The Synthesis of 7-Substituted-2,3-dihydropyrido [4,3-d]pyridazine-1,4-diones and 1,4-Dioxo-7-substituted- 1,2,3,4-tetrahydropyrido[4,3-d]pyridazine 6-Oxides from Methyl Ketones

Abstract

Dedicated to Professor Emeritus Miha

Study on Synthesis and Biological Activity of Some Pyridopyridazine Derivatives

“…2,3-Dihydropyrido [3,4-d]pyridazin-1,4-dione (1) and its derivatives are generally synthesized by the reaction of hydrazine hydrate with 3,4-pyridinedicarboxylic acid derivatives, such as 3,4-pyridinedicarboxylic anhydride, 3,4-pyridinedicarbonitriles, dimethyl or diethyl pyridine-3,4-dicarboxylate, 1H-pyrrolo [3,4-c]pyridine-1,3 (2H)-dione. [13][14][15][16][17] In this study, 3,4-pyridinedicarboxylic acid was used as the starting material and then converted to 3,4-pyridinedicarboxylic anhydride via acetic acid anhydride, followed by the cyclization with hydrazine hydrate. Subsequent to chlorination of pyridazinone ring with phosphorus oxychloride and hydrolysis to monochloro derivatives, the final compounds were obtained via nucleophilic aromatic substitution reaction.…”