Xanthone and Flavone Derivatives as Dual Agents with Acetylcholinesterase Inhibition and Antioxidant Activity as Potential Anti-Alzheimer Agents

Scheme 1

Reagents and conditions for the synthesized xanthones 1, 2, and 3. (a) Eaton’s reaction: P₂O₅/CH₃SO₃H, 90°C, 30 min; 2,6-dihydroxybenzoic acid/phloroglucinol, 80°C, 1 h; (b) GSS reaction: (i) ZnCl₂, POCl₃, MW (400 W), 60°C, 10 min; (ii) 2,6-dihydroxybenzoic acid, MW (400 W), 60°C, 10 min; (iii) phloroglucinol, MW (400 W), 60°C, 60 min; (c) CH₃I, K₂CO₃, 60°C, 3 h; (d) Mannich reaction: (i) dimethylamine/HCHO/CH₃COOH, room temperature, 1 h; (ii) addition of xanthone 2, room temperature, 6 days. The numbering used concerns the NMR assignments.