Showing papers by "Peyman Salehi published in 2004"
TL;DR: The results of the bioassays showed the interesting antimicrobial activity, in which the gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus, were the most sensitive to the oil.
Abstract: The composition and antimicrobial activity of the essential oil of Nepeta crispa Willd., an endemic species from Iran, was studied. The oil was obtained from the aerial parts of the plant and analyzed by GC and GC/MS. Twenty-three compounds, accounting for 99.8% of the total oil, were identified. The main constituents were 1,8-cineol (47.9%) and 4aalpha,7alpha,7abetanepetalactone (20.3%). The antimicrobial activity of essential oil of N. crispa was tested against seven gram-negative or gram-positive bacteria and four fungi. The results of the bioassays showed the interesting antimicrobial activity, in which the gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus, were the most sensitive to the oil. Also, the oil exhibited a remarkable antifungal activity against all the tested fungi.
66 citations
TL;DR: In this paper, a reagent for crossed-aldol condensation with ketones in the presence of silica sulfuric acid under solvent-free conditions is described. But the reagent is reusable for several times without any decrease in the yield of the reactions.
Abstract: Aromatic aldehydes undergo crossed-aldol condensation with ketones in the presence of silica sulfuric acid under solvent-free conditions to afford the corresponding a, b-unsaturated aldol products in excellent yields. The reagent is reusable for several times without any decrease in the yield of the reactions.
55 citations
TL;DR: H 3 PMo 12 O 40 · xH 2 O was found to be an effective catalyst for the preparation of bis-indolyl derivatives from indole and aromatic, aliphatic, heterocyclic aldehydes or ketones in ethanol at room temperature.
Abstract: H 3 PMo 12 O 40 · xH 2 O was found to be an effective catalyst for the preparation of bis-indolyl derivatives from indole and aromatic, aliphatic, heterocyclic aldehydes or ketones in ethanol at room temperature.
41 citations
TL;DR: In this article, a microwave-assisted synthesis of 4(3H)-quinazolinones by the condensation of isatoic anhydride, primary amines and orthoesters in the presence of catalytic amounts of p-toluenesulfonic acidin high yields is reported.
Abstract: Efficient microwave-assisted synthesis of 4(3H)-quinazolinones by the one-pot three-component condensation of isatoic anhydride, primary amines and orthoesters in the presence of catalytic amounts ofp-toluenesulfonic acidin high yields is reported.
33 citations
TL;DR: In this paper, the nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of silica sulfuric acid with high degree of regioselectivity.
Abstract: The nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of silica sulfuric acid with high degree of regioselectivity. The catalyst is reusable and can be applied several times without any decrease in the yield of reactions.
23 citations
Journal Article•
TL;DR: In this article, 3,4-Dihydropyrimidin-2(1H)-ones are synthesized by the three-component condensation of aromatic aldehydes, β-ketoesters and urea or thiourea in methanol or under solvent-free conditions, using aluminum hydrogensulfate as the catalyst.
Abstract: 3,4-Dihydropyrimidin-2(1H)-ones are synthesized by the three-component condensation of aromatic aldehydes, β-ketoesters and urea or thiourea in methanol or under solvent-free conditions, using aluminum hydrogensulfate as the catalyst.
21 citations
TL;DR: In this paper, 3,4-Dihydropyrimidin-2(1H)-ones are synthesized by the three-component condensation of aromatic aldehydes, β-ketoesters and urea or thiourea in methanol or under solvent-free conditions, using aluminum hydrogensulfate as the catalyst.
Abstract: 3,4-Dihydropyrimidin-2(1H)-ones are synthesized by the three-component condensation of aromatic aldehydes, β-ketoesters and urea or thiourea in methanol or under solvent-free conditions, using aluminum hydrogensulfate as the catalyst.
20 citations
TL;DR: An efficient and rapid synthesis of 2,3-disubstituted-4(3H)quinazolinones by condensation of 2-aminobenzamide with orthoesters in the presence of K-10 clay under solven...
Abstract: An efficient and rapid synthesis of 2,3-disubstituted-4(3H)quinazolinones by condensation of 2-aminobenzamide (substituted anthraniamides) with orthoesters in the presence of K-10 clay under solven...
13 citations
TL;DR: In this article, the reaction of thiols to symmetrical disulfides was performed in the presence of γ-picolinium chlorochromate and its silica gel supported.
10 citations
TL;DR: In this article, a method for oxidizing thiols to disulfides in acetonitrile in good yields was proposed, which is generally useful for a wide variety of thiol compounds.
Abstract: 1,4-Diazabicyclo[222]octane-di-N-oxide-di-perhydrate[3pc] selectively oxidizes thiols to disulfides in acetonitrile in good yields The method is generally useful for a wide variety of thiols
10 citations
TL;DR: In this article, a microwave-assisted synthesis of 4(3H)-quinazolinones by the condensation of isatoic anhydride, primary amines and orthoesters in the presence of catalytic amounts of p-toluenesulfonic acidin high yields is reported.
Abstract: Efficient microwave-assisted synthesis of 4(3H)-quinazolinones by the one-pot three-component condensation of isatoic anhydride, primary amines and orthoesters in the presence of catalytic amounts ofp-toluenesulfonic acidin high yields is reported.
TL;DR: In this paper, 3,4-Dihydropyrimidin-2(1H)-ones and their sulfur analogues are efficiently synthesized by the three-component condensation of β-dicarbonyl compounds, aromatic and aliphatic aldehydes, and urea or thiourea in the presence of catalytic amounts of silica sulfuric acid under solvent-free conditions in high yields.
Abstract: 3,4-Dihydropyrimidin-2(1H)-ones and their sulfur analogues are efficiently synthesized by the three-component condensation of β-dicarbonyl compounds, aromatic and aliphatic aldehydes, and urea or thiourea in the presence of catalytic amounts of silica sulfuric acid under solvent-free conditions in high yields. The catalyst is recyclable and can be used several times without any decrease in the products yields.
TL;DR: Alanine/chlorochromic acid/silica gel is a new and selective reagent for the efficient oxidation of sulfides, thiols, oximes, and alcohols as discussed by the authors.
Abstract: Alanine/chlorochromic acid/silica gel is a new and selective reagent for the efficient oxidation of sulfides, thiols, oximes, and alcohols. Oxidation of sulfides is solvent dependent. In chloroform at room temperature sulfoxides are formed as the major products, while in carbon tetrachloride or under solvent-free conditions solfones are produced in good-to-excellent yields.
TL;DR: Friedel-Crafts acylation of alkoxybenzenes was achieved efficiently by a reaction with aliphatic acid anhydrides in the presence of catalytic amounts of aluminum hydrogensulfate, Al(HSO4)3, in nitromethane and under solvent-free conditions as discussed by the authors.
Abstract: Friedel–Crafts acylation of alkoxybenzenes was achieved efficiently by a reaction with aliphatic acid anhydrides in the presence of catalytic amounts of aluminum hydrogensulfate, Al(HSO4)3, in nitromethane and under solvent-free conditions. Alkylbenzenes and aryl halides, as well as aromatic anhydrides, remained intact under these conditions.
01 Jan 2004
TL;DR: Widespread use of antimicrobial agents without any precaution is responsible for antibiotic resistance, which shows the necessity of prevention of infections with use of proper antibiotics.
Abstract: Background: There are many reports about nosocomial infections in ICU patients, their antibiotic resistance and the necessity of combination therapy with two or more different antibiotics. This study was designed to find the predominant pathogens and their antimicrobial resistance in a University hospital intensive care unit. Methods: We obtained samples from patients who had no signs and symptoms of infection on admission in ICU but showed infection signs at least after 48 hours. Cultures were obtained and antibiogram tests were done. Thereafter appropriate Results: About 40 percent of ICU patients were infected through their hospitalization. Urinary tract infection (UTI), respiratory, blood, and CNS infections were the most common infections. Gram-negative rods were including E-coli, Kelebsiella, pseudomonas and enterobacters, Gram-positive pathogens (staphylococcus epidermidis and S-aureus) were reported. Most of pathogens had resistance not only to common antibiotics but also to new generation ones. In most cases, empirical therapy had not been scaled down to definitive regimen with optimal activity, although the pathogen had been isolated and its antimicrobial sensitivities were identified. Conclusion: Widespread i€ use of antimicrobial agents without any precaution is responsible for antibiotic resistance. This shows the necessity of prevention of infections with use of proper antibiotics.
Keywords: ICU, Bacterial, Resistance.
01 Jan 2004
TL;DR: In this article, the authors discuss the limitations of the preparation of formates due to the drastic reaction conditions, the use of uncommon reagents, the formation of undesirable or toxic by-products, and the application of expen-sive catalysts for the synthesis of formylating agents.
Abstract: there are still serious limitations forthe preparation of formates due to the drastic reactionconditions, the use of uncommon reagents, formation ofundesirable or toxic by-products, the application of expen-sive catalysts for preparation of formylating agents andthermal instability of the reagents. Due to the instability ofthe anhydride and acid chloride of formic acid, formylationof alcohols by formic acid is an important synthetic reaction.In continuation of our studies on the applications ofinorganic acidic salts,
Journal Article•
TL;DR: In this article, a mild and efficient method for the oxidation of alcohols by ammonium dichromate in the presence of Al(HSO4)3 and wet SiO2 in solution or under solvent-free conditions is reported.
Abstract: A mild and efficient method for the oxidation of alcohols by ammonium dichromate in the presence of Al(HSO4)3 and wet SiO2 in solution or under solvent-free conditions is reported.