Synthesis and Anti-Aggregatory of Baicalein Derivatives Functionalized On the B-Ring

A concise and efficient synthesis of baicalein derivatives was introduced. Firstly, substituted cinnamoyl chlorides were synthesized starting from benzaldehyde derivatives. Then 3,4,5-trimethoxyphenol were directly acylated with substituted cinnamoyl chlorides to give corresponding chalcones by Fries rearrangement. Under the action of I₂/DMSO, 5,6,7-trimethoxylbaicalein derivatives were feasible obtained by intramolecular cyclization of chalcones. Finally, the demethylation was performed to give the desired baicalein derivatives functionalized on the B-ring in the ideal yields. The final products possess a wide range of pharmacological activity, notably anti-aggregatory and antioxidation.