Domino reactions of 1-substituted N -(cyanomethyl)isoquinolinium salts with salicylic aldehydes

Transformations of N-cyanomethyl-substituted 1-methyl- and 1-phenylisoquinolinium salts were studied in the presence of various o-hydroxybenzaldehydes, leading to the formation of substituted chromeno[2',3':4,5]imidazo[2,1-a]isoquinolines. 1,8-Diazabicyclo- [5.4.0]undec-7-ene was shown to be a superior base in this reaction compared to sodium carbonate.