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Molecules, Volume 5, Issue 3 (March 2000), Pages 200-636

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Open AccessArticle Synthesis of Crown Ethers Containing a Rubicene Moiety
Molecules 2000, 5(3), 620-628; https://doi.org/10.3390/50300620
Received: 10 February 2000 / Accepted: 14 March 2000 / Published: 22 March 2000
Cited by 5 | PDF Full-text (39 KB) | HTML Full-text | XML Full-text
Abstract
A symmetrically disubstituted derivative of the highly fluorescing and photostable rubicene was incorporated in a macrocycle using high dilution conditions and a hydroxyrubicene was functionalized with a modified aminobenzo-15-crown-5. Full article
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Open AccessAbstract Influence of Some Thia- or Azasubstituted Butyric Acid Derivatives on the Chemical Shift of the Benzene Ring Carbon Atoms
Molecules 2000, 5(3), 616-619; https://doi.org/10.3390/50300616
Received: 26 January 2000 / Accepted: 17 March 2000 / Published: 22 March 2000
Cited by 1 | PDF Full-text (15 KB) | HTML Full-text | XML Full-text
Abstract
Eight thia- or azasubstituted butyric acid derivatives were prepared and the influence of these substituents on the chemical shifts of the benzene ring carbon atoms was studied. Full article
Open AccessAbstract Grindelic Acid Production in Grindelia Pulchella Cell Suspension Cultures Elicited with CuSO4
Molecules 2000, 5(3), 614-615; https://doi.org/10.3390/50300614
Published: 22 March 2000
Cited by 2 | PDF Full-text (18 KB) | HTML Full-text | XML Full-text Figures

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Open AccessAbstract Reaction Mechanism for the Cyclization of 3-[γ,γ-Dimethylallyl]Coumaric Acid Methyl Ester in Dimethyl Sulfoxide (DMSO)
Molecules 2000, 5(3), 612-613; https://doi.org/10.3390/50300612
Published: 22 March 2000
PDF Full-text (16 KB) | HTML Full-text | XML Full-text Figures

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Open AccessAbstract Synthesis of 2,3-Butanedione over TS-1, Ti-NCl, TiMCM-41, Ti-Beta, Fe-Si, Fe-Beta and VS-1 Zeolites
Molecules 2000, 5(3), 610-611; https://doi.org/10.3390/50300610
Published: 22 March 2000
Cited by 2 | PDF Full-text (17 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of this work is the synthesis of 2,3-butanedione (diacetyl) by selective oxidation of 2-butanone (methyl ethyl ketone) in the presence of O2 and H2O2 30% as oxidants. All the tests were performed over several selective oxidation zeolite
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The purpose of this work is the synthesis of 2,3-butanedione (diacetyl) by selective oxidation of 2-butanone (methyl ethyl ketone) in the presence of O2 and H2O2 30% as oxidants. All the tests were performed over several selective oxidation zeolite catalysts, synthesized and characterized in our laboratory. Full article
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Open AccessAbstract Structure-Properties Relationship of Dimeric Surfactants from Butyl Glucosides
Molecules 2000, 5(3), 608-609; https://doi.org/10.3390/50300608
Published: 22 March 2000
Cited by 5 | PDF Full-text (28 KB) | HTML Full-text | XML Full-text
Abstract
Carbohydrate containing dimeric surfactants were synthesized starting from Dglucose. Three different spacers were used to link the sugar moieties. The critical micelle concentration (CMC) for these new compounds was determined. Full article
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Open AccessAbstract Phytochemical Study Conyza Sophiaefolia. Antiinflammatory Activity
Molecules 2000, 5(3), 605-607; https://doi.org/10.3390/50300605
Published: 22 March 2000
Cited by 1 | PDF Full-text (18 KB) | HTML Full-text | XML Full-text
Abstract
From the aerial parts of Conyza sophiaefolia a new alicyclic furan diterpene was isolated and characterized as an E-isomer in C6 of centipedic acid. In addition, the new clerodane type diterpene 12-epi-bacchotricuneatin A as well as two known related diterpenoids were identified.
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From the aerial parts of Conyza sophiaefolia a new alicyclic furan diterpene was isolated and characterized as an E-isomer in C6 of centipedic acid. In addition, the new clerodane type diterpene 12-epi-bacchotricuneatin A as well as two known related diterpenoids were identified. The flavone apigenine was also isolated. Structures were determined on the basis of spectroscopic evidence. Full article
Open AccessAbstract Synthesis and Computational Simulation of New Phosphorilated Sulfoximines with Insecticidal Activity
Molecules 2000, 5(3), 602-604; https://doi.org/10.3390/50300602
Published: 22 March 2000
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Abstract
New organophosphorus insecticides of dialkylsulphoximines derived with activity upon acetylcholinesterase were synthesized. The obtained compounds were characterized by NMR and IR, and anticholinesterase activity and toxicity was measured. A simulation through computer was done in order to establish the relationship between structure and
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New organophosphorus insecticides of dialkylsulphoximines derived with activity upon acetylcholinesterase were synthesized. The obtained compounds were characterized by NMR and IR, and anticholinesterase activity and toxicity was measured. A simulation through computer was done in order to establish the relationship between structure and activity. Full article
Open AccessAbstract O-Sulfated Derivatives of Glucuronic Acid
Molecules 2000, 5(3), 600-601; https://doi.org/10.3390/50300600
Published: 22 March 2000
Cited by 2 | PDF Full-text (16 KB) | HTML Full-text | XML Full-text
Abstract
4-O-Substituted D-glucuronic acid derivatives were synthesized from D-glucose in order to study the regioselectivity of sulfation. Full article
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Open AccessAbstract Enantioselective Addition of Grignard Reagents to Aldehydes
Molecules 2000, 5(3), 598-599; https://doi.org/10.3390/50300598
Published: 22 March 2000
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Abstract
The addition of Grignard reagents to aldehydes in the presence of chiral aminoalcohols shows a moderate enantioselectivity. The study carried out with a series of ligands allows the correlation between the structural characteristics and their reactivity. Full article
Open AccessAbstract Polymerization Mechanism of α,α’-bis(Tetrahydrothiophenio)-β-xylene Dichloride
Molecules 2000, 5(3), 596-597; https://doi.org/10.3390/50300596
Published: 22 March 2000
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Abstract
A experimental study was performed regarding the influence of the base nature and solvent on the reactive intermediate concentration in the base-promoted bissulfonium salts polymerization. Such polymerization reaction is part of a synthetic procedure used to prepare conjugated polymers. In addition, a theoretical
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A experimental study was performed regarding the influence of the base nature and solvent on the reactive intermediate concentration in the base-promoted bissulfonium salts polymerization. Such polymerization reaction is part of a synthetic procedure used to prepare conjugated polymers. In addition, a theoretical study suggest that a one-electron transfer could be involved in the initiation step. Full article
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Open AccessAbstract Stereoselective Synthesis of 8-Trialkylstannylmenthols
Molecules 2000, 5(3), 594-595; https://doi.org/10.3390/50300594
Published: 22 March 2000
Cited by 1 | PDF Full-text (19 KB) | HTML Full-text | XML Full-text
Abstract
Trialkyltin menthones of type 2 are obtained selectively by 1,4-addition of trialkylstannyl lithium to (-)-pulegone. Reduction of 2 with borane in THF using as catalyst the reagent prepared from borane and (S)-valinol gave a mixture of the corresponding trialkyltin alcohols 3 (Me: 84%;
[...] Read more.
Trialkyltin menthones of type 2 are obtained selectively by 1,4-addition of trialkylstannyl lithium to (-)-pulegone. Reduction of 2 with borane in THF using as catalyst the reagent prepared from borane and (S)-valinol gave a mixture of the corresponding trialkyltin alcohols 3 (Me: 84%; n-Bu: 90,6%) and 4 (Me: 16% and n-Bu: 9,4%). Full article
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Open AccessAbstract Fluorescence Resonance Energy Transfer Using Spiropyran and Diarylethene Photochromic Acceptors
Molecules 2000, 5(3), 591-593; https://doi.org/10.3390/50300591
Published: 22 March 2000
Cited by 9 | PDF Full-text (28 KB) | HTML Full-text | XML Full-text
Abstract
We describe the preparation and photophysical characterization of two model compounds designed to test a new approach for the quantitative determination of Fluorescence Resonance Energy Transfer (FRET) in biological systems. The method enables modulation of FRET by exploiting the unique reversible spectral properties
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We describe the preparation and photophysical characterization of two model compounds designed to test a new approach for the quantitative determination of Fluorescence Resonance Energy Transfer (FRET) in biological systems. The method enables modulation of FRET by exploiting the unique reversible spectral properties of photochromic diarylethenes and spiropyrans to create switchable energy acceptors. Full article
Open AccessAbstract Catalytic Hydrogenation Reaction of Naringin-Chalcone. Study of the Electrochemical Reaction
Molecules 2000, 5(3), 589-590; https://doi.org/10.3390/50300589
Published: 22 March 2000
Cited by 1 | PDF Full-text (17 KB) | HTML Full-text | XML Full-text
Abstract
The electrocatalytic hydrogenation reaction of naringin derivated chalcone is studied. The reaction is carried out with different catalysts in order to compare with the classic catalytic hydrogenation. Full article
Open AccessAbstract Solvatochromic and Kinetic Response Models in (Ethyl Acetate + Chloroform or Methanol) Solvent Mixtures
Molecules 2000, 5(3), 587-588; https://doi.org/10.3390/50300587
Published: 22 March 2000
Cited by 1 | PDF Full-text (16 KB) | HTML Full-text | XML Full-text
Abstract
The present work analyzes the solvent effects upon the solvatochromic response models for a set of chemical probes and the kinetic response models for an aromatic nucleophilic substitution reaction, in binary mixtures in which both pure components are able to form intersolvent complexes
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The present work analyzes the solvent effects upon the solvatochromic response models for a set of chemical probes and the kinetic response models for an aromatic nucleophilic substitution reaction, in binary mixtures in which both pure components are able to form intersolvent complexes by hydrogen bonding. Full article
Open AccessAbstract A Conformational Study of Flexible Cyclic Compounds (Hydrocarbon Rings of 9-12 Members)
Molecules 2000, 5(3), 585-586; https://doi.org/10.3390/50300585
Published: 22 March 2000
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Abstract
We report here a conformational study of cyclic flexible compounds (rings with 9-12 members). Two methods of systematic search for the minima were used. The results were compared with those obtained using other exploratory methods. Full article
Open AccessAbstract Molecular Interactions Between the Active Sites of RGD (Arg-Gly-Asp) with its Receptor (Integrine)
Molecules 2000, 5(3), 583-584; https://doi.org/10.3390/50300583
Published: 22 March 2000
Cited by 2 | PDF Full-text (308 KB) | HTML Full-text | XML Full-text
Abstract
A study of the molecular interactions between the active sites of RGD (Arg-Gly-Asp) with it Receptor using simultaions is reported. Our calculations indicate that the guanidine-carboxylate complex is energetically favourd with respect to the guanidine-methyl tetrazole complex. Full article
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Open AccessAbstract The Importance of Keto-Enol Forms of Arylpropanoids Acting as Antifungal Compounds
Molecules 2000, 5(3), 580-582; https://doi.org/10.3390/50300580
Published: 22 March 2000
Cited by 4 | PDF Full-text (17 KB) | HTML Full-text | XML Full-text
Abstract
We report here the importance of a keto-enol equilibrium of an arylpropanoid series acting as antifungal agents. An interesting relationship between ln MIC, ∆E enolization and net atomic charges was found. Two compounds were synthesized and their MIC evaluated in order to prove
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We report here the importance of a keto-enol equilibrium of an arylpropanoid series acting as antifungal agents. An interesting relationship between ln MIC, ∆E enolization and net atomic charges was found. Two compounds were synthesized and their MIC evaluated in order to prove the above relationship. Full article
Open AccessAbstract Kinetics of the Aromatic Nucleophilic Substitution Reaction Between 1-Fluoro-2,4-Dinitrobenzene and Perhydroazepine in Ethyl Acetate + Chloroform Solvent Mixtures
Molecules 2000, 5(3), 578-579; https://doi.org/10.3390/50300578
Published: 22 March 2000
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Abstract
In the present work, the kinetic behavior of the title reaction in ethyl acetate + chloroform solvent mixtures is studied. The experimental results are compared with previous findings. Full article
Open AccessAbstract Study of the Cytotoxic and Antifungal Activities of Neolignans 8.O.4´ and Structurally Related Compounds
Molecules 2000, 5(3), 576-577; https://doi.org/10.3390/50300576
Published: 22 March 2000
Cited by 1 | PDF Full-text (15 KB) | HTML Full-text | XML Full-text
Abstract
In the present work we report the antifungal and cytotoxic activities of a neolignan 8.O.4´series. The most active antifungal compounds show a significant cytotoxic effect which might be related. Full article
Open AccessAbstract Development and Validation of a Chromatographic Method for the Analysis of Multicompound Pharmaceutical Preparations
Molecules 2000, 5(3), 574-575; https://doi.org/10.3390/50300574
Published: 22 March 2000
Cited by 1 | PDF Full-text (16 KB) | HTML Full-text | XML Full-text
Abstract
A reverse phase high performance liquid chromatographic assay was carried out for the simultaneous determination of two out of three active principles present in a pharmaceutical preparation. This method was developed to assess the quality of the product. Full article
Open AccessAbstract Bioactive Constituents of Conyza Albida
Molecules 2000, 5(3), 571-573; https://doi.org/10.3390/50300571
Published: 22 March 2000
Cited by 4 | PDF Full-text (20 KB) | HTML Full-text | XML Full-text
Abstract
Alkynes and spathulenol were isolated from Conyza albida (Asteraceae); some of the compounds were lethal against Artemia sp. and cytotoxic against KB cells. Full article
Open AccessAbstract Chemical Study of the Essential Oil of Mutisia Friesiana
Molecules 2000, 5(3), 568-570; https://doi.org/10.3390/50300568
Published: 22 March 2000
Cited by 4 | PDF Full-text (18 KB) | HTML Full-text | XML Full-text
Abstract
The composition of essential oil of Mutisia friesiana (Asteracae) was studied. The oil is a complex system in which 127 compounds were identified. The major components are monoterpenes: b-phellandrene, (Z)-β-ocimene, α and β-pinene and sabinene. Full article
Open AccessAbstract Separation of the Pigment of an Amaranth
Molecules 2000, 5(3), 566-567; https://doi.org/10.3390/50300566
Published: 22 March 2000
Cited by 1 | PDF Full-text (14 KB) | HTML Full-text | XML Full-text
Abstract
It is known that current quality requirements require the utilization of natural colorants in the foods. The objective of the present work is to extract the pigment amaranthus from fresh leaves of Amaranthus hypochondriacus L. cv Don Pedro to characterize it through spectroscopic
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It is known that current quality requirements require the utilization of natural colorants in the foods. The objective of the present work is to extract the pigment amaranthus from fresh leaves of Amaranthus hypochondriacus L. cv Don Pedro to characterize it through spectroscopic techniques, to be used as natural colorants. Full article
Open AccessAbstract First Synthesis of (20S) 3β,16β-Dihydroxy-5-pregnen-20,16-carbolactone (Diosgeninlactone)
Molecules 2000, 5(3), 564-565; https://doi.org/10.3390/50300564
Published: 22 March 2000
Cited by 2 | PDF Full-text (17 KB) | HTML Full-text | XML Full-text
Abstract
Diosgeninlactone (1), a natural product from Solanum vespertilio, was stereoselectively synthesized in high yield from 3β-hydroxy-5-androstene. Full article
Open AccessAbstract A Simple Method for N-Phenoxyethylation of Anilines
Molecules 2000, 5(3), 562-563; https://doi.org/10.3390/50300562
Published: 22 March 2000
Cited by 1 | PDF Full-text (15 KB) | HTML Full-text | XML Full-text
Abstract
We wanted to search for new reaction conditions to prepare the title compounds, to be checked later in novel syntheses of heterocyclic compounds. To the best of our knowledge, there was no report in the literature of any well-established method for the preparation
[...] Read more.
We wanted to search for new reaction conditions to prepare the title compounds, to be checked later in novel syntheses of heterocyclic compounds. To the best of our knowledge, there was no report in the literature of any well-established method for the preparation of N-(2-phenoxyethyl)anilines 1. Full article
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Open AccessAbstract Catalytic Activity of MEL Zeolites Modified with Metallic Couples for the Conversion of Ethane
Molecules 2000, 5(3), 560-561; https://doi.org/10.3390/50300560
Published: 22 March 2000
Cited by 1 | PDF Full-text (16 KB) | HTML Full-text | XML Full-text
Abstract
The transformation of ethane into aromatic hydrocarbons over Zn-metal- containing zeolites at W/F=10 gh/mol and 550°C was studied in a flow reactor at atmospheric pressure. Zn-metal-zeolite modified the activation mode of the alkane, generating highly reactive intermediates and enhancing the aromatic selectivity. Full article
Open AccessAbstract Integral Chemical Analysis of the Amaranth (Amaranthus greggii S. Wats)
Molecules 2000, 5(3), 557-559; https://doi.org/10.3390/50300559
Published: 22 March 2000
PDF Full-text (18 KB) | HTML Full-text | XML Full-text
Abstract
The objective of this work was to obtain information on Amaranthus greggii S. Wats., related to its nutritional value, its agricultural application as leaf vegetable and for animal consumption. The following variables were analyzed: dampness, ashes, protein, mineral, ethereal extract (fat), brute fiber,
[...] Read more.
The objective of this work was to obtain information on Amaranthus greggii S. Wats., related to its nutritional value, its agricultural application as leaf vegetable and for animal consumption. The following variables were analyzed: dampness, ashes, protein, mineral, ethereal extract (fat), brute fiber, oxalic acid, nitrates and carbohydrates. Full article
Open AccessAbstract Synthesis of a Thienothiophene Conjugated Polymer
Molecules 2000, 5(3), 555-556; https://doi.org/10.3390/50300555
Published: 22 March 2000
Cited by 7 | PDF Full-text (17 KB) | HTML Full-text | XML Full-text
Abstract
A new conducting polymer was prepared by chemical and electrochemical polymerization of 3,6-dimethylthieno[3,2-b]thiophene. The galvanostatic deposition afforded uniform, adherent and dark blue films of PDMTT. Electrochemical characterization by cyclic voltammetry showed that it can be repeatedly driven between the doped and undoped species
[...] Read more.
A new conducting polymer was prepared by chemical and electrochemical polymerization of 3,6-dimethylthieno[3,2-b]thiophene. The galvanostatic deposition afforded uniform, adherent and dark blue films of PDMTT. Electrochemical characterization by cyclic voltammetry showed that it can be repeatedly driven between the doped and undoped species with a coulombic efficiency of nearly 100%. Full article
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Open AccessAbstract Comparison Between Aqueous and Nonaqueous AOT-Heptane Reverse Micelles Using Acridine Orange as Molecular Probe
Molecules 2000, 5(3), 553-554; https://doi.org/10.3390/50300553
Published: 22 March 2000
Cited by 4 | PDF Full-text (16 KB) | HTML Full-text | XML Full-text
Abstract
Aqueous and nonaqueous AOT/n-heptane reverse micelles where characterized by UV-Visible and fluorescence spectroscopy of AO. The study shows the presence of the dimer in aqueous reverse micelles which is not present in the nonaqueous systems. It seems that there is a conversion of
[...] Read more.
Aqueous and nonaqueous AOT/n-heptane reverse micelles where characterized by UV-Visible and fluorescence spectroscopy of AO. The study shows the presence of the dimer in aqueous reverse micelles which is not present in the nonaqueous systems. It seems that there is a conversion of the dimer to monomer in the aqueous reverse micelles at high AOT concentration. In the nonaqueous systems, there is only partition of the monomer. The apparent constants of these processes were calculated. Full article
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