The condensation of 2-amino-4,5-dimethoxybenzonitrile (I) with 2-acetyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (II) by means of POCl3 and dimethylacetamide in refluxing CHCl3 gives 2-[1-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin-2-yl)ethylideneamino]-4,5-dimethoxybenzonitrile (III), which is then cyclized with lithium diisopropylamide in THF at -70 C or with ZnCl2 in refluxing dimethylacetamide.