By cyclization of 2-amino-3,4-dihydro-1(2H)-isoquinolinone (I) with m-ethoxybenzimidic acid ethyl ester (II) at 125 C.
The cyclization of 2-amino-3,4-dihydro-1(2H)-isoquinolinone (I) with ethyl 4-chlorobenzimidate (II) by heating at 125 C under vacuum gives 2-(4-chloro-phenyl)-5,6-dihydro-s-triazolo[5,1-a]isoquinoline (III), which is dehydrogenated by means of N-bromoacetamide in refluxing CCl4.
The condensation of 2-amino-1(2H)-isoquinolinone (IV) with imidate (II) by heating at 125 C as before gives 2-(4-cholorobenzimidoylamino)-1(2H)-isoquinolinone (V), which is cyclized by means of NaH in ethoxyethanol.
By cyclization of isoquinolinone (IV) with 4-chlorobenzonitrile (VI) by means of sodium ethoxide in refluxing ethanol.