Convenient Novel Method to Access N-Benzylated Isatoic Anhydride: Reaction Behavior of Isatoic Anhydride with 4-Chlorobenzyl Chloride in the Presence of Bases.

Sodium hydride, potassium carbonate, and other bases are commonly used for N-alkylation of heterocyclic compounds. This report reveals the problems associated with N-benzylation of isatoic anhydride and identifies the plausible byproduct structures formed during the reaction. Subsequently, a novel breakthrough methodology has been developed using diisopropylamine and tetra butyl ammonium bromide. It gives excellent yields >88% in a short reaction time (2 h) at 30 °C with no byproducts, saving on processes as the pure product is directly obtained.