bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Novel Thiazoline and Thiazolidinone Derivatives Surmounted on Substituted Pyrazole Moieties as Potential Antipyretic Agents
Authors: Farghaly A.M. , Chaaban I. , El‐Khawass S.M. , Fahmy S. M.
Published: June 2015

Six novel series of substituted thiazoline (V, VI, VII and VIII) and thiazolidinone derivatives (IX and X) resulting from 2,3‐dihydro‐1, 5‐dimethyl‐3‐oxo‐2‐phenyl‐1H‐pyrazole‐4‐carbaldehyde (I) and 1‐phenyl‐3‐p‐tolyl‐1H‐pyrazolc‐4‐carbaldehyde (II) were synthesized. The course of this synthesis included the preparation of two new scries of disubstituted thiosemicarbazone precursors (III and IV) which were cyclized with phenacyl bromide, ethyl 2‐chloroacetoacetate as well as ethyl bromoacetatc to afford the target thiazolines and thiazolidinoncs. The antipyretic activity of some representative compounds was performed.
Some Cyclization Reactions with 1,3‐Diphenyl‐5‐Imino‐2‐Imidazolidinone‐4‐Thione
Authors: Mohamed Y.A. , Ammar Y.A. , Sh. El‐Sharief A.M. , Aly M.M.
Published: June 2015

1,3‐Diphenyl‐5‐imino‐2‐imidazolidinone‐4‐thione (II) was treated with diazomethanes to give (III‐V). Interaction of (II) with amino compounds furnished the corresponding 4‐substituted imino derivatives (VIa‐m). Imidazoquinoxaline derivatives (VIIIb, c) were obtained through interaction of (II) with o‐phenylenediamines. Condensation of (II) with hydrazines afforded the hydrazones (IX, Xa, b). Semicarbazone and thiosemicarbazone derivatives (XIIa‐d) were prepared from the reaction of (IX) with isocyanates and isothiocyanates. Again (II) was allowed to react with n‐butylmagnesium bromide and HgCl2 to give (XIII) and (XIV) respectively.
Furanocoumarins and Sesquiterpene Ketone from Clausena Lansium Skeels
Authors: Li Wen‐Shyong , McChesney James D.
Published: June 2015

Three known furanocoumarins, imperatorin (1), wampetin (dehydroindicolactone) (2) and 8‐geranoxypsoralen (3) and a new sesquiterpene ketone, (+)‐oplopanone (4), were isolated from Clausena lansium Skeels. The stereochemistry of the last two coumarins was determined by NOESY experiments. The idendity of (+)‐oplopanone was established by comparison of its physical constants and spectroscopic data with those reported for its enantiomer as well as a comparison of its' TLC behavior with that of an authentic sample.
Synthesis and Primary Photoreaction of C18‐Methyl‐β‐Ionylidenemalononitrile
Authors: Yao‐Pinyen  , Lew Miaw‐Chun
Published: June 2015

A synthesis of C18‐methyl‐β‐ionone (8) and C18‐methyl‐β‐ionylidenemalononitrile (13) is reported. Photoreaction of C18‐methyl‐β‐ionylidenemalononitrile resulted in a reversible 7‐cis and 7‐trans isomerization which eventually underwent 1,5‐Hydrogen shift to give the irreversible photoproduct, C18‐methyl‐y‐retro‐ionylidenemalononitrile (14).
The Difference in the Behaviour of Hydrazine and p‐Substituted Phenylhydrazines on Various 4‐(3‐Aryl‐3‐Oxopropenyl) Antipyrines
Authors: El‐Khawass S.M. , Farghaly A.M. , Chaaban I. , Fahmy S.M.
Published: June 2015

A series of novel 4‐(3‐aryl‐4,5‐dihydro‐lH‐pyrazol‐5‐yl)‐l, 5‐dimethyl‐2‐phenyl‐lH‐pyrazol‐3(2H)‐oncs (III) were synthesized. Thus, the key intermediates, 4‐(3‐aryl‐3‐oxopropenyl‐1,5‐ dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐ones (II) were cyclized with hydrazine hydrate containing a few drops of ethanol gave the desired pyrazoline derivatives (III), which can be acetylated to afford the target N‐acetyl derivatives (IV). On the other hand, the same reaction condition using p‐substituted phenylhydrazines, the starting key intermediates (II) were recovered unchanged. The use of glacial acetic acid instead of ethanol, lead to a new series of 1,3‐diarylpyrazoles (VI) by a different pathway. The structure of the newly synthesized compounds was elucidated by elemental analyses, IR, 1H‐NMR and mass spectra.
Synthesis of 4‐Arylpyridines for Intramolecular Cyclization Studies I.
Authors: Shjao Min‐Jen , Perng Cherng‐Yih , Chiu Cheng‐Tung , Liang David
Published: June 2015

4‐Arylpyridines 4a‐4h arc synthesized in good yield by the addition of Grignard reagents or organolithium derived from bromobenzene derivatives 2a‐2h in the presence of catalytic amount of cuprous iodide to N‐ethoxycarbonylpyridinium choloride la‐lh followed by oxygen oxidation.
Ring‐Cleavage Reactions of Five‐ and Six‐Membered Cyclic Ethers with Organolithium Compounds
Authors: Chou Ta‐Shue , Hung Shao‐Hwa , Cheng Chien‐Chung
Published: June 2015

In the presence of one equivalent of boron trifluoride etherate, organolithium compounds cause the ring cleavage reactions of tetrahydrofurans and tetrahydropyran to give the corresponding long‐chain alcohols in moderate yields. These reactions are highly regioselective for unsymmetric cyclic ethers.
Relaxation Studies of 2IZSZ Spin Order in Liquid Benzene: Selection of Chemical Shift Anisotropy Parameters
Authors: Chang Chi‐Fon , Hwang Lian‐Pin
Published: June 2015

The effects of cross‐correlation of chemical shift anisotropy and dipole‐dipole interactions result in the relaxation of 2IzSz spin order. The intensity of relaxation profile is sensitive to the variation of chemical shift anisotropy interactions. With spin‐rotation interaction taken into consideration, it has been successfully applied to the selection of appropriate sets of chemical‐shift anisotropy parameters for benzene.
Correlation of Solvolytic Reactivities. A New YBnBr Scale for Benzylic Bromides
Authors: Liu Kwang‐Ting , Sheu Hun‐Chang
Published: June 2015

Solvolysis of 2‐bromo‐2‐(4′‐fluoromethyl)phenyladamantane (4), and 2‐bromo‐2‐(4′‐trifluoromethyl)phenylpropane (5) were carried out in a number of solvents, and their rate constants measured. Significant deviation from linear logk‐YBr plots was observed, and the order of reactivities, e.g., k(100M) > k(90E) > k(80A), was in the reverse order of Swain's solvent parameter B. Different extent of solvation to the localized and the delocalized cationic transition state was then likely to play an important role. Similar result was also found in the solvolysis of 1‐bromo‐2,2,2‐trifluoro‐1‐(4′‐methylphenyl)‐1‐phenylethane (6). A new Y scale, YBnBr, for the correlation of solvolytic reactivities of benzylic bromides based on k(4) was established. Intervention of solvent assistance in the solvolysis of 5 is discussed.
Studies of Intramolecular Cyclization of 4‐Arylpyridines. II Syntheses of Condensed Tricyclic Pyridines
Authors: Shiao Min‐Jen , Perng Cherng‐Yih , Shen Chien‐Chang
Published: June 2015

A convenient method for the synthesis of condensed tricyclic pyridines using intramolecular cyclization of 4‐arylpyridines is reported. The tricyclic compounds, 2‐azafluorenone (9), 2‐azafluorenone (10), 2‐azafluorenol (11), lactones 12 and 13, and anhydride 14 have been prepared.
New Esters, 2‐(4‐Hydroxy‐3‐Methoxyphenyl)Ethyl Hexa‐ and Octacosanoates from the Leaves of Cinnamomum Reticulatum Hay
Authors: Kuo Yueh‐Hsiung , Shue Ming‐Jeng
Published: June 2015

The leaves of Cinnamomum reticulatum Hay were extracted successively with hexane and acetone successively. Dipentadecyl ketone, n‐dotriaconyl alcohol, 2‐(4‐hydroxy‐3‐methoxyphenyl)ethyl hexa‐ and octacosanoates ( two new esters from hexane extract ), β‐sitosterol, fatty acid, vanillin, p‐hydroxybenzaldehyde, genkwanin, vanillic acid, p‐hydroxybenzoic acid, β‐sitosteryl‐l‐β‐glucopyranoside, meso‐erythritol, glucose, and 4‐(2‐hydroxyethyl)‐2‐methoxyphenyl‐l‐β‐D‐glucopyranoside (from the acetone extract) were isolated. The structures of the new esters were elucidated by chemical and physical evidence.
Studies on the Constituents of Ganoderma Lucidum
Authors: Chiang Hung‐Cheh , Chu Shih‐Chang
Published: June 2015

The methanolic extract of fruit bodies of cultivated Ganoderma lucidum was separated by silica gel column chromatography and preparative thin‐layer chromatography to give ten compounds. On the basis of spectral analysis, chemical procedures and gas chromatography, d‐mannitol (1), ergosta‐7, 22‐dien‐3β‐yl palmitate (2), ergosterol (3), ergosta‐7, 22‐dien‐3β‐ol (4), 5α‐lanosta‐7,9(11),24‐trien‐3β,26‐diol (5), ergosterol peroxide (6), 24,25,26‐trihydroxy‐5α‐lanosta‐7,9(11)‐dien‐3‐one (7), 5α‐lanosta‐7,9(11)‐dien‐3β,24,25,26‐tetraol (8) and 8,9‐epoxyergosta‐5,22‐dien‐3β,15‐diol (9) were identified. Among these compounds, 8,9‐epoxyergosta‐5,22‐dien‐3β,15‐diol was first separated from Ganoderma lucidum.
Enhancement of Chemical Reactions by Microwave Irradiation
Authors: Chen Shui‐Tein , Chiou Shyh‐Horng , Wang Kung‐Tsung
Published: June 2015

Microwaves are low electromagnetic energy which induce molecular perturbation by stimulation of ionic diffusion and by enhancement of dipole rotation without causing rearrangement of molecular structures. Microwave energy irradiated on the samples in various liquid media is lost or absorbed to the samples by the following two mechanisms: ionic conduction and dipole rotation. These two effects take place simultaneously to account for the phenomenon of rapid heating associated with many practical applications of microwave irradiation. In contrast to conventional heating, the salient feat ure of “dipole rotation” constitutes one efficient form of “molecular agitation” or “molecular stirring” which can be explored for many aspects in chemical reactions. We will discuss some of the useful application of “molecular agitation” by means of microwave irradiation such as: 1. rapid hydrolysis of proteins and peptides, 2. selective hydrolysis of aspartyl peptide bond, 3. the racemization of amino acids, 4. rapid hydrolysis of sugars, 5. continuous‐flow process of microwave reactions, and 6. the enhancement of coupling reactions in peptide synthesis.
Kinetic Studies of Chromic Acid Oxidation of Glyoxal
Authors: Lin Tzuen‐Yeuan , Mao Yuh‐Lin , Chuo Chih‐Ming
Published: June 2015

The kinetics of chromic acid oxidation of glyoxal is reported. The reaction is first‐order in glyoxal and indicates a gradual change from a first‐order to a zero‐order dependence on acidity. The kinetic nature of this reaction has been studied and the rate law is consistent with a proposed mechanism as follows; rate = kKb, K[Cr+6][Gx][H+]/(l+0.238[H+]) at 25°C. The product analysis indicates that formic acid is the oxidation product under similar kinetic condition.
A Modified Water‐Gas Shift Reaction. The Decomposition of Alkyl Formate in the Presence of Water Using a Ruthenium Carbonyl
Authors: Jou Der‐Ching , Cheng Chien‐Hong
Published: June 2015

Alkyl formates in the presence of water were rapidly decomposed to H2, CO2 and the corresponding alcohols using Ru3(CO)12 and KOAc as catalyst. Based on the hydrogen gas produced, a turnover rate as fast as 8446/h for ethyl formate at 140°C was observed. The catalyst system was also active for the decomposition of other alkyl formates. The rate of decomposition increased both with increasing amount of KOAc and with decreasing number of carbon atom in the alkyl group of the formate. In addition to Ru3(CO)12, several other transition metal complexes RuCl3, RuCl2(PPh3)3, Os3(CO)12, H2Os3(CO)10, RhCl3, and RhCl(PPh3)3, were active in the catalytic decomposition of alkyl formates, although their activities varied greatly. The Ru3(CO)12‐KOAc system also catalyzed the reduction of nitrobenzene by HCOOEt‐H2O to aniline in EtOH and to a mixture of N‐phenylformamide and N‐methyl‐N‐phenylformamide in HCOOEt. Under coditions the same as for the hydrogenation of nitrobenzene, ethylene styrene and cyclohexenone were reduced to the corresponding alkanes, whereas 1‐hexene and 1‐octene were isomerized to the corresponding 2‐alkene products.
The Flash Vacuum Thermolysis ofN‐Acyl Imidates
Authors: Wu Pei‐Lin , Wang Ching‐Cheng
Published: June 2015

In the flash vacuum thermolysis of methylN‐acyl imidates, the loss of methanol is consistent with the intermediacy of anN‐acylketenimine. Recombination and further reactions may lead to the array of products observed in these thermal reactions. An attempt to trap the intermediateN‐acylketenimine by an intramolecular [2 + 2] cycloaddition was unsuccessful.
Synthesis of Some Pyrimidine 2‐Oxo(Thio)‐4,6‐Dione Derivatives
Authors: El‐Badawi M. , Ibrahim E. S. I. , Farag H. , Abbasi M. M.
Published: June 2015

5‐Arylidenes 1a and 1b, on reaction with ethyl cyanoacetate and diethyl malonate in the presence of ammonium acetate under Michael condensation, yield pyridine derivatives 2 and 3, respectively. Cyclopentapyrimidine derivative 4 can also be obtained by the reaction of 1a with malononitrile in the presence of piperidine. The reaction of 5‐arylidene lb with monochloroacetic acid in an alkaline medium gives the thiazol derivative 5. Also, spiro‐[3′, 5′]cyclohexenyl pyrimidine derivative 6 could be obtained from the reaction of 1d with maleic anhydride. On the other hand, 5‐arylidene 1e reacts with maleic anhydride to give 2‐thiobarbituric acid derivative 7. The condensation reaction of 2‐thiovioluric acid 8 with some hydrazines affords the triazole derivatives 9a‐d. Finally, barbituric acid condenses with isatin to give 5‐arylidene 1f, which can be cyclized with phosphorous pentoxide to afford 10.
Synthesis of Some Antimicrobial Purine Nucleoside Derivatives
Authors: Ahmed A. F. Sayed , Rahman S. Abdel , Hamad M. M. , Hattaba A. A.
Published: June 2015

Some N(6)‐substituted adenosine derivatives and adenosine attached to different amino‐acid residues and peptides at position 8 have been synthesized using improved methods. The biological activities of the prepared compounds towards gram‐positive and gram‐negative bacteria are described.
New Approaches to Absorption Detection in Capillary Chromatography and Capillary Electrophoresis
Authors: Yeung Edward S.
Published: June 2015

Two new approaches for absorption detection in capillary columns are presented. They are applicable to columns as narrow as 10μm i.d. Both provide good sensitivity despite the very short optical pathlengths that are commonly available in commercial systems. The first involves irradiating the column along its axis rather than across the axis. The entire analyte zone can then participate in absorption. Gains up to 1000 fold can be expected. The second is a modification of laser‐excited fluorescence. The absorbing analytes, even though they do not fluoresce efficiently, can transfer their energy to a fluorophore added to the mobile phase. The secondary emission can be used to detect absorption in the nanomolar range.
An Ultrasonic Nebulizer as the Sample Introduction Device for High Performance Liquid Chromatography Combined with Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Wang Su‐Ru , Jiang Shiuh‐Jen
Published: June 2015

A preliminary study of an ultrasonic nebulizer as the sample introduction device for the chromatographic speciation of ionic compounds containing As, Se and Cr is described. The analytical figures of merit observed during chromatographic separations with an ultrasonic nebulizer interfaced to an inductively coupled plasma‐atomic emission spectrometer (ICP‐AES) were comparable to or better than conventional pneumatic nebulization and other sample introduction techniques, in terms of organic solvent tolerance, sensitivity, detection limits and reproducibility. The limits of detection were in the ranges of 10‐14 ppb for Se, 30‐40 ppb for As, and 8‐10 ppb for Cr.
Kinetics and Mechanism of the Cerium(IV) Oxidation of Arnold's Base and the Protonation and Hydroxylation of Michler's Hydrol Blue
Authors: Wu Rong Tay , Jwo Jing‐Jer
Published: June 2015

In aqueous H2SO4, Ce(IV) ion oxidizes rapidly Arnold's base((p‐Me2NC6H4)2CH2, Ar2CH2) to the protonated species of Michler's hydrol((p‐Me2NC6H4)2CHOH, Ar2CHOH) and Michler's hydrol blue((p‐Me2NC6H4)2CH+, Ar2CH+). With Ar2CH2 in excess, the rate law of the Ce(IV)‐Ar2CH2 reaction in 0.100 M H2SO4 is expressed ‐d[Ce(IV)]/dt = kapp[Ar2CH2]0[Ce(IV)] with kapp = 199 ± 8M−1s−1 at25°C. When the consumption of Ce(IV) ion is nearly complete, the characteristic blue color of Ar2CH+ ion starts to appear; later it fades relatively slowly. The electron transfer of this reaction takes place on the nitrogen atom rather than on the methylene carbon atom. The dissociation of the binuclear complex [Ce(III)ArCHAr‐Ce(III)] is responsible for the appearance of the Ar2CH+ dye whereas the protonation reaction causes the dye to fade. In highly acidic solution, the rate law of the protonation reaction of Michler's hydrol blue is ‐d[Ar2CH+]/dt = kobs[Ar2CH+] where Kobs = ((ac + 1)[H*] + bc[H+]2)/(a + b[H+]) (in HClO4) and kobs= ((ac + 1 + e[HSO4−])[H+] + bc[H+]2 + d[HSO4−] + q[HSO4−]2/[H+])/(a + b[H+] + f[HSO4−] + g[HSO4−]/[H+]) (in H2SO4), and at 25°C and μ = 0.1 M, a = 0.0870 M s, b = 0.655 s, c = 0.202 M−1s−1, d = 0.110, e = 0.0070 M−1, f = 0.156 s, g = 0.156 s, and q = 0.124. In highly basic solution, the rate law of the hydroxylation reaction of Michler's hydrol blue is ‐d[Ar2CH+]/dt = kOH[OH−]0[Ar2CH+] with kOH = 174 ± 1 M−1s−1 at 25°C and μ = 0.1 M. The protonation reaction of Michler's hydrol blue takes place predominantly via hydrolysis whereas its hydroxylation occurs predominantly via the path of direct OH attack.
Axial and Equatorial Substitution of Dimethylamine on Phosphorus in the 1,3,2‐Oxazaphosphorinane Ring System: Structures of 2‐Dimethylamino‐Phenyl‐2H‐1,3,2‐oxazaphosphorinane‐2‐Oxides
Authors: Shih Yun‐Er , Liu Yi‐Fang , Wang Jy‐Shih , Liu Ling‐Kang
Published: June 2015

X‐ray structures of trans‐2‐dimethylamino‐5‐phenyl‐2H‐1,3,2‐oxazaphosphorinane‐2‐oxide, 5b, and trans‐2‐dimethylamino‐6‐phenyl‐2H‐1,3,2‐oxazaphosphorinane‐2‐oxide, 6c, have been determined. These two compounds have been prepared in a straightforward manner by a reaction of cyclization of Mc2NP(O)Cl2 with the corresponding 3‐amino‐2‐phenylpropanol and 3‐amino‐1‐phenylpropanol, respectively, to produce (5b, 6b) and (5c, 6c), and were separated into pure forms by chromatography. Crystal data of 5b: space group Pccn, a = 10.675(5), b = 31.685(9), c = 7.217(3) Å, R = 0.065 for 1040 reflections. Crystal data of 6c: space group P‐1, a = 9.803(6), b = 12.455(5), c = 12.690(2) Å, α = 114.11(2), β = 80.88(2), γ = 111.64(4)°, R = 0.035 for 3534 reflections. For the pair 5b and 6b, the slowly‐migrating 5b is trans (Ph and P = O group trans) with the configuration of 2RS, 5RS, hence 6b is the cis isomer. For the pair 5c and 6c, the slowly migrating 6c is trans with the configuration of 2RS, 6SR; hence 5c is the cis isomer. In both X‐ray structures the 1,3,2‐oxazaphosphorinane rings are chair‐like with the P‐end essentially flattened. With a conformationally demanding 5‐phenyl substituent, 5b has an axial Me2N whereas with also a conformationally demanding 6‐phenyl substituent, 6c has an equatorial Me2N. For 6c, the exocyclic P‐N bond has partial double bond character: the geometry about exocyclic N is planar. On the other hand, for 5b, the geometry about exocyclic N deviates considerably from planarity, the sum of the angles around N being 343.3°. In the crystalline state, the two crystallographically independent molecules of 6c are linked together in a hydrogen‐bonded system involving the water molecule.
Preparations of Chiral Menthyl α‐Sulfinylacrylates. The Optically Active Dienophiles with Double Asymmetric‐Induction Capability
Authors: Yang Teng‐Kuci , Teng Tsung‐Fan , Lec Dong‐Sheng
Published: June 2015

The introduction of optically active carboxylates onto the chiral vinyl sulfoxides increased their reactivities toward electron‐rich dienes in Diels‐Alder cycloadditions, thus much milder reaction conditions were used. The two chiral auxiliaries became cither a matched or mismatched pair which can be justified by their ability of chiral induction. Here we report a preparative‐scale synthesis of optically active α‐sulfinylacrylates with double asymmetric capability.
Interfacial Electrochemical Behavior of RuS2 Single Crystal Electrodes in Sulfuric Acid Medium
Authors: Sheu Jiang‐Shing , Shih Yen‐Shiang , Huang Ying‐Sheng
Published: June 2015

The electrochemical behavior of RuS2 has been studied using cyclic voltammetry and Energy Dispersive X‐ray Spectroscopy (EDX) techniques. Cyclic voltammograms reveal one major anodic peak and two major cathodic peaks on the reverse sweep; these peaks are attributed to the electroadsorption/desorption of OH− groups on the electrode surface. It is proposed that the electroadsorption of the OH− group on RuS2 is due to the presence of Ru 4d electrons in the uppermost part of the valence band. Thus, OH− is oxidized by holes on Ru 4d states in the first step. These groups are transferred to S22−sites in the second step. EDX surface analysis reveals preferential release of S22− from the pyrite lattice. A mechanism for the anodic dissolution of RuS2 is proposed, according to which elemental sulfur is not a direct product, but rather the end product which forms from thiosulfate.
UV/VIS Spectral Studies of Catecholase Activity of Binuclear Copper(II) Complexes [Cu2REP(μ‐X)(Y)2]
Authors: Chyn Jong‐Pyng , Chou Jeh‐Li , Shieh Kuan‐Jiunn
Published: June 2015

By means of ultraviolet and visible spectroscopy we have studied the catecholase activity of two binuclear copper(II) complexes of general formula [Cu2REP(u‐X)(Y)2] (1, X=OH and Y=ClO4; 2, X=Y=CI), REP =deprotonated 2, 6‐bis(1′‐(4′‐(2″‐pyridyl)‐2′‐thiabutyl))‐4‐methylphenol. Both complexes promote catalytic autoxidation of 3, 5‐di‐tert‐butylcatechol (3, 5‐DTBC) to 3, 5‐di‐tert‐butylquinone (3, 5‐DTBQ) in methanol, but not in acetonitrile.
3‐Substituted Sydnone Derivatives. Structures of 3‐Cyclohexylsydnone and of Two Forms of 3‐(3‐Pyridyl)sydnone
Authors: Rychlewska Urszula , Hodgson Derek J. , Yeh Andrew , Tien Hsien‐Ju
Published: June 2015

The crystal and molecular structures of three sydnone derivatives are reported. The compound 3‐cyclohexylsydnone crystallizes in space group C2/c of the monoclinic system with sixteen molecules in a cell of dimensions a = 19.326 (3), b = 9.471 (2), c = 20.005 (4)Å, β = 106.85(1)°. The structure has been refined to a final value of 0.0581 for the conventional R‐factor based on 2222 independent observed intensities. Form I of 3‐(3‐pyridyl)sydnone crystallizes in space group P2/n of the monoclinic system with eight molecules in a cell of dimensions a = 7.317(2), b = 9.283 (2), c = 20.891 (6) Å, β = 99.61(2)°. The structure has been refined to a final value of 0.0514 for the conventional R‐factor based on 1208 independent observed intensities. Form II of 3‐(3‐pyridyl)sydnone crystallizes in space group P21/c of the monoclinic system with eight molecules in a cell of dimensions a=9.073 (2), b = 22.267 (5). c = 7.494(2)Å, β = 112.15 (2)°. The structure has been refined to a final value of 0.0462 for the conventional R‐factor based on 1330 independent observed intensities. Each of the three structures contains two crystallographically independent molecules in the cell. In the case of 3‐cyclohexylsydnone, one of the independent molecules exhibits disorder around the exocyclic bond at N(3). A comparison of bond lengths indicates that the (electron donating) cyclohexyl group brings about enhanced electron density in the N(3)‐C(4) bond, and possibly in the N(3)‐N(2) bond. All three structures studied here exhibit intermolecular hydrogen bonding involving C(4)‐H(4)…O(6) interactions. Although there are no stacking interactions in the cyclohexyl derivative, there is evidence for such interactions in the 3‐pyridyl derivatives.
Intramolecular Diels‐Alder Reactions via 3‐(Phenylthio)‐4‐(Trimethylsilyl)‐3‐Sulfolene
Authors: Chou Shang‐Shing P. , Lee Chien‐Ming
Published: June 2015

Deprotonation of the title compound 2 followed by treatment with 5‐iodo‐1‐pentene or 6‐iodo‐l‐hexene gave the alkylated products 3 and 4 which upon refluxing in toluene yielded the dienes 8a and 8b. Intramolecular Diels‐Alder reactions were achieved by heating the dienes 8a and 8b in toluene in a sealed tube at 160–180°C to give bicyclo[4.3.0]nonene 9 and bicyclo[4.4.0]decene 10, respectively, in good yield. The stereochemistry of the cyclization products was determined, and was rationalized by comparison of the possible transition states involved.
Theoretically Calculated Deformation Density of Small Molecules
Authors: Lin Kuan‐Jiuh , Wang Chih‐Chieh , Wang Yu
Published: June 2015

Analysis of the theoretical electron deformation density based on EHMO and ab initio calculations has been applied to the simple molecules F2, H2O and SO2 The effects from varied basis sets for such deformation density were sought. The accumulation of electron density between the bonded atoms calculated from EHMO and ab initio methods with STO‐3G is generally under‐estimated. Such phenomena are significantly improved by using split‐valence basis sets e.g. 3–21G and 4–31G. The addition of d polarization functions is apparently important for the sulfur atom in sulfur‐related bonding. 3–21G or 3–21G* basis sets were found to provide not only valuable deformation density distributions of molecules but also comparable orbital energy states with respect to the experimental values.
Size of Micelles Determined by Static Fluorescence Quenching
Authors: Jeng Jiann‐Jong , Chen Jin‐Ming , Mou Chung‐Yuan
Published: June 2015

We developed a new method to measure the average aggregation number of large rod‐like micelles using static fluorescence self‐quenching of a solubilized fluorophore. The method is based on the increase of self‐quenching of micelle‐solubilized pyrene through excimer formation. We consider the effect of random distribution of pyrene in micelles and the micellar size distribution. The measured average aggregation  M is based on a new M‐weighted raging similar to our exponential‐weighted averaging in the transient decay method. We apply this method to study the effect of a large concentration of salt on the average aggregation behavior of sodium dodecyl sulfate (SDS) and cetyle tetraammonium bromide (CTAB). The sizes increase with increasing ionic concentrations. For SDS, we used the thermodynamic model developed by Missel et al. to calculate < n > M which we compare with experimental results.
Propylamido‐Modified C18 Reversed‐Phase for High‐Performance Liquid Chromatography
Authors: Lin Jer‐Yann , Yang Mei‐Hui
Published: June 2015

The synthesis and chromatographic properties of a propylamido‐modified C18 stationary phase are described. The propylamido‐modified C18 phase was prepared by bonding stearic acid to 3‐aminopropyl‐silica gel. The synthesis was simple and reproducible through amide formation by using N‐hydroxysuccinimide and dicyclohexylcarbodiimide. This prepared stationary phase exhibited excellent abilities to separate polycyclic aromatic hydrocarbons (PAHs), polysiloxanes and phenols by HPLC. The chromatographic results show that both the C3 moiety and the amido‐group in this phase contribute significantly to the HPLC separation process. The chromatographic behavior of the prepared phase and commercial C18 phases was also compared in analyses of PAHs and phenols. Although the commercial C18 phases have been extensively used, both the unique selectivity and the highly reproducible synthesis of our prepared phase make it an excellent complement to ordinary C18 phases.
Synthesis and Coordination of Tripodal‐Containing Copper(I) Complexes
Authors: Wang Hsin‐Ell , Liu Shiuh‐Tzung , Lee Gene‐Hsian , Cheng Ming‐Chu , Peng Shie‐Ming
Published: June 2015

Reaction of copper(I) chloride with 2,2‐bis(diphenylphosphinomethyl)‐l‐phenylthiopropane P2S produced a dimeric species [(P2S)CuC1]2 (2). Treatment of 2 with silver nitrate in acetonitrile gave a hexameric crystalline metal complex {[(P2S)Cu(CH3CN)]6+6NO3} (4), which had a “cyclodextrin‐type” structure. A linear polymeric copper complex [(P2S)Cu(NO3)]n was obtained by recrystallization of 4 in chloroform. These complexes were characterized by single crystal analyses, and their coordination behaviors in solution are discussed.
13C NMR Substituent Parameters of Dithioacetal Groups in Benzene Derivatives. The σp+ Values of Cyclic Dithioacetals
Authors: Tzeng Yih‐Ling , Wong Ken‐Tsung , Cheng Wen‐Lung , Luh Tien‐Yau
Published: June 2015

The 13C NMR spectra of forty‐six cyclic dithioacetals and their derivatives have been studied. A set of shift parameters was established for each of these heterocycles as substituent. Based on the Hammett type correlation for substituted benzenes, the σP +values of cyclic dithioacetal groups have been determined.
Nuclear Magnetic Resonance Studies VII. Carbon‐13 Chemical Shifts of Some Methyl‐Substituted Norbornyl P‐Nitrobenzoates
Authors: Liu Kwang‐Ting , Chen Hui‐Ju , Chiu Pao‐Feng , Lee Shu‐Ming
Published: June 2015

The 13C NMR spectra of two unsubstituted and twelve methyl‐substituted norbornylp‐nitrobenzoates (1–14) were measured and unambiguously assigned. The substituent effects were found to be similar to those observed in the corresponding alcohols, but the magnitudes varied. The γ‐effect is more complicated than solely spatially‐dependent.
Application of The Xα and PM3 Methods to Chloromethanes: Ionization Potentials and Electron Affinities
Authors: Lu Yuh‐Jy , Chao Jeng Shiow‐Yau
Published: June 2015

The resonance energies for attachment of an electron to the chloromethanes and the ionization potentials of the chloromethanes were studied both by the multiple scattering Xα‐SCF method and by the PM3 method. An external positively charged Watson sphere is used to stabilize the resonances in the Xα method. The calculated results provide support for the assignment of the features observed in the electron transmission spectra of the chloromethanes.
Enantioselective Addition of Iodine Azide to α,β‐Unsaturated Carboxylic Acid Derivatives
Authors: Lee Pey‐Chen , Wu Chi‐Cheng , Cheng Ming‐Chu , Yu‐Wang  , Wu Ming‐Jung
Published: June 2015

The addition of iodine azide to chiral conjugated N‐enoyl‐sultam or α,β‐unsaturated N‐acyloxazolidinones generated two asymmetric centers at C(α) and C(β) with high π‐face differentiation and regioselectivity. The diastereomerically pure product was easily obtained by crystallization with purity up to 94% de. The structure of 2a was determined by X‐ray diffraction analysis which also indicated that B and 4 are reactive conformations.
Synthesis and Ring Transformation of Pyrrolo[2,3‐d][1,3]oxazine to Pyrrolo[2,3‐d]Pyrimidines
Authors: Bayomi Said M.
Published: June 2015

A convenient route is reported for the synthesis of fused pyrrolo[2,3‐d][1,3]oxazine and pyrrolo[2,3‐d]‐pyrimidine derivatives from 2‐amino‐1‐benzyl‐3‐t‐butoxycarbonyl]‐4,5‐dimethylpyrrole.
A Facile Diagnostic 1H NMR Method for Syn and anti Hydroxy Systems
Authors: Roos Gregory H. P. , Manickum Thavrin , Malissar Dean G.
Published: June 2015

In diastereomeric hydroxyl‐containing systems, the relative 1H‐NMR chemical shift of the carbamate NH of the in situ generated trichloroacetylisocyanate derivatives appear to be diagnostic for the syn and anti stereochemistry.
Advanced Methodologies for Adsorption/Thermal Desorption with Tenax‐TA for the Analysis of Polycyclic Aromatic Hydrocarbons and Sulfur Compounds
Authors: Sye Wen‐Fa , Wu Chun‐Yi
Published: June 2015

We have evaluated an analytical method for the determination of polycyclic aromatic hydrocarbons (PAHs) and sulfur compounds in air by means of adsorption/temperature‐programmed thermal desorption (ATPTD) with small bed volume (0.08g) Tenax‐TA cartridges, followed by a cryogenic trap in a precolumn with liquid nitrogen as an appropriate concentration method before capillary gas chromatography is described. The enriched components from the adsorption cartridges are transferred to the capillary column with a valveless switching system. Recoveries were determined for the complete ATPTD method. Desorption recoveries near 100% were found for various of polycyclic aromatic hydrocarbons and sulfur compounds. The sulfur compounds known to cause nuisance odors in the atmosphere near sulfur recovery and sewerage treatment works were also determined.
Photoluminescence of Acenaphthenone in Organic Solvents and Aqueoug Media
Authors: Chou Liang‐Chen , Tzeng Huey‐Fen , Fang Tai‐Shan
Published: June 2015

The configuration of the lowest excited state of acenaphthenone, S1(π, π*) or T1(π, π*), depending on the solvent, dominates photoluminescence. The T1(n, π*) state in aprotic organic solvents is responsible for the phosphorescence of acenaphthenone. The wavelengths of the phosphorescence measured in benzene are 576 nm and 635 nm (vibronic) with 3.3 × 10−4 quantum efficiency. However, the S1(π, π*) state in protic solution which dominates the fluorescence emission depending upon acidity is the most distinctive feature of acenaphthenone. The wavelengths of the emissions are 446 nm under water solvation with 0.185 quantum efficiency and 538 nm with 0.097 quantum efficiency under high acidity. The emission at 446 nm is assigned from a H‐bonded keto‐form excited state, whereas the emission at 538 nm is probably due to the excited state of protonated keto‐form. The pKa value in aqueous solution measured by diminution of fluorescence in basic solutions is 12.5 ± 0.4.
Synthesis of 4‐Oxo‐1,2,3,4‐tetrahydro‐β‐carbolines via Palladium‐Catalyzed Intramolecular Cyclization of Bromoenaminones
Authors: Yang Shyh‐Chyun , Wang Huey‐Min , Kuo Ching‐Shwu , Chen Ling‐Ching
Published: June 2015

The synthesis of 4‐oxo‐1,2,3,4‐tetrahydro‐β‐carbolines from bromoenaminones derived from 1‐substituted piperidine‐3,5‐dione is described. The reaction proceeds by the intramolecular cyclization of bromoenaminones involving arylpalladium complexes.
Isoquinoline Alkaloids from Neolitsea Konishii
Authors: Lee Shoei‐Sheng , Yang Hsih‐Chin
Published: June 2015

By combination of centrifugal partition chromatography (CPC) and common separation methods, twelve known bases were isolated and characterized from the first chemical investigation of Neolitsea konishii (H.) K. & S. They belong to isoquinoline alkaloids of four types: eight aporphines, nornuciferine (1), N‐methyllaurotetanine (2), laurolitsine (3), boldine (4), laurotetanine (5), isoboldine (6), actinodaphine (7) and corytuberine (8); two proaporphines, stepharine (9) and glaziovine (10); one benzylisoquinoline, reticuline (11); and one morphinan, pallidine (12). Among these, compounds 3, 6 and 11 are abundant and will be modified for pharmacological tests. The content of various alkaloids in the plant is useful as a basis for chemotaxonomy.
The Mediation Effect of a Polyaniline‐Coated Electrode on the Reduction of Iron (III) Ions
Authors: Chi Hsiang‐Fin , Lin Shujywan , Huang Hsuan‐Jung
Published: June 2015

The mediation effect of polyaniline‐coated platinum electrodes on the reduction of iron(III) ions was studied by the cyclic voltammetry and rotating disk electrode methods. The rate constants of the cross reaction between iron(III) ions and polyaniline (PA) were found to depend upon the amount of PA coated on the electrode. On the basis of the rate constants the PA‐coated electrode mediates the reduction of iron(III) ion efficiently and behaves as well as a metallic electrode.
Determination of Trace Butyltin Compounds in Sea Water by Gas Chromatography‐Atomic Absorption Spectrometry
Authors: Liou Der‐Chyuan , Lou Yuan‐Chi , Whang Chen‐Wen
Published: June 2015

A gas chromatography‐atomic absorption spectrometric (GC‐AAS) method has been developed for the determination of trace butyltin compounds in sea water. Aqueous butyltin compounds were reduced to the volatile hydride forms by NaBH4 and were extracted with dichloromethane simultaneously. The dichloromethane extract was concentrated under reduced pressure, followed by direct injection into the GC‐AAS system for analysis. The butyltin species were separated with a 2‐m glass column packed with 2% OV‐101 on Chromosorb G HP (100‐120 mesh). Following GC separation, each species was transferred into an electrothermally heated (800 °C) quartz furnace for atomization. The tin atoms produced from individual butyltin compound were detected at 224.6 nm by an atomic absorption spectrometer. With a sea water sample (1 L), the detection limits (3σ) for monobutyltin, dibutyltin and tributyltin were approximately 20, 20 and 70 ng Sn L−1, respectively. The method has been applied to the analysis of trace butyltin compounds in the sea water of Keelung Harbor.
Solution Conformation of Gramicidin S Determined by Nuclear Magnetic Resonance and Distance Geometry Calculation
Authors: Yu Chin , Hwang Jan‐Fu , Yeh Chao‐Jung , Chuang Li‐Chin
Published: June 2015

The solution conformation of the homodetic decapeptide antibiotic Gramicidin S has been determined by two‐dimensional 1H NMR spectroscopy and distance geometry followed by energy minimization. All structures corresponding to energy minima have four intramolecular hydrogen bonds between Leu and Val residues.
Spectrophotometric Determination of Ziram by Coprecipitating the Corresponding Copper(II) or Palladium(II) Complex with Naphthalene
Authors: Malik Ashok Kumar , Rao A. L. J.
Published: June 2015

A spectrophotometric method has been developed for the determination of zinc dimethyldithiocarbamate (ziram) by converting it into dimethyldithiocarbamate and coprecipitating its copper(II) and palladium(II) dimethyldithiocarbamate complexes and coprecipitating onto microcrystalline naphthalene. Palladium(II) and copper(II) complexes absorb strongly at 395 nm and 430 nm, respectively. The interference of various ions has been studied and the method has been applied to determine ziram in commercial samples and grains.
Synthesis and Chemistry of 2,5‐Dimethylene‐2,5‐Dihydrofuran
Authors: Chen Ping‐Shu , Chou Chin‐Hsing
Published: June 2015

2,5‐Dimethylene‐2,5‐dihydrofuran (3), generated flash pyrolitically, underwent di‐ and trimerization reactions to give cyclic dimer and trimer. Compound 3 was trapped with methanol, ethanol, bromine, acetic acid, thiophenol and oxygen. Results from trapping experiments suggest that the diradical form of 3 is involved.
Reinvestigation of the Cleavage of Canadine, A Protoberberine Bearing a Methylenedioxy Function, with Sodium in Liquid Ammonia
Authors: Lee Shoei‐Sheng , Lee Jih‐Horng , Lin Chia‐Yin , Ng Siew‐Leng , Chen Chung‐Hsiung
Published: June 2015

Two products, 3‐hydroxy‐9,10‐dimethoxyprotoberberine and 3,9‐dihydroxy‐10‐methoxyprotoberberine in addition to those reported, 2‐hydroxy‐9,10‐dimethoxyprotoberberine and 2,9‐dihydroxy‐10‐methoxyprotoberberine, were identified from cleavage of canadine with sodium in liquid ammonia. This reaction indicates regioselectivity rather than the reported regiospecificity by cleavage mainly at a site para to the N‐methine carbon.
Electron Paramagnetic Resonance Study on Supported Molybdenum Catalysts. Part 1: Interaction of Molybdenum Oxide with Silica and Signal Anlsotropy
Authors: Wang Yih‐Pean , Yeh Chuin‐Tih
Published: June 2015

The effects of reduction, evacuation and adsorbate adsorption on Mo/SiO2 catalysts prepared by impregnation were studied by means of the electron paramagnetic resonance (EPR) technique. Pentavalent molybdenum species in the overlayer (Mo05+, g⟂ = 1.941, g| = 1.895) and at the interface (Moi5+, g⟂ = 1.952, g| = 1.866) between MoO3 and SiO2 were distinguished in the EPR spectra; they were observed from samples reduced at T < 573 K and T > 573 K respectively. The difference in their nature reflected the extent of their interaction with the support. Mo05+ existed in the MoO3 overlayer of the catalyst and interacted only weakly with the support. Moi5+ from the Mo ions connected directly to SiO2 was affected strongly by the support. The anisotropic factor of the measured Moi5+ signals increased with the extent of support interaction.

Superoxide ions (O2, g1 = 2.016, g2 = 2.011, g3 = 2.006) were found upon oxygen adsorption on samples evacuated at temperatures above 573 K. The observed O2 may exist at the interface between MoO3 and the support.
Determination of Iodide as an Organic Derivative by Gas‐Chromatography
Authors: Kou Hwang‐Shang , Wu Hsin‐Lung , Chen Su‐Hwei , Lin Shun‐Jin
Published: June 2015

A simple and specific method is described for the analysis of iodide in trace proportions. The method is based on the reaction of iodide with pentafluorobenzyl 5‐dimethylamino‐1‐naphthalenesulfonate.in a biphasic system. The resulting derivative was determined on a gas chromatograph with a flame‐ionization detector. The detection limit was about 8 nmol of iodide in 1.0 mL of aqueous sample (S/N = 2; sample size, 5 μL). Application of the method to the analysis of available iodine in povidone‐iodine solution proved feasible.
Facile Synthesis of α‐Polythienyls via 1,4‐Diketones
Authors: Luo Thung‐Mei H. , Legoff Eugene
Published: June 2015

Unsubstituted and substituted linear polythienyls including thiophenes in both even and odd numbers are conveniently prepared from the Michael addition of thiophenecarboxaldehydes to Mannich bases and the vinyl sulfone. Cyclization of the resulting 1,4‐diones with Lawesson's reagent gives α‐polythienyls.
Radial Functions of AIH X 1∑+ from Vibration‐Rotational Spectra ana Spectral Properties of the Group 13 Hydrides
Authors: Ogilvie J. F.
Published: June 2015

The coefficients Cj, j ≤ 9, defining the potential‐energy V(z) and coefficients of two other radial functions related to adiabatic and nonadiabatic effects have been determined for AlH in the electronic ground state X 1∑+ by a direct fit to the published frequencies and wavenumbers of vibration‐rotational transitions of 27Al1H and 27Al2H. The functions are valid in the range of internuclear distance/10−10 m [1.24, 2.60]. Some trends in the spectral properties of the group 13 hydrides AlH, GaH, InH and TlH are discussed. The possibility of determining the rotational magnetogyric factor gj from the available data of only wavenumbers of vibration‐rotational transitions is considered; an approximate value gj ∼ −2.25 is deduced for 27Al1H.
Determination of Aggregation Parameters of Hexadecyltrimethylammonium Bromide from Probe Absorption
Authors: Amire O. A. , Layemo F. E. , Burrows H. D.
Published: June 2015

The mean aggregation number (n) and the critical micelle concentrations (CMC) of reverse micelles formed by hexadecyltrimethylammonium bromide have been determined by means of an optical absorption probe (acridine orange). The procedure to obtain these quantities from absorption spectrophotometric measurements is described. The CMC and mean aggregation number are in satisfactory agreement with published results obtained from more sophisticated methods.
Nucleophilic Addition to (η3‐Allyl)Fe(CO)4 Cations with Functionalized Zinc‐Copper Reagents RCu(Znl)CN
Authors: Tau Sen‐I , Yeh Ming‐Chang P.
Published: June 2015

Regioselectivity of the addition of the highly functionalized zinc‐copper reagents to (η3‐allyl)Fe(CO)4 cationic salts was studied. For 1,1‐disubstituted allyl cation 1, the zinc‐copper reagents added predominantly at the unsubstituted terminus. For 1,1,2‐trisubstituted allyl cation 2, reactive zinc‐copper reagents attacked mainly at the unsubstituted terminus while less reactive zinc‐copper reagents added to a coordinated CO ligand. For 1,1,3‐trisubstituted allyl cation 3, the addition occurred at both the less substituted allyl terminus and a coordinated CO ligand.
Photochemical Rearrangements of 6‐Methoxymethylbicyclo[4.4.0]Dec‐1‐En‐3‐One and 6‐Methoxymethylbicyclo[4.3.0]Non‐1‐En‐3‐One
Authors: Lai An‐Kuo , Liao Chun‐Chen
Published: June 2015

The irradiation of the title compounds 6 and 12 in isooctane and benzene was investigated. The photochemical reactions took place sluggishly upon n→π* excitation (λ > 300 nm) in deoxygenated solutions but more rapidly in the presence of air; deconjugation to yield β,γ‐unsaturated ketones and lumiketone rearrangement were the main primary photochemical reactions. In contrast, intramolecular hydrogen abstraction by the Cα‐carbon was the main reaction upon π→* excitation (λ = 254 nm).
Reglochemistry in Electrophilic Reactions of Propanedlthio‐Substituted Allylic Anions Influenced by the γ‐Substituents
Authors: Fang Jim‐Min , Chen Ming‐Yi
Published: June 2015

The dienyl anion 1f, generated from metallation of 2‐(1,3‐pentadienyl)‐1,3‐dithianc with n‐BuLi in THF, reacted exclusively at the C‐1 position (α‐site) with alkylating agents and ketones, but it showed some tendency toward the C‐3 position (γ‐site) in the reactions with benzyl bromide and aliphatic aldehydes. No reaction at the C‐5 position (ϵ‐site) was observed in any studied case. Examination of the related propanedithio‐substituted allylic anions having various γ‐substituents revealed that the regiochemistry was remarkably influenced by the γ‐substituents and the attacking electrophiles. The electronic effect according to the principle of hard and soft acids and bases is proposed to account for the observed regiochemistry, while the steric factor was minor. Two trienes, obtained by alkylations of the dienyl anion 1f with 4‐bromo‐1‐butene and 5‐pentenyl methanesulfonate, were applicable to intramolecular Diels‐Alder reactions to give bicyclic compounds.
Free Radical Reaction between 1,6‐Dienes and P‐Toluenesulfonyl Cyanlde
Authors: Chuang Che‐Ping , Ngoi Tak Ho Johnny
Published: June 2015

A sulfonyl‐radical‐induced addition‐cyclization reaction of 1,6‐dienes with p‐toluenesulfonyl cyanide giving functionalized cyclopentane systems is described.
Acetylation and Debromination of Sydnones Accelerated by Ultrasound
Authors: Tien Hsien‐Ju , Yeh Jong‐Chuan , Wu Shi‐Chen
Published: June 2015

In the presence of a catalytic amount of 60% perchloric acid, 4‐acetyl‐3‐substituted sydnones were obtained more conveniently with greater yields by the sonochemical reaction of 3‐substituted sydnone with acetic anhydride. Some 4‐acetylsydnones which are difficult to synthesize by a known process were obtained in 17‐68% yields.

4‐Bromo‐3‐(bromoaryl)sydnones with activated zinc powder dispersed in methanol were debrominated regioselectively by ultrasound in high yields (60‐96%). 3‐(2′‐/4′‐Amino‐3′,5′‐dibromophenyl)sydnone is synthesized easily from 3‐(2′/4′‐aminophenyl)sydnone by reduction, bromination and debromination subsequently.
Synthesis of (±)‐Lsodeoxypodophyllotoxin
Authors: Zee Sheng‐Hsu , Chou Shan‐Yen
Published: June 2015

A process for the synthesis of (±)‐isodeoxypodophyllotoxin starting from ethyl 3,4‐methylcnedioxy‐benzoacetate and methyl 3,4,5‐trimethoxycinnamate is described.
Additional Isoquinoline Alkaloids from Lltsea Cubeba
Authors: Lee Shoei‐Sheng , Chen Chien‐Kuang , Chen Ih‐Sheng , Liu Karin C. S.
Published: June 2015

By combination of centrifugal partition chromatography (CPC) and common separation methods, seven additional known bases were isolated and characterized from the reinvestigation of L. cubeba besides three previously isolated bases‐ isocorydine (10), N‐methyllaurotetanine (9), and boldine (2). They are laurolitsine (1), laurotetanine (3), isoboldine (4), norisocorydine (5), N‐methyllindcarpine (7), isodomesticine (8), and glaziovine (6). Among these, compound 9 is the most abundant (7.5 × 10−4) and will be modified for pharmacological tests. This work will be of value for chemotaxonomy.
Determination of Tributyltin in Sea Water by Hydride Generation‐Atomic Absorption Spectrometry
Authors: Chen Jia‐Jeng , Lou Yuan‐Chi , Whang Chen‐Wen
Published: June 2015

A hydride generation‐atomic absorption spectrometry (HG‐AAS) procedure is described for the analysis of tributyltin (TBT) in sea water. TBT is first converted to its volatile hydride form by reaction with sodium borohydride, followed by cryogenic trapping at −196°C, and finally detection by atomic absorption spectrometry using an electrically heated quartz atomization cell. The linear range of calibration is 5‐250 ng TBT (as tin). At the 5‐ng level, the relative standard deviation (RSD) is 13%. The absolute detection limit (3σ) is 1.8 ng. Based on a sample volume of 500 mL, this value corresponds to a concentration detection limit 3.6 ng L−1 TBT This method has been successfully applied to the analysis of TBT in sea water collected from Keelung and Kaohsiung harbors.