Treatment of 6-aminoquinoxaline with beta,beta-diactivated alkoxymethylene derivatives gave the corresponding N-(quinoxalin-6-yl)enamines. A variant of the SNV reaction mechanism was proposed for substitution of the alkoxymethylene compounds, on the basis of the structures of the precursor enol ether and the vinylic substitution product and on computations. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).

ChemInformVolume 35, Issue 24 Heterocyclic Compounds Quinoxalines. Part 3. Synthesis, Properties, and Reactions of 5-Substituted Derivatives of 2,3-Diphenylquinoxaline. Jozef Salon, Jozef Salon Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorViktor Milata, Viktor Milata Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorMiloslav Chudik, Miloslav Chudik Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorNadezda Pronayova, Nadezda Pronayova Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorJan Lesko, Jan Lesko Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorMilan Seman, Milan Seman Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorAnna Belicova, Anna Belicova Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this author Jozef Salon, Jozef Salon Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorViktor Milata, Viktor Milata Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorMiloslav Chudik, Miloslav Chudik Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorNadezda Pronayova, Nadezda Pronayova Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorJan Lesko, Jan Lesko Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorMilan Seman, Milan Seman Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorAnna Belicova, Anna Belicova Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this author First published: 19 May 2004 https://doi.org/10.1002/chin.200424145Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume35, Issue24June 15, 2004 RelatedInformation

Alkylation of deprotonated diphenylacetonitrile with halogeneacetones (Cl, Br, I) was studied in N,N-dimethylformamide (DMF). The differences in yields of the alkylation product, 4-oxo-2,2-diphenylvaleronitrile ( I), are caused by variations in the haloacetones and solvents. The detailed structure of a new cyclization by-product, 3,3-diphenyl-5-methyl-5-acetonylpyrrolidin- 2-one (II), in acetone co-solvent was established by X-ray analysis.

Catalytic hydrogenation of 5-nitro-2,3-diphenylquinoxaline led to the corresponding amine which, in turn, afforded products of nucleophilic substitution on reaction with alkoxymethylene derivatives. Thermal cyclization of selected alkoxymethylene derivatives yielded substituted pyridoquinoxalines. The conditions for successful hydrolysis of ester, decarboxylation of the acid, following chlorination of pyridone and reductive removal of the chlorine atom from it to produce parental heterocycle 2,3-diphenyl-pyrido[2,3-f]quinoxaline were found. All of the tested products of the nucleophilic substitution showed no antibacterial activity.

AbstractFor Abstract see ChemInform Abstract in Full Text.

tert-Butylation of biphenyl with tert-butanol has been studied over large-pore H-Y (15) and H-beta (25) zeolites under liquid phase conditions using cyclohexane as a solvent. The identification of main and by-products has been performed by GC-MS analysis. The main products of the alkylation reaction were mono-tert-butylbiphenyls and di-(tert-butyl)biphenyls with preferential formation of para- and para,para′-isomers. Higher alkylbiphenyls with alkyl group from C4 to C10′ were identified as by-products. These compounds can be formed by alkylation of biphenyl and/or mono-tert-butylbiphenyls with different alkenes, generated by dehydration of tert-butanol, followed by oligomerisation and disproportionation of the formed isobutylene. A peculiar effect of the small change in dimensions of micropores of H-beta (elliptic pores 0.76nm×0.64nm) in comparison with H-Y zeolite (circular pores 0.74nm) has been reflected by the transalkylation of mono-tert-butylbiphenyls to cyclohexylbiphenyls and methylcyclopentylbiphenyls over the more acid H-beta zeolite catalyst, whereas this transalkylation has been not monitored in the experiments with H-Y zeolite. The occurrence of transalkylation reactions has been supported by thermodynamic analysis and calculations.

The reaction of N-tert-butyl-2-benzothiazolesulphenamide with acetic anhydride catalyzed by acetic acid in a nonpolar solvent has been studied by NMR, GC–MS and EPR techniques. In the catalytic process homolytic decomposition of N-tert-butyl-2-benzothiazolesulphenamide prevails over the heterolytic pathway which is typical for uncatalyzed reaction. Besides the typical products formed during the uncatalyzed reaction, in the acid catalyzed process products formed by recombination of radicals were confirmed by 13C NMR and mass spectroscopy. In the formation of TBbisBS by homolytic pathway N,N′-dialkylhydrazine radicals and RNH radicals, produced by decomposition of N,N′-dialkylhydrazine, play probably an important role.

An isotachophoretic method with conductivity detection was developed to determine naproxen in the presence of its metabolite 6-O-desmethylnaproxen in human serum. The leading electrolyte contained 10 mM hydrochloric acid, beta-alanine, pH 4.0 and 0.1% methylhydroxypropylcellulose. The terminating electrolyte was 10 mM 2-(N-morpholino)ethanesulfonic acid-tris(hydroxymethyl)aminomethane, pH 6.9, containing 20% (v/v) of ethanol. Naproxen was determined in serum supernatant after simple deproteination of the sample with ethanol. The isotachophoretic results were compared with those obtained by synchronous fluorescence spectrometry.

Treatment of 2,3-dimethylquinoxalin-6-amine with (alkoxymethylidene)malonic derivatives gave the corresponding (quinoxalylamino)ethenes, which on heating cyclized to angularly annelated pyrido[3,2- f ]quinoxalin-10-ones.

Electron ionization mass spectra of ten various 5-substituted quinoline-4-carboxylic acids and their six amides are presented. Spectral fragmentations are discussed. New mass spectra were measured.

Electron impact mass spectra of variety of eight 4-substituted and eight 5-substituted benzoselenadiazoles are presented and their spectral fragmentations are discussed. New mass spectra containing selenium in heterocyclic azole atom containing ring.

Reaction of 5-aminoquinoxaline with alkoxymethylene derivatives affords the corresponding quinoxalinoaminoethylenes. These undergo a thermal cyclization to yield angularly annelated 10H-pyrido[2,3-f]quinoxalines. The structures of all products were deduced from their IR, UV, mass, 1H, and 13C NMR spectra.

N-(2-Benzothiazolyl)- and N-(6-methoxy-2-benzothiazolyl)cyanoacetamides 4, 5 resulted in the reaction of 2-aminobenzothiazole 1 or its 6-methoxy derivative 2 with 1-cyanoacetyl-3,5-dimethylpyrazole 3. Both cyanoacetylamides 4 and 5 have been transformed into the corresponding 2-oxo-2H-pyrimido[2,1-b]-benzothiazole-3-carbonitrile 8 and its 8-methoxy derivative 9 by reaction with triethyl orthoformate, followed by cyclization.

Monoalkylbenzenes, polymethylbenzenes, para-substituted toluenes and monomethylnaphthalenes were oxidized in the vapor phase by oxygen-containing gas in the presence of water over a Sb2O3-promoted V2O5/TiO2 catalyst. This type of catalyst yields carboxylic acids with high selectivity. In the oxidation of substituted alkylbenzenes only alkyl groups were oxidized. No products of oxidative dimerization were detected. Only in the oxidation of methylnaphthalenes, also products of aromatic ring oxidation are formed. A correlation between experimental data and results of quantum-chemical calculations of bond dissociation energies is discussed.

Les reactions de substitution nucleophile entre les 5-amino-1-methylbenzimidazole 1a, 5-amino-1-methyl benzotriazole 1b et 5-amino-2-methyl benzotriazole 1c d'une part et les derives ethoxymethylene substitues des pentane-2,4-dione, 3-oxobutanenitrile, 3-oxobutanoates de methyle et d'ethyle d'autre part ont ete realisees. Les structures des differents produits obtenus ont ete determinees par leurs caracteristiques spectrales (IR, UV, RMN du proton et du 13 C, masse).

Solid phase extraction (SPE) with the porous carbon sorbent CARB GR was used for the preconcentration of metalaxyl residues from a variety of Slovak grape wines with subsequent capillary GC and GC/MS analysis. Recovery was tested at various concentrations of metalaxyl in standard solutions (recovery,R≥92%, relative standard deviation RSD≤4.3%) and in wines. The value of recovery in spiked wines was dependent on the concentration (studied in the range 0.02–1.96 mg/1) and on the variety of wine (R=80–99%; RSD=2–7%). Limits of quantitation (for a sample volume of 50 ml) were determined to be 0.75 μg/1 with GC-FID and 0.50 μg/1 with GC/MS-ITD. Concentration levels of metalaxyl residues were determined in treated wines (with 0.25% Ridomil plus 48 WP) and a strong dependence on the protective term before the harvest was shown.

Solid-phase extraction with a novel porous carbon sorbent CARB GR was used for the clean-up step of dicarboxyimide fungicides residues from variety of Slovak grape wines with subsequent capillary gas chromatography-flame ionization detection, -electron-capture detection (ECD) and -mass spectrometry-ion-trap detection (MS-ITD) analysis. Recovery was tested at various concentration levels of vinclozolin and iprodione in standard solutions (R=80–97%, R.S.D.≤5). The value of recovery in spiked wines is dependent on concentration level (studied in the range of 5.9 μg/1–1.96 mg/l) and on the variety of wine (R=80–86%; R.S.D.=3–5%). Limits of quantitation (for sample volume 50 ml) were determined to be with GC-ECD for both fungicides in ppt range and with GC-MS-ITD in the multiple ion detection mode monitoring in ptt range for vinclozolin and ppb range for iprodione. Concentration levels of vinclozolin residues were determined in treated wines (with 0.1% Ronilan 50 WP) as well as iprodione residues (with 0.15% Rovral 50 WP) and a strong dependence on the protective term before the harvest is shown.