seven benzenoids, two tannins, five flavonoids, one sugar and one nucleoside are isolated from leaves of Tetradium glabrifolium. Their structures are characterized on comparison of spectral data with literature values.
Synthesis of γ‐Butyrolactams by the Palladium‐Catalyzed Cyclization of N‐Allylbromoacetamides
Authors: Yang Shyh‐Chyun , Shea Fang‐Rong
Published: May 2015

N‐Allylbromoacetamides undergo cyclization to give γ‐butyrolactams in the presence of palladium catalysts and a base.
A Novel Charge Distribution Method for the Numerical Solution of the Poisson‐Boltzmann Equation
Authors: Pan Jium‐Tyne , Peng Wen‐Jiun , Lin Thy‐Hou
Published: May 2015

A charge distribution method to solve the linearized Poisson‐Boltzmann equation numerically through use of the finite difference method is proposed, The molecules are mapped by 1 and 0.25 Å grid systems. Each atom is modeled as a point charge and a weighted sum of point charge of every atom that is within its van der Waals radius with a grid point is assigned to the grid point. Depending on a charge distribution factor determined, the charge/grid (q/g) ratio calculated for every grid point inside a molecule can be fixed to a certain value. A grid size of the I Å grid is often fixed for mapping a small or large molecular system. Solvation energies for a group of small molecules calculated by the method arc comparable with those calculated by other methods and the grid energy calculated by the method is also reduced.
Syntheses and Characterization of Manganese‐Tellurolate Complexes by Using Chelating Metalloligand cis‐[Mn(Co)4(TePh)2]− and Potential Electrophilic TeMe+ Reagent
Authors: Liaw Wen‐Feng , Chiou Show‐Jen , Lee Way‐Zen , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

The cis‐[Mn(CO)4(TePh)2]−, similar to bidentate ligand PhTe(CH2)3TePh, acts as a “chelating metalloligand” for the synthesis of metallic tellurolate compounds. The reaction of cis[Mn(CO)4(TePh)2]− with BrMn(CO)5 in THF leads to a mixture of products[(CO)3,BrMn(μ‐TePh)2Mn(CO)4]− (1) and Mn2(μ‐TePh)2(CO)g (2). Complex 1 crystallizes in the triclinic space group Pl̄ with a = 11.309(3) Å, b = 14.780(5) Å, c = 19.212(6) Å, a = 76.05(3)° β = 72.31(3)°, γ = 70.41(3)° V = 2848(2) Å3, Z = 2. Final R = 0.034 and Rw = 0.035 resulting from refinement of 10021 total reflections with 677 parameters, Dropwise addition of (MeTe)2 to a solution of [Me3O][BF4] in CH3CN leads to formation of [Me2TeTeMe][BF4], a potential MeTe+ donor ligand. In contrast to oxidative addition of diphenyl ditelluride to [Mn(CO)s]− to give cis‐[Mn(CO)4(TePh)2]− which was thermally transformed into [(CO)3Mn(μ‐TePh)3Mn(CO)3]−, reaction of [Mn(CO)5]−with [Me2TeTeMe]+ proceeded to give the monomeric species MeTeMn(CO)5 as initial product which was then dimerized into Mn2(μ‐TeMe)2(CO)g (4).
Odorless Chemistry: A Gentle Reductionist Companion to Experiment
Authors: Schaefer Henry'F.
Published: May 2015

Computational quantum chemistry has advanced over the past two decades to the point of recognition as a valuable co‐laborer with experiment. Several examples demonstrate this point. For each of the next 40 years, we predict that an additional 1% of chemical research will shift from experiment to computation. Thus by the year 2036 we foresee a picture of chemical research in which 50% of the effort is computational in nature.
Chemical Bonding State of Chlorine on Ag{100} as Determined by Angle‐Resolved Secondary Ion Mass Spectrometry
Authors: Chang Che‐Chen , Lung Chien‐Hua
Published: May 2015

The power of the angle‐resolved ion desorption technique for straightforward characterization of surfaces is demonstrated. The structural sensitivity of secondary ion desorption has led to a successful application of angle‐resolved ion sputtering yield measurements to the determination of the Cl chemical bonding structure on the Ag {100} surface. Angular distributions of the sputtered Cl− ions show that chlorine dissociates at the surface to yield a bonding state of atomic form at the room temperature. Both the polar and the azimuthal angle dependencies of the sputter intensity for Ag+ and Cl− ions reveal that the Cl adatom is chemi‐sorbed high above the topmost substrate layer of Ag atoms. At all Cl exposures, the Ag‐Cl bond is oriented along the <100> azimuth with the adsorbate occupying a C4 symmetry site, not an a‐top, a bridge, or a high symmetry site. Shadow‐cone enhanced ion desorption spectra show that die geometrical structure of the Cl chemisorbed surface changes slightly as the exposure is increased.
Determination of Ethion Residues in Soil by Extraction and by Mass Spectrometry Using Different Procedures
Authors: Lee Maw‐Rong , Tso Ju‐Chien , Yeh Yao‐Chia
Published: May 2015

Optimized experimental procedures including time of extraction, extraction solvent in Soxhlet extraction technique were sought for detection of trace ethion residues in soil. The largest recoveries over 96% were achieved with a 1:1 mixture of methanol and acetone as extraction solvent for three hours. In comparing EI, CI, EI‐CAD, and PCI‐CAD modes of a four sector mass spectrometry for detection ethion, it was shown the best monitoring mode to be EI monitoring of the M+ of ethion, m/z 384, which fragments to give the m/z 231 product ion. The limit of detection obtained was 170 pg/g in soil.
Dispersed Fluorescence Spectroscopy and Transition Dipole Moment of HCO β 2A′‐X̄2A′
Authors: Chang Hui‐An , Fan Yang‐Hsiung , Chen I‐Chia
Published: May 2015

Dispersed fluorescence spectra of β 2A′ ‐ x̄ 2A′ transitions are measured on exciting HCO to the vibrational levels (0,0,0), (0,0,1), (0,1,0) and (1,0,0) of β 2A′ in a gas cell. Vibrational energies of bound and resonant states are determined for energy up to 17 500 cm−1 from the ground vibrational level of the x̄ 2A′ state. Rotationally resolved spectra of the bands β 2A′ ‐ x̄ 2A′ 203301, 214 and 202312 were recorded and analyzed. Abnormal intensities in the P, Q and R branches are due to the mechanism of “axis switching”. From the ratios of emission intensity of a‐ and b‐type transitions, without taking into account the varied lifetimes of rotational states of the upper electronic state, the directions of transition dipole moments of these bands are determined to be 39 − 43° to the inertial a axis.
Cooperative Study of Precision and Accuracy on the Determinations of Around‐Ppb Levels of Copper and Lead in Environmental Waters
Authors: Cheng Hwa‐Sheng , Pai Su‐Cheng , Yang Mo‐Hsiung , Chang Tsu‐Yen , Ho Wu‐Hsiung , Jen Jen‐Fon , Hsieh Chia‐Feng , Jian Shiuh‐Jen , Hsi Tai‐Sung , Cheng Kuang‐Lu , Lin Teh‐Hsien , Ho Siu‐Mei , Tsai Chung‐Ming
Published: May 2015

The results of a series of inter‐laboratory cross‐check on the determinations of ppb and sub‐ppb levels of copper and lead in environmental samples are described. Thirteen laboratories participated during a five‐stage comparison. Seven analytical methods and two pre‐concentration procedures were performed on certified and real samples. For controlled and blind standards at higher concentration levels (10 ppb or above) the data reported by different participants show good agreement for both elements regardless of the method chosen. However, for samples having lower concentrations (1‐10 ppb level), the relative standard deviation (R.S.D.) and bias increased. A high degree of scattering on data were demonstrated for a deep ocean water at less than 1 ppb level. The results of the present study give direct comparison between different analytical methods, and also reflect the average aptitude of analytical laboratories in Taiwan on the measurements of copper and lead in environmental samples.
Ferro‐and Antiferromagnetic Properties of Metal Complexes with Pyridine‐Substituted Nitronyl Nitroxide Radicals
Authors: Wei Ho‐Hsiang , Wong Hong‐Yue , Lee Gene‐Hsiang , Wang Yu
Published: May 2015

The synthesis, crystal structure and magnetic properties of the non‐transition metals; Cd(II), Zn(II), Hg(II), Mg(II) and the transition metals; Co(II), Ni(II), Cu(II) complexes with 2‐(4‐pyridyl)‐4,4,5,5‐tetra‐methylimidazolinyl‐l‐oxy‐3‐oxide (NITpPy) are presented. The compounds of free radical NITpPy, HgCl2(NITpPy), and Zn(acac)2(NITpPy) crystallize in the same monoclinic system of space group C2/c. The magnetic properties of the temperature‐dependent magnetic susceptibility of NITpPy and its metal complexes are discussed according to the Heisenberg model. A weak ferromagnetic coupling in NITpPy and a weak antiferromagnetic coupling in the metal complexes have been revealed.
Comparison of Electrospray Ionization and Fast Atom Bombardment Mass Spectrometry for the Analysis of Saponins from Alfalfa, Clover, and Mungbeans
Authors: Lee M. K. , Wang S. J. , Jurysta M. , Waller G. R. , Ling Y. C.
Published: May 2015

The determination of seven saponins in crude plant extracts by electrospray ionization mass spectrometry (ESI‐MS) and fast atom bombardment mass spectrometry (FAB‐MS) is described. Distinct protonated and natriated (Na‐adduct) molecular ions in ESI‐MS spectra readily provide molecular weight information, which can be further verified using clusters of molecular ions. Saponin mixtures can be analyzed by ESIMS on varying the potential difference between the capillary and skimmer in the ESI source to decompose impurities. ESI‐MS uses less amount of sample than that required by FAB‐MS. ESI‐MS does not produce structural information, however. The FAB‐MS spectra consist mainly of protonated and deprotonated molecular ions with limited structural information. (‐)‐FAB‐MS is more suitable for analyzing saponin samples than the (+)‐FAB‐MS.
Orbital Energy Order and the Through Bond Interaction in Homonuclear Diatomic Molecules
Authors: Chang Tse‐Chiang
Published: May 2015

The homonuclear diatomic molecules are the simplest systems having both the σ framework and the lone pair orbitals na and b for investigating their through space and through bond interaction. The striking orbital energy order ng∼ na+ nb > nn ∼ na ‐ nb has been accounted for by the through bond interaction. However, when the p‐content in the lone pair orbitals na and nb decreases, one may have the reverse orbital energy order: ng < ng. A reverse orbital energy order has been found in F2 and Cl2, whose na and nb are almost pure s‐type atomic orbitals. The reverse order also occurs in molecule N2 when the internuclear distance is larger man 1.5 Å. It is also found that the detail through space and through bond interaction and the eventual orbital energy order for ng and nu can be accounted for by the Fock operator within the localized molecular orbital space.
Butane Dehydrogenation Reaction on Sulfur Poisoned Group 10 Metal/SiO2 Catalysts
Authors: Chen Hsiu‐Wei , Chou Chi‐Hwei , Hong Cheng Tsung
Published: May 2015

Butane cracking and dehydrogenation reactions on silica supported Ni, Pt, Pd, and S, Pb modified Ni, Pt, Pd catalysts were studied via a fixed bed reaction system. Cracking reaction path prevailed when butane reaction was catalyzed by clean Ni, Pt, Pd and sulfur poisoned Ni catalysts. The addition of sulfur into Pt and Pd catalytic systems can shift the reaction path to dehydrogenation reaction. However, the deactivation problem due to carbonaceous deposit is not improved by the addition of sulfur into the catalytic system. The origin of the sulfur effect on the change of butane reaction pathway is discussed on the basis of the concentrations of Ph and S additives, oxygen perturbation effect, metal loading, carbonaceous deposit and reaction temperatures.
Electrochemical Oxidation of Glucose on Polycrystalline Gold Surface by Treating with Square Wave Potential Signal
Authors: Hsiao M. W. , Adzic R. R.
Published: May 2015

This study concerns with treatment of polycrystalline gold surface with square wave potential program to enhance the signal of electrochemical oxidation of glucose. After such perturbation the glucose oxidation wave is increased almost ten times. Consequently, gold is a useful electrode for sensor applications.
Preparation and Characterization of an Unusual Di‐Cobalt Complex; X‐Ray Crystal Structure of Co(CO)2(μ‐CO)(μ:η2,η4‐C4Ph4)Co(CO)2(PPh3)
Authors: Hong Fung‐E , Lue I‐Ren , Lin Chu‐Chieh
Published: May 2015

Reaction of [MoCo(CO)5(PPh3)2(η5‐C5H5)] (1) with diphenylacetylene in tetrahydrofuran at 50 °C yielded two heterobimetallic compounds, [MoCo(CO)4.(PPh3){μ‐PhC  CPh}(η5‐C5H5)] (4) and [MoCo(CO)5{μ‐PhC  CPh} (η5‐C5H5)] (5). However, an unexpected product, Co(CO)2(μ‐CO)(μ:η2,η4‐C4Ph4)Co(CO)2(PPh3) (6), was observed while attempting to grow the crystals for structural determination of 4. The X‐ray crystal structure of 6 was determined: triclinic, \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document}, a = 11.654(2) Å, b = 12.864(2) Å, c = 13.854(2) Å, α = 89.67(2)°, β = 86.00(2)°, γ= 83.33(2)°, V = 2057.9(6) Å3 Z=2. In 6, two cobalt fragments are at apical and basal positions of the pseudo‐pentagonal pyramidal structure, respectively. The electron count for the apical cobalt fragments is 20, which is rather unusual. It is believed that 6 was formed after the fragmentation and recombination of the fragmented species of 4.
Antihypertensive Activity of dl‐Tetrahydropalmatine, an Active Alkaloid Isolated from the Tubers of Corydalis racemosa
Authors: Chu Lian‐Hwa , Hsu Feng‐Lin , Chueh Fu‐Yu , Niu Chiang‐Shan , Cheng Juei‐Tang
Published: May 2015

The antihypertensive activity of dl‐tetrahydropalmatine hydrochloride (THP), isolated from the tubers of Corydalis racemosa (Thunb.) Pers. (Papaveraceae), was investigated in spontaneously hypertensive rats (SHRs) using intravenous injection. A dose‐dependent lowering of blood pressure was observed in SHRs. Decrease of plasma noradrenaline was also obtained in SHRs that received injection of THP. Direct injection of THP into brain lowered the blood pressure and plasma noradrenaline. This antihypertensive action of THP appears to be produced mainly by an effect on central nervous system to lower sympathetic tone in SHRs.
The Enantioresolution of Methylthiohydantoin‐Amino Acids on R, S‐2‐hydroxypropyl Derivatized β‐Cyclodextrin Bonded Stationary Phase Using the Water‐Based Mobile Phase
Authors: Chen Shushi
Published: May 2015

The enantioresolution of thirteen methylthiohydantoin‐amino acids (MTH‐amino acids), which are substrates for producing D‐amino acids through enzyme‐catalyzed hydrolysis, is described on R, S‐2‐hydroxypropyl derivatized β‐cyclodextrin bonded stationary phase (RSP‐β‐CD CSP) with a water‐based mobile phase. The enantioresolution is relatively sensitive to the structural variation of group which is attached to the carbon at position five on methylthiohydantoin moiety and subsequently turns into side‐chain group of corresponding D‐amino acid produced after hydrolysis. The inclusion complexation is believed to be the mechanism responsible for the observed enantioresolution that cannot be reproduced either on native β‐cyclodextrin CSP under the same chromatographic conditions or on both CSPs using the acetonitrile‐based mobile phase. Approaches for enantioimprovement include varying the percentage of organic modifier in the mobile phase and using the buffer‐typed mobile phase such as triethylammonium acetate (pH 4.1).
Characterization of an Isozyme of β‐Glucosidase from Sweet Almond
Authors: Li Yaw‐Kuen , Chang Li‐Fen , Shu Hsuan‐Hsu , Chir Jiunly
Published: May 2015

A sweet almond β‐glucosidase (EC 3.2.1.21) isozyme was purified from commercial crude product. The process of purification consisted of a Protein‐Pak Q anion exchange chromatography following by a Superdex 75 HR gel filtration separation. The purified enzyme is a monomeric glycoprotein with molecular weight of 58 kDa and pI=4.55 which is distinguished from reported isozymes. The enzyme has apH optimum in the range of 5.2‐5.6 when p‐nitrophenyl‐β‐D‐glycopyranosides are used as substrate and is stable up to 50 °C at that pH range. The purified protein also exhibits profound β‐galactosidase and σ‐L‐arabinosidase activity. The study of substrate specificity revealed that lacking of hydroxymethyl group at C‐5 of glycosides resulted in higher affinity for substrate binding to enzyme, whereas the chemical step of hydrolysis (kcst) was prevented significantly. The pH activity profile displayed a bell‐shaped curve for all measured p‐nitrophenyl‐β‐D‐glycopyranosides with apparent pK1 and pK2 values of 4.4‐4.7 and 6.2‐6.4, respectively. This isozyme was strongly inhibited by δ‐gluconolactone (Ki = 160 μM) and 4‐phenylimidazole (Ki = 17.8 μM) reversibly at pH 6.2. Among the tested glycoses, the binding affinity of N‐acetyl‐β‐D‐glucosamine to the enzyme (Kl = 52 mM) was 6 times stronger than that of glucose and its epimers.
A Cyclization Approach toward Five‐Membered Heteroaromatico‐QuinodimethanesviaFused‐3‐Sulfolenes
Authors: Chou Ta‐Shue , Tsai Chung‐Ying , Lee Shwu‐Jiuan
Published: May 2015

A general strategy involving the zincation of 4‐bromo‐3‐chloro‐2‐sulfolene,in situcondensation with an α‐heterosubstituted acetaldehyde, and subsequent cyclization reaction as the key steps toward the synthesis of furano‐ and thieno‐3‐sulfolenes is described. These fused‐3‐sulfolenes are demonstrated to be good precursors for the correspondingo‐quinodimethanes.
Derivatization, Separation and Determination of Steroids and Triterpenoids by Reverse‐Phase HPLC and UV Detection
Authors: Wang Shu‐Ping , Lai Jeng‐Shiow , Lin Shaw‐Tao
Published: May 2015

The steroids were derivatised with aroyl chloride to yield the corresponding benzoates. Among them, their 4‐methoxybenzoates were obtained in greatest yield and were analyzed by HPLC with the smallest detection limit (10 ng) by means of a UV detector (254 nm). This method of derivatization can be applied for analysis of steroids and triterpenoids from crude products with the HPLC technique.
Nascent Rotational Distributions of MgH in Reaction of Mg(4s 1S0) with H2 and HD
Authors: Liu Dean‐Kuo , Lin King‐Chuen
Published: May 2015

The nascent rotational distributions of MgH(X2σ+, v″ = 0, 1) resulting from the reaction of Mg(4s1S0) with H2 and HD have been determined by using the laser pump‐probe technique. Like the case of Mg(1P1), the distributions appear to be bimodal which peak mainly at high N(26) with minor peaks at low N(6). There are no apparent differences when the escaping mass is doubled. The similarity between product rotational distributions from the 4S state and those from the 3P state, and no evidence of a kinematic isotope effect, reveal that a harpoon‐type mechanism may be operative. Our ab initio calculations reveal that in the entrance channel on the 31A1 surface in C2v symmetry or 1σ+ surface in C∞v symmetry for 4S state, the reaction may lake place via a series of non‐adiabatic curve crossings with the ionic Mg+H2− potential surface.
Phenolics from Acalypha indica
Authors: Ma Ying‐Tsun , Chuang Jin‐I , Lin Jer‐Huei , Hsu Feng‐Lin
Published: May 2015

Two novel hydrolysable tannins, potassium brevifolincarboxylate and acaindinin, together with eight known tannins—1‐O‐galloyl‐β‐D‐glucose, 1,2,3,6‐tetra‐D‐galloyl‐β‐D‐glucose, corilagin, geraniin, acetonylgeraniin A, euphormisin M2, repandusinic acid A, and chebulagic acid, as well as two flavonoid glycosides — quercetin 3‐O‐β‐D‐glucoside and rutin, were isolated from Acalypha indica. Their structures were elucidated on the basis of chemical and spectroscopic evidence.
Chiral Alkoxy Side Chains from (‐)‐Amino Acids in Mediating Asymmetric Synthesis of Tricarbonyl(cyclohexadienyl)iron Complexes
Authors: Chang Tsu‐Hsin , Kuo Chien‐Ren , Ong Chi‐Wi
Published: May 2015

The asymmetric induction in the complexation reaction of (S)‐1‐methyl‐2‐(5‐methyl‐cyclohexa‐1,4‐dienylmethyloxy)‐pyrrolidine 5 and (S)‐2‐(2‐N,N‐dimethylamino‐1‐propanoxy)‐5‐methylcyclohexa‐1,4‐diene 6 having heteroatom adjacent the stereogenic center has been investigated. The diastereoselectivity was determined directly from the diastereotopic peaks in the 1H NMR or by chemical correlation with 9. The conversion of η‐1,4‐complexes 7a and 8a to 9 proceeded with high retention of configuration while that of the η‐2,5‐Fe(CO)3 complexes 7b and 8b undergoes considerable racemization.
First Total Synthesis of 1,2‐Dehydronephthenol
Authors: Li Weidong , Qu Jin , Li Jing , Li Ying , Li Yulin
Published: May 2015

The first total synthesis of 1,2‐Dehydronephthenol (15‐hydroxy‐cembra‐1,3,7,11‐tetraene), a novel cembranoid diterpene, was accomplished starting from trans, trans‐farnesol through seven steps in an overall yield of 17% by employing titanium‐induced intramolecular keto aldehyde reductive olefination‐coupling as the key macrocyclization step.
Photochemistry of Substituted 4,4‐Dimethoxy‐2,5‐Cyclohexadienones
Authors: Hong Fang‐Tsao , Lee Kung‐Shing , Tsai Yow‐Fu , Liao Chun‐Chen
Published: May 2015

4,4‐Dimethoxy‐2,5‐cyclohexadienones 9–14 were prepared from the corresponding hydroquinone monomethyl ethers by oxidation with thallium trinitrate in methanol. Irradiation of solutions of 9–13 in methanol with a broad band of UV light centered at 350 nm in a Rayonet reactor afforded 2‐cyclopentenone derivatives 15–19 in moderate to excellent yields, whereas irradiation of 14 in methanol gave phenol 8 along with other unidentified products. Irradiation of 11–14 in benzene yielded substituted phenols. The plausible reaction pathways for the product formation are discussed.
Bond Alternation and Energy Increment in Linear and Angular Isomers of [N]Phenylenes
Authors: Lin Chiu‐Ling , Chu San‐Yan , Ou Ming‐Chiu
Published: May 2015

From recent accurate ab initio calculation on [N]phenylenes by Schulman and Disch, some regular patterns for bond alternation and energy increment can be found. We interpreted these results by considering a “unit cell” of interior benzene rings fused to two four‐membered rings in either linear or angular fashion. Our model works better in accounting for the structure than for the energy.
The Application of Chelating Agent Incorporated Polymer Modified Electrodes in the Detection of Trace Metals
Authors: Zen J.‐M. , Lee M.‐L. , Huang S.‐Y. , Hsu F.‐S. , Chi N.‐Y. , Chung M.‐J.
Published: May 2015

The use of chelating agent‐modified Nafion®‐coated mercury‐film electrodes (CNCMFEs) in square wave anodic stripping voltammetry (SWASV) for the determination of trace metals is described. The CNCMFE containing appropriate amounts of dimethylglyoxime (DMG) was applied for the determination of Ni(II), Cd(II), and Cu(II). A similar system that contains 2,2′‐bipyridyl (Bpy) was used for the determination of Pb(II). The effect of various model organic substances on the CNCMFEs in SWASV is thoroughly explored. The CNCMFEs are considerably more resistant to organic interferences than the Nafion®‐coated MFE. The implications of these interferences for the reliability and feasibility of stripping measurements using the CNCMFEs in real samples are discussed. Results presented for real samples demonstrate the analytical utility of the CNCMFEs in SWASV.
Molecular Structure of Bis(2,2′‐bipyridine)dioxovanadium(V) Trifluoromethanesulfonate
Authors: Su Chan‐Cheng , Huang Gin‐Song , Liu Shyh‐Jiun , Wang Sue‐Lein , Liao Fen‐Ling
Published: May 2015

Bis(2,2′‐bipyridine)dioxovanadium(V) trifluoromethanesulfonate, obtained from autooxidation of the corresponding oxovanadium(IV) complex, crystallizes in monoclinic, P21/n, with a = 15.433(2), b = 11.013(2), c = 27.423(2) Å, β = 104.79(2)°, Z = 4, R = 0.0697, and Rw = 0.0821. The complex consists of discrete vanadium(V) complex cations and trifluoromethanesulfonate anions. Each asymmetric unit is composed of a pair of enantiomer molecules. The octahedral vanadium complex ion, having a C2 axis, comprises a cis‐VO2, mean V‐O distance of 1.622 ± 0.007 Å, and two cis‐related 2,2′‐bipyridine ligands. The V‐N bonds trans to each other are short, with a mean V‐N distance of 2.108 ± 0.010 Å, while those trans to V=O are somewhat longer, with a mean V‐N distance of 2.292 ± 0.022 Å. The coordination geometry of the vanadium cation is very similar to that of [VO(O2)(2,2′‐bipyridine)2]+.
Molecular Structure of a New Tetrameric μ4‐oxo‐Cu(II)4 Complex Derived from the Dicopper(I) Complex of 4‐Methyl‐2,6‐bis(pyrazol‐1‐ylmethyl)phenolate and Molecular Oxygen
Authors: Chen Chun‐Tong , Sheu Shiann‐Chemg , Lee Gene‐Hsiang , Ho Tong‐Ing , Wang Yu , Lin Yuan‐Chuan , Oliver Su Y.
Published: May 2015

A new dicopper(I) complex of 4‐methyl‐2,6‐bis(pyrazol‐1‐ylmethyl)phenolate (LOH) has been synthesized by the reaction of LOH with Cul to form LOHCu2I2(1), which catalyzes the oxidation of 3,5‐di(t‐butyl)catechol. LOHCu2I2 reacts with molecular oxygen to form a peroxo‐dicopper(II) complex and undergoes cleavage of 0–0 bridge to give a new μ4‐oxo‐Cu11 tetramer with seven‐membered ring coordination as characterized by X‐ray crystallography.
Sodium Aristolochates from the Flowers and Fruits of Aristolochia zollingeriana
Authors: Chiang Chia‐Yu , Leu Yann‐Lii , Chan Yu‐Yi , Wu Tian‐Shung
Published: May 2015

Two new sodium salts of aristolochic acids: sodium aristolochate‐II and ‐IVa, together with ten known compounds: sodium aristolochate‐I, sodium aristolochate‐C, aristolactam, aristolactam‐N‐β‐D‐glucoside, cepharadione‐A, 3,5‐pyridinedicarboxamide, p‐hydroxybenzaldehyde, trans‐methyl p‐coumarate, 6‐hydroxy sitost‐4‐en‐3‐one, β‐sitosterone and β‐sitosterol, and stigmasterol mixture were isolated from the fresh flowers and fruits of Aristolochia zollingeriatia. Their structures were deterimined by spectral and chemical methods. IR and 1H NMR methods to distinguish aristolochic acid from its salt are discussed.
Three New Naphthoquinones from the Stem of Diospyros maritime Blume
Authors: Kuo Yue‐Hsiung , Chang Chi‐I , Kuo Yao‐Haur , Huang Shou‐Ling
Published: May 2015

Three new naphthoquinone derivatives, isolated from the stems of Diospyros maritima Blume, were elucidated as 2′‐ethoxyisodiospyrin, 3′‐ethoxyisodiospyrin, and 3‐ethoxyisodiospyrin, respectively, on the basis of spectral properties.
Identification of Bioactive Components in Antrodia cinnamomea by MS/MS via El Ionization
Authors: Young Dun‐Shyumg , Chiang Hung‐Cheh , Liu Lilian Kao
Published: May 2015

4α‐Methylergosta‐8,24(28)‐dien‐3,7,11‐trion‐26‐oic acid and 4α‐methylergosta‐8,24(28)‐dien‐3,11‐dion‐7β‐ol‐26‐oic acid are two clinically active components found in Antrodia cinnamomea. Using the specific fragmentation in their mass spectra together with the ratio of these diagnostic ions in their respective SIM mass spectra, and/or their MS/MS spectra, a fast, simple, and efficient mass spectral method has been developed for identification of these compounds in Antrodia cinnamomea preparations without prior isolation of the individual compound.
Product Selectivity in Photoelectrochemical Reduction of Benzyl Halides on Semiconductor Photocathodes
Authors: Tsunashima Katsuhiko , Nonaka Tsutomu
Published: May 2015

Electrochemical reduction of benzyl halides on various cathodes was examined under illumination and in the dark. Product selectivity control in the reduction by illumination was accomplished only when p‐type semiconductor photocathodes were used. By estimating the electrophilicity of benzyl halides from their rate constants for methanolysis under illumination and in the dark, it was proposed that the mechanism for the selectivity control by illumination involves a photo‐assisted process for the nucleophilic attack of carbanion intermediate species formed by the two‐electron reduction of the benzyl halides to the unreacted ones as electrophiles.
Ene Reaction of Pummerer‐Type Reaction Intermediate and Synthesis of Pellitorine
Authors: Lin Wei‐Shing , Wang Hucy‐Min , Chen Ling‐Ching
Published: May 2015

Pummerer‐type reaction intermediate 2 of α‐(methylthio)acetic acid (1) has been found to react with 1‐alkenes to afford ene adducts 3. Pellitorine 5 was synthesized from the adduct 3d.
Ultrasonic Effects on Electroorganic Processes. Part 10. Product‐Selectivity in Mixed Kolbe Electrolysis of Carboxylic Acids
Authors: Fujiwara Hiroki , Atobe Mahito , Kanetsuna Hidenori , Nonaka Tsutomu
Published: May 2015

Product‐selectivity was examined in mixed Kolbe electrolysis of carboxylic acids on a platinum anode in aqueous methanolic solutions under ultrasonic irradiation. It was found that an ultrasonic effect on the selectivity is caused not only by promotion of mass transport across the electrode interface but also by adsorption control of intermediated radical species by ultrasonic acoustic and cavitation effects. Namely, formation of the one‐electron oxidation products is favourable at low current densities compared with two‐electron oxidation products under irradiation, while the two‐electron oxidation is promoted at high current density. This is the ultrasonic effect characteristic of the Kolbe electrolysis. The mechanism of the ultrasonic effect is discussed with a hypothesis.
Nitration of 2‐Aryl‐1,1‐dihalocyclopropanes Containing Methyl or Phenyl Group
Authors: Lin Lee‐Huey , Lin Shaw‐Tao , Yang Hucy‐Ju
Published: May 2015

Gem‐dihalocyclopropanes bearing a phenyl group and an additional group were nitrated by using nitric acid in a sulfuric acid matrix. The products from the nitration of aryl rings are major. The presence of a methyl group on the C(2) position of the cyclopropane ring leads to the isoxazoline from nitration at the C(1)‐position instead of that from nitration at the C(2)‐position.
Synthesis and Characterization of Amino‐Functionalized PDPS/PDMS Copolymers
Authors: Yang Mei‐Hui , Chou Chyuan , Lin Chih‐Hwa
Published: May 2015

Various amino‐functionalized polysiloxanes were synthesized in high yields (∼90%) via ring‐opening polymerization of cyclic siloxane monomers through either bulk or solution process. The amino‐functionality was introduced through adding (MeO)2MeSiC3H6NHC2H4NH2 (A) or NH2C3H6(Me)2SiOSi(Me)2‐C3H6NH2 (B) as terminators and/or as reagents mixed with monomers initially. The bulk polymerization of D4 and P4 was initiated with potassium salts such as Me3SiOK or KOH, while the solution living polymerization of D3 and P3 was initiated with LiOH in THF or toluene solution. The optimum conditions for preparing copolymers with different structure types were studied. The purity of the products determined by silica gel column chromatography was found to be higher than 98%. All of the copolymers were characterized with GPC, 1H NMR, and DSC techniques. The silyl derivatives of primary amines were used in GPC characterization. The number‐average molecular weights determined by 1H NMR and those determined by GPC measurements were in excellent agreement. The aminosilane A served either as a terminator, which gave an amino‐terminated polysiloxane, or a reagent which was mixed with comonomers initially and incorporated into the copolymerization to give a side‐chain aminopolysiloxane. When A was used as a terminator, no insertion of A into the copolymer was found. In addition, the molecular weights of the copolymers can be controlled by the amount of terminating aminosilanes added into the system.
Chemical Constituents from Mucuna membranacea
Authors: Lin Yun‐Lian , Tsai Wei‐Jern , Chen Ih‐Sheng , Kuo Yueb‐Hsiung
Published: May 2015

Antiplatelet‐directed fractionation of the ethanolic extract from the root of Mucuna membranacea Hayata resulted in the isolation of friedelin (1), friedelanol (2), β‐sitosterol (3a) & stigmasterol (3b), trans‐p‐coumaric acid (4), protocatechuic acid (5), vanillic acid (6), and flavonoids — geraldol (7), 3′‐methoxydaidzein (8), genistein (9), daidzein (10), cyclosin (11), formononetin (12), orbol (13), isoformononetin (14), pratensein (15) and luteolin (16). Their structures were elucidated on the basis of spectral methods. Compounds 7 and 8 were tested for the antiplatelet aggregation activity and appeared to be specific against collagen‐induced platelet aggregation with a IC50 values of 61.5 and 12.3 μM, respectively.
Silver(I) Complexes of Schiff Bases Derived from Thiophene‐2,5‐dicarboxaldehyde and Furan‐2,5‐dicarboxaldehyde
Authors: Hwang Wen‐Shu , Wang Dong‐Liang , Hsu Sen‐T'sing , Liu Ling‐Kang
Published: May 2015

The reactions of Schiff bases, derived by the condensation of thiophene‐2,5‐dicarbaldehyde and furan‐2,5‐dicarbaldehyde with 2‐thienylmethylamine or 2‐furanmethylamine, with silver nitrate have been studied in refluxing anhydrous methanol under nitrogen atmosphere. Complexes thus formed have been isolated and characterized by elemental analysis, electrical conductance, cyclic voltammetry, and 1H NMR, 13C NMR, IR, LTV‐Vis, and mass spectroscopic studies. The experimental results reveal that the complexes are primarily ionic in nature, consisting of (L)3Ag2 dication and Ag(NO3)3 negatively charged dianions. The molecular structure of one of the complexes, [((C4H3O)CH2NCH(C4H2S)CHNCH2(C4H3O))3Ag2] [Ag(NO3)3] has been studied in the solid state. The complex is crystallized in the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document} with a = 12.889(7) Å, b = 14.884(5) Å, c = 15.084(6) Å, α = 92.18(4)°, β = 79.78(4)°, γ = 110.92(4)°. The structure is disordered. Each Ag in dication is tri‐coordinated by three azomethine N atoms from three ligands, and each ligand employs two azomethine N atoms to coordinate to two Ag ions such that the geometry around the Ag ⃜Ag axis conforms to a propeller‐shape. The two Ag ions are between the two N3 planes with Ag ⃜ Ag distance ca. 4.8.1 Å. There is no bonding between any Ag ion and any thiophene of the three ligands. However, two Ag ions and three thiophene S atoms form a trigonal bipyramidal geometry.
Photorearrangement of Propargyl Bromide as a Probe to Study Propargylic and Allenic Radicals by Infrared Matrix Isolation Technique
Authors: Wu Yuh‐Wern , Hwang Mei‐Lee , Hsu Wei‐Liang , Fang Fen‐Hui
Published: May 2015

The photolysis of propargyl bromide in Ar matrix to form allenyl bromide proceeded with a radical mechanism. The deuterium label study and radical scavenger were used to investigate the mechanism. Neither propargyl nor allenyl radical was trapped in Ar matrix at 8 K. The rates of propargyl and allenyl radicals coupled with bromo radical are significantly fast. The stability of propargyl and allenyl radicals is discussed.
Synthesis of Imidazo[4,5‐b]quinoxaline Ribonucleosides as Linear Dimensional Analogs of Antiviral Polyhalogenated Benzimidazole Ribonucleosides
Authors: Zhu Zhijian , Saluja Sunita , Drach John C. , Townsend Leroy B.
Published: May 2015

We have recently found that 2,5,6‐trichloro‐1‐(β‐D‐ribofuranosyl)benzimidazole (TCRB) and the corresponding 2‐bromo analog have better in vitro activities against HCMV than the clinically used agents ganciclovir and foscarnet. These benzimidazole nucleosides act by a unique mechanism, however, their biological target has not been completely identified. As an approach to probing the target, we have designed imidazo[4,5‐b]quinoxaline nucleosides as linear dimensional analogs of the benzimidazole nucleosides to study the spatial limitation of the binding site in the target enzyme. A convenient route was developed for the synthesis of 2‐substituted 6,7‐dichloroimidazo[4,5‐b]quinoxalines involving a reaction of 2,3,6,7‐tetrachloroquinoxaline with ammonia followed by a ring annulation as the key step. This furnished the versatile heterocycle 6,7‐dichloroimidazo[4,5‐b]quinoxalin‐2‐one. Ribosylation of 2‐substituted imidazo[4,5‐b]quinoxalines was influenced by the functional group at the 2‐position and the 2‐one compound was found to smoothly undergo ribosylation. The 2‐one group of the nucleoside was converted into specifically selected 2‐substituted compounds. Evaluation of the compounds for activity against two herpesviruses and for cytotoxicity showed they were less active and/or more cytotoxic than TCRB. We conclude therefore, that the binding pocket on the protein target of TCRB will tolerate some electronic and size changes.
On the Electric Field Effect on the Dynamics of High Rydberg States of Hydrogen Atom and the Model of ZEKE Spectroscopy
Authors: Chao S. D. , Hayashi M. , Lin S. H. , Schlag E. W.
Published: May 2015

In this paper, the studies of the dynamics of the high Rydberg states for n = 10 and n = 100 of hydrogen atom under the influence of an electric field will be reported. It will be shown from our calculated results that the two time constants of τslow ≈︁ 1 – 10 μs and τfast ≈︁ 1 – 10 ns obseved in ZEKE experiments are obtained in the stray field condition, i.e., F = 10 – 100 mV/cm. To treat the ZEKE states of complex systems like many‐electron atoms, molecules, clusters etc., the inverse Born‐Oppenheimer approximation can be used and it will be discussed.
The Constituents of the Stem and Roots of Aristolochia foveolata
Authors: Leu Yann‐Lii , Chan Yu‐Yi , Hsu Meei‐Yu , Chen Ih‐Sheng , Wu Tian‐Shung
Published: May 2015

One new aristolactam glucoside: aristolactam‐Ia‐N‐D‐glucoside together with seventeen known compounds were isolated from the fresh stems and roots of Aristolochia foveolata. Their structures were determined by spectral and chemical methods. Among seven aristolochic acid derivatives, five were determined to be salt forms by IR and 1H NMR methods.
Study of Host‐Guest Complexation of Alkaline Earth Metal Ion, Aluminum Ion and Transition Metal Ions with Crown Ethers by Fast Atom Bombardment Mass Spectrometry
Authors: Wu Hui‐Fcn , Chen Li‐Wei
Published: May 2015

Complexations of crown ethers with alkali metal ions have been investigated extensively by FAB mass spectrometry over the past decade, but very little attention has been paid to reactions of crown ethers with other classes of metal ions such as alkaline earth metal ions, transition metal ions and aluminum ions. Although fast atom bombardment ionization mass spectrometry has proven to be a rapid and convenient method to determine the binding interactions of crown ethers with metal ions, problems in reliabilities for quantitative measurements of” binding strength for the host‐guest complexes have been described in the literature. Thus, in this paper, applications of FAB/MS for investigating the complexation of crown ethers with various classes of metal ions is discussed. Extensive fragmentations for neutral losses such as C2H4O or C2H4 molecules from the host‐guest complexes could be observed. The reason is attributed to the energetic bombardment processes of FAB occuring in the formation of these complexes. Complexes of cyclen with metal ions also show neutral losses of C2H4NH molecules leading to fragment ions. Transition metal ions usually form (Crown + MCl)+ type of ions, alkaline earth metal ions can form both (Crown + MCl)+ and (Crown + MOH)+ type of ions. But for aluminum ions, only (Crown + Al(OH)2)+ type of ions could he observed.
Synthesis of Dioxa‐Cages as a New Probe for the Stereochemistry of the Bisadducts of p‐Quinone with Cyclopentadiene and Cyclohexadiene
Authors: Yen Chia‐Hui , Tsai Shih‐Hwa , Wu Hsien‐Jen
Published: May 2015

The synthesis of dioxa‐cages via iodine‐induced cyclization reaction can be used as a new method for the determination of the stereochemistry of the bisadducts of p‐quinone with cyclopentadiene and cyclohexadiene. The bisadducts 2 and 8 were converted into the dioxa‐cages 13a and 13b via a three‐step sequence, respectively. The stereochemistry of 13a and 13b was determined on the basis of NOE experiments.
Oxidation of Hydrazides Using Sodium Perborate: Formation of N,N‐Diacylhydrazines
Authors: Jadhav Vidyadhar K. , Wadagaonkar Prakash P. , Salunkhe Manikrao M.
Published: May 2015

Substituted aromatic hydrazides react very smoothly with sodium perborate in glacial acetic acid at room temperature to give N, N′‐diacylhydrazines in excellent yields and purity.
Spin State in (Porphinato)iron(III) Complex. A Spin‐Crossover Complex with Two Magnetically Distinct Sites
Authors: Dong Teng‐Yuan , Cheng Ching‐Hung , Chang Ling‐Shao , Wang Yu
Published: May 2015

The results of low temperature X‐ray determination, Mössbauer and magnetic measurement of spin‐crossover (isothiocyanato)(porphinato)iron(III) hemipyridine are reported. The features in 77 K Mössbauer spectrum include two doublets, one with a quadrupole splitting (ΔEQ) of 1.961 mm s−1 (low‐spin site) and the other with ΔEQ = 0.792 mm s−1 (high‐spin site). As the temperature of the sample is increased to 300 K, the signal intensity of the high‐spin site grows to 92% at the expense of the low‐spin signal. The variable‐temperature magnetic susceptibility data also support that the tetraphenyl complex is a spin‐crossover complex.
Synthesis of Pyrido[2,3‐d]pyrimidines via the Reaction of Activated Nitrites with Aminopyrimidines
Authors: Geies Ahmed A.
Published: May 2015

6‐Aminouracil and 6‐aminothiouracil (1a, b) were reacted with benzylidenemalononitrile 2a to afford the pyrido[2,3‐d]pyrimidines 4a, b. On the other hand, the reaction of 1a, b with benzylidene ethyl cyanoacetate 2b result in a mixture of 5a,b and/or 6a,b respectively. Pyrido[2,3‐d]thiazolo[1,2‐b]pyrimidines 8a‐c were synthesized from the reaction of 4b with α‐halo compounds to give the intermediate derivatives 7a‐c followed by cyclization using 70% H2SO4.
New and Simple Syntheses of the Attractants of the Female Melon Fly, Dacus cucurbitae
Authors: Yen Yao‐Pin , Chen Pao‐Hsing
Published: May 2015

The attractant of the female melon fly, (E)‐6‐nonenyl acetate, and the two analogs, (E)‐7‐dodecenyl acetate and (E)‐7‐decenyl acetate were synthesized via hydrozirconation to control the regioselective coupling reactions and resulted in good yields.
Synthesis of New 2‐[(Substituted‐pyrazolin‐1‐yl)carbonyl]‐thieno[2,3‐b]pyridine Derivatives
Authors: Ho Yuh‐Wen
Published: May 2015

The reaction of 3‐amino‐4,6‐dimethyl‐2‐thieno[2,3‐b]pyridine carbohydrazide (1) with appropriate chalcones 2a‐2d in the presence of acid catalyst produced the corresponding 3‐amino‐2‐[(3,5‐disubstituted‐pyrazolin‐1‐yl)carbonyl]‐4,6‐dimethylthieno[2,3‐b]pyridines 3a‐3d. 3‐Amino‐2‐[(3‐substituted‐pyrazolin‐1‐yl)carbonyl]‐4,6‐dimethylthieno[2,3‐b]pyridines 7a, 7b were also obtained by the cyclization reaction of carbohydrazide 1 with Mannich base derivatives 6a, 6b under basic condition.
Reaction of 4‐Aryl‐3‐thiosemicarbazides with Phenylisothiocyanate: A Facile Synthesis of Thiazole, Pyrazole and Pyrimidine Derivatives
Authors: Wardakhan Wagnat W. , Fleita Daisy H. , Mohareb Rafat M.
Published: May 2015

The reaction of 4‐aryl‐3‐thiosemicarbazides 1a‐d with phenylisothiocyanate gave the intermediate potasium salts 2a‐d. The latter afforded 3a‐d, 13a‐d and 19 upon the reaction with phenacyl bromide, monochloroacetic acid and ethyl bromocyanoacetate respectively.