Acid catalyzed α‐alkylation of β‐aminothiophenes with aldehydes. synthesis of 2‐alkyl 3‐thiophenamines, bis(3‐amino‐2‐thienyl)‐methane derivatives and dithieno[3,2‐b:2′,3′‐e]pyridines

The acid catalyzed reaction of 3‐thiophenamines with aldehydes in the presence of selenophenol as the reducing agent, gives 2‐alkyl‐3‐miophenamines. Without reduction, bis(3‐amino‐2‐thienyl)methane derivatives have been obtained and transformed into dithieno[3,2‐ b :2′,3′‐ e ]pyridines by thermal and acidic treatment when the substrates are primary amines. These new tricyclic heterocycles can be synthesized in a one‐pot procedure from 3‐thiophenamine.