On the protonation and deuteration of N,N‐disubstituted 2‐aminothiophenes, 2‐aminothiazoles, and some 3‐amino substituted analogues

Abstract

AbstractIn contrast to their carbocyclic aniline analogues, N,N‐diarylsubtituted 2‐aminothiophenes are not protonated at their N‐atoms but at the 5‐position or, to a smaller extent, at the 3‐position of the thiophene nucleus giving rise to cationic species of the Wheland type. However, 5‐formyl and 5‐acetyl‐substituted 2‐(N,N‐diarylamino)thiophenes are protonated at the corresponding carbonyl moieties. This finding not only enables insight into the mechanism of electrophilic substitution of N,N‐disubstituted 2‐aminothiophenes but also allows to prepare deurated 2‐aminothiophenes by treatment their non‐deuterated parent compounds with CF3COOD.