Synthesis and Biological Evaluation of Novel 𝜸-Alkylidene Butenolides

Scheme 1

Reagents and conditions: (i) 1.2 eq. piperidine, CH₃CN, Na₂CO₃, r.t. 3 h, 85%; (ii) 1.2 eq. aldehyde, Na₂CO₃, CH₃OH, r.t. 3–12 h; (iii) 1.2 eq. methyl benzylamine, CH₃CN, Na₂CO₃, 60°C, 3 h, 90%; (iv) 1.1 eq. benzoyl piperazine, CH₃CN, Na₂CO₃, r.t. 2 h, 95%.