bluuebunny/crossref_metadata_2025_split huggingface dataset:
The sustainability spectrum and the sciences of sustainability
Authors: Seager Thomas P. 
Published: September 2008

AbstractUnderstanding sustainability requires integrating multiple perspectives and investigative methods to explain multidimensional concepts. However, the traditional approach to research and education is organized along disciplinary lines that tend to exclude awareness of contributions in one field that may inform problems in another. This presents a serious obstacle to advancing an understanding of sustainability, which is focused on the interactions between industrial and ecological systems, rather than examining each system independently. This paper offers a broad description of different perspectives with regard to sustainability including security, reliability, resilience and renewal, and briefly describes the emerging sciences essential to understanding sustainability: ecological economics, industrial ecology, ecosystem health, and sustainable decision making, policy and design. In the latter, the challenges have yet to find an academic locus. Nonetheless, it is in this area that knowledge of sustainability science must be applied and it is consequently most proximate to business leaders, policy makers and designers. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.
Dendritic Nucleotides: Interaction with an Aliphatic Acid Monolayer
Authors: Wang Guojie , Abramov Mikhail , Van Aerschot Arthur , Rozenski Jef , Lei Shengbin , Klymchenko Andrei , Van der Auweraer Mark , De Feyter Steven , Herdewijn Piet 
Published: September 2008

AbstractDendrimeric‐T and dendrimeric‐A with 36 nucleotides were synthesized using phosphoramidite reagents. These dendrimers contain the nucleosides dA and dT, which are the components of the dA‐dT base pair. Branching was obtained using a bifurcated and trifurcated reagent. The dendrimers were purified by ion‐exchange chromatography. No specific interactions between these dendrimers were observed using atomic force microscopy. However, the dendrimeric‐T is able to disrupt monolayers of fatty acids, resulting in a reorientation of the lipids (from head‐to‐tail to head‐to‐head) as demonstrated by scanning tunneling microscopy (STM).
Capnellenes from the Soft Coral Dendronephthya rubeola
Authors: Grote Daniela , Hänel Frank , Dahse Hans‐Martin , Seifert Karlheinz 
Published: September 2008

AbstractFour new acetoxycapnellenes 1–4, the first epoxyprecapnellene 5, along with the known dihydroxycapnellene 6 and monoacetoxycapnellene 7, have been isolated from the soft coral Dendronephthya rubeola. The structures were determined primarily by NMR spectroscopy. The compounds 6 and 7 showed a good antiproliferative activity against the cell line L‐929 (murine fibroblasts) and a good cytotoxic activity against the HeLa (human cervix carcinoma) cell line. Compound 6 strongly inhibits the interaction of the oncogenic transcription factor Myc with its partner protein Max. Myc/Max‐Interaction inhibitors are therapeutically interesting compounds in oncology.
A Recombination‐Based Model for the Origin and Early Evolution of Genetic Information
Authors: Lehman Niles 
Published: September 2008

AbstractRecombination is the exchange of groups of subunits between two entities. It is argued here that this process was central to the origin of life, because it allowed for the creation of useful information from a random pool of linear polymers. The length distribution of such a pool could be broadened if these polymers, such as RNA strands, have the capability of interacting and performing a cross‐strand nucleophilic attack of a hydroxy group on a phosphate. Both the formation of stable secondary structures such as stem‐loops and selection for self‐replication can operate to push the equilibrium length distribution of the pool to longer and more catalytically proficient oligomers. There is empirical and theoretical support for these operations. Finally, in a collection of recombining linear oligomers, the advent of short recognition sequences that favor certain interactions over others, the property of a genotypic ‘self’ could develop, which later can shed its collective nature and be subject to Darwinian evolution. This could have given rise to true replicase enzymes, for example.
Alkaloids from the Roots of Zanthoxylum nitidum and Their Antiviral and Antifungal Effects
Authors: Yang Guohong , Chen Daofeng 
Published: September 2008

AbstractFive alkaloids, 5,6‐dihydro‐6‐methoxynitidine (1), dictamnine (2), γ‐fagarine (3), skimmianine (4), and 5‐methoxydictamnine (5), were isolated from the roots of Zanthoxylum nitidum. Their structures and configurations were elucidated by spectroscopic methods and X‐ray analysis. Compounds 1, 4, and 5 showed in vitro antiviral effect against hepatitis B virus, and compounds 2, 3, and 5 demonstrated marked antimitotic and antifungal activity.
Iridoid and Aromatic Glycosides from Scrophularia ningpoensisHemsl. and Their Inhibition of [Ca2+]i Increase Induced by KCl
Authors: Chen Bin , Liu Yan , Liu Hong‐Wei , Wang Nai‐Li , Yang Bao‐Feng , Yao Xin‐Sheng 
Published: September 2008

AbstractBioassay‐guided fractionation of EtOH extract of the roots of Scrophularia ningpoensis Hemsl. resulted in the isolation of three new iridoid glycosides, i.e., 6″‐O‐caffeoylharpagide (1), 6″‐O‐feruloylharpagide (2), and 6″‐O‐β‐glucopyranosylharpagoside (3), and five new aromatic glycosides, i.e., 2‐(3‐hydroxy‐4‐methoxyphenyl)ethyl O‐α‐arabinopyranosyl‐(1→6)‐O‐α‐rhamnopyranosyl‐(1→3)‐O‐β‐glucopyranoside (4), phenyl O‐β‐xylopyranosyl‐(1→6)‐O‐β‐glucopyranoside (5), 3‐methylphenyl O‐β‐xylopyranosyl‐(1→6)‐O‐β‐glucopyranoside (6), 6‐O‐cinnamoyl β‐fructofuranosyl‐(2→1)‐O‐α‐glucopyranosyl‐(6→1)‐O‐α‐glucopyranoside (7), and 6‐O‐feruloyl β‐fructofuranosyl‐(2→1)‐O‐α‐glucopyranosyl‐(6→1)‐O‐α‐glucopyranoside (8), together with four known compounds, i.e., 6″‐O‐α‐D‐galactopyranosyl harpagoside (9), 6″‐O‐(p‐coumaroyl) harpagide (10), harpagoside (11), and angoroside C (12). Activity of the isolated compounds on [Ca2+]i increase induced by KCl was evaluated on rat cardiac myocytes using confocal laser scanning microscopy. Iridoid glycosides 1, 10, and 11, and aromatic glycosides 5 and 6 significantly inhibited the increase of [Ca2+]i induced by KCl at 100 μM.
Sesquiterpene Glucosides from Chloranthus japonicusSieb.
Authors: Kuang Haixue , Xia Yonggang , Yang Bingyou , Wang Qiuhong , Lü Shaowa 
Published: September 2008

AbstractA new lindenane sesquiterpene glucoside named yinxiancaoside A (1), a new, rare bidesmosidic megastigmane sesquiterpene glucoside named yinxiancaoside B (5), and three known sesquiterpene glucosides, chloranoside A (2), pisumionoside (3), and sarcaglaboside A (4), were isolated from the whole plant of Chloranthus japonicus Sieb. The structures of the new compounds were established by an extensive study of their spectral data, especially 1D‐ and 2D‐NMR. The cytotoxic activity of the isolated compounds against human hepatoma (Hepg‐2), human ovarian carcinoma (OV420), and human breast cancer (MCF‐7) cells was investigated.
Pyridyl Derivatives of Benzaldehyde as Potential Antisickling Agents
Authors: Nnamani Ijeoma N. , Joshi Gajanan S. , Danso‐Danquah Richmond , Abdulmalik Osheiza , Asakura Toshio , Abraham Donald J. , Safo Martin K. 
Published: September 2008

AbstractCompounds that bind to sickle hemoglobin (Hb S) producing an allosteric shift to the high‐affinity Hb S that does not polymerize are being developed to treat sickle cell anemia (SCA). In this study, three series of pyridyl derivatives of substituted benzaldehydes (Classes I–III) that combine structural features of two previously determined potent antisickling agents, vanillin and pyridoxal, were synthesized. When analyzed with normal human whole blood, the compounds form Schiff‐base adducts with Hb and left shift the oxygen equilibrium curve (OEC) to the more soluble high‐affinity Hb, more than vanillin or pyridoxal. Generally, Class‐I compounds with an aromatic aldehyde located ortho to the pyridyl substituent are the most potent, followed by the Class‐II compounds with the aldehyde at the meta‐position. Class‐III compounds with the aldehyde at the para position show the weakest activity. The structure–activity studies of these pyridyl derivatives of substituted benzaldehydes demonstrate significant allosteric potency that may be useful for treating SCA.
Synthesis and Biological Evaluation of 4β‐[(4‐Substituted)‐1,2,3‐triazol‐1‐yl]podophyllotoxins as Potential Anticancer Agents
Authors: Reddy Pitta Bhaskar , Agrawal Satyam Kumar , Singh Swaran , Bhat Bilal A. , Saxena Ajit K. , Kumar Halmuthur M. Sampath , Qazi Gulam N. 
Published: September 2008

AbstractA series of novel 4β‐[(4‐substituted)‐1,2,3‐triazol‐1‐yl]podophyllotoxin derivatives were synthesized by employing CuI‐catalyzed click chemistry and evaluated for their anticancer activity against a panel of seven human cancer cell lines (HT‐29, HCT‐15, 502713, HOP‐62, A‐549, MCF‐7, and SF‐295). The compounds9b, 9c, 9e, 9f, and9hshowed significant cytotoxic activities especially against HT‐29, HCT‐15, 502713 cell lines.
Cytotoxicity of New Stilbenoids from Pholidota chinensis and Their Spin‐Labeled Derivatives
Authors: Wu Bin , Qu Haibin , Cheng Yiyu 
Published: September 2008

AbstractChemical investigation of the leave and stem of Pholidota chinensis Lindl has resulted in the isolation and characterization of three new stilbenoids. Their structures were established on the basis of spectroscopic evidence. A series of spin‐labeled stilbene derivatives were synthesized. All of the new compounds were tested for cytotoxicity, and the results revealed that most of the spin‐labeled stilbene derivatives showed superior cytotoxicity in vitro.
Peptaibiomics: Towards a Myriad of Bioactive Peptides Containing Cα‐Dialkylamino Acids?
Authors: Degenkolb Thomas , Brückner Hans 
Published: September 2008

AbstractFungi are generally regarded as a literally infinite resource of bioactive secondary metabolites displaying remarkable structural diversity. Research on a particular group of linear and cyclic peptide antibiotics comprehensively named peptaibiotics – as result of the abundance of the non‐proteinogenic Cα‐dialkylated α‐amino acids α‐aminoisobutyric acid (Aib) and isovaline (Iva) – has been started 50 years ago. These peptides have gained constantly increasing interest because of their unique bioactivities and conformations. This review, reflecting the history of peptaibiotic research from 1958 to 2008, is focussed on introducing both the structural diversity and natural microheterogeneity of the peptaibiotics, as well as the biodiversity of their fungal producers. Recently introduced state‐of‐the‐art methods for rapid screening and sequencing of peptaibiotics, such as peptaibiomics and intact‐cell MALDI‐TOF mass spectrometry, are discussed. Finally, future prospects in peptaibiotic research are presented. Owing to the ubiquity and biodiversity of the fungal producers in the biosphere, the discovery of a myriad of peptaibiotics within the next decade is predicted.
{[1‐(Arylmethyl)piperidin‐4‐yl]oxy}‐(trifluoromethyl)‐pyridines: Ketanserin Analogues with Insect Growth Regulating Activity
Authors: Cai Ming‐Yi , Li Zhong , Huang Qingchun , Song Gonghua 
Published: September 2008

AbstractA series of {[1‐(arylmethyl)piperidin‐4‐yl]oxy}‐(trifluoromethyl)‐pyridine derivatives were designed and synthesized on the basis of the ketanserin (1) framework, a prototypic mammalian 5‐HT2A receptor antagonist, and the structure–activity relationship (SAR) was also discussed. The result of the bioassay showed that most of the title compounds inhibited the insect growth and exhibited moderate‐to‐good growth regulating activity against the armyworm Pseudaletia separata Walker. Furthermore, the SAR study revealed that, when the determinant feature, interacting with mammalian 5‐HT2A receptor, was preserved, a simplified ArCH2 group greatly contributed to insect growth inhibitory activities. It was also found that the substituted position of the CF3 group at the pyridine ring played a key role, and that the introduction of 1‐[bis(4‐fluorophenyl)methyl]piperazine, an equivalent of the benzoylpiperidine moiety of ketanserin, resulted in bioactivities similar to those of the title compounds, which were in agreement with the model of ketanserin analogues binding to mammalian 5‐HT2 receptors.
Development of Highly Chemoselective Bulky Zincate Complex, tBu4ZnLi2: Design, Structure, and Practical Applications in Small‐/Macromolecular Synthesis
Authors: Furuyama Taniyuki , Yonehara Mitsuhiro , Arimoto Sho , Kobayashi Minoru , Matsumoto Yotaro , Uchiyama Masanobu 
Published: September 2008

AbstractWe present full details of the unique reactivities of the newly developed dianion‐type bulky zincate, dilithium tetra‐tert‐butylzincate (tBu4ZnLi2). With this reagent, halogen–zinc exchange reaction of variously functionalized haloaromatics and anionic polymerization of N‐isopropylacrylamide (NIPAm)/styrene with excellent chemoselectivity were realized. Halogen–zinc exchange reaction followed by electrophilic trapping with propargyl bromide provided a convenient route to functionalized phenylallenes, particularly those with electrophilic functional groups (such as cyano, amide and halogens). Spectral and computational studies of the structure in the gas and liquid phases indicated extraordinary stabilization of this dianion‐type zincate by its bulky ligands.
Stannylated Polynorbornenes as New Reagents for a Clean Stille Reaction
Authors: Carrera Nora , Gutiérrez Enrique , Benavente Rut , Villavieja M. Mar , Albéniz Ana C. , Espinet Pablo 
Published: September 2008

AbstractNew functionalized polynorbornenes have been obtained in good yields by vinylic copolymerization of norbornene with a (norbornenyl)SnBu2Cl monomer, catalyzed by [Ni(C6F5)2(SbPh3)2]. Subsequent functionalization produces a wide variety of polymers with different SnBu2R groups (R=aryl, vinyl, alkynyl). The polymers can be used as R‐transfer reagents in Stille couplings, thereby providing easy workup and separation of the polymeric tin byproducts from the coupling products. Tin contents of around 0.05 wt % are found in the Stille products. The stannylated polymers can be recycled and reused with good efficiency.
Models of the ox1 State of Methylcoenzyme M Reductase: Where are the Electrons?
Authors: Gonzalez Emmanuel , Ghosh Abhik 
Published: September 2008

AbstractThe nature of the nickel center in the ox1 form of methylcoenzyme M reductase (MCRox1), the enzyme that catalyzes the last step of biological methanogenesis, has long been controversial. A recent pulse electron paramagnetic resonance (EPR) study suggested a NiIII‐thiolate, or equivalently a high‐spin NiII thiyl radical, description. The MCRox1 hyperfine parameters are best interpreted in terms of a Ni d SOMO, although a pure d SOMO does not explain the fact that about 7 % of the spin‐density resides on the sulfur. The key goals of this DFT (PW91) study were to judge whether the NiIII‐thiolate description is chemically sensible and, if so, to provide a detailed molecular orbital (MO) description of MCRox1. An NiIII‐thiolate description was indeed found to be reasonable and was obtained as the ground state for symmetrized (Cs) oxaporphyrin‐, pyriporphyrin‐, and isoporphyrin‐based model complexes, as well as for a more realistic, biomimetic model. The model calculations yielded a number of insights, key among which are the following: 1) Although the SOMO topology may be viewed as d‐like, this MO also has a substantial amount of metal d character, allowing it to overlap with a thiolate σ lone pair, which would otherwise be orthogonal. 2) In one case (isoporphyrin), we were able to exploit the symmetry of the molecule to independently optimize the (d)1 and (d)1 NiIII states, which turned out to be very close in energy. 3) The near‐degeneracy of these two states provides an elegant explanation for the tendency of these two orbitals to hybridize. Admixture of substantial d character into the d‐type SOMO of our most realistic model of MCRox1 results in a small but distinct spin population of about 0.04 on the sulfur, apparently nicely confirming the conclusions derived from the pulse EPR study. Other pure functionals also confirm this picture, although the hybrid functional B3LYP yields a spin‐density profile that is clearly at odds with the EPR study.
Solvent‐Dependent Changes in the Triazolinedione–Alkene Ene Reaction Mechanism
Authors: Vougioukalakis Georgios C. , Roubelakis Manolis M. , Alberti Mariza N. , Orfanopoulos Michael 
Published: September 2008

AbstractThe influence of the solvent on the triazolinedione–alkene ene reaction mechanism has been investigated. Both inter‐ and intramolecular kinetic isotope effects with tetramethylethylenes and 2,2,2‐(trideuterio)methyl‐7‐methyl‐2,6‐octadiene‐[D3]‐1,1,1 provide, for the first time, strong evidence for changes in the mechanism of the reaction on going from non‐protic to polar protic solvents. In non‐protic polar or apolar solvents, an aziridinium imide that equilibrates to an insignificant extent with an open intermediate (a dipolar or a polarized biradical) is formed irreversibly in the first, rate‐determining step of the reaction, which is followed by fast hydrogen abstraction. On the contrary, in polar protic solvents, hydrogen abstraction is rate limiting, allowing the main dipolar intermediate to equilibrate with its open intermediate(s) as well as with the starting reagents.
Stereoconversion of Amino Acids and Peptides in Uryl‐Pendant Binol Schiff Bases
Authors: Park Hyunjung , Nandhakumar Raju , Hong Jooyeon , Ham Sihyun , Chin Jik , Kim Kwan Mook 
Published: September 2008

Abstract(S)‐2‐Hydroxy‐2′‐(3‐phenyluryl‐benzyl)‐1,1′‐binaphthyl‐3‐carboxaldehyde (1) forms Schiff bases with a wide range of nonderivatized amino acids, including unnatural ones. Multiple hydrogen bonds, including resonance‐assisted ones, fix the whole orientation of the imine and provoke structural rigidity around the imine CN bond. Due to the structural difference and the increase in acidity of the α proton of the amino acid, the imine formed with an L‐amino acid (1–l‐aa) is converted into the imine of the D‐amino acid (1–D‐aa), with a D/L ratio of more than 10 for most amino acids at equilibrium. N‐terminal amino acids in dipeptides are also predominantly epimerized to the D form upon imine formation with 1. Density functional theory calculations show that 1–D‐Ala is more stable than 1–L‐Ala by 1.64 kcal mol−1, a value that is in qualitative agreement with the experimental result. Deuterium exchange of the α proton of alanine in the imine form was studied by 1H NMR spectroscopy and the results support a stepwise mechanism in the L‐into‐D conversion rather than a concerted one; that is, deprotonation and protonation take place in a sequential manner. The deprotonation rate of L‐Ala is approximately 16 times faster than that of D‐Ala. The protonation step, however, appears to favor L‐amino acid production, which prevents a much higher predominance of the D form in the imine. Receptor 1 and the predominantly D‐form amino acid can be recovered from the imine by simple extraction under acidic conditions. Hence, 1 is a useful auxiliary to produce D‐amino acids of industrial interest by the conversion of naturally occurring L‐amino acids or relatively easily obtainable racemic amino acids.
Investigation of a Possible Solvent Cage Effect in the Reduction of 4‐Aminocyclohexanone by a Hydroxycyclopentadienyl Ruthenium Hydride
Authors: Åberg Jenny B. , Bäckvall Jan‐E. 
Published: September 2008

AbstractNo solvent cage effect could be found in the reduction of 4‐aminocyclohexanone 3 by Shvo's hydroxycyclopentadienyl ruthenium hydride 2. No preference was observed in the complex formation from trapping by aminoalcohol product 4 over external trapping by aminoketone 3 or by Shvo hydride 2. A solvent cage effect has previously been proposed to support an outer‐sphere mechanism in the reduction of imines by 2; this was based on the observation that there was >90% preference for complexation of the newly formed amine over an external amine. Since alcohols form stronger hydrogen bonds than amines a larger cage effect would be expected in the present study. The lack of a cage effect in the present reduction suggests that the previous results from imine reduction require an additional explanation (other than a solvent cage effect).
L‐Proline Catalyzed Enamination of β‐Dicarbonyl Compounds under Solvent‐free Conditions
Authors: KUNDU Dhiman , MAJEE Adinath , HAJRA Alakananda 
Published: September 2008

AbstractA simple, general and efficient method has been developed for synthesis of various β‐enamino ketones and esters by reacting β‐dicarbonyl compounds with amines using a catalytic amount of L‐proline at room temperature under solvent‐free conditions in excellent yields.
Supramolecular Assemblies Using Piperazine with Dicarboxylic Acids and Hydroxy‐carboxylic Acids
Authors: CHEN Zi‐Yun , PENG Meng‐Xia 
Published: September 2008

AbstractThe molecular self‐assembly of piperazine (pip) with 1,4‐cyclohexanedicarboxylic acid (H2chda), m‐phthalic acid (H2mpda), 6‐hydroxy‐2‐naphthalic acid (Hohna) and 1‐hydroxy‐2‐naphthalic acid (Hshna) results in four new supramolecular networks formulated as H2pip·chda (1), H2pip·2Hmpda (2), H2pip·ohna·2H2O (3) and H2pip·shna (4), respectively. Single‐crystal X‐ray diffraction study reveals that compounds 1–3 are three‐dimensional supramolecular networks, while 4 has a one‐dimensional hydrogen‐bonded chain‐based structure, with CCDC: 672051 (1), 672052 (2), 672053 (3) and 672054 (4).
Low Temperature Heat Capacities and Thermodynamic Properties of 2‐Methyl‐2‐butanol
Authors: TONG Bo , TAN Zhi‐Cheng , WANG Shao‐Xu 
Published: September 2008

AbstractThe low‐temperature heat capacity Cp,m of 2‐methyl‐2‐butanol was precisely measured in the temperature range from 80 to 305 K by means of a small sample automated adiabatic calorimeter. Three solid‐solid phase transitions and one solid‐liquid phase transition were found at T=146.355, 149.929, 214.395 and 262.706 K from the experimental Cp‐T curve, respectively. The dependence of heat capacity on temperature was fitted to the following polynomial equations with a least square method. In the temperature range of 80 to 140 K, Cp,m=39.208+8.0724X−1.9583X2+10.06X3+1.799X4−7.2778X5+1.4919X6, X= (T−110)/30; in the temperature range of 155 to 210 K, Cp,m=70.701+10.631X+12.767X2+0.3583X3−22.272X4−0.417X5+12.055X6, X= (T−182.5)/27.5; in the temperature range of 220 to 250 K, Cp,m=99.176+7.7199X−26.138X2+28.949X3+0.7599X4−25.823X5+21.131X6, X= (T−235)/15; and in the temperature range of 270 to 305 K, Cp,m=121.73+16.53X−1.0732X2−34.937X3−19.865X4+24.324X5+18.544X6, X= (T−287.5)/17.5. The molar enthalpies of these transitions were determined to be 0.9392, 1.541, 0.6646 and 2.239 kJ·mol−1, respectively. The molar entropies of these transitions were determined to be 6.417, 10.28, 3.100 and 8.527 J·K−1·mol−1, respectively. The thermodynamic functions [HT−H298.15] and[ST−S298.15], were derived from the heat capacity data in the temperature range of 80 to 305 K with an interval of 5 K.