Condensed isoquinolines. 36*. Cyclization of N-alkyl-3-(2-benzoylbenzyl)azolium salts. A novel method of preparing azolo[<Emphasis Type="Italic">b</Emphasis>]isoquinolines

A novel method is proposed for the preparation of azolob]isoquinolines based on the alkylation of N-alkyl-1,3-diazoles or 1,3-thiazole derivatives using 2-(bromomethyl)phenyl](phenyl)methanone with subsequent cyclization of the quaternary azolium salts in the presence of base. The 10(11)-hydroxy derivatives of the 5,10-dihydro-1H-imidazo1,2-b]isoquinolinium, 6,11-dihydro-5H-benzimidazo-1,2-b]isoquinolinium, 5,10-dihydro-1H-1, 2, 4]triazolo4,3-b]isoquinolinium, or 5,10-dihydro1, 3]-thiazolo3,2-b]isoquinolinium bromides obtained in this way readily lose a molecule of water upon heating with HBr or Ac₂O to give the corresponding quasi-aromatic azolob]isoquinolinium salts.