Regioselective synthesis of phenanthrenes and evaluation of their anti-oxidant based anti-inflammatory potential

• Bioactive compounds: (1) (2) and (3) were synthesized.
• Till date syntheses of 1 and 2 have not been cited in the literature.
• All the compounds (1–4) showed good antioxidant activity.
• In vitro assay proved that the compounds (1–4) have anti-inflammatory effect.

Regioselective synthesis of 9,10-Dihydro-2,5-Dimethoxyphenanthrene-1,7-diol (1) and 9,10-Dihydro-2,7-Dimethoxyphenanthrene-1,5-diol (2) was achieved using regioselective methylation, Wittig reaction, intramolecular cyclization and hydrogenation as key steps. The synthesis was successfully completed in total of 15 steps with 3.3% overall yield in case of 1 and in total of 13 steps with 9.0% overall yield in case of 2. All compounds (1–4) showed good antioxidant and anti-inflammatory activity in in vitro assays and these activities were found to be due the presence of phenolic hydroxyl groups.

9,10-Dihydro-2,5-Dimethoxyphenanthrene-1,7-diol (1) and 9,10-Dihydro-2,7-Dimethoxyphenanthrene-1,5-diol (2) have been synthesized from o-Vanillin and orcinol. Flavanthridine (3) has been prepared from (4). Compounds 1–4 exhibited good antioxidant and anti-inflammatory activity in vitro.Figure optionsDownload as PowerPoint slide