Výsledky vyhledávání - "Iva B. Blagoeva"

Acid catalyzed intramolecular attack of β-phenylthioureido group on amide function. Parallel formation of thiodihydrouracil and 4-iminothiodihydrouracil. Different pathways in the Edman degradation reaction in the formation of six- versus five-membered cy

Autor: Ivan G. Pojarlieff, Violina T. Angelova, Nikolay G. Vassilev, Ergun Atay, Maria M. Toteva, Iva B. Blagoeva, Asen H. Koedjikov

Publikováno v: Journal of Physical Organic Chemistry. 21:14-22

Contrary to the cleavage of a-phenylthioureido peptides 1 proceeding through intermediate 2-anilinothiazolinone 2, the b-analog cis-2-(3-phenylthioureido)cyclopentane-carboxamide 5 forms transiently 4-imino-2-thioxopyrimidine 6. Monitoring amide cycl

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::07dfe53f8f2ce5dc14a0ca558ce620f2
https://doi.org/10.1002/poc.1269

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Interfacial ion exchange between monovalent and divalent anions in cationic micelles, revised in the light of correlation analysis

Autor: Nadia Ouarti, Omar A. El Seoud, Iva B. Blagoeva, Marie-Françoise Ruasse

Publikováno v: Journal of Physical Organic Chemistry. 18:850-855

The pH changes of an aqueous carbonate buffer solution (9 × 10 - 3 M Na 2 CO 3 , 10 - 3 M NaHCO 3 , pH o 10.79), induced by addition of cetyltrimethylammonium chloride (CTA + Cl - ) in concentrations varying from 10 - 3 to 10 M, are employed to dete

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::c06632a2868a411b7ad43e36c995b210
https://doi.org/10.1002/poc.953

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A largegem-dimethyl effect in the cyclization ofω-phenylhydantoic acids: computational modeling of thegem-dimethyl effect on the acid- or base-catalyzed cyclization of hydantoic acids and esters

Autor: Asen H. Koedjikov, Carlos Jaime, Iva B. Blagoeva, V. T. Angelova, Ivan G. Pojarlieff, Petko M. Ivanov

Publikováno v: Journal of Physical Organic Chemistry. 17:423-430

The rates of the cyclization of methyl-substituted 5-phenylhydantoic acids were measured in acid solutions. A particularly strong gem-dimethyl effect (GDME) was observed with the N-methyl compounds amounting to an acceleration of six powers of ten fo

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::49c079c1f0155f9a0cd855c86995350e
https://doi.org/10.1002/poc.748

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σI Values for Arylureido Groups

Autor: Asen H. Koedjikov, Stefan P. Stanchev, Iva B. Blagoeva, Ivan G. Pojarlieff

Publikováno v: Collection of Czechoslovak Chemical Communications. 69:2276-2280

Three (1-arylureido)acetic acids were prepared by means of controlled alkaline hydrolysis of the respective 1-arylimidazolidin-2,4-diones. Their pKa values and that of (3-phenylureido)- acetic acid were determined potentiometrically by titration in 0

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::6665c61111104afb73b3849ab9410eb8
https://doi.org/10.1135/cccc20042276

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Nucleophilic Reactivity of the CTACl-Micelle-Bound Fluoride Ion: The Influence of Water Concentration and Ionic Strength at the Micellar Interface

Autor: Priscilla Leandro Silva, Marie-Françoise Ruasse, Erika B. Tada, Iva B. Blagoeva, Nadia Ouarti, Omar A. El Seoud

Publikováno v: Langmuir. 19:10666-10672

The nucleophilic reactivity of the fluoride ion, F-, toward PNDPP, p-nitrophenyldiphenyl phosphate, was investigated in buffered aqueous solutions of CTACl, cetyltrimethylammonium chloride, at pH 9.8 and 7.9. The pH- and buffer-independent micellar r

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::4e7bd81a3a12d8d8065e3f6985a239d4
https://doi.org/10.1021/la030186q

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Optimization of micellar catalysis of nucleophilic substitution reactions in buffered solutions of cetyltrimethylammonium halide surfactants, part 2: buffers in the pH range 7-8

Autor: Marie-Françoise Ruasse, Omar A. El Seoud, Nadia Ouarti, Iva B. Blagoeva

Publikováno v: Journal of Physical Organic Chemistry. 14:823-831

Binding of the phosphate, tris-(hydroxymethyl)-methylamine, aminomethylpropanediol, and glycinemethylester buffers by cetyltrimethylammonium chloride (CTACl) in aqueous solutions has been probed by investigating: (1) the dependence of the buffer pH (

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::26594cf5bf943494be8951ab6e673135
https://doi.org/10.1002/poc.441

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Assisted hydrolysis of cis-2-(3-phenylthioureido)cyclo pentane-carbonitrile in alkaline solution. Solvent dependent switch from hydrolysis to rearrangement of the iminothiooxopyrimidine intermediate

Autor: Ergun Atay, Iva B Blagoeva, Francis L Chubb, John T Edward, Ivan G Pojarlieff, Maria M Toteva

Publikováno v: Canadian Journal of Chemistry. 78:84-94

The cis and trans isomers of 2-(3-phenylthioureido)cyclopentanecarbonitrile, 1, and the respective carboxamides, 3, and acids, 4, have been prepared. Acid cyclization of both nitriles, faster with the cis isomer, gave the more stable cis-2-thiooxo-cy

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::e0ede91c9c2d599991408661aac7a714
https://doi.org/10.1139/v99-216

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A normal gem-dimethyl effect in the base-catalyzed cyclization of ω-( p-nitrophenyl)hydantoic acids: evidence for hindered proton transfer in the permethylated esters †

Autor: Asen H. Koedjikov, Iva B. Blagoeva, Ivaylo I. Kochiyashki, Ivan G. Pojarlieff, Anthony J. Kirby, Maria M. Toteva

Publikováno v: Journal of the Chemical Society, Perkin Transactions 2. :1953-1960

The cyclization of hydantoic acids 2-UA and 3-UA – kinetics, solvent kinetic isotope effects (SKIE) and buffer catalysis – were studied in an attempt to explain the disappearance of the gem-dimethyl effect (GDME) in the specific base-catalyzed cy

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::7803b24837c51261225b2a36b9808632
https://doi.org/10.1039/b002276o

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Multiple changes in rate-determining step in the acid and base catalyzed cyclizations of ethyl N-(p-nitrophenyl)hydantoates caused by methyl substitution

Autor: Anthony J. Kirby, Ivan G. Pojarlieff, Asen H. Koedjikov, Iva B. Blagoeva

Publikováno v: Canadian Journal of Chemistry. 77:849-859

The slopes of the pH-rate profiles for the cyclization of 2-methyl- and 2,3-dimethyl hydantoates 1-NPU and 2-NPU between pH 1 and 7 change from 1 to 0 and then back to 1. A reaction first order in H+ was observed with the latter compound. The 2,2,3-t

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::bd3fa1469c7dade8d4f64600715d85f8
https://doi.org/10.1139/v99-079

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Bromine−AOT Charge-Transfer Complexes and Hydrogen-Bond Donor Ability of Water in AOT−isooctane−H2O Reverse Micelles and Water-in-Oil Microemulsions

Autor: Juan C. Mejuto, Renata Ciri, Marie-Françoise Ruasse, and J. Ramón Leis, † Luis Garcia-Rio, Iva B. Blagoeva

Publikováno v: The Journal of Physical Chemistry B. 103:4997-5004

Changes, induced by aerosol-OT (sodium bis(2-ethylhexyl) sulfosuccinate, AOT), in the absorption spectrum of bromine, are shown to markedly depend on the nature and the hydration of the AOT-aggregates. A charge-transfer complex (CTC) between bromine

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::6c1cfceb5db31ddc5380e93cf39d3448
https://doi.org/10.1021/jp982789u

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