A series of phenylacetic acid and phenethyl alcohol derivatives with a bicyclic heteroaromatic ring were synthesized. The bicyclic heteroaromatic rings were imidazo [1, 2-a]-pyridine, imidazo [2, 1-b] thiazole, imidazo [1, 2-a] pyrimidine, and indolizine. These compounds were tested for both analgesic and anti-inflammatory activity in the phenylquinone writhing and carrageenin paw edema assays, and the relationship between their structure and activity was discussed. It was thereby found that 2-[4-(imidazo[1, 2-a]-pyridin-2-yl) phenyl] propionic acid (XII-2) had the most potent activity among the compounds tested.
