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FRANCESCA D'ANNA

On the use of multi-parameter free energy relationships: the rearrangement of (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole into (2-aryl-5-phenyl-2H-1,2,3-tryazol-4-yl)ureas

  • Autori: D'Anna, F.; Frenna, V.; Lanza, C.; Macaluso, G.; Marullo, S.; Spinelli, D.; Spisani, R.; Petrillo, G.
  • Anno di pubblicazione: 2010
  • Tipologia: Articolo in rivista (Articolo in rivista)
  • Parole Chiave: ring to ring interconversion, structure/reactivity relationships, changeover of mechanism
  • OA Link: http://hdl.handle.net/10447/50367

Abstract

By usingamulti-parameterapproach(acombinationofHammett/Ingold-Yukawa-Tsuno/Fujita-Nishioka free energyrelationships)themononuclearrearrangementsofheterocycles(MRH)ratesfor five new ortho-substitutedandtennewdi-,tri-,ortetra-substituted(Z)-arylhydrazonesof5-amino-3-benzoyl- 1,2,4-oxadiazoleintotherelevant(2-aryl-5-phenyl-2H-1,2,3-triazol-4-yl)ureas(indioxane/waterandin a largerangeofpSþ values)havebeenrelatedtotheelectronicandproximityeffectsexertedbythe present substituents,alsoconsideringpreviousresultsonsomemono meta- and para-substituted(Z)- arylhydrazones.Ineverycase,excellentcorrelationcoefficients havebeencalculated(r2 or R2 0.996). Once morethestudyofMRHhasfurnishedaninterestingpanelofdifferentreactivity(threepathwaysof reaction havebeenevidenced:general-base-catalyzed,uncatalyzed,andspecific-acid-catalyzed)andthis has beenusefulinenlighteninghowpolysubstitutioncandifferentlyaffecttheMRHrates.Moreover2,6- disubstitutiononthe(Z)-arylhydrazonomoietycausesasignificantincreaseofthereactivityinallofthe three studiedpathways.Allofthecollecteddataappearusefulforunderstandingstructure-reactivity/ activity relationshipsinpolysubstitutedcompounds.