http://www.mdpi.com/section/organic_synthesis http://www.mdpi.com/1420-3049/15/3/1798/ A new macromolecule possessing two dansyl moieties and based on 2-[4-(2-aminoethylthio)butylthio]ethanamine was prepared as a fluorescent sensor and its mercury sensing properties toward various transition metal, alkali, and alkali earth ions were investigated. The designed compound exhibited pronounced Hg2+-selective ON-OFF type fluorescence switching upon binding. The new compoundprovided highly selective sensing to Hg2+ in acetonitrile-water solvent mixtures with a detection limit of 2.49 x 10-7 M or 50 ppb. The molecular modeling results indicated that ions-recognition of the sensor originated from a self assembly process of the reagentand Hg2+ to form a helical wrapping structure with the favorable electrostatic interactions of Hg2+coordinated with sulfur, oxygen, nitrogen atoms and aromatic moieties. http://www.mdpi.com/1420-3049/15/3/1798/ Fri, 12 Mar 2010 00:00:00 CET Molecules 2010-03-12 15 3 Article 1798 1810 1420-3049 Synthesis of a Novel Fluorescent Sensor Bearing Dansyl Fluorophores for the Highly Selective Detection of Mercury (II) Ions 2010-03-12 doi: 10.3390/molecules15031798 Wanichacheva Watpathomsub Lee Grudpan http://www.mdpi.com/1420-3049/15/3/1487/ The direct aerobic coupling reaction of arenes with olefins was successfully achieved by the use of Pd(OAc)2/molybdovanadophosphoric acid (HPMoV) as a key catalyst under 1 atm of dioxygen. This catalytic system could be extended to the coupling reaction of various substituted benzenes with olefins such as acrylates, aclrolein, and ethylene through the direct aromatic C-H bond activation. http://www.mdpi.com/1420-3049/15/3/1487/ Tue, 09 Mar 2010 00:00:00 CET Molecules 2010-03-09 15 3 Review 1487 1500 1420-3049 Pd(II)/HPMoV-Catalyzed Direct Oxidative Coupling Reaction of Benzenes with Olefins 2010-03-09 doi: 10.3390/molecules15031487 Yasushi Obora Yasutaka Ishii http://www.mdpi.com/1420-3049/15/3/1442/ A novel chiral macrocyclic ligand incorporating a chiral salen moiety into a framework containing two biphenyl units was synthesized. Structural properties and conformational aspects of the free ligand and an UO2 complex were studied by using NMR spectroscopy in solution and MM calculations. The Mn(III) complex was tested as catalyst in enantioselective oxidation of prochiral unfunctionalized olefins to the corresponding optically active epoxides under very mild conditions. http://www.mdpi.com/1420-3049/15/3/1442/ Tue, 09 Mar 2010 00:00:00 CET Molecules 2010-03-09 15 3 Article 1442 1452 1420-3049 Synthesis and Conformational Study of a Novel Macrocyclic Chiral(Salen) ligand and its Uranyl and Mn Complexes 2010-03-09 doi: 10.3390/molecules15031442 Maria E. Amato Francesco P. Ballistreri Andrea Pappalardo Gaetano A. Tomaselli Rosa M. Toscano http://www.mdpi.com/1420-3049/15/3/1302/ The palladium-catalyzed hydroarylation of N-methyl-substituted tricyclic imides was studied in order to find a new stereoselective access to a series of new exo-aryl(hetaryl)-substituted tricyclic N-methylimides. http://www.mdpi.com/1420-3049/15/3/1302/ Thu, 04 Mar 2010 00:00:00 CET Molecules 2010-03-04 15 3 Article 1302 1308 1420-3049 Reductive Heck Reactions of N-Methyl-substituted Tricyclic Imides 2010-03-04 doi: 10.3390/molecules15031303 Gokce Goksu Nuket Ocal Dieter E. Kaufmann http://www.mdpi.com/1420-3049/15/2/1041/ An overview of the synthesis and applications of chiral 2,3-epoxy alcohols containing unsaturated chains is presented. One of the fundamental synthetic routes to these compounds is Sharpless asymmetric epoxidation, which is reliable, highly chemoselective and enables easy prediction of the product enantioselectivity. Thus, unsaturated epoxy alcohols are readily obtained by selective oxidation of the allylic double bond in the presence of other carbon-carbon double or triple bonds. The wide availability of epoxy alcohols with unsaturated chains, the versatility of the epoxy alcohol functionality (e.g. regio- and stereo-selective ring opening; oxidation; and reduction), and the arsenal of established alkene chemistries, make unsaturated epoxy alcohols powerful starting materials for the synthesis of complex targets such as biologically active molecules. The popularization of ring-closing metathesis has further increased their value, making them excellent precursors to cyclic compounds. http://www.mdpi.com/1420-3049/15/2/1041/ Tue, 23 Feb 2010 00:00:00 CET Molecules 2010-02-23 15 2 Review 1041 1073 1420-3049 Synthetic Applications of Chiral Unsaturated Epoxy Alcohols Prepared by Sharpless Asymmetric Epoxidation 2010-02-23 doi: 10.3390/molecules15021041 Antoni Riera María Moreno http://www.mdpi.com/1420-3049/15/2/1007/ Medical-grade polyvinyl chloride was coated by polysaccharides through a novel physicochemical approach. An initial surface activation was performed foremost via diffuse coplanar surface barrier discharge plasma in air at ambient temperature and pressure. Then, radical graft copolymerization of acrylic acid through grafting-from pathway was directed to render a well-defined brush of high density, and finally a chitosan monolayer and chitosan/pectin alternating multilayer were bound onto the functionalized surfaces. Surface characteristics were systematically investigated using several probe techniques. In vitro bacterial adhesion and biofilm formation assays indicated that a single chitosan layer was incapable of hindering the adhesion of a Staphylococcus aureus bacterial strain, while up to 30% reduction was achieved by the chitosan/pectin layered assembly. On the other hand, chitosan and chitosan/pectin multilayer could retard Escherichia coli adhesion by 50% and 20%, respectively. Furthermore, plasma treated and graft copolymerized samples were also found effective to diminish the degree of adherence of Escherichia coli. http://www.mdpi.com/1420-3049/15/2/1007/ Tue, 23 Feb 2010 00:00:00 CET Molecules 2010-02-23 15 2 Article 1007 1027 1420-3049 Polysaccharides Coatings on Medical-Grade PVC: A Probe into Surface Characteristics and the Extent of Bacterial Adhesion 2010-02-23 doi: 10.3390/molecules15021007 Ahmad Asadinezhad Igor Novák Marián Lehocký František Bílek Alenka Vesel Ita Junkar Petr Sáha Anton Popelka http://www.mdpi.com/1420-3049/15/2/917/ Organocatalytic asymmetric α-oxidation and amination reactions of carbonyl compounds are highly useful synthetic methodologies, especially in generating chiral building blocks that previously have not been easily accessible by traditional methods. The concept is relatively new and therefore the list of new catalysts, oxidizing and aminating reagents, as well as new substrates, are expanding at an amazing rate. The scope of this review includes new reactions and catalysts, mechanistic aspects and synthetic applications of α-oxidation, hydroxylation, aminoxylation, amination, hydrazination, hydroxyamination and related α-heteroatom functionalization of aldehydes, ketones and related active methylene compounds published during 2005–2009. http://www.mdpi.com/1420-3049/15/2/917/ Thu, 11 Feb 2010 00:00:00 CET Molecules 2010-02-11 15 2 Review 917 958 1420-3049 Organocatalyzed Asymmetric α-Oxidation, α-Aminoxylation and α-Amination of Carbonyl Compounds 2010-02-11 doi: 10.3390/molecules15020917 Tirayut Vilaivan Worawan Bhanthumnavin http://www.mdpi.com/1420-3049/15/2/813/ A sustainable Knoevenagel condensation of a series of aldehydes with malononitrile and ethyl cyanoacetate is described. The process is based on the combination of microwave activation and hydroxyapatite catalysis under solvent-free conditions. Products are obtained in and high yields after short reaction times. The effects of the specific surface of porous calcium hydroxyapatite and microwave activation are discussed. http://www.mdpi.com/1420-3049/15/2/813/ Thu, 04 Feb 2010 00:00:00 CET Molecules 2010-02-04 15 2 Article 813 823 1420-3049 Microwave-Assisted and Efficient Solvent-free Knoevenagel Condensation. A Sustainable Protocol Using Porous Calcium Hydroxyapatite as Catalyst 2010-02-04 doi: 10.3390/molecules15020813 Siham Mallouk Khalid Bougrin Abdelaziz Laghzizil Rachid Benhida http://www.mdpi.com/1420-3049/15/2/649/ An efficient and stereoselective catalytic system for the Heck cross coupling reaction using novel 1,3-dialkyl-3,4,5,6-tetrahydropyrimidinium salts (1, LHX) and Pd(OAc)2 loading has been reported. The palladium complexes derived from the salts 1a-f prepared in situ exhibit good catalytic activity in the Heck coupling reaction of aryl bromides under mild conditions. http://www.mdpi.com/1420-3049/15/2/649/ Thu, 28 Jan 2010 00:00:00 CET Molecules 2010-01-28 15 2 Article 649 659 1420-3049 Palladium-Catalyzed Heck Coupling Reaction of Aryl Bromides in Aqueous Media Using Tetrahydropyrimidinium Salts as Carbene Ligands 2010-01-28 doi: 10.3390/molecules15020649 Sedat Yaşar Emine Özge Özcan Nevin Gürbüz Bekir Çetinkaya İsmail Özdemir http://www.mdpi.com/1420-3049/15/1/570/ Photoresponsive block copolymers (PRBCs) containing azobenzenes and other chromophores can be easily prepared by controlled polymerization. Their photoresponsive behaviors are generally based on photoisomerization, photocrosslinking, photoalignment and photoinduced cooperative motions. When the photoactive block forms mesogenic phases upon microphase separation of PRBCs, supramolecular cooperative motion in liquid-crystalline PRBCs enables them to self-organize into hierarchical structures with photoresponsive features. This offers novel opportunities to photocontrol microphase-separated nanostructures of well-defined PRBCs and extends their diverse applications in holograms, nanotemplates, photodeformed devices and microporous films. http://www.mdpi.com/1420-3049/15/1/570/ Tue, 26 Jan 2010 00:00:00 CET Molecules 2010-01-26 15 1 Review 570 603 1420-3049 Photoresponsive Block Copolymers Containing Azobenzenes and Other Chromophores 2010-01-26 doi: 10.3390/molecules15010570 Haifeng Yu Takaomi Kobayashi http://www.mdpi.com/1420-3049/15/1/315/ A water-soluble and air-stable Pd(NH3)2Cl2/cationic 2,2’-bipyridyl system was found to be a highly-efficient and reusable catalyst for the coupling of aryl iodides and alkenes in neat water using Bu3N as a base. The reaction was conducted at 140 °C in a sealed tube in air with a catalyst loading as low as 0.0001 mol % for the coupling of activated aryl iodides with butyl and ethyl acrylates, providing the corresponding products in good to excellent yields with very high turnover numbers. In the case of styrene, Mizoroki-Heck coupling products were obtained in good to high yields by using a greater catalyst loading (1 mol %) and TBAB as a phase-transfer agent. After extraction, the residual aqueous solution could be reused several times with only a slight decrease in its activity, making the Mizoroki-Heck reaction “greener”. http://www.mdpi.com/1420-3049/15/1/315/ Tue, 12 Jan 2010 00:00:00 CET Molecules 2010-01-12 15 1 Article 315 330 1420-3049 Palladium(II)/Cationic 2,2’-Bipyridyl System as a Highly Efficient and Reusable Catalyst for the Mizoroki-Heck Reaction in Water 2010-01-12 doi: 10.3390/molecules15010315 Shao-Hsien Huang Jun-Rong Chen Fu-Yu Tsai http://www.mdpi.com/1420-3049/15/1/178/ In the last few years click chemistry reactions, and in particular coppercatalyzed cycloadditions, have been used intensively for the preparation of new bioconjugate molecules and materials applicable to biomedical and pharmaceutical areas. This review will be focused on conjugates of the tripeptide Arg-Gly-Asp formed by means of click chemistry reactions. This sequence is a well known binding motif for specific transmembrane proteins and is involved in cellular adhesion to the extracellular matrix, allowing the selective recognition of the biomolecule or polymer in which it is incorporated. http://www.mdpi.com/1420-3049/15/1/178/ Wed, 06 Jan 2010 00:00:00 CET Molecules 2010-01-06 15 1 Review 178 197 1420-3049 Click Chemistry for the Synthesis of RGD-Containing Integrin Ligands 2010-01-06 doi: 10.3390/molecules15010178 Matteo Colombo Aldo Bianchi http://www.mdpi.com/1420-3049/15/1/150/ Two thioacetyl-terminated ferrocene-anthraquinone donor-acceptor molecules with different π-electron conjugative units have been synthesized via a series of Stille and Sonagashira reactions. Their photochemical and electrochemical properties before and after addition of an organic acid are investigated, indicating that these complexes are sensitive to external perturbation of protonation, leading the structural change to an expansion of π-conjugated system by cyclocondensation reaction and promoting intramolecular electron transfer from donor to acceptor. They would be good candidates for studies of novel SAMs, and the properties triggered by protonation-induced intramolecular electron transfer will make the SAMs be useful in designing new functional molecular devices. http://www.mdpi.com/1420-3049/15/1/150/ Mon, 04 Jan 2010 00:00:00 CET Molecules 2010-01-04 15 1 Article 150 163 1420-3049 Thioacetyl-Terminated Ferrocene-Anthraquinone Conjugates: Synthesis, Photo- and Electrochemical Properties Triggered by Protonation-Induced Intramolecular Electron Transfer 2010-01-04 doi: 10.3390/molecules15010150 Wen-Wei Zhang Mio Kondo Takako Fujita Kosuke Namiki Masaki Murata Hiroshi Nishihara http://www.mdpi.com/1420-3049/14/12/5298/ The protecting-group-free asymmetric synthesis of 1,2,4-trideoxy-1,4-imino-L-xylitol is readily achieved in five steps from 2-deoxy-D-ribose and with an overall yield of 48%. Key in this synthesis is the application of our recently developed Vasella-reductive amination and carbamate annulation methodologies to the synthesis of 2-deoxy-aza-sugars. The carbamate annulation occurred with excellent yield and diastereoselectively (>20:1 d.r.), in favour of the 3,4-cis isomer. http://www.mdpi.com/1420-3049/14/12/5298/ Wed, 16 Dec 2009 00:00:00 CET Molecules 2009-12-16 14 12 Article 5298 5307 1420-3049 Protecting-Group-Free Synthesis of 2-Deoxy-Aza-Sugars 2009-12-16 doi: 10.3390/molecules14125298 Emma Marie Dangerfield Catherine Heather Plunkett Bridget Louise Stocker Mattie Simon Maria Timmer http://www.mdpi.com/1420-3049/14/12/5216/ The four-step, asymmetric synthesis of a chiral propargyl alcohol 1 from (R)-pantolactone is described. A key feature of the synthesis is a diastereoselective acetylide addition to a chiral α-alkoxy-aldehyde 7, in which unusual Felkin selectivity is observed, despite the potential for chelation control. Crystalline propargyl alcohol 1 is valuable for complex molecule synthesis, and is easy to prepare in multi-gram quantities and high diastereomeric purity. http://www.mdpi.com/1420-3049/14/12/5216/ Tue, 15 Dec 2009 00:00:00 CET Molecules 2009-12-15 14 12 Article 5216 5222 1420-3049 A Striking Exception to the Chelate Model for Acyclic Diastereocontrol: Efficient Access to a Versatile Propargyl Alcohol for Chemical Synthesis 2009-12-15 doi: 10.3390/molecules14125216 Sami F. Tlais Ronald J. Clark Gregory B. Dudley http://www.mdpi.com/1420-3049/14/12/4936/ In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS) that have been achieved over the last five years. http://www.mdpi.com/1420-3049/14/12/4936/ Tue, 01 Dec 2009 00:00:00 CET Molecules 2009-12-01 14 12 Review 4936 4972 1420-3049 Microwave Multicomponent Synthesis 2009-12-01 doi: 10.3390/molecules14124936 Helmut M. Hügel http://www.mdpi.com/1420-3049/14/12/4880/ The diversity of selenoproteins raises the question of why so many life forms require selenium. Selenoproteins are found in bacteria, archaea, and many eukaryotes. In photosynthetic microorganisms, the essential requirement for selenium has been reported in 33 species belonging to six phyla, although its biochemical significance is still unclear. According to genome databases, 20 species are defined as selenoprotein-producing organisms, including five photosynthetic organisms. In a marine coccolithophorid, Emiliania huxleyi (Haptophyta), we recently found unique characteristics of selenium utilization and novel selenoproteins using 75Se-tracer experiments. In E. huxleyi, selenite, not selenate, is the main substrate used and its uptake is driven by an ATP-dependent highaffinity, active transport system. Selenite is immediately metabolized to low-molecular mass compounds and partly converted to at least six selenoproteins, named EhSEP1–6. The most (EhSEP2) and second-most abundant selenoproteins (EhSEP1) are disulfide isomerase (PDI) homologous protein and thioredoxin reductase (TR) 1, respectively. Involvement of selenium in PDI is unique in this organism, while TR1 is also found in other organisms. In this review, we summarize physiological, biochemical, and molecular aspects of selenium utilization by microalgae and discuss their strategy of selenium utilization. http://www.mdpi.com/1420-3049/14/12/4880/ Mon, 30 Nov 2009 00:00:00 CET Molecules 2009-11-30 14 12 Review 4880 4891 1420-3049 Selenium Utilization Strategy by Microalgae 2009-11-30 doi: 10.3390/molecules14124880 Hiroya Araie Yoshihiro Shiraiwa http://www.mdpi.com/1420-3049/14/11/4747/ Since the serendipitous discovery of ferrocene by Pauson and Kealy in 1951, it has become one of the most important structures in Organic Chemistry. Lately, kinetic resolution has emerged as a useful tool for the synthesis of planar chiral ferrocenes. This review aims to cover and discuss the development of this topic. http://www.mdpi.com/1420-3049/14/11/4747/ Fri, 20 Nov 2009 00:00:00 CET Molecules 2009-11-20 14 11 Review 4747 4757 1420-3049 Kinetic Resolution: A Powerful Tool for the Synthesis of Planar-Chiral Ferrocenes 2009-11-20 doi: 10.3390/molecules14114747 Andrea-Nekane R. Alba Ramon Rios http://www.mdpi.com/1420-3049/14/11/4440/ The amounts of selenium (Se), iron (Fe), and zinc (Zn) in the liver, kidney, and spleen as a function of age of rats measured using instrumental neutron activation analysis were compared between Se-deficient (SeD) rats and normal rats. The SeD model rats can live for more than 50 weeks. The effect of Se-deficinecy in rats might be weak, compared to the marked malfunction of GSH-Px. The SeD rats can be considered as a model of nonlethal chronic oxidative stress. Fluctuations of Fe and Zn in the liver of Se-deficient rats were observed. The amount of redox-relating minerals, such as Fe and Zn, in SeD rat organs is changeable depending on the age. http://www.mdpi.com/1420-3049/14/11/4440/ Thu, 05 Nov 2009 00:00:00 CET Molecules 2009-11-05 14 11 Article 4440 4453 1420-3049 The Effect of Long-Running Severe Selenium-Deficiency on the Amount of Iron and Zinc in the Organs of Rats 2009-11-05 doi: 10.3390/molecules14114440 Ken-ichiro Matsumoto Sachiyo Terada Marie Ariyoshi Aya Okajo Atsushi Hisamatsu Iori Ui Kazutoyo Endo http://www.mdpi.com/1420-3049/14/11/4337/ Despite being close neighbors on the Periodic Table, selenium and tellurium present a totally different abilities to form glasses. Se is a very good glass former, and gives rise to numerous glass compositions which are popular for their transparency in the infrared range and their stability against crystallization. These glasses can be shaped into sophisticated optical devices such as optical fibers, planar guides or lenses. Nevertheless, their transparencies are limited at about 12 μm (depending on the thickness of the optical systems) due to the relatively small mass of the Se element. On the other hand, tellurium is heavier and its use in substitution for Se permits to shift the IR cutoff beyond 20 μm. However, the semimetallic nature of Te limits its glass formation ability and this glass family is known to be unstable and consequently has found application as phase change material in the Digital Versatile Disk (DVD) technology. In this paper, after a review of selenide glasses and their applications, it will be shown how, in a recent past, it has been possible to stabilize tellurium glasses by introducing new elements like Ga or I in their compositions. http://www.mdpi.com/1420-3049/14/11/4337/ Mon, 26 Oct 2009 00:00:00 CET Molecules 2009-10-26 14 11 Review 4337 4350 1420-3049 Forming Glasses from Se and Te 2009-10-26 doi: 10.3390/molecules14114337 Bruno Bureau Catherine Boussard-Pledel Pierre Lucas Xianghua Zhang Jacques Lucas http://www.mdpi.com/1420-3049/14/11/4312/ The C2-symmetrical “salen” ligand (+)-9 bearing two [5]ferrocenophane substituents has been prepared in five steps starting from readily available diacetylferrocene, p-hydroxybenzaldehyde and (R,R)-N,N’-diphenylethylenediamine. Reaction of (+)-9 with Mn(OAc)3, Co(OAc)2 ZnEt2 or UO2(OAc)2 gave the corresponding metal-complexes which were characterised by spectroscopic methods. http://www.mdpi.com/1420-3049/14/11/4312/ Mon, 26 Oct 2009 00:00:00 CET Molecules 2009-10-26 14 11 Article 4312 4325 1420-3049 Synthesis and Characterization of Some Chiral Metal-Salen Complexes Bearing a Ferrocenophane Substituent 2009-10-26 doi: 10.3390/molecules14114312 Angela Patti Sonia Pedotti Francesco Paolo Ballistreri Giuseppe Trusso Sfrazzetto http://www.mdpi.com/1420-3049/14/10/4079/ The molecular combing technique was used to dissociate the nanostructural units of starch granules from the starch fragments after a gelatinization process. With the help of atomic force microscopy (AFM), we observed that some nanostructural chains were just flowing out of the granules. It proves that there are substantive nanostructural units in the starch granules, a phenomenon not previously observed, so these nanostructural units were defined as suspected intermediates. Furthermore, we conclude that blocklets of starch granules are formed through twisting or distortion of nanochains. http://www.mdpi.com/1420-3049/14/10/4079/ Mon, 12 Oct 2009 00:00:00 CEST Molecules 2009-10-12 14 10 Article 4079 4086 1420-3049 Application of the Molecular Combing Technique to Starch Granules 2009-10-12 doi: 10.3390/molecules14104079 Hua Li Zhong-Dong Liu Liu Boxiang Jian-Hui Chen You-Ning Sun Xiao-Ling Lv Ze-Sheng Zhang Pin Sun Pin Zhang Yang-Li Wang http://www.mdpi.com/1420-3049/14/10/4022/ Synthetic polyesters have deeply impacted various biomedical and engineering fields, such as tissue scaffolding and therapeutic delivery. Currently, many applications involving polyesters are being explored with polymers derived from monomers that are endogenous to the human metabolism. Examples of these monomers include glycerol, xylitol, sorbitol, and lactic, sebacic, citric, succinic, α-ketoglutaric, and fumaric acids. In terms of mechanical versatility, crystallinity, hydrophobicity, and biocompatibility, polyesters synthesized partially or completely from these monomers can display a wide range of properties. The flexibility in these macromolecular properties allows for materials to be tailored according to the needs of a particular application. Along with the presence of natural monomers that allows for a high probability of biocompatibility, there is also an added benefit that this class of polyesters is more environmentally friendly than many other materials used in biomedical engineering. While the selection of monomers may be limited by nature, these polymers have produced or have the potential to produce an enormous number of successes in vitro and in vivo. http://www.mdpi.com/1420-3049/14/10/4022/ Mon, 12 Oct 2009 00:00:00 CEST Molecules 2009-10-12 14 10 Review 4022 4050 1420-3049 Design and Applications of Biodegradable Polyester Tissue Scaffolds Based on Endogenous Monomers Found in Human Metabolism 2009-10-12 doi: 10.3390/molecules14104022 Devin G. Barrett Muhammad N. Yousaf http://www.mdpi.com/1420-3049/14/10/3975/ The essential trace element selenium, which is a crucial cofactor in the most important endogenous antioxidative systems of the human body, is attracting more and more the attention of both laypersons and expert groups. The interest of oncologists mainly focuses in the following clinical aspects: radioprotection of normal tissues, radiosensitizing in malignant tumors, antiedematous effect, prognostic impact of selenium, and effects in primary and secondary cancer prevention. Selenium is a constituent of the small group of selenocysteine-containing selenoproteins and elicits important structural and enzymatic functions. Selenium deficiency has been linked to increased infection risk and adverse mood states. It has been shown to possess cancer-preventive and cytoprotective activities in both animal models and humans. It is well established that Se has a key role in redox regulation and antioxidant function, and hence in membrane integrity, energy metabolism and protection against DNA damage. Recent clinical trials have shown the importance of selenium in clinical oncology. Our own clinical study involving 48 patients suggest that selenium has a positive effect on radiation-associated secondary lymphedema in patients with limb edemas, as well as in the head and neck region, including endolaryngeal edema. Another randomized phase III study of our group was performed to examine the cytoprotective properties of selenium in radiation oncology. The aim was to evaluate whether sodium selenite is able to compensate a preexisting selenium deficiency and to prevent radiation induced diarrhea in adjuvant radiotherapy for pelvic gynecologic malignancies. Through this study, the significant benefits of sodium selenite supplementation with regards to selenium deficiency and radiotherapy induced diarrhea in patients with cervical and uterine cancer has been shown for the first time in a prospective randomized trial. Survival data imply that supplementation with selenium does not interfere with the positive biological effects of radiation treatment and might constitute a valuable adjuvant therapy option especially in marginally supplied individuals. More recently there were emerging concerns coming up from two large clinical prevention trials (NPC, SELECT), that selenium increases the possible risk of developing diabetes type II. Despite obvious flaws of both studies and good counterarguments, a controversial debate remains on the possible advantage and risks of selenium in cancer prevention. However, in the light of the recent clinical trials the potential benefits of selenium supplementation in tumor patients are undeniable, even if further research is needed. http://www.mdpi.com/1420-3049/14/10/3975/ Mon, 12 Oct 2009 00:00:00 CEST Molecules 2009-10-12 14 10 Review 3975 3988 1420-3049 Selenium in Oncology: From Chemistry to Clinics 2009-10-12 doi: 10.3390/molecules14103975 Oliver Micke Lutz Schomburg Jens Buentzel Klaus Kisters Ralph Muecke http://www.mdpi.com/1420-3049/14/10/3914/ An efficient three-step solid-phase synthesis of diverse 3,5-disubstituted-2-aminofuranones has been developed. α-Hydroxy acids loaded on a nitrophenyl carbonate derivative of Wang resin are used as acylating agents for the C-acylation of active methylene compounds and the resulting intermediates provided, through a cyclative cleavage reaction, the desired product. http://www.mdpi.com/1420-3049/14/10/3914/ Wed, 30 Sep 2009 00:00:00 CEST Molecules 2009-09-30 14 10 Article 3914 3921 1420-3049 Solid-Phase Synthesis of Optically Active Substituted 2 Aminofuranones Using an Activated Carbonate Linker 2009-09-30 doi: 10.3390/molecules14103914 Dimitris Matiadis Kyriakos C. Prousis Olga Igglessi-Markopoulou http://www.mdpi.com/1420-3049/14/10/3881/ Novel polyfunctional small amphiphilic peptide dendrimers characterized by incorporation of a new core compounds – tris-amino acids or tetrakis-amino alcohols that originated from a series of basic amino acids – were efficiently synthesized. These new core elements yielded molecules with multiple branching and (+5)/(+6) charge at the 1-st dendrimer generation. Dendrimers exhibited significant antimicrobial potency against Gram(+) and Gram(-) strains involving also multiresistant reference strains (S. aureus ATCC 43300 and E. coli ATCC BAA-198). In addition, high activity against fungi from the Candida genus was detected. More charged and more hydrophobic peptide dendrimers expressed hemolytic properties. http://www.mdpi.com/1420-3049/14/10/3881/ Tue, 29 Sep 2009 00:00:00 CEST Molecules 2009-09-29 14 10 Article 3881 3905 1420-3049 Design of Antimicrobially Active Small Amphiphilic Peptide Dendrimers 2009-09-29 doi: 10.3390/molecules14103881 Piotr Polcyn Margarita Jurczak Aleksandra Rajnisz Jolanta Solecka Zofia Urbanczyk-Lipkowska http://www.mdpi.com/1420-3049/14/10/3851/ A family of dendritic tris-bipyridyl ruthenium coordination complexes incorporating two or four carboxylate groups for binding to a TiO2 surface site and another dendritic linker between the metal complex and highly absorptive dyes were formulated as thin films on TiO2 coated glass. The family included phenothiazine-substituted dendrons of increasing structural complexity and higher optical density. The dye-loaded films were characterized by steady-state emission and absorption measurements and by kinetic studies of luminescence and transient absorption. Upon photoexcitation of the bound dyes, rapid electron injection into the metal oxide film was the dominant observed process, producing oxidized dye that persisted for hundreds of milliseconds. Complex decay profiles for emission, transient absorption, and optical bleaching of the dendritic dyes point to highly heterogeneous behavior for the films, with observed persistence lifetimes related directly to structurally enhance electronic coupling between the metal oxide support and the dendritic dyes. http://www.mdpi.com/1420-3049/14/10/3851/ Mon, 28 Sep 2009 00:00:00 CEST Molecules 2009-09-28 14 10 Article 3851 3867 1420-3049 The Effect of Dye Density on the Efficiency of Photosensitization of TiO2 Films: Light-Harvesting by Phenothiazine-Labelled Dendritic Ruthenium Complexes 2009-09-28 doi: 10.3390/molecules14103851 Marye Anne Fox James K. Whitesell Douglas Magde Lin-Yong Zhu http://www.mdpi.com/1420-3049/14/9/3731/ Fifth generation ethylendiamine-core poly(amidoamine) (PAMAM G5) is presented as an efficient capping agent for the preparation of metal and semiconductor nanoparticles by ps laser ablation in water. In particular, we describe results obtained with the fundamental, second and third harmonic of a ps Nd:YAG laser and the influence of laser wavelength and pulse energy on gold particle production and subsequent photofragmentation. In this framework, the role of the dendrimer and, in particular, its interactions with gold clusters and cations are accounted. http://www.mdpi.com/1420-3049/14/9/3731/ Tue, 22 Sep 2009 00:00:00 CEST Molecules 2009-09-22 14 9 Article 3731 3753 1420-3049 Dendrimer-Capped Nanoparticles Prepared by Picosecond Laser Ablation in Liquid Environment 2009-09-22 doi: 10.3390/molecules14093731 Emilia Giorgetti Anna Giusti Francesco Giammanco Paolo Marsili Simona Laza http://www.mdpi.com/1420-3049/14/9/3719/ This review focuses on novel carbosilane dendrimers containing branches with Si-C and Si-O-C bonds. Introduction of organic moieties into the dendrimers is performed by hydrosilation of carbon-carbon double/triple bonds. Versatile organic or organometallic moieties are introduced onto the peripheral regions of dendrimers by coupling and complexation reactions, which clearly demonstrates their potential for variation. http://www.mdpi.com/1420-3049/14/9/3719/ Tue, 22 Sep 2009 00:00:00 CEST Molecules 2009-09-22 14 9 Review 3719 3730 1420-3049 Carbosilane and Carbosiloxane Dendrimers 2009-09-22 doi: 10.3390/molecules14093719 Chungkyun Kim Jang Hwan Hong http://www.mdpi.com/1420-3049/14/9/3700/ The optical functionalities such as exciton recurrence and migration for dendritic systems, e.g., dendrimers, are investigated using the quantum master equation (QME) approach based on the ab initio molecular orbital configuration interaction (MOCI) method, which can treat both the coherent and incoherent exciton dynamics at the first principle level. Two types of phenylacetylene dendrimers, Cayley-tree dendrimer and nanostar dendrimer with anthracene core, are examined to elucidate the features of excion recurrence and migration motions in relation to their structural dependences. It is found that the nanostar dendrimer exhibits faster exciton migration from the periphery to the core than Cayley-tree dendrimer, which alternatively exhibits exciton recurrence motion among dendron parts in case of small relaxation parameters. Such strong structural dependence of exciton dynamics demonstrates the advantage of dendritic molecular systems for future applications in nano-optical and light-harvesting devices. http://www.mdpi.com/1420-3049/14/9/3700/ Tue, 22 Sep 2009 00:00:00 CEST Molecules 2009-09-22 14 9 Article 3700 3718 1420-3049 Theoretical Study on Exciton Dynamics in Dendritic Systems: Exciton Recurrence and Migration 2009-09-22 doi: 10.3390/molecules14093700 Masayoshi Nakano Ryohei Kishi Takuya Minami Kyohei Yoneda http://www.mdpi.com/1420-3049/14/9/3610/ The oxodiperoxo complex MoO(O2)2(tbbpy) (tbbpy = 4,4'-di-tert-butyl-2,2'- bipyridine) was isolated from the reaction of MoO2Cl2(tbbpy) in water under microwaveassisted heating at 120 ºC for 4 h. The structure of the oxodiperoxo complex was determined by single crystal X-ray diffraction. The MoVI centre is seven-coordinated with a geometry which strongly resembles a highly distorted bipyramid. Individual MoO(O2)2(tbbpy) complexes are interdigitated along the [010] direction to form a column. The crystal structure is formed by the close packing of the columnar-stacked complexes. Interactions between neighbouring columns are essentially of van der Waals type mediated by the need to effectively fill the available space. http://www.mdpi.com/1420-3049/14/9/3610/ Wed, 16 Sep 2009 00:00:00 CEST Molecules 2009-09-16 14 9 Article 3610 3620 1420-3049 Microwave-Assisted Synthesis and Crystal Structure of Oxo(diperoxo)(4,4'-di-tert-butyl-2,2'-bipyridine)-molybdenum(VI) 2009-09-16 doi: 10.3390/molecules14093610 Tatiana R. Amarante Filipe A. Almeida Paz Sandra Gago Isabel S. Gonçalves Martyn Pillinger Alírio E. Rodrigues Marta Abrantes http://www.mdpi.com/1420-3049/14/9/3567/ The chemistry of the M (M=Fe, Ca, Ba)-Se-H2O systems at 25 °C is reviewed based on our previous papers. In this paper, the phase equilibria in the Fe(III)-Se(IV)-H2O, Ca-Se(IV,VI)-H2O and Ba-Se(IV,VI)-H2O systems at 25 °C are discussed. Then, the three-stage process for removal of selenium from industrial waste water [Se(IV,VI) < 1,500 mg/L] containing sulfuric acid was introduced. This seems to be a promising process for selenium removal from acidic sulfate waste water containing high concentration levels of selenium to below 0.1 mg/L. http://www.mdpi.com/1420-3049/14/9/3567/ Mon, 14 Sep 2009 00:00:00 CEST Molecules 2009-09-14 14 9 Review 3567 3588 1420-3049 Chemistry of the M (M=Fe, Ca, Ba)-Se-H2O Systems at 25 °C 2009-09-14 doi: 10.3390/molecules14093567 Tadahisa Nishimura Ryosuke Hata Fumihiko Hasegawa http://www.mdpi.com/1420-3049/14/9/3551/ In this work an optimization of the solvent-free acetylation of cellulose with acetic anhydride under microwave heating with iodine as a catalyst was performed. The optimized parameters included the microwave irradiation power from 300 W to 800 W, the reaction time between 5 to 40 min, the reaction temperature from 80 to 130 °C, and the amount of iodine from 1 to 15 mol%. The extent of the acetylation was measured by yield and the degree of substitution (DS), which was determined by a back-titration method. Acetylated cellulose was characterized by FT-IR, CP/MAS 13C-NMR, WRXD, and thermogravimetric analysis. The results showed that within the range of catalyst amounts studied, the DS increased as the amount of iodine used increased, however, it was barely affected by microwave output. It was also found that the reaction time and temperature had an active influence on the extent of acetylation, however, this did not mean that at the higher temperature a better acetylation of cellulose would be obtained. The optimal reaction time and temperature found in this work were 30 min and 130 °C. http://www.mdpi.com/1420-3049/14/9/3551/ Fri, 11 Sep 2009 00:00:00 CEST Molecules 2009-09-11 14 9 Article 3551 3566 1420-3049 Microwave-Assisted Solvent-Free Acetylation of Cellulose with Acetic Anhydride in the Presence of Iodine as a Catalyst 2009-09-11 doi: 10.3390/molecules14093551 Jing Li Li-Ping Zhang Feng Peng Jing Bian Tong-Qi Yuan Feng Xu Run-Cang Sun http://www.mdpi.com/1420-3049/14/9/3509/ Selenium (Se) deficiency has been known for many years to be associated with disease, impaired growth and a variety of other metabolic disorders in mammals. Only recently has the major role that Se-containing proteins, designated selenoproteins, play in many aspects of health and development begun to emerge. Se is incorporated into protein by way of the Se-containing amino acid, selenocysteine (Sec). The synthesis of selenoproteins is dependent on Sec tRNA for insertion of Sec, the 21st amino acid in the genetic code, into protein. We have taken advantage of this dependency to modulate the expression of Sec tRNA that in turn modulates the expression of selenoproteins by generating transgenic, conditional knockout, transgenic/standard knockout and transgenic/conditional knockout mouse models, all of which involve the Sec tRNA gene, to elucidate the intracellular roles of this protein class. http://www.mdpi.com/1420-3049/14/9/3509/ Thu, 10 Sep 2009 00:00:00 CEST Molecules 2009-09-10 14 9 Review 3509 3527 1420-3049 Mouse Models Targeting Selenocysteine tRNA Expression for Elucidating the Role of Selenoproteins in Health and Development 2009-09-10 doi: 10.3390/molecules14093509 Bradley A. Carlson Min-Hyuk Yoo Petra A. Tsuji Vadim N. Gladyshev Dolph L. Hatfield http://www.mdpi.com/1420-3049/14/9/3411/ Essential oil allylbenzenes from have been converted quickly and efficiently into the corresponding benzaldehydes in good yields by a two-step “green” reaction pathway based on a solventless alkene group isomerization by KF/Al2O3 to form the corresponding 1-arylpropene and a subsequent solventless oxidation of the latter to the corresponding benzaldehyde by KMnO4/CuSO4·5H2O. The assistance by microwave irradiation results in very short reaction times (<15 minutes). The green conversion of eugenol (4-allyl-2-methoxyphenol) into vanillin (4-hydroxy-3-methoxybenzaldehyde) has been carried out in a similar way, requiring however two additional microwave-assisted synthetic steps for acetylation of the hydroxy group prior to the oxidation reaction, and for the final deacetylation of vanillin acetate (4-acetoxy-3-methoxybenzaldehyde) by KF/Al2O3 under solvent-free conditions, respectively. http://www.mdpi.com/1420-3049/14/9/3411/ Thu, 03 Sep 2009 00:00:00 CEST Molecules 2009-09-03 14 9 Article 3411 3424 1420-3049 Fast and Green Microwave-Assisted Conversion of Essential Oil Allylbenzenes into the Corresponding Aldehydes via Alkene Isomerization and Subsequent Potassium Permanganate Promoted Oxidative Alkene Group Cleavage 2009-09-03 doi: 10.3390/molecules14093411 Thi X. Thi Luu Trinh To Lam Thach Ngoc Le Fritz Duus http://www.mdpi.com/1420-3049/14/9/3367/ It was found that cesium carbonate has a unique catalytic ability on the reaction of carbonyl compounds with diphenyl diselenide to give the corresponding α-phenylseleno carbonyl compounds in moderate to good yields. Similarly, the α-phenylthiolation of carbonyl compounds with diphenyl disulfide was promoted by the cesium carbonate catalyst. http://www.mdpi.com/1420-3049/14/9/3367/ Wed, 02 Sep 2009 00:00:00 CEST Molecules 2009-09-02 14 9 Communication 3367 3375 1420-3049 Cesium Carbonate-Catalyzed α-Phenylchalcogenation of Carbonyl Compounds with Diphenyl Dichalcogenide 2009-09-02 doi: 10.3390/molecules14093367 Yutaka Nishiyama Yuya Koguma Toshimasa Tanaka Rui Umeda http://www.mdpi.com/1420-3049/14/9/3353/ A variety of aldehydes and ketones were transformed to their corresponding cyanohydrin silyl ethers in good to excellent yields in the presence of 1-5 mol% of tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP). Cyanohydrin carbonates were also readily prepared using 5-10 mol% of TTMPP as an organocatalyst. http://www.mdpi.com/1420-3049/14/9/3353/ Wed, 02 Sep 2009 00:00:00 CEST Molecules 2009-09-02 14 9 Article 3353 3359 1420-3049 Tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP): Efficient Catalysts for the Cyanosilylation and Cyanocarbonation of Aldehydes and Ketones 2009-09-02 doi: 10.3390/molecules14093353 Satoru Matsukawa Izumi Sekine Ayumi Iitsuka http://www.mdpi.com/1420-3049/14/9/3313/ The synthesis and cytotoxic activity of a series of twenty six aroyl and heteroaroyl selenylacetic acid derivatives of general formula Ar-CO-Se-CH2-COOH or Heterar-CO-Se-CH2-COOH are reported. The synthesis was carried out by reaction of acyl chlorides with sodium hydrogen selenide, prepared in situ, and this led to the formation of sodium aroylselenides that subsequently reacted with α-bromoacetic acid to produce the corresponding selenylacetic acid derivatives. All of the compounds were tested against a prostate cancer cell line (PC-3) and some of the more active compounds were assessed against a panel of four human cancer cell lines (CCRF-CEM, HTB-54, HT-29, MCF-7) and one mammary gland-derived non-malignant cell line (184B5). Some of the compounds exhibited remarkable cytotoxic and antiproliferative activities against MCF-7 and PC-3 that were higher than those of the reference compounds doxorubicin and etoposide, respectively. For example, in MCF-7 when Ar = phenyl, 3,5-dimethoxyphenyl or benzyl the TGI values were 3.69, 4.18 and 6.19 μM. On the other hand, in PC-3 these compounds showed values of 6.8, 4.0 and 2.9 μM. Furthermore, benzoylselenylacetic acid did not provoke apoptosis nor did it perturb the cell cycle in MCF-7. http://www.mdpi.com/1420-3049/14/9/3313/ Tue, 01 Sep 2009 00:00:00 CEST Molecules 2009-09-01 14 9 Article 3313 3338 1420-3049 Synthesis and Pharmacological Screening of Several Aroyl and Heteroaroyl Selenylacetic Acid Derivatives as Cytotoxic and Antiproliferative Agents 2009-09-01 doi: 10.3390/molecules14093313 Carmen Sanmartín Daniel Plano Enrique Domínguez María Font Alfonso Calvo Celia Prior Ignacio Encío Juan Antonio Palop http://www.mdpi.com/1420-3049/14/9/3229/ Density-functional theory is used to model the endo and exo transition states for [2,3]-sigmatropic rearrangement of allylic aryl-selenoxides and -selenimides. The endo transition state is generally preferred for selenoxides if there is no substitution at the 2 position of the allyl group. Based upon the relative energies of the endo and exo transition states, enantioselectivity of rearrangements is expected to be greatest for molecules with substitutions at the 1- or (E)-3- position of the allyl group. Ortho substitution of a nitro group on the ancillary selenoxide phenyl ring reduces the activation barriers, increases the difference between the endo and exo activation barriers and shifts the equilibrium toward products. http://www.mdpi.com/1420-3049/14/9/3229/ Fri, 28 Aug 2009 00:00:00 CEST Molecules 2009-08-28 14 9 Article 3229 3236 1420-3049 Theoretical Studies of [2,3]-Sigmatropic Rearrangements of Allylic Selenoxides and Selenimides 2009-08-28 doi: 10.3390/molecules14093229 Craig A. Bayse Sonia Antony http://www.mdpi.com/1420-3049/14/9/3161/ 3-Cyanoamino-1,2- and -2,3-diferrocenylcyclopropenes 6a,b and 11a,b prepared by the reaction of diferrocenylcyclopropenylium salts with sodium cyanamide undergo smooth intramolecular transformations with both conservation of the three-membered ring [affording 3-cyanoimino-1,2-diferrocenylcyclopropene (8)] and its opening [affording Z-3-morpholino- and Z-3-piperidino-3-(cyanoimino)-1,2-diferrocenylprop-1-enes 7a,b and Z-3-cyanoimino-2,3-diferrocenyl-1-methylthioprop-1-ene (10)]. 3-Cyano-imino-1,2-diferrocenylcyclopropene (8) reacts with hydrazine to form 3-amino-6-ferrocenyl-5-ferrocenylmethyl-1,2,4-triazine (12) and Z-2,3-diferrocenylacrylohydrazide N-cyanoimide (13) as a result of intramolecular transformations. The structures of the compounds obtained were determined by IR, 1H- and 13C-NMR spectroscopy and mass spectrometry. The structures of compounds 7a and 10 were additionally confirmed by their X-ray diffraction analysis data. http://www.mdpi.com/1420-3049/14/9/3161/ Wed, 26 Aug 2009 00:00:00 CEST Molecules 2009-08-26 14 9 Article 3161 3175 1420-3049 Intramolecular Transformations of 3-Cyanoamino- and 3-Cyanoimino-1,2-diferrocenylcyclopropenes 2009-08-26 doi: 10.3390/molecules14093161 Elena Ivanovna Klimova Tatiana Klimova Marcos Flores-Alamo Leon Vladimirovich Backinowsky Marcos Martinez Garcia http://www.mdpi.com/1420-3049/14/9/3115/ A large variety of different interactions between the chalcogen atoms, Q, occur in the solid state structures of polyselenides and polytellurides, including both molecular and infinite units. The simplest motifs are classical Q22– dumbbells and nonlinear Qn2– chains (n = 3, 4, 5, ..), e.g. found in alkali metal polychalcogenides. In addition, nonclassical so-called hypervalent motifs exist in the form of linear Q34– units or within larger units such as Q44– and Q54–. Infinitely extended Q units include zigzag, cis/trans and linear chains, as well as planar and slightly puckered layers. Several of those are susceptible to Peierls distortions, leading to the formation of both commensurate and incommensurate superstructures and anomalies in transport properties, including metal-nonmetal transitions. http://www.mdpi.com/1420-3049/14/9/3115/ Mon, 24 Aug 2009 00:00:00 CEST Molecules 2009-08-24 14 9 Review 3115 3131 1420-3049 Solid State Polyselenides and Polytellurides: A Large Variety of Se–Se and Te–Te Interactions 2009-08-24 doi: 10.3390/molecules14093115 Christian Graf Abdeljalil Assoud Oottil Mayasree Holger Kleinke http://www.mdpi.com/1420-3049/14/8/3019/ The conditions for the C-N bond forming reaction (C-N coupling reaction) between α-bromocarboxylate and nitrogen-containing non-aromatic heterocyclic rings under heterogeneous copper(I) oxide catalysis are investigated in this paper. All the generated compounds were fully characterized by IR, NMR and MS spectroscopy. Ab initio/DFT calculations of partial charges on nitrogen atoms in all the discussed heterocycles and on C(2) of carboxylate under applied conditions were predicted. These in silico results correlate relatively with the experimental observations. http://www.mdpi.com/1420-3049/14/8/3019/ Thu, 13 Aug 2009 00:00:00 CEST Molecules 2009-08-13 14 8 Article 3019 3029 1420-3049 Coupling Reactions of α-Bromocarboxylate with Non-Aromatic N-Heterocycles 2009-08-13 doi: 10.3390/molecules14083019 Katerina Brychtova Barbora Slaba Lukas Placek Josef Jampilek Ivan Raich Jozef Csollei http://www.mdpi.com/1420-3049/14/8/2918/ Microwave assisted CpCo(CO)2 catalyzed cross-cyclotrimerizations of 1,7,9,15-hexadecatetrayne with two different nitriles to give unsymmetrically substituted bis(tetrahydroisoquinolines) was studied. The reaction proceeded with a range of alkyl and aryl nitriles with reasonable isolated yields. http://www.mdpi.com/1420-3049/14/8/2918/ Mon, 10 Aug 2009 00:00:00 CEST Molecules 2009-08-10 14 8 Article 2918 2926 1420-3049 Cross-Cyclotrimerization with Two Nitriles as a Synthetic Pathway to Unsymmetrically 3,3’-Disubstituted bis(Tetrahydroisoquinolines) 2009-08-10 doi: 10.3390/molecules14082918 Aneta Kadlčíková Martin Kotora http://www.mdpi.com/1420-3049/14/8/2857/ Two bioactive xanthones from Hypericum perforatum have been synthesized by direct routes. Benzo[c]xanthone 5 can be prepared from intermediate 4. http://www.mdpi.com/1420-3049/14/8/2857/ Mon, 03 Aug 2009 00:00:00 CEST Molecules 2009-08-03 14 8 Article 2857 2861 1420-3049 Quinones as Key Intermediates in Natural Products Synthesis. Syntheses of Bioactive Xanthones from Hypericum perforatum 2009-08-03 doi: 10.3390/molecules14082857 George A. Kraus John Mengwasser http://www.mdpi.com/1420-3049/14/8/2836/ Aqueous in situ one-pot N-Boc-deprotection-cyclization of Nα-Boc-dipeptidyl-tert-butyl and methyl esters under microwave irradiation afforded 2,5-diketopiperazines (DKPs) in excellent yields. This protocol is rapid, safe, environmentally friendly, and highly efficient, and showed that the tert-butoxy moiety is also an excellent leaving group for these cyclizations. http://www.mdpi.com/1420-3049/14/8/2836/ Fri, 31 Jul 2009 00:00:00 CEST Molecules 2009-07-31 14 8 Article 2836 2849 1420-3049 Efficient Microwave Assisted Syntheses of 2,5-Diketopiperazines in Aqueous Media 2009-07-31 doi: 10.3390/molecules14082836 Lemuel Pérez-Picaso Jaime Escalante Horacio F. Olivo María Yolanda Rios http://www.mdpi.com/1420-3049/14/7/2669/ Comparative investigations were carried out regarding the efficiency of introduction of exogenous genes into cultured cells using a cationic polysaccharide DEAE-dextran-MMA (methyl methacrylate ester) graft copolymer (2-diethylaminoethyl-dextran-methyl methacrylate graft copolymer; DDMC) as a nonviral carrier for gene introduction. The results confirmed that the gene introduction efficiency was improved with DDMC relative to DEAE-dextran. Comparative investigations were carried out using various concentrations of DDMC and DNA in the introduction of DNA encoding luciferase (pGL3 control vector; Promega) into COS-7 cells derived from African green monkey kidney cells. The complex formation reaction is thought to be directly proportional to the transformation rate, but the complex formation reaction between DDMC and DNA is significantly influenced by hydrophobic bonding strength along with hydrogen bonding strength and Coulomb forces due to the hydrophobicity of the grafted MMA sections. It is thought that the reaction is a Michaelis-Menten type complex formation reaction described by the following equation: Complex amount = K1 (DNA concentration)(DDMC concentration). In support of this equation, it was confirmed that the amount of formed complex was proportional to the RLU value. http://www.mdpi.com/1420-3049/14/7/2669/ Thu, 23 Jul 2009 00:00:00 CEST Molecules 2009-07-23 14 7 Article 2669 2683 1420-3049 Mechanism of Introduction of Exogenous Genes into Cultured Cells Using DEAE-Dextran-MMA Graft Copolymer as Non-Viral Gene Carrier 2009-07-23 doi: 10.3390/molecules14072669 Yuki Eshita Junko Higashihara Masayasu Onishi Masaaki Mizuno Jun Yoshida Tomohiko Takasaki Naoji Kubota Yasuhiko Onishi http://www.mdpi.com/1420-3049/14/7/2656/ Theoretical calculations for some structural and electronic properties of the azide moiety in the nucleoside reverse transcriptase (RT) inhibitor 3¢-azido-3¢-deoxythymidine (AZT) are reported. These properties, which include geometrical properties in three dimensional space, Hirshfeld charges, electrostatic potential (MEP), vibrational frequencies, and core and valence ionization spectra, are employed to study how the azide group is affected by the presence of a larger fragment. For this purpose, two small but important organic azides, hydrazoic acid and methyl azide, are also considered. The general features of trans Cs configuration for RNNN fragments[1] is distorted in the large AZT bio-molecule. Hirshfeld charge analysis shows charges are reallocated more evenly on azide when the donor group R is not a single atom. Infrared and photoelectron spectra reveal different aspects of the compounds. In conclusion, the electronic structural properties of the compounds depend on the specific property, the local structure and chemical environment of a species. http://www.mdpi.com/1420-3049/14/7/2656/ Wed, 22 Jul 2009 00:00:00 CEST Molecules 2009-07-22 14 7 Article 2656 2668 1420-3049 Electronic Structure of the Azide Group in 3¢-Azido-3¢-deoxythymidine (AZT) Compared to Small Azide Compounds 2009-07-22 doi: 10.3390/molecules14072656 Fang-Fang Chen Feng Wang http://www.mdpi.com/1420-3049/14/7/2594/ Calix[4]pyrrole (1), calix[2]m-benzo[4]pyrrole (2), 10α,20β- and 10α,20α- bis(4-nitrophenyl)-calix[4]pyrroles 3 and 4, respectively, were found to exhibit various organocatalytic activities in the diastereoselective vinylogous addition reaction of 2-trimethylsilyloxyfuran (TMSOF, 7) to aldehydes. The γ-hydroxybutenolide products are obtained in fairly good yields and with moderate diastereoselectivity. The structures of the catalysts, as well as the reaction conditions, strongly influence the efficiency of the reaction. http://www.mdpi.com/1420-3049/14/7/2594/ Wed, 15 Jul 2009 00:00:00 CEST Molecules 2009-07-15 14 7 Article 2594 2601 1420-3049 Calixpyrrole Derivatives: “Multi Hydrogen Bond” Catalysts for γ-Butenolide Synthesis 2009-07-15 doi: 10.3390/molecules14072594 Grazia Cafeo Margherita De Rosa Franz H. Kohnke Annunziata Soriente Carmen Talotta Luca Valenti http://www.mdpi.com/1420-3049/14/7/2535/ Extracellular polymeric substances (EPS) produced by microorganisms are a complex mixture of biopolymers primarily consisting of polysaccharides, as well as proteins, nucleic acids, lipids and humic substances. EPS make up the intercellular space of microbial aggregates and form the structure and architecture of the biofilm matrix. The key functions of EPS comprise the mediation of the initial attachment of cells to different substrata and protection against environmental stress and dehydration. The aim of this review is to present a summary of the current status of the research into the role of EPS in bacterial attachment followed by biofilm formation. The latter has a profound impact on an array of biomedical, biotechnology and industrial fields including pharmaceutical and surgical applications, food engineering, bioremediation and biohydrometallurgy. The diverse structural variations of EPS produced by bacteria of different taxonomic lineages, together with examples of biotechnological applications, are discussed. Finally, a range of novel techniques that can be used in studies involving biofilm-specific polysaccharides is discussed. http://www.mdpi.com/1420-3049/14/7/2535/ Mon, 13 Jul 2009 00:00:00 CEST Molecules 2009-07-13 14 7 Review 2535 2554 1420-3049 Bacterial Extracellular Polysaccharides Involved in Biofilm Formation 2009-07-13 doi: 10.3390/molecules14072535 Barbara Vu Miao Chen Russell J. Crawford Elena P. Ivanova http://www.mdpi.com/1420-3049/14/7/2555/ A series of aromatic diacyl tellurides were prepared in moderate to good yields by the reactions of sodium orpotassium arenecarbotelluroates with acyl chlorides in acetonitrile. X-ray structure analyses and theoretical calculations of 2-methoxybenzoic anhydride and bis(2-methoxybenzoyl) sulfide, selenide and telluride were carried out. The two 2-MeOC6H4CO moieties of bis(2-methoxybenzoyl) telluride are nearly planar and the two methoxy oxygen atoms intramolecularly coordinate to the central tellurium atom from both side of C(11)-Te(11)-C(22) plane. In contrast, the oxygen and sulfur isologues (2-MeOC6H4CO)2E (E = O, S), show that one of the two methoxy oxygen atoms contacts with the oxygen atom of the carbonyl group connected to the same benzene ring. The structure of di(2-methoxybenzoyl) selenide which was obtained by MO calculation resembles that of tellurium isologues rather than the corresponding oxygen and sulfur isologues. The reactions of di(aroyl) tellurides with Grignard reagents lead to the formation of tellurocarboxylato magnesium complexes [MgBr][R(C=Te)O]. http://www.mdpi.com/1420-3049/14/7/2555/ Mon, 13 Jul 2009 00:00:00 CEST Molecules 2009-07-13 14 7 Article 2555 2572 1420-3049 Diaroyl Tellurides: Synthesis, Structure and NBO Analysis of (2-MeOC6H4CO)2Te – Comparison with Its Sulfur and Selenium Isologues. The First Observation of [MgBr][R(C=Te)O] Salts 2009-07-13 doi: 10.3390/molecules14072555 Osamu Niyomura Shoho Nakaiida Ryo Yamada Shinzi Kato Masaru Ishida Masahiro Ebihara Fumio Ando Jugo Koketsu