bluuebunny/crossref_metadata_2025 huggingface dataset:
Photodissociation Dynamics of Benzene at 193 nm
Authors: Hsu Tzu C. , Shu Jiman , Chen Yang , Lin Jim J. , Lee Yuan T. , Yang Xueming
Published: May 2015

Photodissociation of benzene at 193 nm has been investigated using the photofragment translational spectroscopy (PTS) technique. H atom elimination channel for benzene at 193 nm is from a one‐photon dissociation process, while H2 and CH3 elimination channels come from a two‐photon excitation process.
QSPR Analysis of Phenylthio Phenylsulfinyl and Phenylsulfonyl Esters Using Quantum Chemical Semi‐Empirical Descriptors
Authors: Yin Chunsheng , Liu Shushen , Yu Hongxia , Wang Liansheng
Published: May 2015

Quantitative structure‐property relation ships (QSPR) were developed with the quantum semiempirical descriptors computed by AM1 Hamiltonian in MOPAC7.0 for phenylthio, phenylsulfinyl and phenylsulfonyl esters. Using step wise regression analysis with a cross‐validation procedure, the most potent and in formative descriptors were screened out from a group of 19 quantum chemical semi‐empirical descriptors, including steric and electronic types, to build QSPR models. Several equations were obtained and used to estimate and predict octanol/water partition coefficients and reversed phase high‐performance liquid chromatography (HPLC) capacity factors for a series of 30 similar sulfur‐containing compounds. The results indicate that molecular descriptors, including average molecular polarizability (α), energy of the lowest unoccupied molecular orbital (ELUMO), net atomic charge on carbon atoms in the carbonyl (QCO), molecular weight (MW), the most positive atomic charge on hydrogen atom (QH+), and net atomic charge on oxygen atoms in the group‐NO2 (QNQ2) are the main factors affecting the octanol/water partition coefficients of the compounds under study. And quantum descriptors, covering the most negative atomic charge on an atom Q−), net atomic charge on carbon atoms in the carboxy (QCOO), molecular weight (MW), heat of formation (HF), the most positive atomic charge on a hydrogen atom (QH+), and total energy (TE), are the main factors affecting HPLC capacity factors of these compounds. Rational mechanisms for the two physico‐chemical proper ties of the sulfur‐containing carboxylates were discussed and interpreted.
O. Carboxyphenylhydrazoethylacetoacetate as an Analytical Reagent for the Determination of Cu(II) and Co(II) in Complex Materials
Authors: Sirry S. M. , Taha G. M.
Published: May 2015

An extraction‐spectrophotometric method for the determination of trace amounts of copper and cobalt based on their extraction into n‐pentanol with 0. carboxyphenylhydrazoethylacetoacetate (O.CPHEAA) was per formed. Copper was extracted from pH 6.0 – 8.0 and ionic strength 0.5 M – KCl. The maximum absorption of the extracted Cu(II) ‐ O.CPHEAA complex (1:1 & 1:2 species) occurs at 415 nm. The proposed method succeeded in as saying a concentration of 3–63 μg per 10 mL of n‐pentanol (ϵ = 1.25 × 104L mol−1 cm−1). The method failed to ex tract cobalt ion into various organic sol vents over a pH range of 2–11. The suggested method is highly selective and sensitive according to a wide scheme of interference studied. Copper in some plant samples was accurately estimated using the suggested method. The obtained results and the results of the AAS method were consistent. The reproducibility test shows a relative standard deviation of 1%. Sandell sensitivity for A = 0.001 is 5 × 10−3 μg cm−2.
Cooperativity between Bo Vine Serum Albumin (BSA) and Crystal Line of Calcium Carbonate in Distilled Water
Authors: Yang Lin , Ma Xiao‐Ming , Zhang Xiu‐Ying , Tang Jun‐Ming , Jiang Kai , Guo Yu‐Ming
Published: May 2015

Biological matrices can direct the in organic crystals such as vaterite. Cooperativity between organic matrices and in organic crystals resulted in similar co‐alignment of vaterite in aqueous solution of bovine serum albumin (BSA). And further, the secondary structures of BSA were also changed in the crystallization process. These results indicate the kinds of interactions that may occur in biological systems where large arrays of crystals are co‐aligned.
The Synthesis of Naphthosultine and Benzodisultines and Their Pyrolysis with Dienophiles: Studies on o‐Naphthoquinodimethane and Bis‐o‐Quinodimethane
Authors: Wu An‐Tai , Liu Wen‐Dar , Chung Wen‐Sheng
Published: May 2015

Sealed tube reactions of the naphthosultine 8 with a series of electron‐deficient dienophiles (fumaronitrile, N‐phenylmaleimide, dimethyl fumarate, and dimethyl acetylenedicarboxylate) in toluene at 180 °C gave corresponding 1:1 cycloadducts 11–14 in various amounts along with rearranged naphthosulfolene 7 in 67–95% yields. The reaction of 1,2,4,5‐tetra(bromomethyl)benzene with Rongalite (sodium form aldehyde sulfoxylate) and tetrabutylammonium bromide in DMF gave benzodisultines 17 and 18 in a combined yield of 56%. Sealed tube reactions of benzodisultines 17 and 18 with a series of dienophiles in xylene at 200 °C gave corresponding 1:1 and 1:2 cycloadducts 20–27. The results suggested that thermal extrusion of sulfurdioxide from these sultines led to either o‐naphthoquinodimethane 6 (from 8) or bis‐o‐quinodimethane 19 (from 17 and 18); sub sequent trapping of these reactive intermediates by dienophiles and SO2 gave various 1:1 and 1:2 Diels‐Alder ad ducts in modest to excellent yields.
Trisannelated Benzene Synthesis by Copper(II) Chloride
Authors: Mahmoodi Nosrat O. , Hajati Nezam
Published: May 2015

Different ketones such as cyclohexanone, cyclopentanone, acetophenone, 2‐acetonaphthalene, 4‐methylcyclohexanone in the presence of an hydrous CuCl2 (catalytic amounts) at reflux condition for 2–4 hours, without using a solvent led to dimers 2‐(1‐cyclohexane‐1‐yl)‐cyclohexanone 6, 2‐cyclopentylidene cyclopentanone 10, trimer dodecahydrotriphenylene (DTP) 4, trindan (tricyclopentabenzene) 9, 1,3,5‐ triphenylbenzene (TBP) 12a, 1,3,5‐tri β‐naphthylbenzene 12b and dodecahydro‐2,6,10‐trimethyltriphenylenes 17 and 18.
2,3,7‐Triazabicyclo[3.3.0]octenes Prepared by Tandem Cascade Reaction of Allyl Azides and Olefinic Dipolarophiles
Authors: Yang Chia‐Hsi , Sherf Huang‐Jang , Wang Ruey‐Hsuan , Wang Ju‐Chun
Published: May 2015

Tandem cascade reactions of allylazides and olefinic dipolarophiles to give cis‐fused 2,3,7‐triazabicyclo [3.3.0]octenes (5, 6 or 7) are reported. Therein, an intermolecular dipolar cycloaddition of azide and alkene gave a triazoline which was followed by isomerization of the triazoline to a diazoester (4) and then an intramolecular dipolar cycloaddition from the diazo functional group and the double bond in 4 to give 5. Compound 5 may further more undergo a Michael addition to give 7‐substituted‐ 2,3,7‐ triazabicyclo [3.3.0]oct‐2‐ene (6) or a tautomerization to give 2,3,7‐triazabicyclo[3.3.0]oct‐3‐ene (7). The reaction may be manipulated to stop at a particular stage by adopting a suit able solvent or an appropriate temperature.
Chemical Constituents from the Leaves of Zanthoxylum Schinifolium
Authors: Cheng Ming‐Jen , Yang Cheng‐Hui , Lin Wen‐Yu , Lin Wei‐Yu , Tsai Ian‐Lih , Chen Ih‐Sheng
Published: May 2015

cis‐Fagaramide (1), a new amide, together with fifty known compounds, have been isolated from the leaves of Zanthoxylum schinifolium. These known compounds include twenty‐one coumarins, eleven alkaloids, one furan, four benzenoids, three chlorophylls, four triterpenoids, one diterpenoid, one sesquiterpenoid, and four steroids. The structures of these compounds were determined by means of spectral analyses.
Sesquiterpenes from Ligularia Hodgsonii
Authors: Liao Jian‐Chun , Zhu Qi‐Xm , Yang Xiu‐Ping , Jia Zhong‐Jian
Published: May 2015

A new nor‐sesquiterpenoid eremophilane derivative and a new eudesmane derivative were isolated from the whole plants of Ligularia hodgsonii. Their structures were elucidated by spectroscopic methods and 2D NMR techniques.
Advent and Progress of Spin Chemistry
Authors: Hayashi Hisaharu
Published: May 2015

The field of Spin Chemistry includes various subjects concerned with the influence of magnetic fields on chemical and biochemical reactions such as magnetic field and magnetic isotope effects (MFE and MIF) and chemically induced dynamic nuclear and electron polarization (CIDNP and CIDEP). Although this field started in the middle 1960s, it has been expanding now and has established its identity as one of the most promising research areas in the 21st century. The first half of this review shows how the field of Spin Chemistry was brought about from a veil of secrecy. This review also shows how the author's group has contributed to the advent and progress of Spin Chemistry. The second half of this review introduces the recent results obtained by the author's group for the MFEs on photo chemical reactions in solution with a pulsed‐magnet (maximum field ∼ 30 T), a pico second‐laser photolysis apparatus, and higher spin species than S = 1.
Extraction Behaviour of Cyanex‐923 and Cyanex‐471X Towards the Rhodium(III) from Bromide Media and Its Separation from other Platinum Metals
Authors: Duche S. N. , Chavan D. V. , Dhadke P. M.
Published: May 2015

The extraction of Rh(III) from bromide media with Cyanex‐923 and Cyanex‐471X in toluene was studied. The quantitative extraction of Rh(III) with extractants was found by studying the different parameters like, hydrobromic acid concentration, extractant concentration, diluents and effect of temperature on extraction. The optimum condition was [HBr] = 1.0–1.5 moll−1, [SnCl2] = 0.2 moll−1 with [Cyanex‐923] = 0.15 moll−1, while it was [HBr] = 1.5–2.0 moll−1, [SnCl2] = 0.4 moll−1 with [Cyanex‐471X] = 0.8 moll−1 in toluene. The quantitative extraction was observed only in the presence of SnCl2 for both extractants. The complete recovery of Rh(III) from the Cyanex‐923 extracted organic phase was observed with the 1:1 mixture of (4.0 moll−1 HCl + 2.0 moll−1 HNO3), and that with the Cyanex‐471X extracted organic phase was found with 1:1 mixture of (2.0 moll−1 H2SO4 + 1.0 moll−1 KMnO4). Stoichiometric ratio of Rh(III) with both extractants was 1:1. The proposed methods were employed for extraction and separation of Rh(III) from other platinum metal ions and also for recovery of Rh(III) from a synthetic solution of spent autocatalysts.
Electrochemical Study of Schiff Bases by Means of Self‐Assembled Monolayers
Authors: Dmg Keqiang , Wang Qingfei , Jia Zhenbm , Tian Na , Wang Ning , Tong Ruting , Wang Xinkui , Shao Huibo
Published: May 2015

In this paper, Schiffbases were investigated using cyclic voltammetry (CV) and impedance electrochemical spectroscopy (EIS) techniques by means of self‐assembled monolayers for the first time, where a 0.1 M KCl solution and the redox couple of Fe(CN)63−/Fe(CN)64−were used as the electrolyte and probing‐pin, respectively. The monolayers formed by the employed Schiff base were proved to be relatively stable, and its electrochemical response in the studied system with different pH values was also de scribed clearly with CV and EIS plots. The results show that the monolayer of Schiff bases could exist in the solution with pH value from 2 to 10. In the EIS measurement in the concentration range from 10−5 M to 5× 10−4 M, a nearly linear relation ship between the charge transfer resistance (Rct) and the logarithm concentration of Cu2+was observed, suggesting that Cu2+ could be titrated with the EIS method quasi‐quantitatively. The phenomenon agreed with the former report very well. Using the self‐assembled monolayers to study Schiff bases with the electrochemical method is the major contribution of our work.
Synthesis of New Reagent 2‐Acetylthiophenethiocynate and its Use in Extraction of Pt(IV) Spectrophotometrically
Authors: Chaudhary Avinash Baliram , Shrinivasan Nirupa , Lokhande Rama Sadashiv
Published: May 2015

2‐Acetyl thiophenethiocynate (ATT) was synthesized and its characterization study was carried out using elemental analysis, IR and NMR techniques. The new reagent was proposed as an extractant for the development of the extractive spectrophotometric method for determination of Pt(IV) metal. The reagent complexes with the metal to produce a yellow colored complex which was then extracted into ethyl acetate at pH 11.2–11.6 having an absorption maxima at 400 nm. The thermal study showed that the extraction reactions are exothermic in nature with the reagent, and the stoichiometric ratio of Pt(IV) to 2‐acetyl thiophenethiocynate in the organic phase was 1:2. The method permits separation and determination of platinum from real and binary mixtures. The separation of Pt(IV) from bivalent metal ions has been also studied.
Studies on the Reaction of α‐Chloroformylarylhydrazine Hydrochloride1 with N‐Heterocyclic Compounds
Authors: Chiu Chun‐Yen , Kuo Chao‐Nan , Kuo Wen‐Fa , Yeh Mou‐Yung
Published: May 2015

In addition to pyridines, α‐chloroformylarylhydrazine hydrochloride 1 can also react with some N‐heterocyclic compounds. The cycloaddition of 1 with isoquinoline was achieved to obtain 3. The production of 4, 5, 6 given by cycloaddition of 1 with pyridazine was de pendent on the reaction condition. Some heterocyclic compounds bearing an X‐C=N (X:S, N) group on the ring can react with 1 to gain the derivatives of 2,4‐dihydro‐1,2,4‐triazol‐3‐one. 7, 8, 9 and 10 were given by reaction of 1 with 1,3,5‐triazine, 1,4,5,6‐tetrahydropyrimidine, 1,3‐thiazole and 2‐amino‐1,3‐thiazole, respectively. The reactions for 2‐amino‐1,3,4‐thiadiazole and 3‐amino‐1,2,4‐triazole had the same product 11.
Synthesis and Characterization of Transition Metal Complexes of Potassium 3‐(Pyridine‐4‐Carbonylmethyl)‐Dithiocarbazate
Authors: Liu Dong , Liu Su‐Yan , Yang Xin‐Ping , Xu Peng‐Fei , Zhang Zi‐Yi
Published: May 2015

The preparation and characterization of some dipositive metalion complexes de rived from potassium 3‐(pyridine‐4‐carbonylmethyl)‐dithiocarbazate (PCDHK) are reported. The solid complexes of the composition ML·nH2O (M=Cu(II), Co(II), Mn(II), Zn(II), Cd(II), Ni(II), Pb(II), L = PCD−2, n = 0, 1, PCD−2=PCDHK‐K+‐H+) and ML2·2H2O (M=UO2(IV), L=PCDH−1, PCDH−1=PCDHK‐K+) have been characterized by elemental analyses, IR, UV, and 1HNMR spectra. The IR spectral data indicate that PCDHK be haves as either a mononegative or binegative ligand and coordinates in a tridentate or bridging tetradentate manner.
Chemical Components from Leontopodium Nanum
Authors: Wang Ying , Zhu Qi‐Xiu , Yang Min , Jia Zhong‐Jian
Published: May 2015

Phytochemical investigation of the whole plant of Leontopodium nanum afforded a new coumarin named leontonanin (1), together with six known compounds, umbelliferone (2), 3,4′, 7‐trihydroxyflavone (3), oleanolic acid (4), β‐sitosterol (5), daucosterol (6) and stearic acid (7). The structure of compound (1) was elucidated by spectroscopic methods including 2D‐NMR techniques.
Radicals Containing Hydrogen, Carbon and Oxygen Atoms
Authors: Bersohn Richard
Published: May 2015

There is much new information available on radicals containing C, H and O atoms. Indeed, most of the data discussed in this review did not exist twenty years ago. New, more powerful laser and microwave experimental techniques have greatly expanded our knowledge of the energetics, spectra, reactions and decomposition processes of these radicals. This review attempts to give a unified discussion of the radicals.
Preparation and Structure of [(η5‐C5H5)Fe(CO){C(O)Ph}2]2Li2(2,2′‐Bipyridine): A Sequential Treatment of Nucleophile Followed by Lewis Base
Authors: Liu Ling‐Kang , Peng James , Huang Candice
Published: May 2015

Unable to elaborate (η5‐C5H5)Fe(CO)2C(O)Ph by the nucleophile/electrophile sequences, the treatment of nucleophile PhLi followed by Lewis base 2,2′‐bipyridine instead leads to the meaningful isolation of [(η5‐C5H5)Fe(CO) {C(O)Ph}2]2Li2(2,2′‐bipyridine).
Hydrous Pyrolysis of Methylphenanthrenes – Degradation and Isomerization
Authors: Wu Suh‐Huey , Wang Yane‐Shih , Fan Lian‐Xin , Chang Robert T. D. , Huang Ded‐Shih
Published: May 2015

A simulation of the chemical transformations of methylphenanthrenes in sediment was performed using hydrous pyrolysis technique. The results indicate that isomerization is not the primary cause of the change in the MPI1 index. Rather, the degradation reaction of methylphenanthrenes to phenanthrene is one of the most likely causes reversing the trend of the MPI1 index with increasing the heating temperature. An unusual isomerization between 2‐methylphenanthrene and 9‐methylphenanthrene was also observed during the course of heating experiments. A plausible mechanism involving [1,5]‐methyl shift was proposed for this isomerization reaction.
Kinetic and Thermodynamic Parameters of the Thermal Decomposition of Some Metal Complexes of 4‐Benzamido‐3‐Thiosemicarbazone Derivatives
Authors: Emam M. E. M.
Published: May 2015

The kinetic and thermodynamic parameters such as reaction order, activation energy, enthalpy, free energy and entropy change related to the thermal decomposition of Co(II), Ni(II) and Cu(II) hydrazone complexes of 4‐benzamido‐1‐(4‐actylpyridine)‐3‐thiosemicarbazone (BACPT) and 4‐benzamido‐1‐(pyridine‐3‐aldehye)‐3‐thiosemicarb‐azone (BAPT) were evaluated from differential thermal analysis (DTA) curves using Thomas‐Clarke's method. The thermal stability of these complexes are discussed in relation to the nature of the metalion and of the ligand present. A suitable mechanism for the thermal decomposition process of the complexes based on the data of the thermogravimetric analysis (TGA) was suggested.
Syntheses and Structures of Zinc(II) Co‐Ordination Polymers Bridged by Flexible Bidentate Nitrogen Ligands
Authors: Suen Maw‐Cherng , Wu Ymg‐Yann , Dong Guo‐Chung , Chen Jhy‐Der , Keng Tai‐Chiun , Wang Ju‐Chun
Published: May 2015

The reaction of Zn(NO3)2·6H2O and bpp (bpp = 1,3‐Bis(4‐pyridyl)pronpane) in CH3OH afforded the complex [Zn(bpp)(NO3)2]n, 1. The IR has been recorded and the structure has been determined. Crystal data for 1: Space group P2(1)/n, a = 11.749(1), b = 11.413(1), c = 11.942(1) Å, β = 96.06(6)°. V = 1592.5(3) Å3, Z = 4 with final residuals R1 = 0.0484 and wR2 = 0.0984. The complexes show supramolecular structure in the solid state by intermolecular hydrogen bonding interaction.
Synthesis and Spectroscopic [Electronic, IR, NMR (1H, 13C, 89Y)] Characterization of Hexaisopropoxoniobates and ‐Tantalates of Yttrium(III) and Lanthanides(III)
Authors: Mishra Shashank , Tripathi Upendra M. , Singh Anirudh , Mehrotra Ram C.
Published: May 2015

Hexaisopropoxoniobates/tantalates of lathanides of the type [Ln{(μ‐OPri)2M(OPri)4}3] (M = Nb, Ln = Y(1), La(2), Nd(3), Er(4), Lu(5); M = Ta, Ln = Y(6), Gd(7)) have been prepared by the reactions of LnCl3.3PriOH with three equivalents of KM(OPri)6 in benzene. Reactions in 1:2 molar ratio of LnCl3.3PriOH with KTa(OPri)6 yielded derivatives of the type [{(PriO)3Ta(μ‐OPri)3}Ln{(μ‐OPri)2Ta(OPri)4}(Cl)] (Ln = Y(8), Gd(9)), which on interactions with one equivalent of KOPri afforded [{(PriO)3Ta(μ‐OPri)3}Ln {(μ‐OPri)2Ta(OPri)4}(OPri)] (Ln = Y(10), Gd(11)). All these derivatives have been characterized by elemental analyses and molecular weight measurements as well as by their spectroscopic [IR, 1H and 13C NMR (Y, La, Lu), electronic (Nd, Er)] studies. 89Y NMR studies have also been carried out on derivatives (6), (8), and (10).
2‐Aminocyclopentene‐1‐Dithiocarboxylic Acid‐Naphthalene Adsorbent for the Preconcentration and Determination of a Trace Copper in Real Samples by Spectrophotometric Method
Authors: Gholivand Mohammad B. , Sobhani Shahin , Khirdoosh Fahimeh
Published: May 2015

A solid uncharged complex produced from 2‐aminocyclopentene‐1‐dithiocarboxylic acid (synthetic reagent) on naphthalene provides a very sensitive, selective and economical method for the preconcentration and determination of trace amounts of copper in drug and alloy samples. The 2‐aminocyclopentene‐1‐dithiocarboxylate of copper is retained quantitatively on microcrystalline naphthalene in the pH range 2.8–3.3. After filtration the solid mass consisting of copper complex‐naphthalene is dissolved with 4 mL of dimethylformamide (DMF). The absorbance is measured at 462 nm with a spectrophotometer against the reagent blank and molar absorptivity found to be 2.8 × 105 liter mol−1 cm−1. Beer's law is obeyed over the concentration range of 0.1–16.0 μg of copper in 4 mL of the dimethylformamide solution.

Detection limit is 3 ng mL−1 [signal to noise ratio = 2]. Ten replicate determinations on a sample containing 1 μg of copper gave a relative standard deviation of 0.76%. The interference of a large number of anions and cations have been studied and the optimized conditions developed were utilized for determination of copper in various real samples.
Chiral Liquid Crystals Synthesized from 2(S)‐[2(R)‐Methylhexyloxy]Propanol and its (S,S)‐Diastereomer
Authors: Lee Hui‐Chen , Hsie Ming‐Jing , Yeh Shu‐Wen , Cheng Pao‐Swu , Tsai Wen‐Liang
Published: May 2015

Two new chiral alcohols, 2(S)‐[2(R)‐methylhexyloxy]propanol (5) and 2(S)‐[2(S)‐methylhexyloxy]propanol (6), were prepared from the corresponding propionic acid ethyl ester 1 and 2 in the presence of sodium borohydride. They were used as the chiral moiety for the synthesis of two diastereomeric liquid crystals 7 and 8. Both of them exhibit the phase sequence I‐SmA‐SmC*‐SmX‐Cr. The mesogenic properties of the (S,S)‐diastereomer 8 are more unique in comparison with those of the (S,R)‐diastereomer 7. It possesses not only lower SmA and SmC* phase transition temperature, 103 °C vs. 112 °C for SmA phase and 31 °C vs. 65 °C for SmC* phase, but wider SmA and SmC* phase range, 40 °C vs. 31 °C for SmA phase and 72 °C vs. 47 °C for SmC* phase. The diastereomer 8 also has a larger Ps value than that of 7, 24 vs. 15 nC cm−2 measured at Tc ‐ T = 10 °C. The difference in these mesogenic properties is discussed by comparing their conformation difference at the molecular part of benzoate.
Synthesis of Some New Fused/Spiroheterocyclic Compounds Incorporating Quinone Compounds
Authors: Khalafallah A. K. , El‐Aal R. M. Abd , Kanzi N. A. A. El
Published: May 2015

A series of fused and spiro pyrazolones, isoxazolines, pyrimidines, β‐lactams, and thiazolidinones incorporating 4‐amino‐2‐methyl‐5,10‐dioxo‐1,5,10,11‐tetrahydrobenz[g]quinoline 3‐carbonitrile 1 and 4‐amino‐2‐methyl‐5,6,11‐trioxo‐1,4,4a,5,6,11,12,12a‐octahydro‐1,12‐diazanaphthacene 3‐carbonitrile 2. 7,8a‐c, 15,16a‐c, 19,20a‐d, 21,22a‐d, have been synthesised by cyclocondensation addition reaction and cycloaddition reaction of hydrazines, hydroxylamine, urea, thiourea, monochloroacetyl chloride and mercaptoacetic acid with the synthesised 15,16a‐c and 17,18a‐c.
A Simple and Efficient Method for the Oxidation of Aryl Substituted Semicarbazide with NaNO2/NaHSO4·H2O/SiO2 under Mild Conditions
Authors: Li Xiao‐Chuan , Wang Yu‐Lu , Wang Jin‐Ye
Published: May 2015

In this paper, eighteen aryl substituted semicarbazide underwent efficient oxidation to aryl azo compounds using NaNO2/NaHSO4·H2O/SiO2 under mild conditions with excellent yields.
Antimicrobial Activity of Some Novel Thiourea, Hydrazine, Fused Pyrimidine and 2‐(4‐Substituted)anilinobenzoazole Derivatives Containing Sulfonamido Moieties
Authors: El‐Gaby Mohamed S. A. , Micky Jehane A. , Taha Nadia M. , Sh. El‐Sharief Marwa A. M.
Published: May 2015

Thiophosgenation of sulfonamides 1a‐c in the presence of dilute HCl at room temperature furnished the isothiocyanatosulfonamides 2a‐c and treatment with aromatic amines gave 1,3‐disubstituted thioureas 3a,b. Also, interaction of two molecules of 2c with 1,4‐phenylenediamine yielded the novel bisthiourea 4. Cyclocondensation of 2 with ortho amino carboxylic acid compounds such as anthranilic acids 8, 5‐amino‐1‐phenyl‐pyrazol‐4‐carboxylic acid 9 and 4,5,6,7‐tetrahydro‐2‐amino‐benzo[b]thiophene‐3‐carboxylic acid 10 furnished the fused thiopyrimidines 11a‐d, 12 and 13, respectively. 2‐Anilinobenzoazole derivatives 15a‐c, 16a, b and 17a,b were obtained through cyclocondensation of 2 with 1,2‐dinucleophiles.
Cytotoxic Components from the Leaves of Schefflera Taiwaniana
Authors: Kuo Yueh‐Hsiung , Lo Jir‐Mehng , Chan Yih‐Fwu
Published: May 2015

The isolation and identification of eighteen components from the leaves of Schefflera taiwaniana are presented. Their structures were determined on the basis of spectral data as well as direct comparison with authentic samples. These compounds include two polyacetylenes, one carotenoid‐like, three sesquiterpenes, one diterpene, four triterpenes, two tocopherols, and five alkyl 4‐hydroxycinnamate mixtures. Among these, 4‐hydroxy‐trans‐cinnamic acid docosyl ester and 4‐hydroxy‐cis‐cinnamic acid tetracosyl ester are new compounds. Some of these components exhibit cytotoxic activity.
Chemical Constituents of the Aerial Part of Celastrus Hypoleucus
Authors: Wang Hong , Tian Xuan , Chen Yao‐Zu
Published: May 2015

Fourteen compounds including eight triterpenoids, 12‐oleanaen‐3β‐ol (β‐amyrin) (1), 12‐oleanaen‐3β‐caffeate (2), 9(11),12‐oleanadien‐3β‐ol (3), 9(11),12‐oleanadien‐3‐one (4), 9(11),12‐oleanadien‐3 β‐caffeate (5), friedela‐3‐one (friedelin) (6), friedela‐3‐one‐29‐ol (7), and 12‐gammateraen‐3 β‐ol (tetrehymanol) (8); one steroid, β‐sitosterol (9); one long‐chain acid, octadecadienoic acid (10); two esters, ester of n‐octaolecyl‐4‐hydroxy‐cinnamate (11), and ester of n‐octadecyl‐caffeic acid (12); one diterpene, 8β,19‐dihydroxy‐3‐oxopimar‐15‐ene (13); one sesquiterpene, 1β,2β,9α‐trihydroxy‐β‐dihydroagarofuran (14) were isolated from the aerial part of Celastrus hypoleucus. These compounds were characterized and identified by physical and spectral methods. All compounds were isolated for the first time from this plant. Among them 12‐oleanaen‐3β‐caffeate (2) and 9(11),12‐oleanadien‐3β‐caffeate (5) are two new compounds, and ester of n‐octadecyl‐caffeic acid (12) possessed antilipoperoxidative effect by specifically scavenging the hydroxyl free radical (•OH) in vitro.
Studies on Chemical Constituents of Salix Matsudana
Authors: Wang Jin‐Xin , Zheng Shang‐Zhen , Sun Li‐Ping , Shen Xu‐Wei , Li Ying
Published: May 2015

Two new phytane‐type diterpene‐γ‐lactones named Hanliuin III (3) and Hanliuin IV (4), together with two previously reported diterpenes, six known flavonoids and five other known compounds were isolated from Salix matsudana. The structures of two new compounds were deduced from spectroscopic methods and 2D NMR techniques.
Bioorganic Studies on Rhodopsins
Authors: Nakanishi Koji , Berova Nina , Fishkin Nathan , Fujioka Naoko
Published: May 2015

A summary of ongoing bioorganic studies on rhodopsin, the most intensively studied G‐protein coupled receptor (GPCR) is given. The article includes: (i) general descriptions of rhodopsin and (ii) various naturally occurring retinal chromophores in animals, fish and microorganisms; (iii) the rationale for 6‐s‐cis‐11‐sicis retinal being the common chromophoric structure in visual pigments; (iv) electrostatic charge distribution within the opsin binding site; (v) the visual transduction cycle; and (vi) the changes occurring in the chromophore/receptor interactions allong the visual transduction path.
Synthetic Chemistry and Function of Bacterial Cell Surface Glycoconjugates
Authors: Kusumoto Shoichi , Fukase Koichi , Oikawa Masato , Suda Yasuo
Published: May 2015

Typical bacterial glycoconjugates are known to stimulate immunological systems of higher animals and thereby play important roles in the primary defense of animals against bacterial infection. Lipopolysaccharide (LPS) of gram‐negative bacteria is a representative of such glycoconjugates. LPS was first discovered as a potent bacterial toxin and named endotoxin but was soon found to exhibit immunostimulating activity. By the use of our synthetic pure preparations, the lipophilic partial structure of LPS, designated lipid A, proved to be the active entity responsible for both endotoxic and immunostimulating activities of LPS. This paper deals with our recent chemical synthesis and functional study of lipid A and related compounds. Synthesis is described of its various structural analogues, radio‐labeled compound and Re‐type LPS that contains two additional sugar moieties linked to lipid A.
Syntheses, Fluxional Behavior and Crystal Structures of the Endo and Exo η3‐Allyl Monocarbonyl Dithiocarbonate and Dithiocarbamate Molybdenum Complexes: Crystal Structures of exo‐[Mo(η3‐allyl)(η2‐S2COC2H5)(CO)(η2‐dppm)]and endo‐[Mo(η3‐allyl)(η2‐S2CNC4H8)(CO)(η2‐dppe)]
Authors: Yih Kuang‐Hway , Lee Gene‐Hsiang , Wang Yu
Published: May 2015

The novel endo and exo complexes [Mo(η3‐C3H5)(η2‐L2)(CO)(η2‐dppm)] are accessible by the reactions of the complexes [Mo(η3‐C3H5)(CO)2(η2‐L2)(X)] (L2, X = S2COEt, CH3CN; S2CNC4H8; S2CNEt2) with dppm. X‐ray crystal structures of exo‐2 and endo‐5 have been employed to elucidate the two orientations.
Matrix Effect of Alkali and Alkaline Earth Metal Halides on Fluorescence Quantum Yield of Indium in Laser‐Induced Fluorescence Flame Spectrometry
Authors: Ke Ching‐Bin , Lin King‐Chuen
Published: May 2015

As interfered with by alkali and alkaline earth metal halides added as the matrix in an acetylene/air flame, the fluorescence quantum yield of In as the analyte in a laser‐induced fluorescence (LIF) flame spectrometry has been thoroughly characterized. The fluorescence quantum yield is determined by a ratio of F to A, where F is the measured fluorescence of In and A is the difference between the absorption signals recorded for the analyte and the blank solutions. The normalized fluorescence signal is treated to prevent deviations due to variations of the atomization efficiency under the conditions with and without the matrix added. The fluorescence quantum yield is measured to be almost independent of the matrix concentration up to 500 ppm (μg/mL) studied, under conditions of either optical unsaturation or saturation. By considering a quenching effect induced by electron‐atom collisions, the calculated fluorescence quantum yields are consistent with our observations.
Controlling of Solution Concentration on Nucleation During Hydrothermal Synthesis of Analcime
Authors: Lin I‐Chieh , Lo Huann‐Jih , Song Sheng‐Rong , Fang Jiann‐Neng , Chen Yaw‐Lin , Chen Huei‐Fen , Li Li‐Jun , Liu Chia‐Mei
Published: May 2015

Hydrothermal experiments of analcime nucleation and glass dissolution were carried out in autoclaves under the conditions of autogeneous pressures, temperatures of 150 °C ∼ 210 °C, and 0.25 M ∼ 0.75 M NaOH solutions. The curves of the glass dissolution and analcime formation are S‐shaped. Yet, the two curves are essentially parallel to each other. The time required for a complete dissolution of glass or the commencement of analcime formation is shorter when the concentration of NaOH solution or the temperature is higher. The amount of the weight percent of analcime synthesized is obviously less than the glass dissolved at a given time of an experiment. The weight difference between glass dissolved and analcime (dehydrated) formed is calculated to be represented as the solution concentration.

During an experiment, the solution concentration increases gradually to a maximum, then decreases slowly to a constant value with time. On the other hand, nucleation is also gradually increased to a maximum, then is decreased finally to zero with time in a bell‐shaped curve. It is clear that nucleation of analcime is mainly controlled by the solution concentration.
The HPLC Enantioresolution of Selected Native or Derivatized Amino Acids on Teicoplanin Bonded Chiral Stationary Phase Using a Methanol‐Based Mobile Phase
Authors: Chen Shushi
Published: May 2015

The facile HPLC enantiomeric resolution of a variety of selected native or derivatized amino acids is carried out on the glycopeptide antibiotic teicoplanin bonded chiral stationary phase using a methanol‐based mobile phase and found very sensitive to the structural variations. This mobile phase is mainly composed of methanol. Organic additives such as acetic acid and triethylamine are introduced to the mobile phase in small percentages to control the analyte's retention time. Additive of low viscosity such as ethyl ether or petroleum ether is incorporated in the mobile phase as well to improve the resolution. Further increasing its percentage in the mobile phase deteriorates the resolution slightly; however, it extends the retention scale of enantiomers. The change in enantioselectivity is found to be insignificant under these circumstances. The hydrogen bonding and π‐π complexation in the hydrophobic pocket of teicoplanin chiral selector is believed to be the mechanism mainly responsible for the enantioresolution observed in this report.
Speciation of Arsenic in Environmental and Biological Samples
Authors: Aggarwal S. G. , Diwan B. D. , Agarwal S. , Gupta V. K. , Mundhara G. L.
Published: May 2015

A novel arsine generator glass assembly is constructed and reported for the spectrophotometric determination and speciation of arsenic in real samples. In an arsine generator, sodium borohydride is added dropwise to the acidic sample solution and arsine thus formed is reacted with silver diethyldithiocarbamate (Ag‐DDTC) ‐ Tritron‐X (TX‐100) solution in pyridine to form a red coloured complex. The complex showed the absorption maximum at λmax 540 nm. The molar absorptivity of the method was found to be (1.55) × 104 L mole−1 cm−1 at this wavelength. The presence of non‐ionic surfactant, i.e. TX‐100 in the Ag‐DDTC solution, makes the method ≈ 3 times more sensitive than the conventional Ag‐DDTC method. Beer's law is obeyed in the concentration range of 0.05–2.80 mg L−1 of arsenic. The detection limit of the method was calculated to be 20 μg L−1 As. Speciation of arsenite from other forms of arsenic in sample solutions was carried out by extraction of arsenite with Pb‐DDTC in chloroform, followed by spectrophotometric determination. After arsenite separation the sample is used for the arsenate determination. Total arsenic was determined by acid decomposition of the same sample. The speciation data were found to be comparable (±2%) with ICP‐MS, with better precision (< 1%). The method has been successfully applied for the speciation of arsenic in drinking water and dust samples of arsenic affecting the Rajnandgaon district of Chhattisgarh, India, and urine and blood samples of patients with arsenical diseases. Concentration of total arsenic in tube‐well water of this area was 3–6 times more than the permissible limit. Dust samples contained less amounts of arsenic than the ground water.
Synthesis of 2‐Thioxohydropyridine‐3‐Carbonitrile, 2‐Alkylthiopyridine, Thienopyridine, Pyrazolopyridine Derivatives and Their Theoretical Calculations
Authors: Attaby Fawzy A. , Elghandour Ahmed H. H. , Mustafa Hussein M. , Ibrahem Yasser M.
Published: May 2015

Cyanothioacetamide (1) reacted with but‐2‐enal (2) to give the corresponding 4‐methyl‐2‐sulfanylpyridine‐3‐carbonitrile (7) which was used as a good starting material for the synthesis of 1‐(3‐amino‐4‐methylthieno[2,3‐b]pyridin‐2‐yl)ethan‐1‐one (10), 3‐amino‐4‐methylthieno[2,3‐b]pyridine‐2‐carboxamide (15), 3‐amino‐4‐methylthieno[2,3‐b]pyridine‐2‐carboxylate (18) and 3‐amino‐4‐methylthieno[2,3‐b]pyridin‐2‐ylarylketone 25a‐c through its reactions with each of (1‐chloroacetone (8), 3‐chloropentane‐2,4‐dione (11) or ethyl 2‐chloro‐3‐oxo‐butanoate (19)), 2‐chloroacetamide (13), ethyl 2‐chloroacetate (16) and 2‐bromo‐1‐arylethan‐1‐one 23a‐c, respectively. Considering the data of elemental analyses, IR, 1HNMR, mass spectra and theoretical calculations, structures of the newly synthesized heterocyclic compounds were elucidated.
Chemical Constituents of Two Liverworts Metacalypogeia Alternifolia and Chandonanthus Hirtellus
Authors: Shy Horng‐Shing , Wu Chia‐Li , Paul Claudia , König Wilfried A. , Ean Uni‐Juni
Published: May 2015

A novel linear dihydrodichromene derivative, metacalypogin, was identified from the Taiwanese liverwort Metacalypogeia alternifolia. Together with data from M. cordifolia, the chemical marker of the genus Metacalypogeia is obvious chroman derivatives, which is far different from that of Calypogeia, the other genus in the same family. In addition, two isomeric diterpenoids of cembrane‐type were identified from the Chinese liverwort Chandonanthus hirtellus. The relative stereostructures of the latter two isomers were proved by X‐ray crystallography. Both compounds were unstable in chloroform solution and further oxidized to the corresponding peroxy hemiacetal derivatives.
Complex Formation between the Lumenal Domain of Adenovirus E3–19k Protein and the Extracellular Domain of Class I MHC Molecule In Vitro
Authors: Liao Ping‐Hsi , Chen Te‐Hsiang , Liao Pei‐Yu
Published: May 2015

The Ad2 E3–19k protein inhibits the transport of newly synthesized class I MHC molecules to the cell surface, thereby interfering with antigen presentation. The details of the interaction between E3–19k protein and class I MHC molecules have not been well‐defined. In this present study, we describe the use of gel filtration HPLC for confirming the binding interaction of two domain proteins, E3–19k and MHC class I antigen, and subsequently the characterization of protein complex by SDS‐PAGE. Our results demonstrate the complex formation between Ad2 lumenal E3–19k (108 amino acids, wt 108) and HLA‐A*0201 molecule in vitro. Titration experiments will be employed in the future to determine stoichiometry and verify the specific interactions.
Comparative Adsorption of Lead(II) on Flake and Bead‐Types of Chitosan
Authors: Wan Ngah W. S. , Ab Ghani S. , Hoon L. L.
Published: May 2015

The adsorption of Pb(II) ions from aqueous solutions by chitosan flakes and beads was studied. The chitosan beads were prepared by casting an acidic chitosan solution into alkaline solution. Experiments were carried out as a function of pH, agitation period and initial concentration of Pb2+ ions. The uptake of Pb2+ ions from aqueous solution was determined from changes in concentration as measured by atomic absorption spectroscopy. The maximum uptake of Pb2+ ions on chitosan beads was greater than that on chitosan flakes. Adsorption isothermal data could be interpreted by the Langmuir equation. The experimental data of the adsorption equilibrium from Pb2+ ion solutions correlated well with the Langmuir isotherm equation. SEM analyses were also conducted for visual examination of the chitosan flakes and beads. Physical properties including surface area and average pore diameter were characterized by N2 adsorption experiment.
New Applications of an Old Theory ‐ the Rouse Theory ‐ in Polymer Dynamics and Viscoelasticity
Authors: Lin Y.‐H.
Published: May 2015

As recently shown by a close agreement between the calculated and measured viscoelastic spectra of a binary blend solution over a wide frequency range, the quantitative validity of the Rouse theory is discussed, pointing out why the traditional way of testing by a single parameter ‐ the viscosity ‐ is misleading. A “bird's‐eye” view of the Rouse theory in relation to various aspects of polymer dynamics and viscoelasticity is shown. This represents a fresh way of looking at some of interrelations between fundamental problems in chain dynamics. This paper illustrates the application potential of the Rouse theory by reviewing the research schemes that make use of the well‐tested theory to elucidate two fundamental problems: (1) onset of entanglement and (2) the motions associated with a single Rouse segment. It is shown that through careful designs of research, analyses in terms of the Rouse theory can provide vitally important and informing results.
Femtosecond Fluorescence Dynamics of trans‐Azobenzene in Hexane on Excitation to the S1(n, π*) State
Authors: Lu Ying‐Chih , Chang Chih‐Wei , Diau Eric Wei‐Guang
Published: May 2015

Femtosecond fluorescence dynamics of trans‐azobenzene in hexane have been investigated on excitation to the S1(n, π*) state at 432 nm using the up‐conversion technique. Two transient components were observed to represent the fast and the slow S1 fluorescence dynamics in the wavelength range of 550–732 nm. Based on the results obtained from recent ab initio calculations (Ishikawa, T.; Noro, T.; Shoda, T., J. Chem. Phys. 2001, 115, 7503), a dynamical picture is given in the following. Upon initial excitation to the S1 state, the excited molecule is moving away from the first detection window within the observed 200–300 fs. The structural relaxation from the Franck‐Condon region may be responsible for the observed fast S1 dynamics with the driving force being the CNNC twisting motion along the rotational coordinate. For the rest of the motion on the S1 global potential surface, the excited molecule may search for the S0/S1 conical intersection for an efficient internal conversion to the ground state. The nuclear motions for the observed slow S1 dynamics not only involve the CNNC torsional coordinate but also the other degrees of freedom such as the CNN bending coordinate on the multidimensional S1 potential energy surface. The whole electronic relaxation process occurs within the observed 1–2 ps. The slow S1 dynamics were found to vary with the fluorescence wavelengths due to the influence of the solvent‐induced vibrational relaxation in the S1 state; the vibrational relaxation should occur on a time scale comparable to the time scale of the electronic relaxation (S1→S0 internal conversion).
Molecular Rydberg States and Ionization Energy Studied by Two‐Photon Resonant Ionization Spectroscopy
Authors: Chen Yit‐Tsong
Published: May 2015

In this article, I will review the excited valence/Rydberg states and ionization energies of vinyl chloride, propyne, and allyl radical that we have examined recently in our laboratory by 2+1 resonance enhanced multiphoton ionization (REMPI) spectroscopy. In these studies, we have emphasized spectroscopic investigations from the first excited electronic states to the first ionization energies of the molecules and radicals of interest. In spectroscopic analysis, successful electronic identifications have been facilitated with theoretical (ab initio and density functional) calculations. In particular, we have applied calculated Franck‐Condon factors to assist vibrational assignment for experimental vibronic spectra. The spectroscopic studies of these polyatomic excited valence/Rydberg states help us to illuminate the photodissociation pathways and to manifest the complicated chemical‐reaction mechanisms due to the multi‐dimensionality in polyatomic molecular potential energy surfaces.
On the First Overtone Spectra of Protonated Water Clusters [H+(H2O)3–5] in the Free‐OH Stretch Region
Authors: Wu C.‐C. , Chaudhuri C. , Jiang J. C. , Lee Y. T. , Chang H.‐C.
Published: May 2015

The gas‐phase near‐infrared spectra of protonated water clusters [H+(H2O)n, n = 3–5] have been obtained using a vibrational predissociation ion trap spectrometer coupled with a tunable optical parametric oscillator laser. The spectral bands in the frequency range from 7000 to 7500 cm−1 are assigned to the first overtone vibrations of non‐hydrogen‐bonded (free) OH stretches. Assignments of the spectra are made with reference to the data for H2O vapor, (H2O)2 in Ar matrices, and considering the presence of the excess proton in the clusters. Blue shifts of the bands are observed to increase with cluster size and are interpreted in terms of a charge screening effect. The observations have allowed determination of the anharmonicity coefficients of these cluster ions on the basis of the calculations using the term value expression of vibrational energy.
Local Structure and Electronic States of Li(Mn2‐xCox)O4 Studied by X‐ray Absorption Spectroscopy
Authors: Shen C. H. , Liu R. S. , Jang L.‐Y. , Lee J. F. , Chen J. M.
Published: May 2015

The local structure and electronic states of Co3+ substituted lithium manganate spinels of the composition Li(Mn2‐xCox)O4 (0 ≤ x ≤ 0.4) have been probed by X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) spectroscopies at the Mn and Co edges. The substitution of Co3+ into the Mn sites causes an oxidation of Mn3+ to Mn4+, decreasing the localized Jahn‐Teller distortion of the lattice. This in turn leads to a shortening of the Mn‐O(M) bond length and a reduction in local structural disorder of the Mn(Co)O6 octahedra. The data show that the replacement of d4 Mn3+ by d6 Co3+ in the octahedral sites of the spinel structure eliminates the local disorder in the lattice around the Mn3+O6 octahedra which are distorted by Jahn‐Teller stabilization of the electronic state.
Functionalization of Molecularly Templated Mesoporous Silica
Authors: Yang Chia‐Min , Chao Kuei‐Jung
Published: May 2015

This review describes the chemistry of the formation and functionalization of molecularly templated mesoporous silica, as well as applications of functionalized mesoporous silica. The functionalization can be selectively placed on the internal or external surfaces, or even within the pore walls of mesoporous silica. Applications of functionalized mesoporous silica are highlighted on catalysis, sorption and separation, host‐guest synthesis of nanostructured materials and microelectronics.
Octasilsesquioxane Chemistry I. Attachment of Four Surface Bridges to Octasilsesquioxane Quasi‐cube Framework
Authors: Liu Ling‐Kang , Chu Jiane‐Bond , Slanina Zdenek , Chow Tahsin J.
Published: May 2015

The Pt/C catalyzed hydrosilylation of Si8O12(CH=CH2)8 and 8 equiv of HSiMe2Cl produced Si8O12(CH2CH2SiMe2Cl)8 that was de‐hydrochlorinated with 4 equiv of Z‐HOCH2CH2=CHCH2OH in the presence of excess TMEDA. This preparation resulted in the attachment of four surface bridges (‐CH2CH2SiMe2OCH2CH=CHCH2OSiMe2CH2CH2‐Z‐) on the quasi‐cube Si8O12 framework. As a parallel study, the theoretical calculations of Si8O12(‐CH2CH2SiH2OCH2CH=HCH2OSiH2CH2CH2‐Z‐)4 were carried out at PM3 semi‐empirical level to find optimized geometries for use in four subsequent ab initio computations using standard basis sets of 3–21G* and 6–31G*. The calculations suggest that one should expect about equimolar mixture of the tetra‐adducts produced by the bridging over the edges of the quasi‐cube, either over four parallel edges or over two orthogonal pairs of parallel edges, but not by bridging across the faces of the quasi‐cube.
Studies on the Reaction of α‐Chloroformylarylhydrazine Hydrochloride with Imidazole and 1,2,4‐Triazole
Authors: Chiu Chun‐Yen , Chung Jen‐Hua , Kuo Wen‐Fa , Yeh Mou‐Yung
Published: May 2015

α‐Imidazolformylarylhydrazine 2 and α‐[1,2,4]triazolformylarylhydrazine 3 have been synthesized through the nucleophilic substitution reaction of 1 with imidazole and 1,2,4‐triazole, respectively. 2,2′‐Diaryl‐2H,2′H‐[4,4′]bi[[1,2,4]‐triazolyl]‐3,3′‐dione 4 was obtained from the cycloaddition of α‐chloroformylarylhydrazine hydrochloride 1 with 1,2,4‐triazole at 60 °C and in absence of n‐Bu3N. The inducing factor for cycloaddition of 1 with 1,2,4‐triazole was ascertained as hydrogen ion by the formation of 4 from the reaction of 3 with hydrochloric acid. 4 was also acquired from the reaction of 3 with 1 and this could confirm the reaction route for cycloaddition of 1 with 1,2,4‐triazole. Some acylation reagents were applied to induce the cyclization reaction of 2 and 3.1 possessing chloroformyl group could induce the cyclization of 2 to give 2‐aryl‐4‐(2‐aryl‐4‐vinyl‐semicarbazide‐4‐yl)‐2,4‐dihydro‐[1,2,4]‐triazol‐3‐one 6. 7 was obtained from the cyclization of 2 induced by some acyl chlorides. Acetic acid anhydride like acetyl chloride also could react with 2 to produce 7D. 5‐Substituted‐3‐aryl‐3H‐[1,3,4]oxadiazol‐2‐one 8 was produced from the cyclization reaction of 3 induced by some acyl chlorides or acetic acid anhydride. The 1,2,4‐triazole group of 3 played a role as a leaving group in the course of cyclization reaction. This was confirmed by the same product 8 which was acquired from the reaction of 1, possessing a better leaving group: Cl, with some acyl chlorides or acetic acid anhydride.
Hypervalent Iodine(III) Mediated Synthesis of 2‐Substituted‐5‐Aryloxazoles
Authors: Kang Iou‐Jiun , Wang Huey‐Min , Lin Mei‐Ling , Chen Ling‐Ching
Published: May 2015

A direct and efficient method for the preparation of 2‐substituted‐5‐aryloxazoles was realized by reaction of aryl methyl ketones with various nitriles in the presence of phenyliodine(III) triflate.