THE SYNTHESIS AND REACTIONS OF 4-(2-THIENYL)TETRAHYDROISOQUINOLINES AND 4-(3-THIENYL)TETRAHYDROISOQUINOLINES

Tetrahydroisoquinoline derivatives substituted in the 4-position by ei ther a 2- or 3-substituted thiophene ring have been synthesised. Simpl e electrophilic substitution reactions of these systems take place as expected in the alpha-position of the thiophene ring. Metalation react ions are more complex and take place at the benzylic 4-position of the tetrahydroisoquinoline nucleus in the case of the 2-substituted thiop hene derivatives or at either the thiophene alpha-positions or the ben zylic 4-position depending on the nature of the attacking electrophile in the case of the 3-substituted thiophene system.