The synthesis and reactions of 4-(2- and 3-thienyl)-tetrahydroisoquinolines

Article abstract of DOI:10.1002/jhet.5570330420

Tetrahydroisoquinoline derivatives substituted in the 4-position by either a 2- or 3-substituted thiophene ring have been synthesised. Simple electrophilic substitution reactions of these systems take place as expected in the α-position of the thiophene ring. Metalation reactions are more complex and take place at the benzylic 4-position of the tetrahydroisoquinoline nucleus in the case of the 2-substituted thiophene derivatives or at either the thiophene α-positions or the benzylic 4-position depending on the nature of the attacking electrophile in the case of the 3-substituted thiophene system.