2-Amino/Azido/Hydrazino-5-alkoxy-5H-[1]benzopyrano[4,3-d]pyrimidines: Synthesis and Pharmacological Evaluation

New series of 5-alkoxy-benzopyranopyrimidine derivatives were developed from the chemical modulation of the substituent in position 2 of the scaffold, with the aim to produce analgesic/antiphlogistic agents more potent than analogues previously reported. The 2-hydrazino derivatives exhibited a good analgesic activity in writhing test; the analgesic doses of the compounds did not affect mice spontaneous locomotor activity thus any confounding sedative effect could be excluded. These derivatives revealed also an Aspirin-like profile with a strong inhibition of AA-induced platelet aggregation, probably due to a strong, non selective, inhibition of cyclooxygenases. Inspite of the inhibition of COX activity displayed in vitro, the compounds did not caused gastric damage in rats after acute oral administration. As concerns 2-azido derivatives a different pharmacological behaviour was observed, particularly for in vivo tests.