Scheme 1. Synthesis of the target 2-(quinoline-4-carbonyl)hydrazide-acrylamide hybrids 5 and 6a–i. Reagents: (i) 4-Br-C₆H₄COCH₃, 33% KOH, C₂H₅OH, reflux 12 h; (ii) C₂H₅OH, Conc. H₂SO₄, reflux 12 h; (iii) NH₂NH₂, C₂H₅OH, reflux 7 h; (iv) respective 2-(4-methoxybenzamido)carboxylate, NaOAc, C₂H₅OH, reflux 18 h.