1‐[(Dimethylamino)methyl]pyrrol aus Trimethyl (1‐pyrrolyl)‐ammonium‐Ion

1‐[(Dimethylamino)methyl]pyrrole from Trimethyl (1‐pyrrolyl)ammonium Ion Trimethyl (1‐pyrrolyl)ammonium iodide ( 5a ) and the corresponding p ‐toluene‐sulfonate 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 .