Perchloric Acid–Silica (HClO 4 ⋅SiO 2 )‐Catalyzed Synthesis of 14‐Alkyl‐ or 14‐Aryl‐14 H ‐dibenzo[ a , j ]xanthenes and N ‐[(2‐Hydroxynaphthalen‐1‐yl)methyl]amides

The synthesis of 14‐aryl‐ or 14‐alkyl‐14 H ‐dibenzo[ a , j ]xanthenes 3 involving the treatment of naphthalen‐2‐ol ( 1 ) with arenecarboxaldehydes or alkanals 2 in the presence of HClO 4 ⋅SiO 2 as a heterogeneous catalyst was achieved ( Table 1 ), and this reaction was extended to the preparation of N ‐[(2‐hydroxynaphthalen‐1‐yl)methyl]amides 5 by a three‐component reaction with urea ( 4a ) or an amide 4b – d as a third reactant ( Table 2 ).