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dc.contributor.CRUESPUNIVERSIDADE DE ESTADUAL DE CAMPINASpt_BR
dc.typeArtigo de periódicopt_BR
dc.titleDouble Transacetalization Of Diacylium Ions.pt_BR
dc.contributor.authorSparrapan, Rpt_BR
dc.contributor.authorMendes, M Apt_BR
dc.contributor.authorEberlin, M Npt_BR
unicamp.authorR Sparrapan, State University of Campinas-UNICAMP, Institute of Chemistry, CP 6154, 13083-970 Campinas, SP, Brazil.pt_BR
unicamp.author.externalM A Mendes,pt
unicamp.author.externalM N Eberlin,pt
dc.subjectAcetalspt_BR
dc.subjectIsocyanatespt_BR
dc.subjectMass Spectrometrypt_BR
dc.description.abstractA novel gas-phase reaction of diacylium ions of the O=C=X(+)=C=O type (X = N, CH) is reported: double transacetalization with cyclic acetals or ketals. The reaction is exothermic and highly efficient, and forms members of a new class of highly charged-delocalized ions: cyclic ionic diketals. Pentaquadrupole double- and triple-stage mass spectrometric (MS(2) and MS(3)) experiments reveal the high double transacetalization reactivity of O=C=N(+)=C=O and O=C=CH(+)=C=O, whereas the synthesis of differently substituted cyclic ionic diketals is performed in MS(3) experiments via sequential mono- and double transacetalization of O=C=N(+)=C=O and O=C=CH(+)=C=O with different acetals. With cyclic acetals, the acylium-thioacylium ion O=C=N(+)=C=S reacts promptly and selectively by mono-transacetalization at its acylium site, but the free thiacylium site of its cyclic ionic ketal is nearly unreactive by double transacetalization. Therefore, only the acylium site of O=C=N(+)=C=S can be efficiently protected by transacetalization. Low-energy MS(3) collision-induced dissociation of the cyclic ionic diketals of O=C=N(+)=C=O and O=C=CH(+)=C=O sequentially frees each of the protected acylium site to form the mono-derivatized ion, and then the fully deprotected diacylium ion.en
dc.relation.ispartofJournal Of Mass Spectrometry : Jmspt_BR
dc.relation.ispartofabbreviationJ Mass Spectrompt_BR
dc.date.issued2000-Febpt_BR
dc.identifier.citationJournal Of Mass Spectrometry : Jms. v. 35, n. 2, p. 189-98, 2000-Feb.pt_BR
dc.language.isoengpt_BR
dc.description.volume35pt_BR
dc.description.firstpage189-98pt_BR
dc.rightsfechadopt_BR
dc.rights.holderCopyright 2000 John Wiley & Sons, Ltd.pt_BR
dc.sourcePubMedpt_BR
dc.identifier.issn1076-5174pt_BR
dc.identifier.doi10.1002/(SICI)1096-9888(200002)35:2<189::AID-JMS929>3.0.CO;2-Ipt_BR
dc.identifier.urlhttp://www.ncbi.nlm.nih.gov/pubmed/10679981pt_BR
dc.date.available2015-11-27T12:22:41Z-
dc.date.accessioned2015-11-27T12:22:41Z-
dc.description.provenanceMade available in DSpace on 2015-11-27T12:22:41Z (GMT). No. of bitstreams: 1 pmed_10679981.pdf: 172039 bytes, checksum: 3022c81a9d4957b8c415ad79ce0841fb (MD5) Previous issue date: 2000en
dc.identifier.urihttp://repositorio.unicamp.br/jspui/handle/REPOSIP/194589-
dc.identifier.idPubmed10679981pt_BR
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