bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solid‐State NMR Study on Relationships between Miscibility and Chain Mobility in Poly(4‐Methylstyrene)/Poly(Cyclohexyl Methacrylate) Blend
Authors: Wu Ru‐Rong , Kao Hsien‐Ming , Jang Fan‐Hwei , Woo E. M. 
Published: May 2015

AbstractThe phase behavior and motional mobility in binary blends of poly(4‐methylstyrene) (P4MS) and poly(cyclohexyl methacrylate) (PCHMA) have been examined by 13C solid state NMR techniques. The blend miscibility was studied by measuring the 1H spin‐relaxation times in the laboratory frame (T1H) and in the rotating frame (T1ρH), respectively. Although intermolecular spin diffusion contributes to the proton relaxations in accordance with homogeneity, T1ρH data shows signs of in complete averaging. The T1ρH relaxation behavior indicates the existence of heterogeneous do mains with shortest dimensions in the nanometer range, which is also sup ported by the intermolecular cross polarization experiments with variable contact times. In addition, according to the resuits of carbon T1ρ relaxation time measurements, it is concluded that mixing is intimate some what enough to cause a reduction in local chain mobility for P4MS and vice versa for PCHMA.
Nuclear Magnetic Resonance Study of the Stoichiometry and Stability of Several Li+‐Crown Ether Complexes in Various Acetonitrile‐Nitrobenzene Mixtures
Authors: Karkhaneei Ebrahim , Zebrajadian Mohammad Hasan , Shamsipur Mojtaba 
Published: May 2015

AbstractLithium‐7 NMR spectrometry was used to study the complexation reaction between lithium ions and several 12‐, 15‐ and 18‐membered crown ethers in a number of binary acetonitrile‐nitrobenzene mixtures. Formation constants of the resulting 1:1 complexes in different solvent mixtures were determined by computer fitting of the chemical shift‐mole ratio data. There is an inverse relationship between the complex stability and the amount of acetonitrile in the mixed solvent. Among different sized crown ethers used, 15‐crowns were found to form the most stable Li+ complexes in the series. The influence of substitution on the macrocyclic rings on the stability of the resulting complexes is discussed.
A Bipotentiostat Based 4‐Electrode Detection System for HPLC Analysis
Authors: Chao Ming‐Huei , Huang Hsuan‐Jung 
Published: May 2015

AbstractWith the assist of a microcomputer interfacing, a bipotentiostat in corporated 4‐electrode detection system was developed as a versatile electrochemical detector for HPLC. An amperometric chromatogram and two three‐dimensional chromatovoltammograms characterizing the electrochemical characteristics of analytes can be obtained in a single chromatographic run. By following the three operation modes developed, both the oxidizable and reducible analytes contained in sample solutions can be determined. The analytical capability of the 4‐electrode detection system was demonstrated by the analysis of solutions containing hydroquinone, catechol and ascorbic acid. From the calibration graphs obtained, linear coefficients better than 0.9992 were found for hydroquinone and catechol in a concentration range of 1.0 × 10−4 to 1.0 × 10−7 M, and a linear coefficient of 0.9929 was found for ascorbic acid in a concentration range of 1.0 × 10−4 to 1.0 × 10−6 M. The detection limits (based on S/N = 3) found were about 1.0 × 10−7 M for hydroquinone and catechol and was 1.0 × 10−6 M for ascorbic acid.
Alkaloids from Lindera Glauca
Authors: Chang Yuh‐Chwen , Chen Chung‐Yi , Chang Fang‐Rong , Wu Yang‐Chang 
Published: May 2015

AbstractA new amide, N‐cis‐sinapoyltyramine (1), and twelve known compounds were isolated from the aerial parts of Lindera glauca. The structure of the new compound has been established by the study of extensive 2D NMR data.
New Sesquiterpenes from the Roots and Stems of Aristolochia Mollissima
Authors: Wu Tian‐Shung , Chan Yu‐Yi , Lin Fu‐Wen 
Published: May 2015

AbstractTwo new sesquiterpenes, madolins Y (1) and Z (2) were isolated from the dried roots and stems of Aristolochia mollissima, and their structures were determined by spectroscopic methods.
Acid Catalyzed Dissociation of 4‐Aminopyridine Complex of Pentacyanoferrate (II)
Authors: Chen Mei‐Ling , Yeh Andrew 
Published: May 2015

AbstractFe(CN)5ampy3− (ampy = 4‐aminopyridine) complex was unstable at pH ≤ 4 with respect to the dissociation due to the protonations of the complex. The first protonation on the 4‐aminopyridine ligand at pKa = 3.2 resulted in a ≅ 150‐fold in crease in rate of dissociation as compared to that of the complex in the neutral solution. However, further protonation of the complex on the cyanide ligand at pKa = 1.5 in creased the rate only slightly. The large in crease in the rate constant of dissociation for Fe(CN)5ampyH2− complex suggests that in the transition state the proton is likely shifted from the amino group and becomes coordinated to a pair of dπ electrons directed at the face of the coordinated octahedron.
The Syntheses and Reactions of 3‐Arylsydnone‐4‐carboxamide Phenylhydrazones
Authors: Shih Mei‐Hsiu , Lu Li‐Hui , Yeh Mou‐Yung 
Published: May 2015

AbstractReactions of aniline with 3‐arylsydnone‐4‐carbohydroximic acid chlorides (1) gave the de sired substitution products5. 3‐Arylsydnone‐4‐carboxamide phenylhydrazones (7) were obtained unexpectedly by the reaction of carbohydroximic acid chlorides1with phenylhydrazine in suitable conditions. Compounds7could react with both aromatic and aliphatic aldehydes in the presence of acid catalyst to give 3‐aryl‐4‐(1′‐phenyl‐5′‐substituted‐1′,2′,4′‐triazol‐3′‐yl)sydnones (11).
Synthesis of Some New Spiro, Isolated and Fused Heterocycles Based on 1H‐indole‐2‐One
Authors: El‐Emary T. I. , Ahmed R. A. , Bakhite E. A. 
Published: May 2015

AbstractThe reaction of 3‐benzoylcyanomethylidine‐1(H)‐indole‐2‐one (1) with a variety of active methylene compounds, thioglycolic acid, glycine, hydrazine hydrate and phenyl hydrazine led to the formation of compounds 4a‐d‐10. 3‐Thiosemicarbazide‐1(H)‐indole‐2‐one 2 on reaction with α‐halocarbonyl compounds gave compounds 11a‐c, 12a‐c. The latter compounds on heating with phosphoryl chloride, cyclization takes place via losing water to give the angular tetracyclic compounds 13a,b and 14a‐c. Cyanoacetic hydrazone derivative 3 readily cyclized upon heating in triethyl orthoformate to give the tricyclic system, oxopyridazino indole 15.On the other hand, the reaction of 3 with benzylidine malononitrile and benzylidene ethylcyanoactate gave the pyranyl hydrazone derivatives 16a,b.
Two Polymeric Linear Tri‐nickel(II) Complexes: [Ni3(μ3‐dpa)4(C4O4Me)]n(BF4)n and [Ni3(μ3‐dpa)4(N3)]n(PF6)n Synthesis, Structural Characterization and Magnetic Properties
Authors: Peng Chi‐How , Wang Chih‐Chieh , Lee Hsiao‐Ching , Lo Wei‐Chung , Lee Gene‐Hsiang , Peng Shie‐Ming 
Published: May 2015

AbstractTwo new linear tri‐nickel(II) complexes with an infinite polymeric chain, [Ni3(μ3‐dpa)4(C4O4Me)](BF4) 1 and [Ni3(μ3‐dpa)4(N3)](PF6) 2, [dpa− = di(α‐pyridyl)amido anion], have been synthesized and their structures were determined by X‐ray diffraction. Compound 1 crystallizes in the monoclinic system, space group C 2/c, with a = 19.9078(3), b = 13.2986(2), c = 37.6622(5) Å, β = 94.091(1)°, Z = 8. Compound 2 crystallizes in the monoclinic system, space group P 21/n, with a = 13.323(4), b = 23.217(3), c = 17.528(5) Å, β = 94.42(3)°, Z = 4. The two complexes are described as one‐dimensional systems with the (C4O4Me)−, 1, or N3−, 2, serving as a μ‐(1,3) bridged ligand at the two axial sites of each [Ni3(μ3‐dpa)4]2+ fragment. The Ni‐Ni distances of 2.400(1) and 2.402(1) in 1 and 2.389(2), 2.385(2) in 2 are obviously shorter than those of 2.4325(7), 2.4356(7) in the monomeric complex [Ni3(μ3‐dpa)4(N3)2] 3. The magnetic properties of complexes 2 and 3 were studied by susceptibility measurements vs temperature. The χM vs T plots of both complexes show a strong antiferromagnetic behavior. The simulated J13 values are −95 cm−1 and −97 cm−1 for 2 and 3, respectively.
Analysis of Polymer Additives by Matrix‐Assisted Laser Desorption Ionization/Time of Flight Mass Spectrometer Using Delayed Extractionand Collision Induced Dissociation
Authors: Hsiao Shih Tsung , Tseng Mei Chun , Chen Yet Ran , Her Guor Rong 
Published: May 2015

AbstractMatrix‐assisted laser desorption/ionization (MALDI) in combination with mass spectrometry proved to be a viable method for identifying additives in polyethylene ex tracts. The MALDI mass spectra of additives standards were found to be very simple consisting of [M+H]+ and/or [M+Na]+ pseudo molecular ions with little fragment ions. For real samples, which of ten contain more than one additive, the production of only one or two ions for each additive makes the tentative assignment much easier. Collision induced dissociation (CID) of the pseudomolecular ion is used to confirm the tentative assignment. The analysis of highmolecular weight additives, such as Chimassorb 944 and Tinuvin 622 indicated that MALDI was superior to other ionization techniques such as electrospray ionization (ESI), desorption chemical ionization (DCI) and fast atom bombardment (FAB) in the analysis of high molecular weight polymer additives. Sample preparation was found to be more critical than DCI in the analysis of real sample. The signals were interfered by the low molecule weight polyethylenemolecules, which were co‐extracted with the additives. This problem was partially overcome by using acetone in stead of methanol to precipitate the low molecular weight polyethylenemolecules.
Chemically Bonded Fullerene C60 Capillary Column for the Electrophoretic Separation of Plant Phenols
Authors: Shiue Chia‐Chann , Lin Shu‐Yu , Liu Chuen‐Ying 
Published: May 2015

AbstractA novel mixed‐mode stationary phase for open tubular capillary electrochromatography (CEC) was prepared. With 3‐aminopropyltrimethoxysilane as the spacer, the chemical reagent in conjunction with the fullerene played an important role in the electrochromatographic separation of the plant phenols. The fullerene C 60‐based column has the properties of both hydrophilic and hydrophobic interaction sites and provides a positively charged capillary surface responsible for the reversed electroosmotic flow (EOF) in the column during CEC operation. Comparative studies for the fullerene‐bonded phase, the intermediate phase with amino group and the bare fused‐silica were carried out. Under the conditions of acetate buffer (20 mM, pH 5.0) and applied voltage of −15 kV, the separation of catechin, salicylic acid, myricetin, quercetin, gallic acid, caffeic acid and p‐coumaric acid could be achieved. The proposed method was also applied to the analysis of plant phenols in grape juice.
Organic Amorphous Material N.N.N.N′‐tetraaryl(Ar12Ar22)‐1,1′‐biphenyl‐4,4′‐diamine
Authors: Maiti B. C. , Wang S. Z. , Cheng C. P. , Huang D. J. , Chao C.‐I. 
Published: May 2015

AbstractA series of N,N,N,N′‐tetraaryl(Ar 12Ar22)‐1,1′‐biphenyl‐4,4′‐diamine were synthesized by the Pd(0) catalyzed C‐N bond formation methodology. The physical properties, including glass transit ion temperature (Tg), melting point (Mp) and oxidation potential were measured. For Ar1 = 2‐naphthyl and Ar2 = 3‐toly (4f) and Ar2 = 3‐ethylphenyl (4h), the DSC charts indicate that they have Tg, but no observable Mp. These two compounds are amorphous in solid state. The X‐ray powder diffraction pat tern of4f further confirmed that it is truly amorphous through out the temperature range in which it is solid. There fore, we have demonstrated that a low molecular weight organic solid can be amorphous. This is an important aspect in the prep a ration of morphologically stable amorphous thin film. Other compounds with Ar1 = Ph, 1‐naphthyl while Ar2 = 3‐toly or 3‐ethylphenyl are normal compounds with both Tg and Mp when prepared in their glassy state by rapid cooling of their melt. The oxidation potentials for compounds with Ar1 = 1‐naphthyl and 2‐naphthyl and identical Ar2 are exactly the same. The molecular structural features must be important factors for an organic solid to be in the amorphous state.
Enantioseparation of Amino Acids and Amino Alcohols on a Chiral Stationary Phase Derived from L‐Alanyl‐ and Piperidinyl‐Disubstituted Cyanuric Chloride
Authors: Lin Chen‐Hsing , Lin Ching‐Erh , Chen Chia‐Chong , Liao Li‐Fang 
Published: May 2015

AbstractA silica‐base chiral stationary phase (CSP) derived from L‐alanyl‐ and piperidinyl‐disubstituted cyanuric chloride was prepared for the enantioseparation of methyl esters of N‐(3,5‐dinitrobenzoyl)amino acids and amino alcohols. This CSP provides good chiral recognition and effective separation of enantiomers of both methyl esters of N‐(3,5‐dinitrobenzoyl)amino acids, except for proline, and N‐(3,5‐dinitrobenzoyl)amino alcohols by high‐performance liquid chromatography. The enantioselectivity depends mainly on three preferential interactions which include a π‐π interaction and two hydrogen‐bonding interactions. However, steric interaction between substituents attached to the chiral center of chiral selectands and the chiral selector also plays a significant role in chiral recognition. Comparison of chromatographic results of the CSP prepared in this study with those of the CSP containing pyrrolidinyl group attached to the s‐triazine moiety, reported previously (J. Chromatogr. A, 722 (1996) 189), reveals that influences of steric interaction and the basic nature of piperidinyl substituent attached to the s‐triazine ring of the chiral selector on chiral discrimination may not be neglected.
Water‐Exchange and Relaxometric Studies of Gd(III) Complexes with DTPA‐bis(amide) Ligands
Authors: Cheng Tsan‐Hwang , Lin Kuei‐Tang , Ou Ming‐Hung , Shih Hsin‐Ling , Liu Gin‐Chung , Wang Yun‐Ming 
Published: May 2015

AbstractThe water 1H and 17O NMR relaxation properties of aqueous solutions containing Gd(III) che lates of the DTPA‐BIPA, DTPA‐BAA, DTPA‐BDEA and DTPA‐BMA ligands were investigated, and the results were compared with those previously reported for the Gd(III) complex with DTPA ligand. The significant deviation from the monoexponential behavior at the estimation of temperature dependence of 1H longitudinal relaxation rate for Gd(III) complexes with DTPA‐BIPA, DTPA‐BAA and DTPA‐BDEA ligands is characteristic of the slow chemical ex change. The measurements of 17O NMR trans verse relaxation rates and EPR transverse electronic relaxation rates in the range 276–343 K, allowed the assessment of the water‐exchange lifetime between the coordination site and the bulk solvent. With this approach, we obtained the water‐exchange life time (τM) of 1515, 1429, 1538 and 2128 ns for [Gd(DTPA‐BIPA)(H2O)], [Gd(DTPA‐BAA)(H2O)], [Gd(DTPA‐BDEA)(H2O)] and [Gd(DTPA‐BMA)(H2O)], respectively. Compared with the τM value of 303 ns for [Gd(DTPA)(H2O)]2−, we are able to conclude that the water residence life time in creases when the two terminal carboxylate groups of DTPA were substituted by two amide groups.
Indirect Determination of Thiocyanate with Ammonium Sulfate and Isopropyl Alcohol by Extraction‐Flotation of Copper
Authors: Shen Yi‐Yang , Xing Yun , Li Quan‐Mm 
Published: May 2015

AbstractA new method for the in direct determination of thiocyanate with ammonium sulfate and isopropyl alcohol by extraction‐flotation of cop per in the presence of ascorbic acid is described. A small amount of Cu(II) is reduced to Cu(I) by ascorbic acid, then Cu(I) is precipitated with SCN−. In the course of phase separation of isopropyl alcohol from water, the precipitated CuSCN stays in the interface of isopropyl alcohol and water. A good linear relationship is observed between the flotation yield of Cu(II) and the amount of SCN−. The detection limit for thiocyanate is 1.0 × 10−5 M, and the linear range is 1.0 × 10−5 ∼ 7.8 × 10−5M. Every parameter was optimized and the reaction mechanism was studied. The method is simple and rapid and it was successfully applied to the determination of thiocyanate in urine and saliva of smokers and non‐smokers and in venous blood of patients in fused with sodium nitroprusside.
Synthesis of Some New Pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidin‐4(3H)‐Ones and Pyrido[3′,2′: 4,5]thieno[2,3‐e]‐1,2,4‐triazolo[1,5‐c]pyrimidine Derivatives
Authors: Ho Yuh‐Wen 
Published: May 2015

Abstract2,3‐Disubstituted‐pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidin‐4(3H)‐ones 8a‐8c, 9a‐9c were obtained by treatment of pyrido[3′,2′:4,5]thieno[3,2‐d][1,3]oxazin‐4(3H)‐one derivative 3,3‐diacetylamino‐thieno[2,3‐b]pyridine derivative 5 and 3‐ethoxymethyleneaminothieno[2,3‐b]pyridine derivative 7a with appropriate amines, respectively. Condensation of compounds 8b, 9b with appropriate α‐chlorocarbonyl compounds gave the corresponding 3‐substituted carbonylmethylene‐pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidin‐4(3H)‐one derivatives 13a‐d. 3‐N‐Substituted‐pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidin‐4(3H)‐ones 15a,b, 16a,b and 18a,b were also obtained by cyclization of carbohydrazide 14 with different reagents under a variety of conditions. On the other hand, cyclization of 3‐amino‐4‐imino‐pyrido[3′,2″:4,5]thieno[3,2‐d]pyrimidin‐4(3H)‐ones 21a,b with appropriate orthoesters afforded the corresponding 3,5‐dialkyl‐pyrido[3′,2′:4,5]thieno[2,3‐e]‐1,2,4‐triazolo[1,5‐c]pyrimidines 22a‐f.
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

AbstractPhotodissociation 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

AbstractQuantitative 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

AbstractAn 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

AbstractBiological 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

AbstractSealed 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

AbstractDifferent 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

AbstractTandem 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.