title: On the dichotomic behavior of the Z-2,4-dinitrophenylhydrazone of 5-amino-3-benzoyl-1,2,4-oxadiazole with acids in toluene and in dioxane/water: rearrangement versus hydrolysis.
abstract: The mononuclear rearrangement (MRH) of the Z-2,4-dinitrophenylhydrazone (4a) and of the Z-phenylhydrazone (4b) of 5-amino-3-benzoyl-1,2,4-oxadiazole into the relevant triazoles 5a and 5b in toluene has been quantitatively investigated in the presence of trichloroacetic acid (TCA) and of piperidine at 313.1 K. While the behavior in the presence of piperidine recalls the one previously evidenced for some Z-hydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazole, the study of the reactivity in the presence of TCA has most interestingly evidenced a general-acid-catalyzed rearrangement for "both" 4a and 4b. Thus, 4a offers the first example of a solvent-dependent dichotomic behavior in MRH processes on 1,2,4-oxadiazole derivatives as far as it undergoes an "acidic hydrolysis" in dioxane/water and a "rearrangement" in toluene.
authors.affiliation: Dipartimento di Chimica Organica E. Paterno, Università degli Studi di Palermo, Viale delle Scienze, Parco d'Orleans 2, 90128 Palermo, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: D'Anna
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Frenna
authors.forename: Gabriella
authors.initials: G
authors.lastname: Macaluso
authors.forename: Stefano
authors.initials: S
authors.lastname: Morganti
authors.forename: Patrizia
authors.initials: P
authors.lastname: Nitti
authors.forename: Vitalba
authors.initials: V
authors.lastname: Pace
authors.forename: Domenico
authors.initials: D
authors.lastname: Spinelli
authors.forename: Raffaella
authors.initials: R
authors.lastname: Spisani