Enzyme-solvent-monomer molecular interactions and their effect on horseradish peroxidase-catalyzed polymerization of m-cresol in ethanol/water mixtures were studied. A mechanistic approach of the effect of reaction medium composition on the poly (m-cresol) molecular weight and polydispersity was elucidated from the standpoint molecular interactions. Solvent effects on the enzyme activity and structure were studied by reaction kinetics and spectroscopic methods including UV-vis, fluorescence, circular dichroism and electron paramagnetic spectroscopy (EPR). In view of the results from these studies, the observed polymer molecular weight profile could be deduced from the solubility of the polymer as well as the partitioning of the monomer between solvent and the enzyme active site.

AbstractDie Nitrierung der Naphthochinone (I) mit Nitronium‐tetrafluoroborat gibt die 5‐Nitroderivate (IIa) bzw. (IIb); analog wird aus Phthalsäureanhydrid die Nitrover‐bindung (III) erhalten.

The nitration of 1,4-naphthoquinone derivatives and phthalic anhydride by nitronium tetrafluoroborate in tetramethylene sulphone is reported. The reaction of 2,3-dicyano-1,4-dimethoxynaphthalene with nitronium hexafluorophosphate in acetonitrile gave 2,3-dicyano-1,4-naphthoquinone and N-methylacetamide. On the basis of the above observation the mechanism of oxidative demethylation of methyl naphthyl ethers by nitronium salts is discussed.

Chemischer InformationsdienstVolume 3, Issue 5 Isocyclic Compounds ChemInform Abstract: LADUNGSUEBERTRAGUNGSKOMPLEXE VON 1,4-NAPHTHOCHINONAKZEPTOREN SUPRABHAT CHATTERJEE, SUPRABHAT CHATTERJEESearch for more papers by this author SUPRABHAT CHATTERJEE, SUPRABHAT CHATTERJEESearch for more papers by this author First published: February 1, 1972 https://doi.org/10.1002/chin.197205094Read 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. Volume3, Issue5February 1, 1972 RelatedInformation

The naphthoquinone acceptors form stable charge-transfer complexes in solutions of aprotic solvents with aromatic hydrocarbons as donors. From the charge-transfer transition energies of the complexes as well as from the polarographic half-wave reduction potentials of the acceptors relative electron affinities of the acceptors are determined. In addition, the association constant, molar extinction coefficients, oscillator strengths, and enthalpies of formation of the complexes were obtained from charge-transfer spectral studies with hexamethylbenzene as donor. The average electron affinities of 2,3-dichloro-(0·90 eV), 2,3-dichloro-5-nitro-(1·18 eV), 2,3,5,6-tetrachloro-7-nitro-(1·30 eV), 2,3-dicyano-(1·53 eV), 2,3-dicyano-5-nitro-(1·68 eV), and 2,3-dicyano-5,6-dichloro-7-nitro-1,4-naphthoquinone (1·75 eV) obtained from the charge-transfer spectral studies clearly show the cumulative effects of electron-withdrawing substituents on the naphthoquinone π-system. The π-acid character of 1,4-naphtho-quinone aceptors are also correlated with the calculated molecular orbital energies and with the experimental polarographic half-wave reduction potential.

11,11,12,12-Tetracyano-1,4-naphthaquinodimethane and related derivatives are synthesised from cis-2,3,5,8,9,10-hexahydro-1,4-naphthaquinone. As a strong electron acceptor the former forms charge-transfer complexes with aromatic hydrocarbons. Its electron affinity (1·49 eV) was obtained from charge-transfer spectra and polarography. Pertinent parameters derived by simple HMO methods are also evaluated.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdditions and Corrections-2,4-Diaminopyrimidines from Dicyandiamide. III. Reaction with Monocyclic KetonesEdward Modest, Suprabhat Chatterjee, and Heljo ProtopapaCite this: J. Org. Chem. 1965, 30, 12, 4396Publication Date (Print):December 1, 1965Publication History Published online30 July 2002Published inissue 1 December 1965https://pubs.acs.org/doi/10.1021/jo01023a626https://doi.org/10.1021/jo01023a626research-articleACS PublicationsRequest reuse permissionsArticle Views24Altmetric-Citations-LEARN 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

AS part of a continuing programme of synthesis of condensed pyrimidine ring systems as potential antimetabolites and antitumour agents, the preparation of the hitherto unreported 1,5-pyrimido[4,5-b]-diazepine ring system (I) was undertaken in these laboratories1. This ring system is analogous to the 1,5-benzodiazepines extensively examined by a number of investigators2–8. The preparation of the pyrimidodiazepines (I) was attempted by condensation of 4,5-diaminopyrimidine derivatives with β-diketones, as in the synthesis of the corresponding 1,5-benzodiazepines