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Molecules, Volume 14, Issue 11 (November 2009), Pages 4300-4803

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Open AccessReview Synthetic Approaches and Biological Activities of 4-Hydroxycoumarin Derivatives
Molecules 2009, 14(11), 4790-4803; https://doi.org/10.3390/molecules14114790
Received: 19 October 2009 / Revised: 16 November 2009 / Accepted: 18 November 2009 / Published: 23 November 2009
Cited by 57 | PDF Full-text (273 KB)
Abstract
The main purpose of this review is to summarize recent chemical syntheses and structural modifications of 4-hydroxycoumarin and its derivatives, of interest due to their characteristic conjugated molecular architecture and biological activities. Full article
Open AccessArticle Silica Sulfuric Acid Promotes Aza-Michael Addition Reactions under Solvent-Free Condition as a Heterogeneous and Reusable Catalyst
Molecules 2009, 14(11), 4779-4789; https://doi.org/10.3390/molecules14114779
Received: 3 November 2009 / Revised: 19 November 2009 / Accepted: 23 November 2009 / Published: 23 November 2009
Cited by 31 | PDF Full-text (185 KB)
Abstract
A highly efficient, inexpensive, recyclable, convenient, and green protocol for chemoselective aza-Michael addition reactions of amines/thiols to α,β-unsaturated compounds using silica sulfuric acid (SSA or SiO2-SO3H) was developed. This method is simple, convenient and the title
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A highly efficient, inexpensive, recyclable, convenient, and green protocol for chemoselective aza-Michael addition reactions of amines/thiols to α,β-unsaturated compounds using silica sulfuric acid (SSA or SiO2-SO3H) was developed. This method is simple, convenient and the title compounds are produced in good to excellent yields. Full article
Open AccessArticle Spectroscopic Analyses of the Biofuels-Critical Phytochemical Coniferyl Alcohol and Its Enzyme-Catalyzed Oxidation Products
Molecules 2009, 14(11), 4758-4778; https://doi.org/10.3390/molecules14114758
Received: 21 October 2006 / Revised: 16 November 2006 / Accepted: 19 November 2009 / Published: 23 November 2009
PDF Full-text (564 KB)
Abstract
Lignin composition (monolignol types of coniferyl, sinapyl or p-coumaryl alcohol) is causally related to biomass recalcitrance. We describe multiwavelength (220, 228, 240, 250, 260, 290, 295, 300, 310 or 320 nm) absorption spectroscopy of coniferyl alcohol and its laccase- or peroxidase-catalyzed products
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Lignin composition (monolignol types of coniferyl, sinapyl or p-coumaryl alcohol) is causally related to biomass recalcitrance. We describe multiwavelength (220, 228, 240, 250, 260, 290, 295, 300, 310 or 320 nm) absorption spectroscopy of coniferyl alcohol and its laccase- or peroxidase-catalyzed products during real time kinetic, pseudokinetic and endpoint analyses, in optical turn on or turn off modes, under acidic or basic conditions. Reactions in microwell plates and 100 μL volumes demonstrated assay miniaturization and high throughput screening capabilities. Bathochromic and hypsochromic shifts along with hyperchromicity or hypochromicity accompanied enzymatic oxidations by laccase or peroxidase. The limits of detection and quantitation of coniferyl alcohol averaged 2.4 and 7.1 μM respectively, with linear trend lines over 3 to 4 orders of magnitude. Coniferyl alcohol oxidation was evident within 10 minutes or with 0.01 μg/mL laccase and 2 minutes or 0.001 μg/mL peroxidase. Detection limit improved to 1.0 μM coniferyl alcohol with Km of 978.7 ± 150.7 μM when examined at 260 nm following 30 minutes oxidation with 1.0 μg/mL laccase. Our assays utilized the intrinsic spectroscopic properties of coniferyl alcohol or its oxidation products for enabling detection, without requiring chemical synthesis or modification of the substrate or product(s). These studies facilitate lignin compositional analyses and augment pretreatment strategies for reducing biomass recalcitrance. Full article
(This article belongs to the Special Issue High-throughput Screening)
Open AccessReview Kinetic Resolution: A Powerful Tool for the Synthesis of Planar-Chiral Ferrocenes
Molecules 2009, 14(11), 4747-4757; https://doi.org/10.3390/molecules14114747
Received: 27 October 2009 / Revised: 16 November 2009 / Accepted: 19 November 2009 / Published: 20 November 2009
Cited by 28 | PDF Full-text (403 KB)
Abstract
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
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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. Full article
(This article belongs to the Special Issue Ferrocenes)
Open AccessArticle Preparation of Superhydrophobic Polymeric Film on Aluminum Plates by Electrochemical Polymerization
Molecules 2009, 14(11), 4737-4746; https://doi.org/10.3390/molecules14114737
Received: 15 October 2009 / Revised: 16 November 2009 / Accepted: 19 November 2009 / Published: 19 November 2009
Cited by 25 | PDF Full-text (319 KB)
Abstract
6-(N-Allyl-1,1,2,2-tetrahydroperfluorododecyl)amino-1,3,5-triazine-2,4-dithiol monosodium (ATP) was used to prepare polymeric thin films on pure aluminum plates to achieve a superhydrophobic surface. The electrochemical polymerization process of ATP on aluminum plates in NaNO2 aqueous solution and the formation of poly(6-(N-allyl-1,1,2,2-tetrahydroperfluorododecyl)amino-1,3,5-triazine-2,4-dithiol) (PATP)
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6-(N-Allyl-1,1,2,2-tetrahydroperfluorododecyl)amino-1,3,5-triazine-2,4-dithiol monosodium (ATP) was used to prepare polymeric thin films on pure aluminum plates to achieve a superhydrophobic surface. The electrochemical polymerization process of ATP on aluminum plates in NaNO2 aqueous solution and the formation of poly(6-(N-allyl-1,1,2,2-tetrahydroperfluorododecyl)amino-1,3,5-triazine-2,4-dithiol) (PATP) thin film were studied by means of optical ellipsometry and film weight. The chemical structure of the polymeric film is investigated using FT-IR spectra and X-ray photoelectron spectroscopy (XPS). Contact angle goniometry was applied to measure the contact angles with distilled water drops at ambient temperature. The experimental results indicate that the polymeric film formed on pure aluminum plates exhibits superhydrophobic properties with a distilled water contact angle of 153°. The electrochemical polymerization process is time-saving, inexpensive, environmentally friendly and fairly convenient to carry out. It is expected that this technique will advance the production of superhydrophobic materials with new applications on a large scale. Moreover, this kind of polymeric thin film can be used as a dielectric material due to its insulating features. Full article
Open AccessArticle Chemical Composition and Phytotoxic Effects of Essential Oils of Salvia hierosolymitana Boiss. and Salvia multicaulis Vahl. var. simplicifolia Boiss. Growing Wild in Lebanon
Molecules 2009, 14(11), 4725-4736; https://doi.org/10.3390/molecules14114725
Received: 19 October 2009 / Revised: 14 November 2009 / Accepted: 18 November 2009 / Published: 19 November 2009
Cited by 37 | PDF Full-text (123 KB)
Abstract
The chemical composition of the essential oils of S. hierosolymitana Boiss. and S. multicaulis Vahl. var. simplicifolia Boiss. collected in Lebanon was studied by means of GC and GC-MS analysis. In all 115 compounds were identified: 82 for S hierosolymitana and 72 for
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The chemical composition of the essential oils of S. hierosolymitana Boiss. and S. multicaulis Vahl. var. simplicifolia Boiss. collected in Lebanon was studied by means of GC and GC-MS analysis. In all 115 compounds were identified: 82 for S hierosolymitana and 72 for S. multicaulis var. simplicifolia. The presence of carbonylic compounds (17%) characterizes the oil from S. hierosolymitana,while S. multicaulis var. simplicifolia oil is rich of monoterpenes (34.5%) and sesquiterpenes (46.9%). The effects of the essential oils on germination and initial radical elongation of Raphanus sativus L. (radish) and Lepidium sativum L. (garden cress) were studied, indicating in a different activity against radical elongation of the species tested. Full article
Open AccessArticle Njaoaminiums A, B, and C: Cyclic 3-Alkylpyridinium Salts from the Marine Sponge Reniera sp.
Molecules 2009, 14(11), 4716-4724; https://doi.org/10.3390/molecules14114716
Received: 9 October 2009 / Revised: 3 November 2009 / Accepted: 17 November 2009 / Published: 19 November 2009
Cited by 8 | PDF Full-text (239 KB)
Abstract
Three novel cyclic 3-alkylpyridinium salts, named njaoaminiums A, B, and C (1-3), were isolated from the marine sponge Reniera sp., collected off the coasts of Pemba Island, Tanzania. The structural determination of the compounds was based on 1D and 2D NMR studies
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Three novel cyclic 3-alkylpyridinium salts, named njaoaminiums A, B, and C (1-3), were isolated from the marine sponge Reniera sp., collected off the coasts of Pemba Island, Tanzania. The structural determination of the compounds was based on 1D and 2D NMR studies and mass spectral determinations. Njaoaminiums B (2) and C (3) are the first examples of cyclic 3-alkylpyridinium salts bearing a methyl substituent on the alkyl chains. These compounds are assumed to be biosynthetic precursors of the njaoamines, previously isolated from the same sponge. The absolute configurations of the methyls of 2 and 3 were assigned by comparison between experimental and TDDFT calculated circular dichroism spectra on the most stable conformer. Compound 2 showed weak cytotoxicity against the three human tumor cell lines MDA-MB-231, A549, and HT29. Full article
Open AccessArticle Chemosystematic Value of the Essential Oil Composition of Thuja species Cultivated in Poland—Antimicrobial Activity
Molecules 2009, 14(11), 4707-4715; https://doi.org/10.3390/molecules14114707
Received: 21 October 2009 / Revised: 5 November 2009 / Accepted: 9 November 2009 / Published: 19 November 2009
Cited by 32 | PDF Full-text (218 KB)
Abstract
In the framework of the correlation between chemotaxonomy and chemical analysis studies, the chemical composition of the essential oils of four varieties of Thuja species cultivated in Poland − T. occidentalis ‘globosa’, T. occidentalis ‘aurea’, T. plicata and T. plicata ‘gracialis’
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In the framework of the correlation between chemotaxonomy and chemical analysis studies, the chemical composition of the essential oils of four varieties of Thuja species cultivated in Poland − T. occidentalis ‘globosa’, T. occidentalis ‘aurea’, T. plicata and T. plicata ‘gracialis’ − were investigated by GC and GC-MS. Thirty-one compounds were identified from T. occidentalis ‘globosa’, representing 96.92% of the total oil; twenty-seven from T. occidentalis ‘aurea’ (94.34%); thirty-one from T. plicata (94.75%); and thirty compounds from T. plicata ‘gracialis’ (96.36%). The main constituents in all samples were the monoterpene ketones α- and β-thujone, fenchone and sabinene, as well as the diterpenes beyerene and rimuene.The chemosystematic value of the total ketone content of all samples (which varied from 54.30–69.18%) has been discussed and investigated. The constituents, beyerene and the mixture of α- and β-thujone, were isolated from the oils and tested against six Gram-positive and -negative bacteria and three pathogenic fungi. The oils of the two T. plicata species exhibited significant antimicrobial activity, while the mixture of α- and β-thujone showed very strong activity as well. Full article
(This article belongs to the Special Issue Molecular Diversity Feature Papers)
Open AccessCorrection Omran, O.-A. The Reaction of Diethyl Bromomalonate with p-tert-butylthiacalix[4]arene: An Approach to Asymmetrical Derivatives Molecules 2009, 14, 1755-1761
Molecules 2009, 14(11), 4689; https://doi.org/10.3390/molecules14114689
Received: 17 November 2009 / Published: 19 November 2009
PDF Full-text (58 KB)
Abstract
We found following errors in our paper published in Molecules recently [1]. [...] Full article
Open AccessReview Steroidal Triterpenes: Design of Substrate-Based Inhibitors of Ergosterol and Sitosterol Synthesis
Molecules 2009, 14(11), 4690-4706; https://doi.org/10.3390/molecules14114690
Received: 22 September 2009 / Revised: 5 November 2009 / Accepted: 10 November 2009 / Published: 18 November 2009
Cited by 10 | PDF Full-text (1064 KB)
Abstract
This article reviews the design and study, in our own laboratory and others, of new steroidal triterpenes with a modified lanosterol or cycloartenol frame. These compounds, along with a number of known analogs with the cholestane skeleton, have been evaluated as reversible or
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This article reviews the design and study, in our own laboratory and others, of new steroidal triterpenes with a modified lanosterol or cycloartenol frame. These compounds, along with a number of known analogs with the cholestane skeleton, have been evaluated as reversible or irreversible inhibitors of sterol C24-methyltransferase (SMT) from plants, fungi and protozoa. The SMT catalyzes the C24-methylation reaction involved with the introduction of the C24-methyl group of ergosterol and the C24-ethyl group of sitosterol, cholesterol surrogates that function as essential membrane inserts in many photosynthetic and non-photosynthetic eukaryotic organisms. Sterol side chains constructed with a nitrogen, sulfur, bromine or fluorine atom, altered to possess a methylene cyclopropane group, or elongated to include terminal double or triple bonds are shown to exhibit different in vitro activities toward the SMT which are mirrored in the inhibition potencies detected in the growth response of treated cultured human and plant cells or microbes. Several of the substrate-based analogs surveyed here appear to be taxaspecific compounds acting as mechanism-based inactivators of the SMT, a crucial enzyme not synthesized by animals. Possible mechanisms for the inactivation process and generation of novel products catalyzed by the variant SMTs are discussed. Full article
(This article belongs to the Special Issue Triterpenes and Triterpenoids 2013)
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Open AccessArticle Cellulose/Gold Nanocrystal Hybrids via an Ionic Liquid/Aqueous Precipitation Route
Molecules 2009, 14(11), 4682-4688; https://doi.org/10.3390/molecules14114682
Received: 9 October 2009 / Revised: 12 November 2009 / Accepted: 17 November 2009 / Published: 18 November 2009
Cited by 14 | PDF Full-text (764 KB)
Abstract
Injection of a mixture of HAuCl4 and cellulose dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble)
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Injection of a mixture of HAuCl4 and cellulose dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble) metal/cellulose hybrids, which could find applications in sensing, sterile filtration, or as biomaterials. Full article
(This article belongs to the collection Ionic Liquids)
Open AccessArticle New Lipophilic Piceatannol Derivatives Exhibiting Antioxidant Activity Prepared by Aromatic Hydroxylation with 2-Iodoxybenzoic Acid (IBX)
Molecules 2009, 14(11), 4669-4681; https://doi.org/10.3390/molecules14114669
Received: 2 October 2009 / Revised: 17 November 2009 / Accepted: 17 November 2009 / Published: 17 November 2009
Cited by 12 | PDF Full-text (384 KB)
Abstract
Piceatannol (E-3,5,3’,4’-tetrahydroxystilbene) is a phytoalexin synthesized in grapes in response to stress conditions. It exhibits strong antioxidant and antileukaemic activities due to the presence of the catechol moiety. To modify some physical properties like solubility, and miscibility in non-aqueous media some
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Piceatannol (E-3,5,3’,4’-tetrahydroxystilbene) is a phytoalexin synthesized in grapes in response to stress conditions. It exhibits strong antioxidant and antileukaemic activities due to the presence of the catechol moiety. To modify some physical properties like solubility, and miscibility in non-aqueous media some new previously unreported piceatannol derivatives having lipophilic chains on the A-ring were prepared in good yields by a simple and efficient procedure. The key step was a chemo- and regioselective aromatic hydroxylation with 2-iodoxybenzoic acid (IBX). The new compounds showed antioxidant activity and seemed promising for possible applications as multifunctional emulsifiers in food, cosmetic and pharmaceutical fields. Full article
(This article belongs to the Special Issue Organic Iodine Chemistry)
Open AccessArticle Synthesis of Pregnane Derivatives, Their Cytotoxicity on LNCap and PC-3 Cells, and Screening on 5α-Reductase Inhibitory Activity
Molecules 2009, 14(11), 4655-4668; https://doi.org/10.3390/molecules14114655
Received: 8 September 2009 / Revised: 4 November 2009 / Accepted: 8 November 2009 / Published: 17 November 2009
Cited by 15 | PDF Full-text (572 KB)
Abstract
A series of epoxy- and/or 20-oxime pregnanes were synthesized from commercially available pregnenolone. Compounds 1, 3, 7, 8 and 11-13 were evaluated for cytotoxicity activity towards LNCaP (androgen-dependent) and PC-3 (androgenindependent) prostate cancer cells. Compound 13 showed the highest activity on both LNCaP
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A series of epoxy- and/or 20-oxime pregnanes were synthesized from commercially available pregnenolone. Compounds 1, 3, 7, 8 and 11-13 were evaluated for cytotoxicity activity towards LNCaP (androgen-dependent) and PC-3 (androgenindependent) prostate cancer cells. Compound 13 showed the highest activity on both LNCaP (IC50 15.17 μM) and PC-3 (IC50 11.83 μM) cell lines. Compound 11 showed weak activity on LNCaP cells (IC50 71.85 μM) and 8 showed the weak activity on PC-3 cells (IC50 68.95 μM), respectively. The 5α-reductase II (5AR2) inhibitory effects of compounds 1-3, 5 and 7-13 were investigated in a convenient screening model, in which compounds 5, 8, 11 and 12 were observed to be potential inhibitors of 5α-reductase, in particular, the 4-azasteroid 11, that also inhibited cell proliferation of androgen-dependent cells and 8, that in addition inhibited PC-3 cells more potently than LNCaP cells. Full article
Open AccessArticle High-Performance Liquid Chromatographic Quantification of Flavonoids in Eriocaulaceae Species and Their Antimicrobial Activity
Molecules 2009, 14(11), 4644-4654; https://doi.org/10.3390/molecules14114644
Received: 9 October 2009 / Revised: 13 November 2009 / Accepted: 16 November 2009 / Published: 16 November 2009
Cited by 5 | PDF Full-text (163 KB)
Abstract
Quantification of prepared samples by analysis using high performance liquid chromatography with DAD detection was developed to analyze rutin, 6-methoxyapigenin, and 6-methoxyapigenin-7-O-β-D-glucopyranoside isolated from methanolic extracts of different genus: Syngonanthus, Leiothix and Eriocaulon (Eriocaulaceae). The linearity, accuracy, and the inter-day
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Quantification of prepared samples by analysis using high performance liquid chromatography with DAD detection was developed to analyze rutin, 6-methoxyapigenin, and 6-methoxyapigenin-7-O-β-D-glucopyranoside isolated from methanolic extracts of different genus: Syngonanthus, Leiothix and Eriocaulon (Eriocaulaceae). The linearity, accuracy, and the inter-day precision of the procedure were evaluated. The calibration curves were linear. The recoveries of the flavonoids in the samples analyzed were 96.3% to 98.5%. The percentage coefficient of variation for the quantitative analysis of the flavonoids in the analyses of the samples was under 5%. The antimicrobial activity of the five methanol extracts of these Eriocaulaceae species was assayed against the microorganisms Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella setubal, Saccharomyces cerevisiae and Candida albicans. Measured MIC values ranged from 1.25 to 10.00 mg/mL. The flavonoid contents suggest that Eriocaulaceae species may be a promising source of compounds to produce natural phytomedicines. Full article
Open AccessArticle 3-(2-Aminophenyl)-4-methyl-1,3-thiazole-2(3H)-thione as an Ecofriendly Sulphur Transfer Agent to Prepare Alkanethiols in High Yield and High Purity
Molecules 2009, 14(11), 4634-4643; https://doi.org/10.3390/molecules14114634
Received: 29 October 2009 / Revised: 10 November 2009 / Accepted: 11 November 2009 / Published: 12 November 2009
Cited by 4 | PDF Full-text (239 KB)
Abstract
A new process is described for preparing very pure linear alkanethiols and linear α,ω-alkanedithiols using a sequential alkylation of the title compound, followed by a ring closure to quantitatively give the corresponding 3-methyl[1,3]thiazolo[3,2-a]-[3,1]benzimidazol-9-ium salt and the alkanethiol derivative under mild conditions. The alkanethiol
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A new process is described for preparing very pure linear alkanethiols and linear α,ω-alkanedithiols using a sequential alkylation of the title compound, followed by a ring closure to quantitatively give the corresponding 3-methyl[1,3]thiazolo[3,2-a]-[3,1]benzimidazol-9-ium salt and the alkanethiol derivative under mild conditions. The alkanethiol and the heteroaromatic salt are easily separated by a simple extraction process. The intermediate thiazolium quaternary salts resulting from the first reaction step can be isolated in quantitative yields, affording an odourless protected form of the thiols. Full article
(This article belongs to the Special Issue Advances in Heteroaromatic Chemistry)
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