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 an aspirin-like profile with a strong inhibition of AA-induced platelet aggregation. probably due to a strong, non selective, inhibition of cyclooxygenases. In spite of the inhibition of COX activity displayed in vitro, the compounds did not cause gastric damage in rats after acute oral administration. A different pharmacological profile was observed for the 2-azido derivatives, particularly in vivo.