Syntheses and reactions of halo‐ and arylazo‐substituted 3‐(3‐(2‐naphthyl)acryloyl)tropolones: Formation of (naphthalen‐ 2‐yl)vinyl)‐substituted heterocycle‐fused troponoid compounds

The starting substrate 3‐(3‐(2‐naphthyl)acryloyl)tropolone ( 1 ) was achieved by the aldol condensation reaction of 3‐acetyltropolone with 2‐naphthaldehyde. Compound ( 1 ) reacted with bromine to give 7‐bromo‐( 2 ) and 5,7‐dibromo‐3‐(3‐(2‐naphthyl)acryloyl)tropolone ( 3 ) according to the amount of the brominated reagent. Iodination of 1 gave 7‐iodo‐3‐(3‐(2‐naphthyl)acryloyl)tropolone ( 4 ). Azo‐coupling reactions of 1 , 2 , and 4 gave 5‐arylazo‐3‐(3‐(2‐naphthyl)acryloyl) tropolones ( 5 , 6 , 7 , 8 ). Compounds 1 , 2 , 3 , 4 reacted with hydroxyamine to give 3‐[2‐(2‐naphthyl)vinyl]‐8 H ‐cyclohepta[ d ]isoxazol‐8‐ones ( 9 , 10 , 11 , 12 ). The reactions of 1 , 2 , 3 , 4 with phenylhydrazine and substituted phenylhydrazines gave 3‐[2‐(2‐naphthyl)vinyl]‐1‐phenylcyclohepta[ c ]pyrazol‐8(1 H )‐ones ( 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ). J. Heterocyclic Chem., (2009).