bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of New Pyrazolothiazole Derivatives from 4-Thiazolidinones
Authors: Turgut Zuhal , Yolacan Cigdem , Aydogan Feray , Bagdatli Emine , Ocal Nuket
Published: October 2008

The synthesis of new 2,3,5,6-aryl substituted tetrahydro-2H-pyrazolo[3,4-d]- thiazoles 4a-j as potential biologically active compounds by the cyclocondensation of phenyl hydrazine with new 5-arylidene derivatives 2a-j of 2,3-disubstituted-1,3- thiazolidin-4-ones 1a-e is reported.
RETRACTED: Li et al. Synthesis of Gefitinib from Methyl 3-Hydroxy-4-methoxy-benzoate. Molecules 2007, 12, 673–678
Authors: McPhee Derek , Lin Shu-Kun
Published: October 2008

It has been brought to our attention by an alert medicinal chemist from the P. R. China that Scheme 3 and the Experimental section of this paper [1] had been copied from an earlier paper by Gong et al. [2], published in Chinese [3].[...]
Structural, Thermoanalytical and Molecular Modeling Studies on N-(3-hydroxypropyl) 3α,12α-Dihydroxy-5β-cholan-24-amide and Its Monohydrates
Authors: Valkonen Arto , Kolehmainen Erkki , Lahtinen Manu , Sievänen Elina , Noponen Virpi , Tolonen Minna , Kauppinen Reijo
Published: October 2008

The synthetic method for preparing N-(3-hydroxypropyl) 3α,12α-dihydroxy-5β- cholan-24-amide can lead to formation of at least three different crystal forms – an anhydrous compound and two monohydrates. The structural and thermal properties of these forms have been characterized by 13C-CP/MAS-NMR and IR spectroscopy, thermo- gravimetry, differential scanning calorimetry and by powder and single crystal x-ray crystallography. In addition, theoretical 13C-NMR chemical shift calculations were also performed for the anhydrous compound and for the first monohydrate, starting from single crystal structures and the structures of these species have now been verified. The first monohydrate, C27H47NO4 · H2O, crystallizes in orthorhombic space group P212121 with cell parameters: a = 7.1148(2), b = 18.1775(5), c = 20.1813(6), Z = 4.
Comments on “Antibacterial Effect of Five Zingiberaceae Essential Oils” by Laohakunjit et al., Molecules 2007, 12, 2047-2060
Authors: Bueno Jose
Published: October 2008

The paper mentioned in the title of this letter, published in a recent issue of Molecules [1], contains, in my considered opinion, serious factual errors in the reported GC/MS identification of some components of the studied essential oils.[...]
Hydrogels as Reaction Vessels: Acenaphthylene Dimerization in Hydrogels Derived from Bile Acid Analogues
Authors: Bhat Shreedhar , Maitra Uday
Published: October 2008

Many chemical reactions which are otherwise clean often lead to the formation of multiple products. Such products may be formed due to a lack of chemo-, regio- and/or stereoselectivity. For such reactions to be useful, one should be able to control them to yield a single desired product. Of the many approaches used in this context, the use of reaction media with features different from those of isotropic solutions has been very effective. Surfactant micelles have been shown to control the product selectivity in photochemical reactions, but the dynamic nature of the micelles probably results in differential effects on reaction selectivity. In this article we provide the results on photodimerization reactions performed in bile salt gels.
Citation of Two Retracted Papers Shows Both the Impact Advantage and an Unintended Consequence of Open Access
Authors: Lin Shu-Kun , McPhee Derek
Published: October 2008

Recently we have observed and commented on the negative effect of non-Open Access (non-OA) papers published in 2005 on the impact factors of the MDPI journals Molecules and International Journal of Molecular Sciences [1].[...]
Novel and Efficient Synthesis of N,N-dialkylamino-O-alkyl-2-(1-methyl-2-oxopropylidene)phosphorohydrazido Oximes. Part 3.
Authors: Kumar Rajesh , Gupta Arvind K. , Kaushik Mahabir P.
Published: October 2008

A novel and efficient method has been developed for the synthesis of N,N-dialkylamino-O-alkyl-2-(1-methyl-2-oxopropylidene)phosphorohydrazido oximes 5. The reactions involve the condensation of diacetylmonoxime and N,N-dialkylamino-O- alkylphosphorohydrazides in the presence of activated silica and give the corresponding target oximes in excellent yields under mild conditions.
Structural Studies of Two Tinuvin® P Analogs: 2-(2,4-Dimethyl-phenyl)-2H-benzotriazole and 2-Phenyl-2H-benzotriazole
Authors: Claramunt Rosa María , María Dolores Santa , Pinilla Elena , Torres M. Rosario , Elguero José
Published: October 2008

2-(2,4-Dimethylphenyl)-2H-benzotriazole (1) has been synthesized in a three step procedure starting from 2,4-dimethyl-N-(2-nitrophenyl)benzamide via a 5-(2,4- dimethylphenyl)-1-(2-nitrophenyl)-1H-tetrazole intermediate. Its structure and those of Tinuvin® P and 2-phenyl-2H-benzotriazole (5) have been studied by multinuclear NMR (1H-, 13C- and 15N-) in solution and in the solid state. X-ray diffraction analysis of 1 and 5 allowed to us establish the molecular conformation around the single bond connecting the two aromatic systems, in agreement with the conclusions drawn from the NMR study. In the case of 1 ab initio geometry optimization was achieved at the Hartree-Fock HF/6- 31G** and DFT B3LYP/6-31G** levels.
Diastereoselective Spiroannulation of Phenolic Substrates: Advances Towards the Asymmetric Formation of the Manumycin m-C7N Core Skeleton
Authors: Plourde Guy L. , Spaetzel Randy R. , Kwasnitza Jolene S. , Scully Thomas W.
Published: October 2008

The asymmetric syntheses of two new spirolactones prepared in optically pure form from L-3-nitrotyrosine are described. The key step, an oxidative spiroannulation, was carried out on the optically active phenols 11a and 11b and afforded the new spirolactones 5a and 5b in 85% and 83% yields, respectively, as mixtures (3:1 dr) of diastereomers. The major diastereomers from these mixtures could be isolated in optically pure form by trituration using acetone-hexanes as the solvent. Thus, the optically active spirolactones (+)-5a (+ 92.8o, c=0.125 acetone) and (+)-5b (+112.0o, c= 0.125 acetone) were obtained after four synthetic steps from L-3-nitrotyrosine in 41% and 43% yield, respectively.
H14[NaP5W30O110] as a Heterogeneous Recyclable Catalyst for the Air Oxidation of Thiols Under Solvent Free Conditions
Authors: Hekmatshoar Rahim , Sajadi Sodeh , Heravi Majid M. , Bamoharram Fatemeh F.
Published: October 2008

The catalytic oxidation of thiols to the corresponding disulfides usingPreyssler’s catalyst H14[NaP5W30O110] has been studied. These highly selective oxidationsgave good yields of the target disulfides.
Flavonoids: Hemisynthesis, Reactivity, Characterization and Free Radical Scavenging Activity
Authors: Es-Safi Nour-Eddine , Ghidouche Souhila , Ducrot Paul Henri
Published: October 2008

Phenolic compounds form one of the main classes of secondary metabolites. They display a large range of structures and they are responsible for the major organoleptic characteristics of plant-derived-foods and beverages, particularly color and taste properties and they also contribute to the nutritional qualities of fruits and vegetables. Phenolic compounds are also highly unstable compounds which undergo numerous enzymatic and chemical reactions during postharvest food storage and processing thus adding to the complexity of plant polyphenol composition. Among these compounds flavonoids constitute one of the most ubiquitous groups of all plant phenolics. Owing to their importance in food organoleptic properties and in human health, a better understanding of their structures, their reactivity and chemical properties in addition to the mechanisms generating them appears essential to predict and control food quality. The purpose of this work is an overview of our findings concerning the hemisynthesis, the reactivity and the enzymatic oxidation of some flavonoids and shed light on the mechanisms involved in some of these processes and the structures of the resulting products. The free radical scavenging activity of some of the synthesized compounds is also presented and a structure-activity relationship is discussed. The first part of this review concerns the synthesis and structural characterization of modified monomeric flavanols. The use of these compounds as precursor for the preparation of natural and modified dimeric procyanidin derivatives was then explored through different coupling reactions. The full characterization of the synthesized compounds was achieved by concerted use of NMR and ESI-MS techniques. The free radical scavenging activity of some of the synthesized compounds was investigated. The second part of this review concerns the enzymatic oxidation of several flavonols by Trametes versicolor laccase. Most of the major oxidation products have been isolated as pure compounds and their structures unambiguously established through spectroscopic methods. Correlation between the structure of the oxidation product and the substitution pattern of the starting materials allows mechanistic features of this transformation to be elucidated.
A Standard Addition Method to Assay the Concentration of Biologically Interesting Polyphenols in Grape Berries by Reversed-Phase HPLC
Authors: Sakkiadi Aphrodite-Victoria , Georgiou Constantino A. , Haroutounian Serkos A.
Published: October 2008

A reversed-phase HPLC method which allows the simultaneous assay of (+)- catechin, (–)-epicatechin, trans-resveratrol, quercetin and quercetin glycosides in grape berries is described. Kromasil 100 served as stationary phase and a gradient of acetic acid, water and methanol was used. The analytical run requires 42 min for complete sample elution. Satisfactory peak resolution was achieved following a novel extraction process and direct injection of a 20 μL sample. The method was used for the analyses of eighteen samples. Linearities were in the range of 0.98 to 0.999 regression coefficient, for all phenolics, while detection limits ranged from 30 μg mL–1 for trans-resveratrol to 1.5 mg mL–1 for (+)-catechin. Recoveries ranged from 95.1 to 98.7% while the method provided good precision, with standard deviations between 3.5 and 6.1%, n=5.
A New Sesquiterpene Glycoside from the Aerial Parts of Saussurea triangulata
Authors: Yang Min Cheol , Kim Sung Min , Lee Kyu Ha , Kim Ki Hyun , Lee Kang Ro
Published: October 2008

Column chromatographic separation of a MeOH extract of the aerial parts of Saussurea triangulata led to the isolation of a new sesquiterpene glycoside 6, together with three quinic acid derivatives, two phenolics, two sesquiterpene glycosides and two flavonoids. The new compound 6 was identified as amarantholidol A glycoside by spectroscopic and chemical methods.
Notice of Dual Publication: Madkour *, H.M.F.; Mahmoud, M.R.; Nassar, M.H.; Habashy, M.M. Behaviour of Some Activated Nitriles Toward Barbituric Acid, Thiobarbituric Acid and 3-Methyl-1-Phenylpyrazol-5-one. Molecules 2000, 5, 746-755
Authors: Lin Shu-Kun
Published: October 2008

We have been notified that this paper has also been published almost verbatim in another scientific journal [1].[...]
Relative Stereochemistry of a Diterpene from Salvia cinnabarina
Authors: Bisio Angela , Pagano Bruno , Romussi Alessia , Bruno Olga , De Tommasi Nunziatina , Romussi Giovanni , Mattia Carlo Andrea
Published: October 2008

The relative stereochemistry of 3,4-secoisopimara-4(18),7,15-triene-3-oic acid, a diterpenoid with antispasmodic, hypotensive and antibacterial activities isolated from Salvia cinnabarina, was determined by an X-ray diffraction analysis of a single crystal of a suitable crystalline derivative.
A Novel Flavonoid C-glycoside from Sphaeranthus indicus L. (Family Compositae)
Authors: Mishra Bhuwan B. , Yadav S. B. , Singh Rakesh K. , Tripathi Vyasji
Published: October 2008

A novel flavonoid C-glycoside, 5-hydroxy-7-methoxy-6-C-glycosylflavone (1), was isolated from the aerial part of Sphaeranthus indicus. Its structure was elucidated by spectroscopic methods.
Membranolytic Activity of Bile Salts: Influence of Biological Membrane Properties and Composition
Authors: Garidel Patrick , Hildebrand Annegret , Knauf Katja , Blume Alfred
Published: October 2008

The two main steps of the membranolytic activity of detergents: 1) the partitioning of detergent molecules in the membrane and 2) the solubilisation of the membrane are systematically investigated. The interactions of two bile salt molecules, sodium cholate (NaC) and sodium deoxycholate (NaDC) with biological phospholipid model membranes are considered. The membranolytic activity is analysed as a function of the hydrophobicity of the bile salt, ionic strength, temperature, membrane phase properties, membrane surface charge and composition of the acyl chains of the lipids. The results are derived from calorimetric measurements (ITC, isothermal titration calorimetry). A thermodynamic model is described, taking into consideration electrostatic interactions, which is used for the calculation of the partition coefficient as well as to derive the complete thermodynamic parameters describing the interaction of detergents with biological membranes (change in enthalpy, change in free energy, change in entropy etc). The solubilisation properties are described in a so-called vesicle-to-micelle phase transition diagram. The obtained results are supplemented and confirmed by data obtained from other biophysical techniques (DSC differential scanning calorimetry, DLS dynamic light scattering, SANS small angle neutron scattering).
Electrochemical Behavior and Antioxidant and Prooxidant Activity of Natural Phenolics
Authors: Simić Aleksandra , Manojlović Dragan , Šegan Dejan , Todorović Marija
Published: October 2008

We have investigated the electrochemical oxidation of a number natural phenolics (salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, protocatechuic acid, o-coumaric acid, m-coumaric acid, p-coumaric acid, caffeic acid, quercetin and rutin) using cyclic voltammetry. The antioxidant properties of these compounds were also studied. A structural analysis of the tested phenolics suggests that multiple OH substitution and conjugation are important determinants of the free radical scavenging activity and electrochemical behavior. Compounds with low oxidation potentials (Epa lower than 0.45) showed antioxidant activity, whereas compounds with high Epa values (>0.45) act as prooxidants.
Preparation of Benzalkonium Salts Differing in the Length of a Side Alkyl Chain
Authors: Kuca Kamil , Marek Jan , Stodulka Petr , Musilek Kamil , Hanusova Petra , Hrabinova Martina , Jun Daniel
Published: October 2008

Benzalkonium salts are widely used as disinfectants, biocides and detergents,among a variety of other applications. The cationic surface-activity of these saltsdetermines their potential to act as a biocide on both target and non-target organisms. Inthis study, a quick synthesis of a complete set of the benzalkonium salts differing in thelength of an alkylating chain (from C2 to C20) is described. Moreover, their 1H-NMR, HPLC-MS, TLC and HPLC analysis were recorded.
Synthesis, Chemical Characterization and Biological Screening for Cytotoxicity and Antitumor Activity of Organotin (IV) Derivatives of 3,4-Methylenedioxy 6-nitrophenylpropenoic Acid
Authors: Ahmad Muhammad Sheeraz , Hussain Mukhtiar , Hanif Muhammad , Ali Saqib , Mirza Bushra
Published: October 2008

A series of mono-, di- and triorganotin compounds with general formulae [RSnL2Cl], R = Bu (compound 3), [R2SnL2], where R = Me, Et, Bu, Oct (compounds 1, 2, 4 and 6) and [R3SnL], where R = Bu, Cy and Ph (compounds 5, 7 and 8) and where L = 3,4-methylenedioxy-6-nitrophenylpropenoic acid have been prepared and characterized by elemental analysis, multinuclear (1H-, 13C- and 119Sn-) NMR and mass spectrometry. The ligand and its respective organotin complexes were screened for cytotoxicity using the brine shrimp lethality assay and for antitumor activity using the crown gall tumor inhibition (potato disc) assay. The bioassay results support the conclusion that the biological activities of these synthetic compounds are in the following order: [RSnL2Cl] < [R2SnL2] < [R3SnL].
Synthesis of Novel N-(4-Ethoxyphenyl) Azetidin-2-ones and Their Oxidative N-Deprotection by Ceric Ammonium Nitrate
Authors: Jarrahpour Aliasghar , Zarei Maaroof
Published: October 2008

It is shown that the N-(p-ethoxyphenyl) group on β-lactams can be oxidatively removed by ceric ammonium nitrate in good yield. Fourteen new N-(p-ethoxyphenyl)-2-azetidinones 8a-n were synthesized through standard [2+2] ketene-imine cycloadditions (Staudinger reaction). Treatment of these compounds with ceric ammonium nitrate yielded the N-dearylated 2-azetidinones 9a-n in good to excellent yields. The effects of solvent, molar equiv of CAN and different temperatures have been investigated and optimum conditions were established.
Bioreversible Derivatives of Phenol. 1. The Role of Human Serum Albumin as Related to the Stability and Binding Properties of Carbonate Esters with Fatty Acid-like Structures in Aqueous Solution and Biological Media
Authors: Ostergaard Jesper , Larsen Claus
Published: October 2008

With the overall objective of assessing the potential of utilizing plasma protein binding interactions in combination with the prodrug approach for improving the pharmacokinetics of drug substances, a series of model carbonate ester prodrugs of phenol, encompassing derivatives with fatty acid-like structures, were characterized in vitro. Stability of the derivatives was studied in aqueous solution, human serum albumin solution, human plasma, and rat liver homogenate at 37°C. Stability of the derivatives in aqueous solution varied widely, with half-lives ranging from 31 to 1.7 × 104 min at pH 7.4 and 37°C. The carbonate esters were subject to catalysis by plasma esterases except for the t-butyl and acetic acid derivatives, which were stabilized in both human plasma and human serum albumin solutions relative to buffer. In most cases, however, hydrolysis was accelerated in the presence of human serum albumin indicating that the derivatives interacted with the protein, a finding which was confirmed using the p-nitrophenyl acetate kinetic assay. Different human serum albumin binding properties of the phenol model prodrugs with fatty acid-like structure and neutral carbonate esters were observed. In the context of utilizing plasma protein binding in combination with the prodrug approach for optimizing drug pharmacokinetics, the esterase-like properties of human serum albumin towards the carbonate esters potentially allowing the protein to act as a catalyst of parent compound regenerations is interesting.
Bioreversible Derivatives of Phenol. 2. Reactivity of Carbonate Esters with Fatty Acid-like Structures Towards Hydrolysis in Aqueous Solutions
Authors: Ostergaard Jesper , Larsen Claus
Published: October 2008

A series of model phenol carbonate ester prodrugs encompassing derivatives with fatty acid-like structures were synthesized and their stability as a function of pH (range 0.4 – 12.5) at 37°C in aqueous buffer solutions investigated. The hydrolysis rates in aqueous solutions differed widely, depending on the selected pro-moieties (alkyl and aryl substituents). The observed reactivity differences could be rationalized by the inductive and steric properties of the substituent groups when taking into account that the mechanism of hydrolysis may change when the type of pro-moiety is altered, e.g. n-alkyl vs. t-butyl. Hydrolysis of the phenolic carbonate ester 2-(phenoxycarbonyloxy)-acetic acid was increased due to intramolecular catalysis, as compared to the derivatives synthesized from ω-hydroxy carboxylic acids with longer alkyl chains. The carbonate esters appear to be less reactive towards specific acid and base catalyzed hydrolysis than phenyl acetate. The results underline that it is unrealistic to expect that phenolic carbonate ester prodrugs can be utilized in ready to use aqueous formulations. The stability of the carbonate ester derivatives with fatty acid-like structures, expected to interact with the plasma protein human serum albumin, proved sufficient for further in vitro and in vivo evaluation of the potential of utilizing HSA binding in combination with the prodrug approach for optimization of drug pharmacokinetics.
Antibacterial Activity of Some 3-(Arylideneamino)-2-phenylquinazoline-4(3H)-ones: Synthesis and Preliminary QSAR Studies
Authors: Nanda Ashis Kumar , Ganguli Subarna , Chakraborty Ranadhir
Published: October 2008

Synthesis of ten 3-(arylideneamino)-2-phenylquinazoline-4(3H)-ones is reported. All the compounds contained a common phenyl group at the 2-position, while the substituents on the arylideneamino group were varied. The compounds were investigated for their antimicrobial activity against both Gram-positive (Staphylococcus aureus 6571 and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli K12 and Shigella dysenteriae 6) using a turbidometric assay method. It was found that the incorporation of the 3-arylideneamino substituent enhanced the anti-bacterial activity of the quinazolone system. The preliminary QSAR studies were done using some computer derived property descriptors, calculated values of partition coefficients as well as usual Hammett’s sigma constants and the substituent’s molar refractivity.
A Simple and Efficient Approach to the Synthesis of Endo and Exo Bicyclo[6.1.0]nona-3,5-diene-9-carboxaldehyde
Authors: Ghandi Mehdi , Mashayekhi Gholamreza
Published: October 2008

Monobromination of 1,5-cyclooctadiene, followed by cyclopropanation with ethyl diazoacetate, led to the formation of endo and exo ethyl 4,5-dibromobicyclo[6.1.0]nonane-9-carboxylates 3a and 3b. Bis-dehydrobromination of 3a and 3b using 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) afforded the endo and exo ethyl bicyclo[6.1.0]nona-3,5-diene-9-carboxylates 4a and 4b. Reduction of these compounds to the corresponding alcohols 5a and 5b and subsequent oxidation with pyridinium chlorochromate (PCC) resulted in the formation of the target compounds endo and exo bicyclo[6.1.0]nona-3,5-diene-9-carboxaldehydes 6a and 6b.
Dopamine-Imprinted Polymers: Template-Monomer Interactions, Analysis of Template Removal and Application to Solid Phase Extraction
Authors: Luliński Piotr , Maciejewska Dorota , Bamburowicz-Klimkowska Magdalena , Szutowski Mirosław
Published: October 2008

A dopamine-imprinted polymer (MIP) was prepared in aqueous methanolsolution at 60oC by free-radical cross-linking polymerization of methacrylic acid in thepresence of ethylene glycol dimethacrylate as the cross-linker and dopamine hydrochlorideas the template molecule. Its ability to isolate dopamine was evaluated as the basis of asolid phase extraction procedure and compared with that of a non-imprinted polymer(NIP). The binding of dopamine was 84.1% and 29.1% for MIP and NIP, respectively.Various reported post-polymerization treatments to reduce template bleeding wereexamined. In our case the lowest bleeding was achieved after applying a combinedprocedure: continuous extraction in a Soxhlet apparatus (CE), followed by microwave-assisted extraction (ME) to a level of 0.061 μg/mL. A simplified model of the template-monomer complexes allowed rationalization of monomer choice based on the heats ofcomplex formation at a PM3 level of theory.
Synthesis and Bioevaluation of 5-Fluorouracil Derivatives
Authors: Tian Zhi-Yong , Du Gang-Jun , Xie Song-Qiang , Zhao Jin , Gao Wen-Yuan , Wang Chao-Jie
Published: October 2008

A series of six novel 5-fluorouracil derivatives 1-6 were synthesized and theirstructures confirmed by 1H- and 13C-NMR, MS and elemental analysis. The preliminary invitro antitumor activities against B16, K562 and CHO cells and the in vivo inhibitions ofliver cancer H22 demonstrated that some of these compounds effectively inhibit the growthof tumor cells, but the in vivo trials in mice revealed that the compounds also exhibitedserious liver and lung tissue toxicity. The hydrolysis experiments indicated that this type ofcompound did not readily liberate 5-fluorouracil, as expected.
Syntheses of Calix[4]Pyrroles by Amberlyst-15 Catalyzed Cyclocondensations of Pyrrole with Selected Ketones
Authors: Chauhan Shive  Murat Singh , Garg Bhaskar , Bisht Tanuja
Published: October 2008

A facile and efficient protocol is reported for the synthesis of calix[4]pyrrolesand N-confused calix[4]pyrroles in moderate to excellent yields by reaction of dialkyl orcycloalkyl ketones with pyrrole catalyzed by reusable AmberlystTM-15 under eco-friendlyconditions.
Synthesis and Biological Activity of N-Substituted-3-chloro-2-azetidinones
Authors: Chavan Ameya  A. , Pai Nandini  R.
Published: October 2008

2-Aminobenzothiazole-6-carboxylic acid (1), on condensation with chloroacetylchloride yielded 2-(2-chloroacetylamino)benzothiazole-6-carboxylic acid (2), which onamination with hydrazine hydrate yielded in turn 2-(2-hydrazinoacetylamino)benzo-thiazole-6-carboxylic acid (3). Compound 3, on condensation with various aromaticaldehydes afforded a series of 2-{2-[N’-(arylidene)hydrazino]acetylamino}benzothiazole-6-carboxylic acids 4a-h, which upon dehydrative annulation in the presence ofchloroacetyl chloride and triethylamine yielded 2-{2-[3-chloro-2-(aryl)-4-oxoazetidin-1-ylamino]-acetylamino}benzothiazole-6-carboxylic acids 5a-h. The synthesized compounds4a-h and 5a-h were screened for their antibacterial activity against four microorganisms:Staphylococcus aureus (Gram positive), Bacillus subtilis (Gram positive), Psuedomonasaeruginosa (Gram negative) and Escherichia coli (Gram negative). They were found toexhibit good to moderate antibacterial activity. The antifungal activity of these compoundswere also tested against three different fungal species. None of them were active againstthe species tested.
A Novel Synthesis of Bromobenzenes Using Molecular Bromine
Authors: Özkan Hamdi , Dişli Ali , Yıldırır Yılmaz , Türker Lemi
Published: October 2008

Certain substituted bromobenzenes have been synthesized in acceptable yieldsusing a novel Sandmeyer type reaction. The reactions are relatively quick and possiblyproceed via a radical mechanism.
Cyclization-activated Prodrugs
Authors: Gomes Paula , Vale Nuno , Moreira Rui
Published: October 2008

Many drugs suffer from an extensive first-pass metabolism leading to druginactivation and/or production of toxic metabolites, which makes them attractive targets forprodrug design. The classical prodrug approach, which involves enzyme-sensitive covalentlinkage between the parent drug and a carrier moiety, is a well established strategy toovercome bioavailability/toxicity issues. However, the development of prodrugs that canregenerate the parent drug through non-enzymatic pathways has emerged as an alternativeapproach in which prodrug activation is not influenced by inter- and intraindividualvariability that affects enzymatic activity. Cyclization-activated prodrugs have beencapturing the attention of medicinal chemists since the middle-1980s, and reached maturityin prodrug design in the late 1990s. Many different strategies have been exploited in recentyears concerning the development of intramoleculary-activated prodrugs spanning fromanalgesics to anti-HIV therapeutic agents. Intramolecular pathways have also a key role intwo-step prodrug activation, where an initial enzymatic cleavage step is followed by acyclization-elimination reaction that releases the active drug. This wor
Synthesis and Molecular Structure of Ethyl [N-tosyl-(R)-prolyloxy]-2(S)-[4-cyano-8,8-ethylenedioxy-5-oxo-5,6,7,8-tetrahydroindolizin-3-yl] Acetate, a Key Intermediate in the Total Synthesis of (20S)-Camptothecins
Authors: Kuang Yun-Yan , Chen Fen-Er
Published: October 2008

The synthesis of optically active [N-tosyl-(R)-prolyloxy]-2(S)-[4-cyano-8,8-ethylenedioxy-5-oxo-5,6,7,8-tetrahydroindolizin-3-yl] acetate (4a), a key intermediate forthe total asymmetric synthesis of 20(S)-camptothecin anticancer drugs, is described. Itsstructure was characterized by 2D-NMR techniques and the absolute configuration wasfurther confirmed for the first time by X-ray crystal structure analysis.
Comparative Study of Regioselective Synthesis of β-Aminoalcohols under Solventless Conditions Catalyzed by Sulfated Zirconia and SZ/MCM-41
Authors: Negrón-Silva Guillermo , Hernández-Reyes C.  Xochitl , Angeles-Beltrán Deyanira , Lomas-Romero Leticia , González-Zamora Eduardo , Méndez-Vivar Juan
Published: October 2008

Sulfated zirconia and SZ/MCM-41 were used as catalysts for the synthesis of β-aminoalcohols via epoxide aminolysis. Sulfated zirconia was prepared by sol-gel andSZ/MCM-41 was obtained by impregnation. Solid catalysts were characterized by XRD,SEM-EDS, UV-Vis, FT-IR pyridine desorption and Nitrogen physisorption. Both acidmaterials were useful as catalysts, even when they were recycled several times. The β-aminoalcohols were characterized by FT-IR, 1H- and 13C-NMR and GC-MS.
Synthesis of New L-Ascorbic Ferulic Acid Hybrids
Authors: Voisin-Chiret Anne Sophie , Bazin Marc-Antoine , Lancelot Jean-Charles , Rault Sylvain
Published: October 2008

A feasibility and chemical study of the coupling conditions of L-ascorbic acidwith ferulic acid derivatives are described on the basis of the known synergistic effects ofmixtures of various antioxidants. Novel L-ascorbic ferulic hybrids linked at the C-3hydroxyl group were prepared with the aim to protect the alcohol function and the enediolsystem.
Hantzsch Synthesis of 2,6-Dimethyl-3,5-dimethoxycarbonyl-4-(o-methoxyphenyl)-1,4-dihydropyridine; a Novel Cyclisation Leading to an Unusual Formation of 1-Amino-2-methoxycarbonyl-3,5-bis(o-methoxyphenyl)-4-oxa-cyclohexan-1-ene
Authors: Filipan-Litvić Mirela , Litvić Mladen , Cepanec Ivica , Vinković Vladimir
Published: October 2008

Hantzsch condensation of two equivalents of methyl-3-aminocrotonate with (m-and p)-methoxybenzaldehyde afforded the expected products 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(m-methoxyphenyl)-1,4-dihydropyridine and 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(p-methoxyphenyl)-1,4-dihydropyridine, whereas o-methoxy-benzaldehyde produced mainly 1-amino-2-methoxycarbonyl-3,5-bis(o-methoxy-phenyl)-4-oxa-cyclohexan-1-ene. The structure of the product, not previously reported in theliterature, was determined by 1D and 2D NMR spectra and its MS fragmentation. This isthe first example of cyclisation leading to a substituted pyran rather than 1,4-DHP undertypical Hantzsch reaction conditions. A plausible mechanism for its formation ispostulated.
The Drug Release Profile from Calcium-induced Alginate Gel Beads Coated with an Alginate Hydrolysate
Authors: Murata Yoshifumi , Jinno Daisaku , Liu Dongchun , Isobe Takshi , Kofuji Kyouko , Kawashima Susumu
Published: October 2008

Calcium-induced alginate gel bead (Alg-Ca) coated with an alginate hydrolysate(Alg), e.g. the guluronic acid block (GB) was prepared and the model drug, hydrocortisonerelease profiles were investigated under simulated gastrointestinal conditions. Theirmolecular weights were one sixth or one tenth that of Alg and the diffraction patterns of thehydrolysates resembled that of Alg. The drug release rate from Alg-Ca coated with GBapparently lowered than that of Alg-Ca (coating-free) in the gastric juice (pH1.2). And thecoating did not resist the disintegration of Alg-Ca in the intestinal juice (pH 6.8) and thegel erosion accelerated the drug release. On the other hand, for the coated Alg-Cacontaining chitosan, the drug release showed zero-order kinetics without rapid erosion ofAlg-Ca. The drug release rate from Alg-Ca was able to be controlled by the coating andmodifying the composition of the gel matrix.
Essential Oils of Satureja Species: Insecticidal Effect on Culex pipiens Larvae (Diptera: Culicidae)
Authors: Michaelakis Antonios , Theotokatos Spiridon  A. , Koliopoulos Georgios , Chorianopoulos Nikos  G.
Published: October 2008

The chemical composition of the essential oils of the wild growing plants of Greek S. spinosa L., S. parnassica subsp. parnassica Heldr.& Sart ex Boiss., S. thymbra and S. montana were determined by GC and GC/MS analysis. The larvicidal activities of the essential oils were assayed against Culex pipiens biotype molestus. The analytical data indicated that various monoterpene hydrocarbons and phenolic monoterpenes constitute the major constituents of the oils, but their concentration varied greatly among the oils examined. The bioassay results indicated that the oils possess significant larvicidal activities and represent an inexpensive source of natural substances mixture that exhibit potentials for use to control the mosquito larvae.
Synthesis of 1-Aryl-3-phenethylamino-1-propanone Hydrochlorides as Possible Potent Cytotoxic Agents
Authors: Mete Ebru , Gul Halise Inci , Kazaz Cavit
Published: October 2008

1-Aryl-3-phenethylamino-1-propanone hydrochlorides 1-10, which are potentialpotent cytotoxic agents, were synthesized via Mannich reactions using paraformaldehyde,phenethylamine hydrochloride as the amine component and acetophenone, 4’-methyl-, 4’-methoxy-, 4’-chloro-, 4’-fluoro-, 4’-bromo-, 2’,4’-dichloro-, 4’-nitro-, 4’-hydroxyacetophenone or 2-acetylthiophene as the ketone component. Yields were in the87-98 % range. Of the compounds synthesized, compounds 2, 6-8 and 10 were new. Theoptimum reaction conditions were investigated by changing the mol ratios of the reactants,the solvents and the acidity levels using 1 and 10 as representative targets. It was observedthat the best mol ratio of the ketone, paraformaldehyde and phenethylamine hydrochloridewas 1:1.2:1 (compared with a 2:2.1 ratio), and the most suitable reaction medium wasethanol containing concentrated hydrochloric acid (compared with only ethanol or nosolvent). This study may serve as a guide for the conditions of the reactions to synthesizecompounds having similar chemical structures.
Substituted N-Phenylpyrazine-2-carboxamides, Their Synthesis and Evaluation as Herbicides and Abiotic Elicitors
Authors: Doležal Martin , Tůmová Lenka , Kešetovičová Diana , Tůma Jiří , Kráľová Katarína
Published: October 2008

The condensation of substituted pyrazine-2-carboxylic acid chlorides with ring-substituted anilines yielded five substituted pyrazine-2-carboxylic acid amides. Thesynthesis, and analytical, lipophilicity and biological data of the newly synthesizedcompounds are presented in this paper. The photosynthesis inhibition, antialgal activityand the effect of a series of pyrazine derivatives as abiotic elicitors on the accumulation offlavonoids in a callus culture of Ononis arvensis (L.) were investigated. The most activeinhibitor of the oxygen evolution rate in spinach chloroplasts was 6-chloro-pyrazine-2-carboxylic acid (3-iodo-4-methylphenyl)-amide (2, IC50 = 51.0 μmol·L-1). The highestreduction of chlorophyll content in Chlorella vulgaris was found for 5-tert-butyl-N-(4-chloro-3-methylphenyl)-pyrazine-2-carboxamide (3, IC50 = 44.0 μmol·L-1). The maximalflavonoid production (about 900%) was reached after a twelve-hour elicitation processwith 6-chloropyrazine-2-carboxylic acid (3-iodo-4-methylphenyl)-amide (2).
Two New Triterpenoids from Photinia serrulata
Authors: Song Yaling , Wang Yuehu , Lu Qing , Gao Jinming , Bi Minggang , Cheng Yongxian
Published: October 2008

Two new triterpenoids, 2α,3β,11α,13β-tetrahydroxy-12-ketooleanan-28-oic acid(1) and 3β-hydroxy-12-keto-9(11)-ursen-28,13β-olide (2) were isolated from the leaves ofPhotinia serrulata. Their structures were identified by spectral methods. Compounds 1 and2 were assessed for cytotoxic activity against three human tumor cell lines (A-549, HCT-8,and BEL-7402), and they showed no cytotoxic effects at concentrations up to 5μg/mL.
Oxidative Degradations of the Side Chain of Unsaturated Ent-labdanes. Part II
Authors: Catalán Luis  Espinoza , Marín Karen  Catalán , Altamirano Héctor  Carrasco , Fritis Mauricio  Cuellar , Chamy María  Cristina
Published: October 2008

A route for the degradation of the side chain of ent-labdane derivatives has beendevised, giving the useful synthon 2β,12-dihydroxy-13,14,15,16,17-pentanor-ent-labdane-8-one (8). The use of this compound in the preparation of terpenylquinone derivatives shallbe reported elsewhere. In addition we have synthesized the compound 2β,12-diacetoxy-8β,17-epoxy-13,14,15,16-tetranor-ent-labdane (10), which upon catalytic epoxide ringopening in alkaline or acid media gave rise in all cases to the formation of tricycliccompounds.
Synthesis and Antiviral Bioactivities of 2-Aryl- or 2-Methyl-3-(substituted- Benzalamino)-4(3H)-quinazolinone Derivatives
Authors: Gao Xingwen , Cai Xuejian , Yan Kai , Song Baoan , Gao Lili , Chen Zhuo
Published: October 2008

A simple and general method has been developed for the synthesis of various4(3H)-quinazolinone derivatives by the treatment of the appropriate 3-amino-2-aryl-4(3H)-quinazolinone with a substituted benzaldehyde in ethanol. The structures of the compoundswere characterized by elemental analysis, IR, 1H-NMR and 13C-NMR spectra. The title 2-aryl- or 2-methyl-3-(substituted-benzalamino)-4(3H)-quinazolinone compounds III-1~III-31 were found to possess moderate to good antiviral activity. Semi-quantitative PCR andReal Time PCR assays were used to ascertain the target of action of compound III-31against TMV. The studies suggest that III-31 possesses antiviral activity due to inductionof up-regulation of PR-1a and PR-5, thereby inhibiting virus proliferation and movementby enhancement of the activity of some defensive enzyme.
Synthesis of a New Scaffold: the 7H,8H-Pyrimido[1,6-b]pyridazin-6,8-dione Nucleus
Authors: Herold Franciszek , Kałucka Małgorzata , Król Marek , Herold Joanna , Kleps Jerzy , Turło Jadwiga
Published: October 2008

This paper describes a modified method of preparation of a number of α-aryl-α-(pyridazin-3-yl)-acetonitriles via the C-arylation reaction of the corresponding carbanionsof phenylacetonitriles using 3-chloropyridazine derivatives. KOH and DMSO were used inthe deprotonation process, which made the reaction very simple and safe to perform.Nitriles were obtained in the hydrolysis reaction to the corresponding α-aryl-α-(pyridazin-3-yl)-acetamide derivatives, which were next subjected to cyclization to afford the finalproducts. A number of new derivatives of 7H,8H-pyrimido[1,6-b]pyridazin-6,8-dione weresynthesized in the cyclocondensation reaction of respective α-aryl-α-(pyridazin-3-yl)-acetamides with diethyl carbonate in the presence of EtONa. The structure andcomposition of the new compounds were confirmed by IR, 1H- and 13C- NMR analysesand by elemental C, H and N analysis.
Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition
Authors: Micuch Peter , Fisera Lubor , Ondrus Vladimír , Ertl Peter
Published: October 2008

The cycloaddition of the chiral nitrile oxide 1 to 1-R-substituted 3,3-methylene-5,5-dimethyl-2-pyrrolidinones 2 (where R is H, n-butyl-, 1,1-dimethylethoxycarbonyl-, 1-methylethenyl- and acetyl-) proceeds regioselectively under the formation of spiroisoxazolines, namely 7-R-substituted-6-oxo-8,8-dimethyl-1-oxa-2,7-diazaspiro[4,4]non-2-enes 5 and 6. The asymmetric induction expected by the a-chiral centre of the nitrile oxide 1 was not very effective, diastereoisomers 5 and 6 were formed in an approximate 50:50 ratio. The stereoselectivity of the 1,3-dipolar cycloaddition of the arylnitrile oxide 7 with the chiral lactam 3 and the achiral lactone 4 are investigated. The attack of the 1,3-dipole occurred from the less hindered face of the dipolarophile 3 and 4, giving the major isomer 8 and 10, respectively.
o-Nitroaryl-bis(5-methylfur-2-yl)methanes as Versatile Synthons for the Synthesis of Nitrogen-Containing Heterocycles
Authors: Butin Alexander  V. , Abaev Vladimir  T. , Stroganova Tat’yana  A. , Gutnov Andrey  V.
Published: October 2008

2-Nitroaryldifurylmethanes 1a and 1b, readily available by condensation of 2-nitrobenzaldehyde and 6-nitroveratraldehyde with 2-methylfuran, were transformed into indole, cinnoline and benzothiazine-3,1 derivatives. The reduction of 2-nitroaryldifurylmethanes gave the corresponding anilines 2a,b or indole 3 depending on the reaction conditions. A plausible mechanism for the last reaction involving intramolecular heterocyclic addition between a nitroso-group and a furan ring is proposed. Diazotisation of the amine 2b gave a cinnoline derivative - a product of intramolecular oxidative furan ring opening. Treatment of isothiocyanates 7a,b with perchloric acid resulted in a new rearrangement with furan ring migration leading to the 4-Hbenzothiazine-3,1 derivatives.
Synthesis and Reactions of Furo[2,3-b]pyrroles
Authors: Krutosiková A. , Ramsden C.  A. , Dandárová M. , Lycka A.
Published: October 2008

Methyl 6H-furo[2,3-b]pyrrole-5-carboxylate (2a) was prepared by thermolysis of the corresponding methyl 2-azido-3-(3-furyl)propenoate (1). 6-Methyl (2b) and 6-benzyl (2c) derivatives were obtained using phase-transfer catalysis conditions (PTC). The formylation of 2a-2c gave 2-formylated compounds (3a-3c). Compounds 4b, 4c were prepared by reactions of corresponding esters 2b, 2c with hydrazine in refluxing ethanol. By reaction of 3a-3c with hydroxylammonium chloride in acetic anhydride in the presence of pyridine, methyl 2-cyano-6-R1-furo[2,3-b]pyrrole-5-carboxylates (5a-5c) were obtained. The reaction of these compounds with sodium azide and ammonium chloride in dimethylformamide led to methyl 2-(5'-tetrazolyl)-6-R1-furo[2,3-b]pyrrole-5-carboxylates (6a-6c). A series of 5-methoxycarbonyl-6-R1-furo[2,3-b]pyrrole-2-carbaldehyde N,N-dimethylhydrazones (7a-7c) was prepared from methyl 2-formyl-6-R1-furo[2,3-b]pyrrole-5-carboxylates (3a-3c) and unsym-dimethylhydrazine. The correlation of the 13C and 15N chemical shifts with the data of the calculated (AM1) net atomic charges is discussed.
The Intramolecular Radical Cation Induced Diels-Alder Reaction in the Diene - Diene Format
Authors: Rusterholz David  B. , Gorman David  B. , Gassman Paul  G.
Published: October 2008

Two 1,3,8,10-undecatetraenes were synthesized to test the viability of the intramolecular radical cation induced Diels-Alder reaction in the diene - diene format. Cyclization was successful only for the substituted tetraene with the lower oxidation potential. The major hexahydroindene product possessed a trans ring juncture demonstrating a selectivity for the endo stereochemistry.
10-Undecenoic Acid, an Inexpensive Source for the Synthesis of the Pheromones of Cotton Pests, Peach Tree Borer and Cherry Tree Borer
Authors: Pawar Archana  S. , Chattopadhyay Subrata
Published: October 2008

The aldehyde 7, derived from 10-undecenoic acid (5) on cis-selective Wittig reaction with pentylidenetriphenylphosphorane, subsequent deprotection and oxidation gave the pheromone (11Z)-hexadecenal (1). Wittig-Horner olefination of 1 with the phosphonate 9 furnished the conjugated ester 10 which on base catalyzed isomerization to the (3Z)-ester 11 followed by LAH reduction and acetylation gave (3Z,13Z)-octadeadien-1-yl acetate (2). Compound 10 on the other hand was chemoselectively reduced and acetylated to furnish the pheromone (2E,13Z)-octadeadien-1-yl acetate (4). For the synthesis of (3E,13Z)-octadeadien-1-yl acetate (3), 1 was condensed with malonic acid under modified condition to afford the acid 13 which was converted to 3 by standard reaction protocol.
Synthesis and Characterization of Heptamethine Cyanine Dyes
Authors: Li Qun , Tan Ji , Peng Bi-Xian
Published: October 2008

A series of meso-chlorine substituted heptamethine-cyanine dyes and related heptamethine cyanine dyes unsubstituted on the vinyl chain were synthesized by condensation of 2,3,3-trimethyl indolenium salts with reactive intermediates, 2-chloro-formyl-3-hydroxy-methylenecyclohexene or N-[5-(phenylamino)-2,4-phentadienylidene] aniline monohydro-c hloride. The structures of the dyes were characterized by virtue of 1HNMR, 13C-NMR, IR, MS, etc. The reaction conditions and physicochemical properties of the dyes were extensively explored with classical photo-physical techniques
Synthesis of the Demospongic Compounds, (6Z, 11Z)-Octadecadienoic Acid and (6Z, 11Z)-Eicosadienoic Acid
Authors: Kulkarni B. A. , Chattopadhyay S. , Chattopadhyay A. , Mamdapur V. R.
Published: October 2008

n/a
Amberlyst 15 Catalyzed Prenylation of Phenols: One-Step Synthesis of Benzopyrans
Authors: Kalena G.  P. , Jain A. , Banerji A.
Published: October 2008

A convenient one-step synthesis of 2,2-dimethylchromans and chromenes using Amberlyst 15 as a catalyst is described.
(R,R)-Tartaric Acid Dimethyl Diester from X-Ray and Ab Initio Studies: Factors Influencing Its Conformation and Packing
Authors: Rychlewska Urszula , Warzajtis B. , Hoffmann M. , Rychlewski J.
Published: October 2008

The conformation of dimethyl (R,R)-tartrate has been analyzed on the basis of the single crystal X-ray diffraction method as well as by ab-initio quantum chemical studies. The results showed that the extended T conformation containing two planar hydroxyester moieties predominates in both ab-initio and X-ray studies. The lowest energy conformer in ab-initio calculations has C2 symmetry and hydrogen bonds between a hydroxyl group and the nearest carbonyl oxygen. The second in energetical sequence, with an energy difference of only 1.2 kcal/mol, is the asymmetrical conformer, which differs from the lowest energy form by the rotation of one of the ester groups by 180°. Intramolecular OH...O hydrogen bonds observed in this rotamer again involve only proximal functional groups. This conformer is present in the crystal structure of the studied compound, although its conformation in the solid state is no longer stabilized by intramolecular hydrogen bonds of the type mentioned above. In the crystal, hydroxyl groups are mostly involved in intermolecular hydrogen bonds and form only a weak intramolecular hydrogen bond with each other. The planar arrangement of the α-hydroxyester moieties combined with the extended conformation of the carbon chain seems to be stabilized by the intramolecular hydrogen bonds between neighboring functional groups and by the long range dipole-dipole interactions between two pairs of CO and (β)C-H bonds.
13C NMR Spectral Prediction by Means of Generalized Atom Center Fragment Method
Authors: Xu Jun
Published: October 2008

Knowledge-based NMR spectral prediction relies on the correlations between substructures and sub-spectra. To extract the correlations, a systematic substructure measurement has been developed to classify substructures according to their chemical shift values. Historically, the atom center fragment (ACF) concept has been used as a means to systematically measure substructures for NMR spectral prediction. The assumption behind this concept is that the chemical shift value of an atom is influenced by its chemical environment. Based upon the study of the ACF-type approaches, a generalized atom center fragment (GACF) approach is proposed in this paper. In the GACF approach, a substructure consists of a center atom, core layer, and external layers. The center atom and the core layer, are identified as the super center atom. The external layers are the chemical environment. A number of algorithms have been developed to measure GACF substructures from a structure database, and create the NMR knowledge base for NMR spectral prediction.
Improved Method for the Synthesis of New 1,5-Benzothiazepine Derivatives as Analogues of Anticancer Drugs
Authors: Sharma Anoop  K. , Singh Gajendra , Yadav Ashok  K. , Prakash L.
Published: October 2008

(±)cis-2-(4-Methoxyphenyl)-3-hydroxy/methoxy-2,3-dihydro-1,5-benzothiazepin-4[5H/5-chloroacetyl/5-(4'-methylpiperazino-1')acetyl]-ones have been synthesized by the condensation of 2-aminobenzene thiols with methyl(±)trans-3-(4-methoxyphenyl)glycidate in xylene. The synthesized compounds have been characterized by elemental analyses and spectral data and screened for their antimicrobial activity.