Cycloaddition reaction relevant to the mechanism of the ninhydrin reaction. X-Ray crystal structure of protonated Ruhemann's purple, a stable 1,3-dipole

Abstract

Trapping experiments with dipolarophiles provide evidence for the formation of 1,3-dipoles as interemediates in the ninhydrin reaction and protonated Ruhemann's purple is shown to be a stable N-protonated 1,3-dipole by trapping experiments and by an X-ray crystal structure determination.