New 1,2,3-triazolo[4,5-d]1,2,4-triazolo[3,4-b]pyridazine derivatives II

✍ Scribed by Giuliana Biagi; Fabio Ciambrone; Irene Giorgi; Oreste Livi; Valerio Scartoni; Pier Luigi Barili

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2002
• Tongue: English
• Weight: 54 KB
• Volume: 39
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570390506

✦ Synopsis

Abstract

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 nucle‐ophilic 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‐pyri‐dazine 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.