Ring Size Influence on the Cyclocondensation Mode of GABA–Nitrile Imine Adducts

Abstract

γ-Aminobutyric acid (GABA) adds onto nitrile imine 1, 3-dipolar species (generated in situ from their N-arylhydrazonoyl chloride precursors 1a-c) to deliver the corresponding acyclic amidrazone adducts 10a-c. In the presence of 1, 1’-carbonyldiimidazole, the latter adducts undergo cyclocondensation involving the activated carboxyl and the amidrazone-CH 2 NH groups to afford the respective N-[1-(arylhydrazono)-2-oxopropan-1-yl] pyrrolidin-2-ones (11a-c). The constitution of 10 and 11 is evidenced from analytical and spectral (IR, MS and NMR) data.