Showing papers in "Synthetic Communications in 2003"

TL;DR: In this article, a series of 5-oxo-5,6,7,8-tetrahydro-4H-benzo-[b]-pyran derivatives were prepared by the reaction of arylmethylidenemalononitriles or 2-cyano-3-aryl-l-acrylate with 5,5dimethyl-1,3-cyclohexanedione (dimedone) in DMF at room temperature catalyzed by KF-alumina.

TL;DR: Hy-Zeolite is found to be a versatile catalyst for the electrophilic substitution reaction of indoles with carbonyl compounds to afford the corresponding bis(indolyl) methanes in good yields.

TL;DR: In this article, the authors performed Knoevenagel condensation in absence of solvent with a mild Lewis acid Lanthanum(III) chloride, to prepare substituted alkenes.

TL;DR: In this article, a straightforward method for the synthesis of alkylidene/arylidene malonates and arylidsene cyanoacetates, utilizing proline as an alternative to traditional catalysts is presented.

TL;DR: In this article, a one-pot synthesis of α-aminophosphonates from aldehydes and amines using trimethyl phosphite catalyzed by aluminum chloride at ambient temperature is reported.

TL;DR: In this article, the mono-nitration of phenols with ferric nitrate has been achieved in high regio-selectivities in 1-3h at 30-60°C using the ionic liquid 1,3-di-n-butylimidazolium tetraflouroborate [bbim]BF4 as the solvent.

TL;DR: InCl3·4H2O catalyzes the cross-aldol condensation of different ketones with various aldehydes to give α,β-unsaturated carbonyl compounds in good to excellent yields.

TL;DR: In this paper, a one-pot procedure for the synthesis of 2,5-disubstituted-1,3,4-oxadiazoles by condensing mono-arylhydrazides with acid chlorides in HMPA solvent under the microwave heating is described.

TL;DR: A reaction of appropriate indol-2,3-diones with 4-aminoantipyrine has resulted in the formation of 3-(2, 3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl-imino)-indol 2-ones in quantitative yields which upon cyclocondensation with mercaptoacetic acid afforded a series of new spiro heterocycles as mentioned in this paper.

TL;DR: In this article, the condensation of cyclopentanone or cyclohexanone with aromatic aldehydes catalyzed by KF/Al2O3 in MeOH under ultrasound irradiation was studied.

TL;DR: In this paper, a novel one-pot Biginelli-type reaction has been developed, where aromatic and aliphatic aldehydes with β-dicarbonyl compounds and thiourea in the presence of catalytic amount 5 mol% of Yb(OTf)3 at 100°C for 60 − 90 min under solvent-free conditions, and yields of the classical Biginelli reaction can be increased from 20 − 50% to 81 − 91% while the reaction time was shortened from 18 − 48h to 60 −90 min.

TL;DR: In this article, microwave-assisted Beckmann rearrangements of ketoximes in room temperature ionic liquids have been successfully achieved using only 5 mol% of H2SO4 as a catalyst.

TL;DR: In this paper, a method for the synthesis of 1H-pyrazole-4-carboxylic acid esters is described, and a comparison between the conventional and microwave assisted Vilsmeier reaction is carried out.

TL;DR: In this article, an efficient H2NSO3H-catalyzed solvent-free tetrahydropyranylation of various alcohols at room temperature was investigated.

TL;DR: In this paper, the N,N-disubstituted carbamoyltrimethylsilanes can be prepared by the addition of LDA to a mixture of TMSCl and the appropriate formamide in THF at −78°C.

TL;DR: Aryl t-butyl sulfides underwent quantitative tertbutyl/acetyl exchange reactions affording thioacetic acid S-aryl esters when treated with acetyl chloride and boron tribromide.

TL;DR: In this article, a facile and efficient procedure for one-pot synthesis of amides from ketones in the presence of P2O5/SiO2 reagent in dry media under microwave irradiation was developed.

TL;DR: In this paper, a new reagent for reducing various sulfoxides to the corresponding sulfides in good yields under mild conditions was found, which is called TiCl4/In system.

TL;DR: In this paper, a 2,5-bis (unsaturated alkyloxymethyl)-furan led to macrocyclic furanic derivatives in the presence of Grubb's catalyst via dimerization or direct intramolecular metathesis according to the length of the sidearm.

TL;DR: In this article, it was observed that, hydrazinium monoformate is more effective than hydrazine or formic acid and reduction of nitro group occurs without hydrogenolysis in the low cost zinc dust compared to expensive metals like palladium.

TL;DR: In this paper, the catalytic enantioselective epoxidation promoted by quaternary ammonium salt as a phase transfer catalyst is described, and the chalcone derivatives with sodium hypochlorite under mild reaction conditions are treated with good yields with good to moderate enantiomeric excesses.

TL;DR: In this article, an efficient methodology for the Baylis-Hillman reaction of p-nitrobenzaldehyde (1), naphtaldehyde (4a), and pyperonal (4b) with methyl acrylate by using 4-dimethylaminopyridine (DMAP) as a catalyst was presented.

TL;DR: Me3S(O)+I− (1) and Me3S+I−(2) form stable, dry mixtures with KOt-Bu and NaH, respectively, which remain stable upon prolonged storage (>1 year.

TL;DR: In this paper, an efficient Co(II) catalyzed auto oxidation of 1,4-dihydropyridines to pyridine in good yield is described.

TL;DR: In this paper, an improved procedure was developed for the direct conversion of carboxylic esters to secondary amides by simple treatment with primary amines in presence of indium triiodide.

TL;DR: In this article, a diverse set of N-methyl secondary amines are obtained in high yields by an expedient reductive alkylation of commercially available methanolic methylamine.

TL;DR: An efficient one-pot synthesis of 2,4(1H,3H)-quinazolinediones and 2-thioxoquinazolinone derivatives is given by the condensation of isatoic anhydride, primary amine and urea or thiourea in the absence of organic or inorganic reagents under microwave irradiation as discussed by the authors.

TL;DR: In this article, the authors studied the oxidation of organic compounds under ion exchange resin (IER) catalysis by KMnO4 under reflux conditions in CH2Cl2.

TL;DR: Sodium fluoride catalyzed Friedlander condensation of 2-aminonicotinaldehye with various carbonyl compounds containing α-methylene group in the solid state furnished corresponding 1,8-naphthyridines.

TL;DR: In this article, Spengler and Bischler-Napieralski reaction products have been prepared using microwave irradiation on silicagel support under solvent free condition.