Synthesis and activity on free radical processes and inflammation of 9,10-dihydro-5,8-dimethoxy-triptycene-quinones.

Three triptycene quinones bearing methoxy groups were prepared following a Diels-Alder methodology and were evaluated for antioxidant and anti-inflammatory activity bearing in mind their structural features that could justify intervention with free radical processes. Improved synthetic pathways were achieved for target molecules 9,10-dihydro-5,8-dimethoxy-9,10-[o]benzenoanthracene-1,4-dione (4), 9,10-dihydro-2-hydroxy-5,8-dimethoxy-9,10-[o]benzenoanthracene-1,4-dione (6), and 9,10-dihydro-2,5,8-trimethoxy-9,10-[o]benzenoanthracene-1,4-dione (9). Under our experimental conditions these compounds showed very significant antioxidant activity offering protection against lipid peroxidation of rat hepatic microsomal fraction while inhibiting the reaction completely at very low concentrations (12.