ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUse of polymeric catalysts in the pore-size-specific functionalization of porous polymersVladimir Smigol, Frantisek Svec, and Jean M. J. FrechetCite this: Macromolecules 1993, 26, 21, 5615–5620Publication Date (Print):October 1, 1993Publication History Published online1 May 2002Published inissue 1 October 1993https://pubs.acs.org/doi/10.1021/ma00073a013https://doi.org/10.1021/ma00073a013research-articleACS PublicationsRequest reuse permissionsArticle Views353Altmetric-Citations46LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
The kinetics of the amine catalyzed intramolecular imidization of alkyl and phenyl phthalamates with a variety of amines were measured in deuteriated chloroform at 40.1 °C. An overall second-order kinetic rate law, rate =koverall[amine][phthalamate], was obtained from our experiments. Although pre-association between the amides and the amines through hydrogen-bonding interaction was suggested by proton NMR spectroscopy, the catalytic ability of amines was found to be related to their basicity rather than to their hydrogen-bonding ability or nucleophilicity. This observation implies the involvement of proton transfer from the amide to the amine in the critical transition state. In addition, by changing the leaving group from phenoxy to butoxy group, the reaction rate constants decrease by a factor of 30 to 70. On the basis of these kinetic results, we propose that the intramolecular imidization proceeds through an amine assisted cyclization to a zwitterionic intermediate, followed by the expulsion of the alkoxy or phenoxy group to provide phthalimide and the corresponding alcohol.
Two types of insoluble polystyrene resins bearing vinylbenzaldehyde units have been prepared and used with high efficiency as temporary protecting groups in the synthesis of 2,3 disubstituted derivatives of methyl α-D-glucopyranoside.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhoto-crosslinking of a polyurethane with pendant methacryloyl-Terminated 4-Alkoxy-4'-sulfamoylstilbene NLO ChromophoresJody E Beecher, Tony Durst, Jean M. J. Frechet, Adelheid Godt, and Craig S. WillandCite this: Macromolecules 1994, 27, 13, 3472–3477Publication Date (Print):June 1, 1994Publication History Published online1 May 2002Published inissue 1 June 1994https://pubs.acs.org/doi/10.1021/ma00091a005https://doi.org/10.1021/ma00091a005research-articleACS PublicationsRequest reuse permissionsArticle Views243Altmetric-Citations16LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Read moreADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnantioselective addition of diethylzinc to aldehydes catalyzed by polymer-supported chiral amino alcohols. Evidence for a two zinc species mechanismShinichi Itsuno and Jean M. J. FrechetCite this: J. Org. Chem. 1987, 52, 18, 4140–4142Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https://pubs.acs.org/doi/10.1021/jo00227a043https://doi.org/10.1021/jo00227a043research-articleACS PublicationsRequest reuse permissionsArticle Views656Altmetric-Citations131LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Read moreAbstract The crosslinking chemistry of a new elastomer based on brominated poly(isobutylene‐co‐4‐methylstyrene) has been investigated using model compounds. In order to mimic the conditions that prevail within the highly allphatic rubber, the study was carried out in mineral oil using catalysts that are compatible with such low polarity media. Electrophilic aromatic substitution reactions occur in a system consisting of p ‐isopropylbenzyl bromide and p ‐isopropyl toluene in the presence of zinc oxide and zinc stearate. The reaction proceeds after a significant induction period while no induction period is seen for a similar reaction with zinc bromide as the catalyst. The in situ formation of reactive species containing ZnBr bonds appears to be an important step in the overall process. The stoichiometric ratio of zinc salt to benzylic bromide is important. High ratios lead to the accumulation of benzylic stearate or benzylic alcohol in the system which retards the alkylation reaction. The model study emphasizes the importance of stoichiometry of reagents in this reaction and provides insight into the crosslinking mechanism. © 1993 John Wiley & Sons, Inc.
Read moreADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical synthesis and structure proof of a stereoregular linear mannan, poly[.alpha.-(1->6')-anhydro-D-mannopyranose]Jean Frechet and Conrad SchuerchCite this: J. Am. Chem. Soc. 1969, 91, 5, 1161–1164Publication Date (Print):February 1, 1969Publication History Published online1 May 2002Published inissue 1 February 1969https://pubs.acs.org/doi/10.1021/ja01033a021https://doi.org/10.1021/ja01033a021research-articleACS PublicationsRequest reuse permissionsArticle Views199Altmetric-Citations59LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Read moreADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUse of polymers as protecting groups in organic synthesis. Application of polystyrylboronic acid to the one-pot synthesis of acylated carbohydrate derivativesJean M. J. Frechet, Lucy J. Nuyens, and Elizabeth SeymourCite this: J. Am. Chem. Soc. 1979, 101, 2, 432–436Publication Date (Print):January 1, 1979Publication History Published online1 May 2002Published inissue 1 January 1979https://doi.org/10.1021/ja00496a027Request reuse permissionsArticle Views468Altmetric-Citations49LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (741 KB) Get e-Alertsclose Get e-Alerts
Read moreThe synthesis of dendritic polyether macromolecules based on a 3, 5-dihydroxybenzyl alcohol building block and having carboxylate groups as chain-ends is described. These novel macromolecules behave as unimolecular micelles and their ability to solvate hydrophobic molecules has been investigated by UV–VIS spectroscopy. A dramatic increase in the saturation concentration of various polycyclic aromatic compounds in water was observed which was of a magnitude similar to that observed for micelles derived from sodium dodecyl sulfate. A relationship between the solubilizing power of the dendrimer and the electron density of the polycyclic aromatic was found. A linear relationship between the solubilizing ability and the concentration of the dendrimer, even at concentrations as low as 5 × 10–7 mol dm–3, indicates that these materials do not have a critical micelle concentration. Increases in the ionic strength of an aqueous solution of the dendrimer caused an increase in the saturation concentration of the hydrophobic molecules. A recyclable solubilization and extraction system is discussed. The synthesis of a globular dendritic macromolecular amphiphile designed to reside at the interface of an organic solvent and water is also described. This 'hybrid' dendritic amphiphile consisting of two distinct sectors, one hydrophilic and the other hydrophobic is prepared by stepwise alkylation of a core molecule, 4,4′-dihydroxybiphenyl with the two dissimilar dendritic fragments.
Read moreADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of hyperbranched polyurethanes prepared from blocked isocyanate monomers by step-growth polymerizationRalph Spindler and Jean M. J. FrechetCite this: Macromolecules 1993, 26, 18, 4809–4813Publication Date (Print):August 1, 1993Publication History Published online1 May 2002Published inissue 1 August 1993https://pubs.acs.org/doi/10.1021/ma00070a013https://doi.org/10.1021/ma00070a013research-articleACS PublicationsRequest reuse permissionsArticle Views2293Altmetric-Citations162LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Read moreAbstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Read moreADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConcurrent stabilization and imaging of a novel polymer for second harmonic generation via in situ photopolymerizationJody E. Beecher, Jean M. J. Frechet, Craig S. Willand, Douglas R. Robello, and David J. WilliamsCite this: J. Am. Chem. Soc. 1993, 115, 25, 12216–12217Publication Date (Print):December 1, 1993Publication History Published online1 May 2002Published inissue 1 December 1993https://pubs.acs.org/doi/10.1021/ja00078a091https://doi.org/10.1021/ja00078a091research-articleACS PublicationsRequest reuse permissionsArticle Views98Altmetric-Citations12LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
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