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

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.