1-pyrrole from Trimethyl(1-pyrrolyl)ammonium Ion

Article abstract of DOI:10.1002/hlca.19830660626

Trimethyl(1-pyrrolyl)ammonium iodide (5a) and the corresponding p-toluenesulfonate 5b are transformed by strong bases into 1-<(dimethylamino)methyl>pyrrole (9), i.e. into a N-Mannich base, a type of compound novel in the pyrrole series.In this reaction, which is very fast in DMSO the cation of compounds 5 is deprotonated to form the nitrogen ylide 6.The latter undergoes a Stevens-type rearrangement to 9.Several facts, namely the negative outcome of a cross-reaction experiment with 3,4-dimethylpyrrole and of an attempt to obtain 9 from pyrrole and dimethyl(methylidene)ammonium iodide in the presence of one equivalent of sodium methoxide, as well as unsuccessful CIDNP studies point to a rearrangement mechanism via the contact ion pair 12.