New synthesis of 5,6,7,8-tetrahydro-4H-thieno[2,3-d]azepine

This paper describes two new access routes to 5,6,7,8-tetrahydro-4H-thieno2,3-d]azepine from 2-(2-thienyl)ethylamine or its N-(2-chlorobenzyl) derivative. One of these two syntheses involves a new ring expansion from a 6,7-dihydro3,2-c]pyridinium derivative, chloromethylated in position 4.