Novel tetrahydro-isoquinoline derivatives and a process for the manufacture thereof

摘要

Novel compounds of the formula where R is C1- 4 alkyl or H, R1 and R2 are each C1- 4 alkoxy or together form a methylene group, R3 and R4 are each C1- 4 alkyl or together form a -(CH2)3-, -(CH2)4- or buta-1,3-dien-4-yl group, and A is a carbonyl or -CHOH- group, and acid addition salts thereof, are prepared by reacting the appropriate 6,7- or 1,6,7-substituted tetrahydroisoquinoline or an acid addition salt thereof with formaldehyde and a 3,4-substituted acetophenone, and, if desired, reducing the ketone formed with an alkali-metal aluminium- or boro-hydride, or catalytically using a palladium or platinum catalyst. The condensation preferably is performed in an inert organic solvent (e.g. ethanol) under reflux. Pharmaceutical preparations having analgesic and antitussive action contain the above compounds with a conventional carrier, for oral or parenteral administration.