Synthesis and Reactions of Halo‐, Arylazo‐substituted 3‐(3‐(1‐naphthyl)acryloyl)tropolones. Formation of (Naphthalen‐1‐yl)vinyl)substituted Heterocycle‐fused Troponoid Compounds

The starting substrate 3‐(3‐(1‐naphthyl)acryloyl)tropolone ( 3 ) was achieved by the aldol condensation reaction of 3‐acetyltropolone with 1‐naphthaldehyde. Compound 3 reacted with bromine to afford 7‐bromo‐3‐ (3‐(1‐naphthyl)acryloyl)tropolone ( 4 ), 5,7‐dibromo‐3‐(3‐(1‐naphthyl)acryloyl)tropolone (5) according to the molar ratio of the reactants. Iodination of 3 gave 7‐iodo‐3‐(3‐(1‐naphthyl)acryloyl)tropolone ( 6 ). Azo‐coupling reactions of 3 gave the 5‐arylazo‐3‐(3‐(1‐naphthyl)acryloyl)tropolones ( 7 – 8 ). Compounds 3 , 4 , 6 reacted respectively with hydroxyamine to give the corresponding 3‐[2‐(1‐naphthyl)vinyl]‐8 H ‐cyclohepta[ d ]isoxazol‐8‐ones ( 9 – 11 ). The reactions of 3 , 5 with phenylhydrazine and substituted phenylhydrazines gave 3‐[2‐(1‐naphthyl)vinyl]‐1‐phenylcyclohepta[ c ]pyrazol‐8(1 H )‐ones ( 12 – 18 ).