Convenient approach to ω-aminoalkylthiophenes

[Display omitted] •Five- through seven-membered cyclic enaminoesters.•A facile method for the synthesis of ω-aminoalkylthiophenes.•Intramolecular cyclization of ω-aminoalkylthiophenes.•Thieno[2,3-c]azepine and thieno[2,3-c]azocine derivatives. Starting from readily accessible cyclic enaminoesters, arylisothiocyanates and α-haloketones, a facile method for the synthesis of ω-aminoalkylthiophene hydrobromides was developed. It was shown that in the first step cyclic enaminoesters react with arylisothiocyanates exclusively at the enamine position. Upon treatment with base, free 5-aminopentylthiophenes were prepared. In the case of shorter alkyl substituents (4-aminobutyl and 3-aminopropyl) the free ω-aminoalkylthiophenes undergo intramolecular condensation of the amino and ketone groups affording novel fused heterocycles—thieno[2,3-c]azepine and thieno[2,3-c]azocine.