Can the absence of solvation of neutral reagents by ionic liquids be responsible for the high reactivity in base-assisted intramolecular nucleophilic substitutions in these solvents?
[reaction: see text] The kinetics of the rearrangement of the Z-phenylhydrazone of 3-benzoyl-5-phenyl-1,2,4-oxadiazole (1a) into the relevant 4-benzoylamino-2,5-diphenyl-1,2,3-triazole (2a) induced by amines have been studied in two room-temperature ionic liquids (IL-1, [BMIM][BF4] and IL-2, [BMIM][PF6]). The data collected show that the reaction occurs faster in ionic liquids than in other conventional solvents previously studied (both polar or apolar, protic or aprotic). Presumably, this could depend on their peculiar ability to minimize the strong substrate-solvent, amine-solvent and amine-amine interactions occurring in conventional solvents.
D'Anna
Francesca
F
Dipartimento di Chimica Organica E. Paterno, Università degli Studi di Palermo, Viale delle Scienze, Parco d'Orleans 2, 90128 Palermo, Italy. fdanna@unipa.it
Frenna
Vincenzo
V
Noto
Renato
R
Pace
Vitalba
V
Spinelli
Domenico
D