New tricyclic 1,2,3-triazolo-1,2,4-triazolo-pyridazine derivatives, bearing a methyl substituent on the 1,2,3-triazole ring, were prepared as potential biological agents. N-Methylation of dimethyl 1,2,3-triazole-4,5-dicarboxylate allowed synthesis of the isomeric 1-methyl-4,7-dihydroxy and 2-methyl-4,7-dihydroxy triazolo-pyridazines 4a and 4b which, by a chlorination reaction, gave the corresponding 1-methyl-4-chloro-(6a), 1-methyl-7-chloro-(6b) and 2-methyl-4-chloro-(9) substituted 1,2,3-triazolo-pyridazines. The nucleophilic substitution with hydrazine hydrate and the suitable cyclization to form the 1,2,4-triazole ring, provided the expected tricyclic isomeric derivatives 8a, 8b and 11 respectively. The p-methoxybenzyl substituent, introduced as a leaving group to obtain either v-triazolo-pyridazine or v-triazolo-s-triazolo-pyridazine derivatives unsubstituted on the 1,2,3-triazole ring, appeared inadequate. Some compounds underwent binding assays toward the adenosine A 1 and A 2A receptors.

Pyridazine derivativesPyridazine derivatives R 0500 New 1,2,3-Triazolo[4,5-d]1,2,4-triazolo[3,4-b]pyridazine Derivatives. Part 2. -Novel tricyclic pyridazine derivatives [cf. (XII), (XIII), (XIV), (XIX)], bearing a methyl substituent on the 1,2,3-triazole ring, are prepared as potential biological agents. Some compounds are subjected to biological evaluation by binding assays toward the benzodiazepine and adenosine A 1 and A 2A receptors. All the compounds evaluated lack activity. -(BIAGI, G.; CIAMBRONE, F.; GIORGI, I.; LIVI*, O.; SCARTONI, V.; BARILI, P. L.; J.