Reactions with alpha-substituted cinnamonitriles: synthesis of benzo [h] quinolines and naphthol [1,2, b] pyrans

Alpha-substituted cinnamonitrile derivatives [1a-i] reacted with alpha-tetralone [2] in the presence of ammonium acetate to yield 5, 6-dihydrobenzo [h] quinoline derivatives with different substituents at 2,3, and 4 positions [3,7-9]. Substituting sodium acetate for ammonium acetate led to the formation of the 5, 6-dihydro-2-imino-4-phenylnaphtho [1, 2-b] pyran-3-carbonitrile [5]