Acid-catalysed proton exchange on pyrrole and alkylpyrroles

Abstract

The rates of deuteriodeprotonation at the α- and β-positions of pyrrole have been determined as a function of acidity, concentration of deuterioacetic acid, and temperature in D₂O–dioxan solution. The reaction is subject to general acid catalysis. The rates of exchange on several alkylpyrroles were measured and relative positional reactivities found to agree with the predictions of Klopman's ‘Polyelectron Perturbation’ theory using orbital energies and wavefunctions obtained by the INDO MO method.