5,007 research outputs found
Detection of human papillomavirus DNA in pterygia from different geographical regions
No full text(Scarpa is corresponding author
A facile synthesis of 3,5-diaminopyrazole-4-carbothioamides and 3,5- diaminopyrazole-4-carboxylates
No full textSimple and convenient synthesis of hitherto unknown 3,5-diaminopyrazole- 4-carbothioamides 3 as well as new ethyl 3,5-diaminopyrazole-4-carboxylates 7 is reported. The key intermediates were 2-cyanopropenethioamides 2 and 2- (ethoxycarbonyl)propenethioamides 5 which were readily obtained by reaction of phenyl isothiocyanate with 3-(2-acylhydrazino)-3-aminopropenenitriles 1 and ethyl 3-(2-acylhydrazino)-3-aminopropenoates 4 respectively. Intramolecular cyclization of compounds 2 afforded pyrazole-4-carbothioamides 3 while propenethioamides 5 gave pyrazole-4-carboxylates 7
Reaction of N-1-acylacetamidrazones with trifluoroacetylvinyl ethers. Synthesis of new 4-trifluoromethyl- and 6-trifluoromethylpyridines
No full textThe reaction between N-1-acylacetamidrazones 1 and enol ether 2 is described. Depending on the reaction conditions and on the substitution pattern of amidrazones 2-acylhydrazino-4-methyl-6-trifluoromethylpyridines 3 and/or 2-acylhydrazino-6-methyl-4-trifluoromethylpyridines 4 were obtained
New trifluoromethylated pyridines from functionalized N-1-acylacetamidrazones
No full textPolyfunctionalized trifluoromethylpyridines 4, 5 were readily synthesized from trifluoroacetylvinyl ether 3, using N-1-acylacetamidrazones 1, 2 as starting material
Facile synthesis of 2,2-dimethylchromans by Mo(CO)(6) catalyzed reaction of aryl prenyl ethers
No full text2,2-Dimethylchromans 3a-g are synthesized in good yields by a one-pot reaction of the aryl prenyl ethers 1a-g with a catalytic amount of Mo(CO)(6) in refluxing toluene
A new and efficient synthesis of phthalazin-1(2H)-ones
No full text2-Amino-2-(aroylhydrazono)ethyl aryl ethers, readily obtained from a wide range of aryloxyacetonitriles, are converted to phthalazin-1(2H)-ones derivatives in high yields by heating in PrOH in the presence of p-TsOH
Mo(CO)(6) catalyzed one-pot conversion of allyl aryl ethers to dihydrobenzofurans
No full textMolybdenum hexacarbonyl effectively catalyses a tandem Claisen rearrangement-cyclization reaction of allyl aryl ethers to give good yields of dihydrobenzofurans
A study of the stereochemistry of the dealkoxycarbonylation of some sulfur-substituted cyclopropanes.
No full text2-sulfenyl- and 2-sulfonyl-phenyl groups can affect the stereochemistry of the products in the reaction of some ester-stabilized cyclopropyl carbanions. As these substituents are not particularly effective chelating groups, the possibility of the intervention of a ct anomeric effect between the sulfur atom and the more extended orbital lobe of the cyclopropyl carbanion is considered. Evidences of the intermediacy of a pyramidal ester enolate are presented. The dimethyl 3-isopropyl-2-phenylsulfonyl-1,1-cyclopropane dicarboxylate 12 undergoes dealkoxycarbonylation, probably through a ring-opening ring-closure process, to give the corresponding monoester 15 with complete control of the relative stereochemistry of the three substituents
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