New structural analogs of papaverine: 3 benzyl 6,7 dimethoxy (di and tetrahydro) isoquinolines
Syntheses of 3 benzyl 3,4 dihydroisoquinolines by cyclisation of a N acyl α benzylhomoveratrylamine by means of polyphosphoric acid ester, in boiling toluene, gave yields between 60 and 90%. While the hydrogenation of these dihydroisoquinolines to tetrahydroisoquinolines with an alkaline borohydride gave satisfactory result, their dehydrogenation into isoquinolines could not be accomplished. Pharmacological properties of the hydrobromides or hydrochlorides of the bases of the two series of the aforementioned 3 benzylisoquinolines and comparison of their activities with those of papaverine and the analogues 1 and 4 benzylisoquinolines are reported.
