CONVERSION OF PHENOLICS TO LIGNANS - SINAPIC ACID TO THOMASIDIOIC ACID

Changes in sinapic acid when exposed to aqueous alkaline conditions we re elucidated. Sinapic acid was exposed to a volatile buffer (pH 8.5) for 24 h, lyophilized, acidified, extracted, and characterized using n uclear magnetic resonance and mass spectroscopy. The product obtained was identified as the lignan thomasidioic acid. This identification wa s confirmed by comparison with a synthesized authentic sample of thoma sidioic acid. Conversion of sinapic acid to thomasidioic acid under al kaline conditions previously has not been reported. Thomasidioic acid was present after exposure of sinapic acid to pH 8.5 for as few as 6 h . Thomasidioic acid also was formed at pH 7.