title: Acid- and base-catalysis in the mononuclear rearrangement of some (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole in toluene: effect of substituents on the course of reaction.
abstract: The reaction rates for the rearrangement of eleven (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole 3a-k into the relevant (2-aryl-5-phenyl-2H-1,2,3-triazol-4-yl)ureas 4a-k in the presence of trichloroacetic acid or of piperidine have been determined in toluene at 313.1 K. The results have been related to the effect of the aryl substituent by using Hammett and/or Ingold-Yukawa-Tsuno correlations and have been compared with those previously collected in a protic polar solvent (dioxane/water) as well as with those on the analogous rearrangement of the corresponding (Z)-arylhydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazole 1a-k in benzene. Some light can thus be shed on the general differences of chemical reactivity between protic polar (or dipolar aprotic) and apolar solvents.
authors.affiliation: Dipartimento STEMBIO, Università degli Studi di Palermo, Viale delle Scienze-Parco d'Orleans II, 90128 Palermo, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: D'Anna
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Frenna
authors.forename: Franco
authors.initials: F
authors.lastname: Ghelfi
authors.forename: Salvatore
authors.initials: S
authors.lastname: Marullo
authors.forename: Domenico
authors.initials: D
authors.lastname: Spinelli
mesh_terms: D000468:Alkalies / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D001688:Biological Products / Q000737:chemistry; D002384:Catalysis; D004146:Dioxanes / Q000737:chemistry; D006835:Hydrazones / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D015394:Molecular Structure; D010069:Oxadiazoles / Q000737:chemistry*; D010880:Piperidines / Q000737:chemistry; D013329:Structure-Activity Relationship; D013696:Temperature; D014050:Toluene / Q000737:chemistry; D014238:Trichloroacetic Acid / Q000737:chemistry; D014508:Urea / Q000737:chemistry; D014867:Water
chemical_list: C463599:3-benzoyl-5-phenyl-1,2,4-oxadiazole; D000468:Alkalies; D000588:Amines; D001688:Biological Products; D004146:Dioxanes; D006835:Hydrazones; D010069:Oxadiazoles; D010880:Piperidines; D014867:Water; D014050:Toluene; D014238:Trichloroacetic Acid; C032727:piperidine; D014508:Urea