Showing papers in "Journal of Heterocyclic Chemistry in 1999"

TL;DR: In this paper, the authors present the most elegant and promising set of synthetic routes for the synthesis of 2-aminothiophenes by the Gewald reaction applications of this facile methodology to pharmaceuticals and dyestuffs have been demonstrated

TL;DR: Microwave-enhanced solvent-free synthetic approach is described that features simplicity, manipulative ease of the operation and conservation of solvents as the main advantages as discussed by the authors, which has found application in facile organic functional group transformations, is applied to rapid assembly of heterocyclic compounds.

TL;DR: Several new 2,5-disubstituted 1,3,4-oxadiazoles have been synthesized in good yields by reaction of aromatic acids with hydrazine dihydrochloride in a mixture of orthophosphoric acid, phosphorus pentoxide and, in general, with addition of phosphorus oxychloride to the reaction mixture as mentioned in this paper.

TL;DR: A number of symmetrically 3,5 disubstituted 4-amino-1,2,4-triazoles have been prepared by the reaction of aromatic nitriles with hydrazine dihydrochloride or sulfate with an excess of hydrazin hydrate in ethyl ene or diethylene glycol under a nitrogen atmosphere as mentioned in this paper.

TL;DR: In this paper, nucleophilic addition of organometallics to chiral 1-acylpyridinium salts occurs with high diastereoselectivity to give N-acyl-2,3-dihydro-4-pyridones, which are useful building blocks for the asymmemc synthesis of various alkaloids.

TL;DR: In this paper, the synthesis of various pyrazoles reported by us and some other research groups during 1989-1998 was reviewed. But the focus of the review was not on the development of potent pyrazolines, but on potential pyrazole formulations aiming at agrochemicals and drugs.

TL;DR: A review of the synthesis and reactions of 4H-3,1-Benzoxazin-4-ones can be found in this paper, where only those with carbon substituents at the 2 position are included.

TL;DR: Anilines react with 3-amino-1-propanol in dioxane in the presence of a catalytic amount of a ruthenium catalyst and tin(II) chloride dihydrate together with a hydrogen acceptor to afford the corresponding quinolines in moderate yields.

TL;DR: In this article, the synthesis of a new series of 6-amino-4-aryl-5-cyanopyrazolo[3,4-b]pyridines was described.

TL;DR: In this paper, the synthesis of 1,2-disubstituted-3-hydroxy-4(1H)-quinolinones by the cyclization of N-substitized phenacyl or acetonyl anthranilates is described.

TL;DR: In this article, 1-(Benzotriazol-1-yl)alkyl esters 2a-u were obtained in yields averaging 86% by the direct reaction of various aldehydes with the corresponding N-acylbenzotitriazoles in the presence of a catalytic amount of potassium carbonate (10−25 mole %).

TL;DR: Methyl 2-(benzyloxycarbonyl)aimno-3-dimemylaminopropenoate (2) was prepared from methyl N-(bensyloxy carbonyl)-glycinate (1) and t-butoxybis(dimethylamino)methane, and used as a reagent for preparation of substituted 3-amino compounds 7, 8, 20, 36, 38 and 53-57 in yields better than 80% as discussed by the authors.

TL;DR: In this article, a one-pot synthesis of 1-methyl- and 1-phenylpyrazole-3(5)-ethyl esters 2,3a-e by the cyclocondensation of β-alkoxyvinyl trichloromethyl ketones 1a − e with methyl and phenyl hydrazine hydrochloride under mild conditions, is reported.

TL;DR: In this paper, a kinetic study of the oxidative cyclization reaction of some 2,4-diaryl-substituted aldehyde thiosemicarbazones 1a-n induced by ferric chloride and by cupric perchlorate was performed.

TL;DR: In this article, a lecture review describes a new and general cumyl Directed Metalation Group (DMG) and a phosphine oxide DMG (Schemes 7 and 8).

TL;DR: The procedure includes the generation of a benzotriazole stabilized carbanion, oxidation of the resulting anion to a radical, and elimination of nitrogen followed by ring closure to produce phenanthridines.

TL;DR: In this paper, a cycloaddition of E-2-arylidene-1-indanones and Z-aurones with diazomethane provided trans-spiro 1-pyrazolines and trans-cyclopropane derivatives.

TL;DR: In this article, the synthesis and isolation of the intermediates N-[1-aryl(alkyl)-3-oxo-4, 4, 4-trichloro-1-buten-1yl]-o-phenylenediamines 2a-f and the corresponding 2- trichloromethyl-4-aryl-3H-1,5-benzodiazepines 3c-g or benzimidazoles 4a-b derivatives obtained from the intramolecular cyclization of β-alkoxyvinyl trich

TL;DR: In this article, the preparation of 1,2,4-triazolo[1,5-c]quinazolines 4a-d, 5, 6-dihydro, and 8-d by cyclocondensation of 1a-c with carboxylic acids and carboxyl anhydrides, respectively, is described.

TL;DR: The structure elucidation of 6,7-dihydropyrazolo[1,5-a]pyrimidines 3 is based on nmr measurements and these compounds showed moderate anthelmintic in vitro activity against the Nipposirongylus brasiliensis model.

TL;DR: In this article, the reaction of a series of β-methoxyvinyl trifluoromethyl ketones with N-methylhydroxylamine is reported.

TL;DR: In this article, the enol ethers were formed as a mixture of E- and Z-isomers from the addition of ethanol to 1,4-pentadiyn-3-ones 2 in sodium ethoxide/ethanol.

TL;DR: In this paper, a series of α-arylsulfonyl-α-bromoacetophenones were obtained in moderate yield from readily available α, α, β, α-β, α-, α,β-, α-, β-, β,β,β-β-phenylthiazole or selenazole.

TL;DR: In this article, 2-thioxopyrimidine-type building blocks were obtained from the key intermediates 4 and 8, respectively, for linear and angular heterocyclic systems having the imidazole and 1 2,4-triazole ring.

TL;DR: The structural characterization of novobiocin-2″,3″-carbonate observed in the Test Assay procedure used for Novobocin is reported for the first time in this paper.

TL;DR: In this article, a 4 + 2 hetero Diels-Alder reaction with a high degree of regio and stereo control was used to synthesize substituted pyridazines.